blob: 6313c38c930e62025c0e76a057d83023b77a6bb5 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * kernel/cpuset.c
3 *
4 * Processor and Memory placement constraints for sets of tasks.
5 *
6 * Copyright (C) 2003 BULL SA.
Paul Jackson825a46a2006-03-24 03:16:03 -08007 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
9 * Portions derived from Patrick Mochel's sysfs code.
10 * sysfs is Copyright (c) 2001-3 Patrick Mochel
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 *
Paul Jackson825a46a2006-03-24 03:16:03 -080012 * 2003-10-10 Written by Simon Derr.
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 * 2003-10-22 Updates by Stephen Hemminger.
Paul Jackson825a46a2006-03-24 03:16:03 -080014 * 2004 May-July Rework by Paul Jackson.
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 *
16 * This file is subject to the terms and conditions of the GNU General Public
17 * License. See the file COPYING in the main directory of the Linux
18 * distribution for more details.
19 */
20
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/cpu.h>
22#include <linux/cpumask.h>
23#include <linux/cpuset.h>
24#include <linux/err.h>
25#include <linux/errno.h>
26#include <linux/file.h>
27#include <linux/fs.h>
28#include <linux/init.h>
29#include <linux/interrupt.h>
30#include <linux/kernel.h>
31#include <linux/kmod.h>
32#include <linux/list.h>
Paul Jackson68860ec2005-10-30 15:02:36 -080033#include <linux/mempolicy.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/mm.h>
35#include <linux/module.h>
36#include <linux/mount.h>
37#include <linux/namei.h>
38#include <linux/pagemap.h>
39#include <linux/proc_fs.h>
Paul Jackson6b9c2602006-01-08 01:02:02 -080040#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <linux/sched.h>
42#include <linux/seq_file.h>
David Quigley22fb52d2006-06-23 02:04:00 -070043#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070044#include <linux/slab.h>
45#include <linux/smp_lock.h>
46#include <linux/spinlock.h>
47#include <linux/stat.h>
48#include <linux/string.h>
49#include <linux/time.h>
50#include <linux/backing-dev.h>
51#include <linux/sort.h>
52
53#include <asm/uaccess.h>
54#include <asm/atomic.h>
Ingo Molnar3d3f26a2006-03-23 03:00:18 -080055#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Paul Jacksonc5b2aff2006-01-08 01:01:51 -080057#define CPUSET_SUPER_MAGIC 0x27e0eb
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Paul Jackson202f72d2006-01-08 01:01:57 -080059/*
60 * Tracks how many cpusets are currently defined in system.
61 * When there is only one cpuset (the root cpuset) we can
62 * short circuit some hooks.
63 */
Paul Jackson7edc5962006-01-08 01:02:03 -080064int number_of_cpusets __read_mostly;
Paul Jackson202f72d2006-01-08 01:01:57 -080065
Paul Jackson3e0d98b2006-01-08 01:01:49 -080066/* See "Frequency meter" comments, below. */
67
68struct fmeter {
69 int cnt; /* unprocessed events count */
70 int val; /* most recent output value */
71 time_t time; /* clock (secs) when val computed */
72 spinlock_t lock; /* guards read or write of above */
73};
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075struct cpuset {
76 unsigned long flags; /* "unsigned long" so bitops work */
77 cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */
78 nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */
79
Paul Jackson053199e2005-10-30 15:02:30 -080080 /*
81 * Count is atomic so can incr (fork) or decr (exit) without a lock.
82 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 atomic_t count; /* count tasks using this cpuset */
84
85 /*
86 * We link our 'sibling' struct into our parents 'children'.
87 * Our children link their 'sibling' into our 'children'.
88 */
89 struct list_head sibling; /* my parents children */
90 struct list_head children; /* my children */
91
92 struct cpuset *parent; /* my parent */
93 struct dentry *dentry; /* cpuset fs entry */
94
95 /*
96 * Copy of global cpuset_mems_generation as of the most
97 * recent time this cpuset changed its mems_allowed.
98 */
Paul Jackson3e0d98b2006-01-08 01:01:49 -080099 int mems_generation;
100
101 struct fmeter fmeter; /* memory_pressure filter */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102};
103
104/* bits in struct cpuset flags field */
105typedef enum {
106 CS_CPU_EXCLUSIVE,
107 CS_MEM_EXCLUSIVE,
Paul Jackson45b07ef2006-01-08 01:00:56 -0800108 CS_MEMORY_MIGRATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 CS_REMOVED,
Paul Jackson825a46a2006-03-24 03:16:03 -0800110 CS_NOTIFY_ON_RELEASE,
111 CS_SPREAD_PAGE,
112 CS_SPREAD_SLAB,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113} cpuset_flagbits_t;
114
115/* convenient tests for these bits */
116static inline int is_cpu_exclusive(const struct cpuset *cs)
117{
Paul Jackson7b5b9ef2006-03-24 03:16:00 -0800118 return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119}
120
121static inline int is_mem_exclusive(const struct cpuset *cs)
122{
Paul Jackson7b5b9ef2006-03-24 03:16:00 -0800123 return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124}
125
126static inline int is_removed(const struct cpuset *cs)
127{
Paul Jackson7b5b9ef2006-03-24 03:16:00 -0800128 return test_bit(CS_REMOVED, &cs->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129}
130
131static inline int notify_on_release(const struct cpuset *cs)
132{
Paul Jackson7b5b9ef2006-03-24 03:16:00 -0800133 return test_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134}
135
Paul Jackson45b07ef2006-01-08 01:00:56 -0800136static inline int is_memory_migrate(const struct cpuset *cs)
137{
Paul Jackson7b5b9ef2006-03-24 03:16:00 -0800138 return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
Paul Jackson45b07ef2006-01-08 01:00:56 -0800139}
140
Paul Jackson825a46a2006-03-24 03:16:03 -0800141static inline int is_spread_page(const struct cpuset *cs)
142{
143 return test_bit(CS_SPREAD_PAGE, &cs->flags);
144}
145
146static inline int is_spread_slab(const struct cpuset *cs)
147{
148 return test_bit(CS_SPREAD_SLAB, &cs->flags);
149}
150
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151/*
Paul Jackson151a4422006-03-24 03:16:11 -0800152 * Increment this integer everytime any cpuset changes its
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 * mems_allowed value. Users of cpusets can track this generation
154 * number, and avoid having to lock and reload mems_allowed unless
155 * the cpuset they're using changes generation.
156 *
157 * A single, global generation is needed because attach_task() could
158 * reattach a task to a different cpuset, which must not have its
159 * generation numbers aliased with those of that tasks previous cpuset.
160 *
161 * Generations are needed for mems_allowed because one task cannot
162 * modify anothers memory placement. So we must enable every task,
163 * on every visit to __alloc_pages(), to efficiently check whether
164 * its current->cpuset->mems_allowed has changed, requiring an update
165 * of its current->mems_allowed.
Paul Jackson151a4422006-03-24 03:16:11 -0800166 *
167 * Since cpuset_mems_generation is guarded by manage_mutex,
168 * there is no need to mark it atomic.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 */
Paul Jackson151a4422006-03-24 03:16:11 -0800170static int cpuset_mems_generation;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
172static struct cpuset top_cpuset = {
173 .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
174 .cpus_allowed = CPU_MASK_ALL,
175 .mems_allowed = NODE_MASK_ALL,
176 .count = ATOMIC_INIT(0),
177 .sibling = LIST_HEAD_INIT(top_cpuset.sibling),
178 .children = LIST_HEAD_INIT(top_cpuset.children),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179};
180
181static struct vfsmount *cpuset_mount;
Paul Jackson3e0d98b2006-01-08 01:01:49 -0800182static struct super_block *cpuset_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
184/*
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800185 * We have two global cpuset mutexes below. They can nest.
186 * It is ok to first take manage_mutex, then nest callback_mutex. We also
Paul Jackson053199e2005-10-30 15:02:30 -0800187 * require taking task_lock() when dereferencing a tasks cpuset pointer.
188 * See "The task_lock() exception", at the end of this comment.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800190 * A task must hold both mutexes to modify cpusets. If a task
191 * holds manage_mutex, then it blocks others wanting that mutex,
192 * ensuring that it is the only task able to also acquire callback_mutex
Paul Jackson053199e2005-10-30 15:02:30 -0800193 * and be able to modify cpusets. It can perform various checks on
194 * the cpuset structure first, knowing nothing will change. It can
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800195 * also allocate memory while just holding manage_mutex. While it is
Paul Jackson053199e2005-10-30 15:02:30 -0800196 * performing these checks, various callback routines can briefly
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800197 * acquire callback_mutex to query cpusets. Once it is ready to make
198 * the changes, it takes callback_mutex, blocking everyone else.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 *
Paul Jackson053199e2005-10-30 15:02:30 -0800200 * Calls to the kernel memory allocator can not be made while holding
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800201 * callback_mutex, as that would risk double tripping on callback_mutex
Paul Jackson053199e2005-10-30 15:02:30 -0800202 * from one of the callbacks into the cpuset code from within
203 * __alloc_pages().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800205 * If a task is only holding callback_mutex, then it has read-only
Paul Jackson053199e2005-10-30 15:02:30 -0800206 * access to cpusets.
207 *
208 * The task_struct fields mems_allowed and mems_generation may only
209 * be accessed in the context of that task, so require no locks.
210 *
211 * Any task can increment and decrement the count field without lock.
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800212 * So in general, code holding manage_mutex or callback_mutex can't rely
Paul Jackson053199e2005-10-30 15:02:30 -0800213 * on the count field not changing. However, if the count goes to
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800214 * zero, then only attach_task(), which holds both mutexes, can
Paul Jackson053199e2005-10-30 15:02:30 -0800215 * increment it again. Because a count of zero means that no tasks
216 * are currently attached, therefore there is no way a task attached
217 * to that cpuset can fork (the other way to increment the count).
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800218 * So code holding manage_mutex or callback_mutex can safely assume that
Paul Jackson053199e2005-10-30 15:02:30 -0800219 * if the count is zero, it will stay zero. Similarly, if a task
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800220 * holds manage_mutex or callback_mutex on a cpuset with zero count, it
Paul Jackson053199e2005-10-30 15:02:30 -0800221 * knows that the cpuset won't be removed, as cpuset_rmdir() needs
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800222 * both of those mutexes.
Paul Jackson053199e2005-10-30 15:02:30 -0800223 *
224 * The cpuset_common_file_write handler for operations that modify
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800225 * the cpuset hierarchy holds manage_mutex across the entire operation,
Paul Jackson053199e2005-10-30 15:02:30 -0800226 * single threading all such cpuset modifications across the system.
227 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800228 * The cpuset_common_file_read() handlers only hold callback_mutex across
Paul Jackson053199e2005-10-30 15:02:30 -0800229 * small pieces of code, such as when reading out possibly multi-word
230 * cpumasks and nodemasks.
231 *
232 * The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800233 * (usually) take either mutex. These are the two most performance
Paul Jackson053199e2005-10-30 15:02:30 -0800234 * critical pieces of code here. The exception occurs on cpuset_exit(),
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800235 * when a task in a notify_on_release cpuset exits. Then manage_mutex
Paul Jackson2efe86b2005-05-27 02:02:43 -0700236 * is taken, and if the cpuset count is zero, a usermode call made
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 * to /sbin/cpuset_release_agent with the name of the cpuset (path
238 * relative to the root of cpuset file system) as the argument.
239 *
Paul Jackson053199e2005-10-30 15:02:30 -0800240 * A cpuset can only be deleted if both its 'count' of using tasks
241 * is zero, and its list of 'children' cpusets is empty. Since all
242 * tasks in the system use _some_ cpuset, and since there is always at
Sukadev Bhattiproluf400e192006-09-29 02:00:07 -0700243 * least one task in the system (init), therefore, top_cpuset
Paul Jackson053199e2005-10-30 15:02:30 -0800244 * always has either children cpusets and/or using tasks. So we don't
245 * need a special hack to ensure that top_cpuset cannot be deleted.
246 *
247 * The above "Tale of Two Semaphores" would be complete, but for:
248 *
249 * The task_lock() exception
250 *
251 * The need for this exception arises from the action of attach_task(),
252 * which overwrites one tasks cpuset pointer with another. It does
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800253 * so using both mutexes, however there are several performance
Paul Jackson053199e2005-10-30 15:02:30 -0800254 * critical places that need to reference task->cpuset without the
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800255 * expense of grabbing a system global mutex. Therefore except as
Paul Jackson053199e2005-10-30 15:02:30 -0800256 * noted below, when dereferencing or, as in attach_task(), modifying
257 * a tasks cpuset pointer we use task_lock(), which acts on a spinlock
258 * (task->alloc_lock) already in the task_struct routinely used for
259 * such matters.
Paul Jackson6b9c2602006-01-08 01:02:02 -0800260 *
261 * P.S. One more locking exception. RCU is used to guard the
262 * update of a tasks cpuset pointer by attach_task() and the
263 * access of task->cpuset->mems_generation via that pointer in
264 * the routine cpuset_update_task_memory_state().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 */
266
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800267static DEFINE_MUTEX(manage_mutex);
268static DEFINE_MUTEX(callback_mutex);
Paul Jackson4247bdc2005-09-10 00:26:06 -0700269
270/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 * A couple of forward declarations required, due to cyclic reference loop:
272 * cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file
273 * -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir.
274 */
275
276static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode);
277static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry);
278
279static struct backing_dev_info cpuset_backing_dev_info = {
280 .ra_pages = 0, /* No readahead */
281 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
282};
283
284static struct inode *cpuset_new_inode(mode_t mode)
285{
286 struct inode *inode = new_inode(cpuset_sb);
287
288 if (inode) {
289 inode->i_mode = mode;
290 inode->i_uid = current->fsuid;
291 inode->i_gid = current->fsgid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 inode->i_blocks = 0;
293 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
294 inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info;
295 }
296 return inode;
297}
298
299static void cpuset_diput(struct dentry *dentry, struct inode *inode)
300{
301 /* is dentry a directory ? if so, kfree() associated cpuset */
302 if (S_ISDIR(inode->i_mode)) {
303 struct cpuset *cs = dentry->d_fsdata;
304 BUG_ON(!(is_removed(cs)));
305 kfree(cs);
306 }
307 iput(inode);
308}
309
310static struct dentry_operations cpuset_dops = {
311 .d_iput = cpuset_diput,
312};
313
314static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name)
315{
Christoph Hellwig5f45f1a2005-06-23 00:09:12 -0700316 struct dentry *d = lookup_one_len(name, parent, strlen(name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 if (!IS_ERR(d))
318 d->d_op = &cpuset_dops;
319 return d;
320}
321
322static void remove_dir(struct dentry *d)
323{
324 struct dentry *parent = dget(d->d_parent);
325
326 d_delete(d);
327 simple_rmdir(parent->d_inode, d);
328 dput(parent);
329}
330
331/*
332 * NOTE : the dentry must have been dget()'ed
333 */
334static void cpuset_d_remove_dir(struct dentry *dentry)
335{
336 struct list_head *node;
337
338 spin_lock(&dcache_lock);
339 node = dentry->d_subdirs.next;
340 while (node != &dentry->d_subdirs) {
Eric Dumazet5160ee62006-01-08 01:03:32 -0800341 struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 list_del_init(node);
343 if (d->d_inode) {
344 d = dget_locked(d);
345 spin_unlock(&dcache_lock);
346 d_delete(d);
347 simple_unlink(dentry->d_inode, d);
348 dput(d);
349 spin_lock(&dcache_lock);
350 }
351 node = dentry->d_subdirs.next;
352 }
Eric Dumazet5160ee62006-01-08 01:03:32 -0800353 list_del_init(&dentry->d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 spin_unlock(&dcache_lock);
355 remove_dir(dentry);
356}
357
358static struct super_operations cpuset_ops = {
359 .statfs = simple_statfs,
360 .drop_inode = generic_delete_inode,
361};
362
363static int cpuset_fill_super(struct super_block *sb, void *unused_data,
364 int unused_silent)
365{
366 struct inode *inode;
367 struct dentry *root;
368
369 sb->s_blocksize = PAGE_CACHE_SIZE;
370 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
371 sb->s_magic = CPUSET_SUPER_MAGIC;
372 sb->s_op = &cpuset_ops;
373 cpuset_sb = sb;
374
375 inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR);
376 if (inode) {
377 inode->i_op = &simple_dir_inode_operations;
378 inode->i_fop = &simple_dir_operations;
379 /* directories start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -0700380 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 } else {
382 return -ENOMEM;
383 }
384
385 root = d_alloc_root(inode);
386 if (!root) {
387 iput(inode);
388 return -ENOMEM;
389 }
390 sb->s_root = root;
391 return 0;
392}
393
David Howells454e2392006-06-23 02:02:57 -0700394static int cpuset_get_sb(struct file_system_type *fs_type,
395 int flags, const char *unused_dev_name,
396 void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397{
David Howells454e2392006-06-23 02:02:57 -0700398 return get_sb_single(fs_type, flags, data, cpuset_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399}
400
401static struct file_system_type cpuset_fs_type = {
402 .name = "cpuset",
403 .get_sb = cpuset_get_sb,
404 .kill_sb = kill_litter_super,
405};
406
407/* struct cftype:
408 *
409 * The files in the cpuset filesystem mostly have a very simple read/write
410 * handling, some common function will take care of it. Nevertheless some cases
411 * (read tasks) are special and therefore I define this structure for every
412 * kind of file.
413 *
414 *
415 * When reading/writing to a file:
416 * - the cpuset to use in file->f_dentry->d_parent->d_fsdata
417 * - the 'cftype' of the file is file->f_dentry->d_fsdata
418 */
419
420struct cftype {
421 char *name;
422 int private;
423 int (*open) (struct inode *inode, struct file *file);
424 ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes,
425 loff_t *ppos);
426 int (*write) (struct file *file, const char __user *buf, size_t nbytes,
427 loff_t *ppos);
428 int (*release) (struct inode *inode, struct file *file);
429};
430
431static inline struct cpuset *__d_cs(struct dentry *dentry)
432{
433 return dentry->d_fsdata;
434}
435
436static inline struct cftype *__d_cft(struct dentry *dentry)
437{
438 return dentry->d_fsdata;
439}
440
441/*
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800442 * Call with manage_mutex held. Writes path of cpuset into buf.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 * Returns 0 on success, -errno on error.
444 */
445
446static int cpuset_path(const struct cpuset *cs, char *buf, int buflen)
447{
448 char *start;
449
450 start = buf + buflen;
451
452 *--start = '\0';
453 for (;;) {
454 int len = cs->dentry->d_name.len;
455 if ((start -= len) < buf)
456 return -ENAMETOOLONG;
457 memcpy(start, cs->dentry->d_name.name, len);
458 cs = cs->parent;
459 if (!cs)
460 break;
461 if (!cs->parent)
462 continue;
463 if (--start < buf)
464 return -ENAMETOOLONG;
465 *start = '/';
466 }
467 memmove(buf, start, buf + buflen - start);
468 return 0;
469}
470
471/*
472 * Notify userspace when a cpuset is released, by running
473 * /sbin/cpuset_release_agent with the name of the cpuset (path
474 * relative to the root of cpuset file system) as the argument.
475 *
476 * Most likely, this user command will try to rmdir this cpuset.
477 *
478 * This races with the possibility that some other task will be
479 * attached to this cpuset before it is removed, or that some other
480 * user task will 'mkdir' a child cpuset of this cpuset. That's ok.
481 * The presumed 'rmdir' will fail quietly if this cpuset is no longer
482 * unused, and this cpuset will be reprieved from its death sentence,
483 * to continue to serve a useful existence. Next time it's released,
484 * we will get notified again, if it still has 'notify_on_release' set.
485 *
Paul Jackson3077a262005-08-09 10:07:59 -0700486 * The final arg to call_usermodehelper() is 0, which means don't
487 * wait. The separate /sbin/cpuset_release_agent task is forked by
488 * call_usermodehelper(), then control in this thread returns here,
489 * without waiting for the release agent task. We don't bother to
490 * wait because the caller of this routine has no use for the exit
491 * status of the /sbin/cpuset_release_agent task, so no sense holding
492 * our caller up for that.
493 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800494 * When we had only one cpuset mutex, we had to call this
Paul Jackson053199e2005-10-30 15:02:30 -0800495 * without holding it, to avoid deadlock when call_usermodehelper()
496 * allocated memory. With two locks, we could now call this while
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800497 * holding manage_mutex, but we still don't, so as to minimize
498 * the time manage_mutex is held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 */
500
Paul Jackson3077a262005-08-09 10:07:59 -0700501static void cpuset_release_agent(const char *pathbuf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502{
503 char *argv[3], *envp[3];
504 int i;
505
Paul Jackson3077a262005-08-09 10:07:59 -0700506 if (!pathbuf)
507 return;
508
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 i = 0;
510 argv[i++] = "/sbin/cpuset_release_agent";
Paul Jackson3077a262005-08-09 10:07:59 -0700511 argv[i++] = (char *)pathbuf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 argv[i] = NULL;
513
514 i = 0;
515 /* minimal command environment */
516 envp[i++] = "HOME=/";
517 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
518 envp[i] = NULL;
519
Paul Jackson3077a262005-08-09 10:07:59 -0700520 call_usermodehelper(argv[0], argv, envp, 0);
521 kfree(pathbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522}
523
524/*
525 * Either cs->count of using tasks transitioned to zero, or the
526 * cs->children list of child cpusets just became empty. If this
527 * cs is notify_on_release() and now both the user count is zero and
Paul Jackson3077a262005-08-09 10:07:59 -0700528 * the list of children is empty, prepare cpuset path in a kmalloc'd
529 * buffer, to be returned via ppathbuf, so that the caller can invoke
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800530 * cpuset_release_agent() with it later on, once manage_mutex is dropped.
531 * Call here with manage_mutex held.
Paul Jackson3077a262005-08-09 10:07:59 -0700532 *
533 * This check_for_release() routine is responsible for kmalloc'ing
534 * pathbuf. The above cpuset_release_agent() is responsible for
535 * kfree'ing pathbuf. The caller of these routines is responsible
536 * for providing a pathbuf pointer, initialized to NULL, then
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800537 * calling check_for_release() with manage_mutex held and the address
538 * of the pathbuf pointer, then dropping manage_mutex, then calling
Paul Jackson3077a262005-08-09 10:07:59 -0700539 * cpuset_release_agent() with pathbuf, as set by check_for_release().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 */
541
Paul Jackson3077a262005-08-09 10:07:59 -0700542static void check_for_release(struct cpuset *cs, char **ppathbuf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543{
544 if (notify_on_release(cs) && atomic_read(&cs->count) == 0 &&
545 list_empty(&cs->children)) {
546 char *buf;
547
548 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
549 if (!buf)
550 return;
551 if (cpuset_path(cs, buf, PAGE_SIZE) < 0)
Paul Jackson3077a262005-08-09 10:07:59 -0700552 kfree(buf);
553 else
554 *ppathbuf = buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 }
556}
557
558/*
559 * Return in *pmask the portion of a cpusets's cpus_allowed that
560 * are online. If none are online, walk up the cpuset hierarchy
561 * until we find one that does have some online cpus. If we get
562 * all the way to the top and still haven't found any online cpus,
563 * return cpu_online_map. Or if passed a NULL cs from an exit'ing
564 * task, return cpu_online_map.
565 *
566 * One way or another, we guarantee to return some non-empty subset
567 * of cpu_online_map.
568 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800569 * Call with callback_mutex held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 */
571
572static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
573{
574 while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
575 cs = cs->parent;
576 if (cs)
577 cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
578 else
579 *pmask = cpu_online_map;
580 BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
581}
582
583/*
584 * Return in *pmask the portion of a cpusets's mems_allowed that
585 * are online. If none are online, walk up the cpuset hierarchy
586 * until we find one that does have some online mems. If we get
587 * all the way to the top and still haven't found any online mems,
588 * return node_online_map.
589 *
590 * One way or another, we guarantee to return some non-empty subset
591 * of node_online_map.
592 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800593 * Call with callback_mutex held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 */
595
596static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
597{
598 while (cs && !nodes_intersects(cs->mems_allowed, node_online_map))
599 cs = cs->parent;
600 if (cs)
601 nodes_and(*pmask, cs->mems_allowed, node_online_map);
602 else
603 *pmask = node_online_map;
604 BUG_ON(!nodes_intersects(*pmask, node_online_map));
605}
606
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800607/**
608 * cpuset_update_task_memory_state - update task memory placement
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 *
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800610 * If the current tasks cpusets mems_allowed changed behind our
611 * backs, update current->mems_allowed, mems_generation and task NUMA
612 * mempolicy to the new value.
613 *
614 * Task mempolicy is updated by rebinding it relative to the
615 * current->cpuset if a task has its memory placement changed.
616 * Do not call this routine if in_interrupt().
617 *
Paul Jackson4a01c8d2006-03-31 02:30:50 -0800618 * Call without callback_mutex or task_lock() held. May be
619 * called with or without manage_mutex held. Thanks in part to
620 * 'the_top_cpuset_hack', the tasks cpuset pointer will never
621 * be NULL. This routine also might acquire callback_mutex and
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800622 * current->mm->mmap_sem during call.
Paul Jackson5aa15b52005-10-30 15:02:28 -0800623 *
Paul Jackson6b9c2602006-01-08 01:02:02 -0800624 * Reading current->cpuset->mems_generation doesn't need task_lock
625 * to guard the current->cpuset derefence, because it is guarded
626 * from concurrent freeing of current->cpuset by attach_task(),
627 * using RCU.
628 *
629 * The rcu_dereference() is technically probably not needed,
630 * as I don't actually mind if I see a new cpuset pointer but
631 * an old value of mems_generation. However this really only
632 * matters on alpha systems using cpusets heavily. If I dropped
633 * that rcu_dereference(), it would save them a memory barrier.
634 * For all other arch's, rcu_dereference is a no-op anyway, and for
635 * alpha systems not using cpusets, another planned optimization,
636 * avoiding the rcu critical section for tasks in the root cpuset
637 * which is statically allocated, so can't vanish, will make this
638 * irrelevant. Better to use RCU as intended, than to engage in
639 * some cute trick to save a memory barrier that is impossible to
640 * test, for alpha systems using cpusets heavily, which might not
641 * even exist.
Paul Jackson053199e2005-10-30 15:02:30 -0800642 *
643 * This routine is needed to update the per-task mems_allowed data,
644 * within the tasks context, when it is trying to allocate memory
645 * (in various mm/mempolicy.c routines) and notices that some other
646 * task has been modifying its cpuset.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 */
648
Randy Dunlapfe85a992006-02-03 03:04:23 -0800649void cpuset_update_task_memory_state(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650{
Paul Jackson053199e2005-10-30 15:02:30 -0800651 int my_cpusets_mem_gen;
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800652 struct task_struct *tsk = current;
Paul Jackson6b9c2602006-01-08 01:02:02 -0800653 struct cpuset *cs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654
Paul Jackson03a285f2006-01-08 01:02:04 -0800655 if (tsk->cpuset == &top_cpuset) {
656 /* Don't need rcu for top_cpuset. It's never freed. */
657 my_cpusets_mem_gen = top_cpuset.mems_generation;
658 } else {
659 rcu_read_lock();
660 cs = rcu_dereference(tsk->cpuset);
661 my_cpusets_mem_gen = cs->mems_generation;
662 rcu_read_unlock();
663 }
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800664
665 if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800666 mutex_lock(&callback_mutex);
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800667 task_lock(tsk);
668 cs = tsk->cpuset; /* Maybe changed when task not locked */
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800669 guarantee_online_mems(cs, &tsk->mems_allowed);
670 tsk->cpuset_mems_generation = cs->mems_generation;
Paul Jackson825a46a2006-03-24 03:16:03 -0800671 if (is_spread_page(cs))
672 tsk->flags |= PF_SPREAD_PAGE;
673 else
674 tsk->flags &= ~PF_SPREAD_PAGE;
675 if (is_spread_slab(cs))
676 tsk->flags |= PF_SPREAD_SLAB;
677 else
678 tsk->flags &= ~PF_SPREAD_SLAB;
Paul Jacksoncf2a473c2006-01-08 01:01:54 -0800679 task_unlock(tsk);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800680 mutex_unlock(&callback_mutex);
Paul Jackson74cb2152006-01-08 01:01:56 -0800681 mpol_rebind_task(tsk, &tsk->mems_allowed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 }
683}
684
685/*
686 * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
687 *
688 * One cpuset is a subset of another if all its allowed CPUs and
689 * Memory Nodes are a subset of the other, and its exclusive flags
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800690 * are only set if the other's are set. Call holding manage_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 */
692
693static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
694{
695 return cpus_subset(p->cpus_allowed, q->cpus_allowed) &&
696 nodes_subset(p->mems_allowed, q->mems_allowed) &&
697 is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
698 is_mem_exclusive(p) <= is_mem_exclusive(q);
699}
700
701/*
702 * validate_change() - Used to validate that any proposed cpuset change
703 * follows the structural rules for cpusets.
704 *
705 * If we replaced the flag and mask values of the current cpuset
706 * (cur) with those values in the trial cpuset (trial), would
707 * our various subset and exclusive rules still be valid? Presumes
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800708 * manage_mutex held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 *
710 * 'cur' is the address of an actual, in-use cpuset. Operations
711 * such as list traversal that depend on the actual address of the
712 * cpuset in the list must use cur below, not trial.
713 *
714 * 'trial' is the address of bulk structure copy of cur, with
715 * perhaps one or more of the fields cpus_allowed, mems_allowed,
716 * or flags changed to new, trial values.
717 *
718 * Return 0 if valid, -errno if not.
719 */
720
721static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
722{
723 struct cpuset *c, *par;
724
725 /* Each of our child cpusets must be a subset of us */
726 list_for_each_entry(c, &cur->children, sibling) {
727 if (!is_cpuset_subset(c, trial))
728 return -EBUSY;
729 }
730
731 /* Remaining checks don't apply to root cpuset */
732 if ((par = cur->parent) == NULL)
733 return 0;
734
735 /* We must be a subset of our parent cpuset */
736 if (!is_cpuset_subset(trial, par))
737 return -EACCES;
738
739 /* If either I or some sibling (!= me) is exclusive, we can't overlap */
740 list_for_each_entry(c, &par->children, sibling) {
741 if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
742 c != cur &&
743 cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
744 return -EINVAL;
745 if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
746 c != cur &&
747 nodes_intersects(trial->mems_allowed, c->mems_allowed))
748 return -EINVAL;
749 }
750
751 return 0;
752}
753
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700754/*
755 * For a given cpuset cur, partition the system as follows
756 * a. All cpus in the parent cpuset's cpus_allowed that are not part of any
757 * exclusive child cpusets
758 * b. All cpus in the current cpuset's cpus_allowed that are not part of any
759 * exclusive child cpusets
760 * Build these two partitions by calling partition_sched_domains
761 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800762 * Call with manage_mutex held. May nest a call to the
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700763 * lock_cpu_hotplug()/unlock_cpu_hotplug() pair.
Paul Jacksonabb5a5c2006-07-23 11:36:08 -0700764 * Must not be called holding callback_mutex, because we must
765 * not call lock_cpu_hotplug() while holding callback_mutex.
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700766 */
Paul Jackson212d6d22005-08-25 12:47:56 -0700767
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700768static void update_cpu_domains(struct cpuset *cur)
769{
770 struct cpuset *c, *par = cur->parent;
771 cpumask_t pspan, cspan;
772
773 if (par == NULL || cpus_empty(cur->cpus_allowed))
774 return;
775
776 /*
777 * Get all cpus from parent's cpus_allowed not part of exclusive
778 * children
779 */
780 pspan = par->cpus_allowed;
781 list_for_each_entry(c, &par->children, sibling) {
782 if (is_cpu_exclusive(c))
783 cpus_andnot(pspan, pspan, c->cpus_allowed);
784 }
Paul Jacksonabb5a5c2006-07-23 11:36:08 -0700785 if (!is_cpu_exclusive(cur)) {
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700786 cpus_or(pspan, pspan, cur->cpus_allowed);
787 if (cpus_equal(pspan, cur->cpus_allowed))
788 return;
789 cspan = CPU_MASK_NONE;
790 } else {
791 if (cpus_empty(pspan))
792 return;
793 cspan = cur->cpus_allowed;
794 /*
795 * Get all cpus from current cpuset's cpus_allowed not part
796 * of exclusive children
797 */
798 list_for_each_entry(c, &cur->children, sibling) {
799 if (is_cpu_exclusive(c))
800 cpus_andnot(cspan, cspan, c->cpus_allowed);
801 }
802 }
803
804 lock_cpu_hotplug();
805 partition_sched_domains(&pspan, &cspan);
806 unlock_cpu_hotplug();
807}
808
Paul Jackson053199e2005-10-30 15:02:30 -0800809/*
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800810 * Call with manage_mutex held. May take callback_mutex during call.
Paul Jackson053199e2005-10-30 15:02:30 -0800811 */
812
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813static int update_cpumask(struct cpuset *cs, char *buf)
814{
815 struct cpuset trialcs;
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700816 int retval, cpus_unchanged;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817
Paul Jackson4c4d50f2006-08-27 01:23:51 -0700818 /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
819 if (cs == &top_cpuset)
820 return -EACCES;
821
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 trialcs = *cs;
823 retval = cpulist_parse(buf, trialcs.cpus_allowed);
824 if (retval < 0)
825 return retval;
826 cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
827 if (cpus_empty(trialcs.cpus_allowed))
828 return -ENOSPC;
829 retval = validate_change(cs, &trialcs);
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700830 if (retval < 0)
831 return retval;
832 cpus_unchanged = cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800833 mutex_lock(&callback_mutex);
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700834 cs->cpus_allowed = trialcs.cpus_allowed;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800835 mutex_unlock(&callback_mutex);
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -0700836 if (is_cpu_exclusive(cs) && !cpus_unchanged)
837 update_cpu_domains(cs);
838 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839}
840
Paul Jackson053199e2005-10-30 15:02:30 -0800841/*
Paul Jacksone4e364e2006-03-31 02:30:52 -0800842 * cpuset_migrate_mm
843 *
844 * Migrate memory region from one set of nodes to another.
845 *
846 * Temporarilly set tasks mems_allowed to target nodes of migration,
847 * so that the migration code can allocate pages on these nodes.
848 *
849 * Call holding manage_mutex, so our current->cpuset won't change
850 * during this call, as manage_mutex holds off any attach_task()
851 * calls. Therefore we don't need to take task_lock around the
852 * call to guarantee_online_mems(), as we know no one is changing
853 * our tasks cpuset.
854 *
855 * Hold callback_mutex around the two modifications of our tasks
856 * mems_allowed to synchronize with cpuset_mems_allowed().
857 *
858 * While the mm_struct we are migrating is typically from some
859 * other task, the task_struct mems_allowed that we are hacking
860 * is for our current task, which must allocate new pages for that
861 * migrating memory region.
862 *
863 * We call cpuset_update_task_memory_state() before hacking
864 * our tasks mems_allowed, so that we are assured of being in
865 * sync with our tasks cpuset, and in particular, callbacks to
866 * cpuset_update_task_memory_state() from nested page allocations
867 * won't see any mismatch of our cpuset and task mems_generation
868 * values, so won't overwrite our hacked tasks mems_allowed
869 * nodemask.
870 */
871
872static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
873 const nodemask_t *to)
874{
875 struct task_struct *tsk = current;
876
877 cpuset_update_task_memory_state();
878
879 mutex_lock(&callback_mutex);
880 tsk->mems_allowed = *to;
881 mutex_unlock(&callback_mutex);
882
883 do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
884
885 mutex_lock(&callback_mutex);
886 guarantee_online_mems(tsk->cpuset, &tsk->mems_allowed);
887 mutex_unlock(&callback_mutex);
888}
889
890/*
Paul Jackson42253992006-01-08 01:01:59 -0800891 * Handle user request to change the 'mems' memory placement
892 * of a cpuset. Needs to validate the request, update the
893 * cpusets mems_allowed and mems_generation, and for each
Paul Jackson04c19fa2006-01-08 01:02:00 -0800894 * task in the cpuset, rebind any vma mempolicies and if
895 * the cpuset is marked 'memory_migrate', migrate the tasks
896 * pages to the new memory.
Paul Jackson42253992006-01-08 01:01:59 -0800897 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800898 * Call with manage_mutex held. May take callback_mutex during call.
Paul Jackson42253992006-01-08 01:01:59 -0800899 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
900 * lock each such tasks mm->mmap_sem, scan its vma's and rebind
901 * their mempolicies to the cpusets new mems_allowed.
Paul Jackson053199e2005-10-30 15:02:30 -0800902 */
903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904static int update_nodemask(struct cpuset *cs, char *buf)
905{
906 struct cpuset trialcs;
Paul Jackson04c19fa2006-01-08 01:02:00 -0800907 nodemask_t oldmem;
Paul Jackson42253992006-01-08 01:01:59 -0800908 struct task_struct *g, *p;
909 struct mm_struct **mmarray;
910 int i, n, ntasks;
Paul Jackson04c19fa2006-01-08 01:02:00 -0800911 int migrate;
Paul Jackson42253992006-01-08 01:01:59 -0800912 int fudge;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 int retval;
914
Paul Jackson38837fc2006-09-29 02:01:16 -0700915 /* top_cpuset.mems_allowed tracks node_online_map; it's read-only */
916 if (cs == &top_cpuset)
917 return -EACCES;
918
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 trialcs = *cs;
920 retval = nodelist_parse(buf, trialcs.mems_allowed);
921 if (retval < 0)
Paul Jackson59dac162006-01-08 01:01:52 -0800922 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
Paul Jackson04c19fa2006-01-08 01:02:00 -0800924 oldmem = cs->mems_allowed;
925 if (nodes_equal(oldmem, trialcs.mems_allowed)) {
926 retval = 0; /* Too easy - nothing to do */
927 goto done;
928 }
Paul Jackson59dac162006-01-08 01:01:52 -0800929 if (nodes_empty(trialcs.mems_allowed)) {
930 retval = -ENOSPC;
931 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 }
Paul Jackson59dac162006-01-08 01:01:52 -0800933 retval = validate_change(cs, &trialcs);
934 if (retval < 0)
935 goto done;
936
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800937 mutex_lock(&callback_mutex);
Paul Jackson59dac162006-01-08 01:01:52 -0800938 cs->mems_allowed = trialcs.mems_allowed;
Paul Jackson151a4422006-03-24 03:16:11 -0800939 cs->mems_generation = cpuset_mems_generation++;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800940 mutex_unlock(&callback_mutex);
Paul Jackson59dac162006-01-08 01:01:52 -0800941
Paul Jackson42253992006-01-08 01:01:59 -0800942 set_cpuset_being_rebound(cs); /* causes mpol_copy() rebind */
943
944 fudge = 10; /* spare mmarray[] slots */
945 fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */
946 retval = -ENOMEM;
947
948 /*
949 * Allocate mmarray[] to hold mm reference for each task
950 * in cpuset cs. Can't kmalloc GFP_KERNEL while holding
951 * tasklist_lock. We could use GFP_ATOMIC, but with a
952 * few more lines of code, we can retry until we get a big
953 * enough mmarray[] w/o using GFP_ATOMIC.
954 */
955 while (1) {
956 ntasks = atomic_read(&cs->count); /* guess */
957 ntasks += fudge;
958 mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
959 if (!mmarray)
960 goto done;
961 write_lock_irq(&tasklist_lock); /* block fork */
962 if (atomic_read(&cs->count) <= ntasks)
963 break; /* got enough */
964 write_unlock_irq(&tasklist_lock); /* try again */
965 kfree(mmarray);
966 }
967
968 n = 0;
969
970 /* Load up mmarray[] with mm reference for each task in cpuset. */
971 do_each_thread(g, p) {
972 struct mm_struct *mm;
973
974 if (n >= ntasks) {
975 printk(KERN_WARNING
976 "Cpuset mempolicy rebind incomplete.\n");
977 continue;
978 }
979 if (p->cpuset != cs)
980 continue;
981 mm = get_task_mm(p);
982 if (!mm)
983 continue;
984 mmarray[n++] = mm;
985 } while_each_thread(g, p);
986 write_unlock_irq(&tasklist_lock);
987
988 /*
989 * Now that we've dropped the tasklist spinlock, we can
990 * rebind the vma mempolicies of each mm in mmarray[] to their
991 * new cpuset, and release that mm. The mpol_rebind_mm()
992 * call takes mmap_sem, which we couldn't take while holding
993 * tasklist_lock. Forks can happen again now - the mpol_copy()
994 * cpuset_being_rebound check will catch such forks, and rebind
995 * their vma mempolicies too. Because we still hold the global
Ingo Molnar3d3f26a2006-03-23 03:00:18 -0800996 * cpuset manage_mutex, we know that no other rebind effort will
Paul Jackson42253992006-01-08 01:01:59 -0800997 * be contending for the global variable cpuset_being_rebound.
998 * It's ok if we rebind the same mm twice; mpol_rebind_mm()
Paul Jackson04c19fa2006-01-08 01:02:00 -0800999 * is idempotent. Also migrate pages in each mm to new nodes.
Paul Jackson42253992006-01-08 01:01:59 -08001000 */
Paul Jackson04c19fa2006-01-08 01:02:00 -08001001 migrate = is_memory_migrate(cs);
Paul Jackson42253992006-01-08 01:01:59 -08001002 for (i = 0; i < n; i++) {
1003 struct mm_struct *mm = mmarray[i];
1004
1005 mpol_rebind_mm(mm, &cs->mems_allowed);
Paul Jacksone4e364e2006-03-31 02:30:52 -08001006 if (migrate)
1007 cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
Paul Jackson42253992006-01-08 01:01:59 -08001008 mmput(mm);
1009 }
1010
1011 /* We're done rebinding vma's to this cpusets new mems_allowed. */
1012 kfree(mmarray);
1013 set_cpuset_being_rebound(NULL);
1014 retval = 0;
Paul Jackson59dac162006-01-08 01:01:52 -08001015done:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 return retval;
1017}
1018
1019/*
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001020 * Call with manage_mutex held.
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001021 */
1022
1023static int update_memory_pressure_enabled(struct cpuset *cs, char *buf)
1024{
1025 if (simple_strtoul(buf, NULL, 10) != 0)
1026 cpuset_memory_pressure_enabled = 1;
1027 else
1028 cpuset_memory_pressure_enabled = 0;
1029 return 0;
1030}
1031
1032/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 * update_flag - read a 0 or a 1 in a file and update associated flag
1034 * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
Paul Jackson825a46a2006-03-24 03:16:03 -08001035 * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE,
1036 * CS_SPREAD_PAGE, CS_SPREAD_SLAB)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 * cs: the cpuset to update
1038 * buf: the buffer where we read the 0 or 1
Paul Jackson053199e2005-10-30 15:02:30 -08001039 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001040 * Call with manage_mutex held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 */
1042
1043static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf)
1044{
1045 int turning_on;
1046 struct cpuset trialcs;
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -07001047 int err, cpu_exclusive_changed;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048
1049 turning_on = (simple_strtoul(buf, NULL, 10) != 0);
1050
1051 trialcs = *cs;
1052 if (turning_on)
1053 set_bit(bit, &trialcs.flags);
1054 else
1055 clear_bit(bit, &trialcs.flags);
1056
1057 err = validate_change(cs, &trialcs);
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -07001058 if (err < 0)
1059 return err;
1060 cpu_exclusive_changed =
1061 (is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs));
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001062 mutex_lock(&callback_mutex);
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -07001063 if (turning_on)
1064 set_bit(bit, &cs->flags);
1065 else
1066 clear_bit(bit, &cs->flags);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001067 mutex_unlock(&callback_mutex);
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -07001068
1069 if (cpu_exclusive_changed)
1070 update_cpu_domains(cs);
1071 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072}
1073
Paul Jackson053199e2005-10-30 15:02:30 -08001074/*
Adrian Bunk80f72282006-06-30 18:27:16 +02001075 * Frequency meter - How fast is some event occurring?
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001076 *
1077 * These routines manage a digitally filtered, constant time based,
1078 * event frequency meter. There are four routines:
1079 * fmeter_init() - initialize a frequency meter.
1080 * fmeter_markevent() - called each time the event happens.
1081 * fmeter_getrate() - returns the recent rate of such events.
1082 * fmeter_update() - internal routine used to update fmeter.
1083 *
1084 * A common data structure is passed to each of these routines,
1085 * which is used to keep track of the state required to manage the
1086 * frequency meter and its digital filter.
1087 *
1088 * The filter works on the number of events marked per unit time.
1089 * The filter is single-pole low-pass recursive (IIR). The time unit
1090 * is 1 second. Arithmetic is done using 32-bit integers scaled to
1091 * simulate 3 decimal digits of precision (multiplied by 1000).
1092 *
1093 * With an FM_COEF of 933, and a time base of 1 second, the filter
1094 * has a half-life of 10 seconds, meaning that if the events quit
1095 * happening, then the rate returned from the fmeter_getrate()
1096 * will be cut in half each 10 seconds, until it converges to zero.
1097 *
1098 * It is not worth doing a real infinitely recursive filter. If more
1099 * than FM_MAXTICKS ticks have elapsed since the last filter event,
1100 * just compute FM_MAXTICKS ticks worth, by which point the level
1101 * will be stable.
1102 *
1103 * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
1104 * arithmetic overflow in the fmeter_update() routine.
1105 *
1106 * Given the simple 32 bit integer arithmetic used, this meter works
1107 * best for reporting rates between one per millisecond (msec) and
1108 * one per 32 (approx) seconds. At constant rates faster than one
1109 * per msec it maxes out at values just under 1,000,000. At constant
1110 * rates between one per msec, and one per second it will stabilize
1111 * to a value N*1000, where N is the rate of events per second.
1112 * At constant rates between one per second and one per 32 seconds,
1113 * it will be choppy, moving up on the seconds that have an event,
1114 * and then decaying until the next event. At rates slower than
1115 * about one in 32 seconds, it decays all the way back to zero between
1116 * each event.
1117 */
1118
1119#define FM_COEF 933 /* coefficient for half-life of 10 secs */
1120#define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */
1121#define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
1122#define FM_SCALE 1000 /* faux fixed point scale */
1123
1124/* Initialize a frequency meter */
1125static void fmeter_init(struct fmeter *fmp)
1126{
1127 fmp->cnt = 0;
1128 fmp->val = 0;
1129 fmp->time = 0;
1130 spin_lock_init(&fmp->lock);
1131}
1132
1133/* Internal meter update - process cnt events and update value */
1134static void fmeter_update(struct fmeter *fmp)
1135{
1136 time_t now = get_seconds();
1137 time_t ticks = now - fmp->time;
1138
1139 if (ticks == 0)
1140 return;
1141
1142 ticks = min(FM_MAXTICKS, ticks);
1143 while (ticks-- > 0)
1144 fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
1145 fmp->time = now;
1146
1147 fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
1148 fmp->cnt = 0;
1149}
1150
1151/* Process any previous ticks, then bump cnt by one (times scale). */
1152static void fmeter_markevent(struct fmeter *fmp)
1153{
1154 spin_lock(&fmp->lock);
1155 fmeter_update(fmp);
1156 fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
1157 spin_unlock(&fmp->lock);
1158}
1159
1160/* Process any previous ticks, then return current value. */
1161static int fmeter_getrate(struct fmeter *fmp)
1162{
1163 int val;
1164
1165 spin_lock(&fmp->lock);
1166 fmeter_update(fmp);
1167 val = fmp->val;
1168 spin_unlock(&fmp->lock);
1169 return val;
1170}
1171
1172/*
Paul Jackson053199e2005-10-30 15:02:30 -08001173 * Attack task specified by pid in 'pidbuf' to cpuset 'cs', possibly
1174 * writing the path of the old cpuset in 'ppathbuf' if it needs to be
1175 * notified on release.
1176 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001177 * Call holding manage_mutex. May take callback_mutex and task_lock of
Paul Jackson053199e2005-10-30 15:02:30 -08001178 * the task 'pid' during call.
1179 */
1180
Paul Jackson3077a262005-08-09 10:07:59 -07001181static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182{
1183 pid_t pid;
1184 struct task_struct *tsk;
1185 struct cpuset *oldcs;
1186 cpumask_t cpus;
Paul Jackson45b07ef2006-01-08 01:00:56 -08001187 nodemask_t from, to;
Paul Jackson42253992006-01-08 01:01:59 -08001188 struct mm_struct *mm;
David Quigley22fb52d2006-06-23 02:04:00 -07001189 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
Paul Jackson3077a262005-08-09 10:07:59 -07001191 if (sscanf(pidbuf, "%d", &pid) != 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 return -EIO;
1193 if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
1194 return -ENOSPC;
1195
1196 if (pid) {
1197 read_lock(&tasklist_lock);
1198
1199 tsk = find_task_by_pid(pid);
Paul Jackson053199e2005-10-30 15:02:30 -08001200 if (!tsk || tsk->flags & PF_EXITING) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 read_unlock(&tasklist_lock);
1202 return -ESRCH;
1203 }
1204
1205 get_task_struct(tsk);
1206 read_unlock(&tasklist_lock);
1207
1208 if ((current->euid) && (current->euid != tsk->uid)
1209 && (current->euid != tsk->suid)) {
1210 put_task_struct(tsk);
1211 return -EACCES;
1212 }
1213 } else {
1214 tsk = current;
1215 get_task_struct(tsk);
1216 }
1217
David Quigley22fb52d2006-06-23 02:04:00 -07001218 retval = security_task_setscheduler(tsk, 0, NULL);
1219 if (retval) {
1220 put_task_struct(tsk);
1221 return retval;
1222 }
1223
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001224 mutex_lock(&callback_mutex);
Paul Jackson053199e2005-10-30 15:02:30 -08001225
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 task_lock(tsk);
1227 oldcs = tsk->cpuset;
Paul Jackson181b6482006-09-29 02:01:48 -07001228 /*
1229 * After getting 'oldcs' cpuset ptr, be sure still not exiting.
1230 * If 'oldcs' might be the top_cpuset due to the_top_cpuset_hack
1231 * then fail this attach_task(), to avoid breaking top_cpuset.count.
1232 */
1233 if (tsk->flags & PF_EXITING) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234 task_unlock(tsk);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001235 mutex_unlock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 put_task_struct(tsk);
1237 return -ESRCH;
1238 }
1239 atomic_inc(&cs->count);
Paul Jackson6b9c2602006-01-08 01:02:02 -08001240 rcu_assign_pointer(tsk->cpuset, cs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241 task_unlock(tsk);
1242
1243 guarantee_online_cpus(cs, &cpus);
1244 set_cpus_allowed(tsk, cpus);
1245
Paul Jackson45b07ef2006-01-08 01:00:56 -08001246 from = oldcs->mems_allowed;
1247 to = cs->mems_allowed;
1248
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001249 mutex_unlock(&callback_mutex);
Paul Jackson42253992006-01-08 01:01:59 -08001250
1251 mm = get_task_mm(tsk);
1252 if (mm) {
1253 mpol_rebind_mm(mm, &to);
Paul Jackson2741a552006-03-31 02:30:51 -08001254 if (is_memory_migrate(cs))
Paul Jacksone4e364e2006-03-31 02:30:52 -08001255 cpuset_migrate_mm(mm, &from, &to);
Paul Jackson42253992006-01-08 01:01:59 -08001256 mmput(mm);
1257 }
1258
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 put_task_struct(tsk);
Paul Jackson6b9c2602006-01-08 01:02:02 -08001260 synchronize_rcu();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 if (atomic_dec_and_test(&oldcs->count))
Paul Jackson3077a262005-08-09 10:07:59 -07001262 check_for_release(oldcs, ppathbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 return 0;
1264}
1265
1266/* The various types of files and directories in a cpuset file system */
1267
1268typedef enum {
1269 FILE_ROOT,
1270 FILE_DIR,
Paul Jackson45b07ef2006-01-08 01:00:56 -08001271 FILE_MEMORY_MIGRATE,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 FILE_CPULIST,
1273 FILE_MEMLIST,
1274 FILE_CPU_EXCLUSIVE,
1275 FILE_MEM_EXCLUSIVE,
1276 FILE_NOTIFY_ON_RELEASE,
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001277 FILE_MEMORY_PRESSURE_ENABLED,
1278 FILE_MEMORY_PRESSURE,
Paul Jackson825a46a2006-03-24 03:16:03 -08001279 FILE_SPREAD_PAGE,
1280 FILE_SPREAD_SLAB,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 FILE_TASKLIST,
1282} cpuset_filetype_t;
1283
1284static ssize_t cpuset_common_file_write(struct file *file, const char __user *userbuf,
1285 size_t nbytes, loff_t *unused_ppos)
1286{
1287 struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
1288 struct cftype *cft = __d_cft(file->f_dentry);
1289 cpuset_filetype_t type = cft->private;
1290 char *buffer;
Paul Jackson3077a262005-08-09 10:07:59 -07001291 char *pathbuf = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 int retval = 0;
1293
1294 /* Crude upper limit on largest legitimate cpulist user might write. */
1295 if (nbytes > 100 + 6 * NR_CPUS)
1296 return -E2BIG;
1297
1298 /* +1 for nul-terminator */
1299 if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0)
1300 return -ENOMEM;
1301
1302 if (copy_from_user(buffer, userbuf, nbytes)) {
1303 retval = -EFAULT;
1304 goto out1;
1305 }
1306 buffer[nbytes] = 0; /* nul-terminate */
1307
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001308 mutex_lock(&manage_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309
1310 if (is_removed(cs)) {
1311 retval = -ENODEV;
1312 goto out2;
1313 }
1314
1315 switch (type) {
1316 case FILE_CPULIST:
1317 retval = update_cpumask(cs, buffer);
1318 break;
1319 case FILE_MEMLIST:
1320 retval = update_nodemask(cs, buffer);
1321 break;
1322 case FILE_CPU_EXCLUSIVE:
1323 retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer);
1324 break;
1325 case FILE_MEM_EXCLUSIVE:
1326 retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
1327 break;
1328 case FILE_NOTIFY_ON_RELEASE:
1329 retval = update_flag(CS_NOTIFY_ON_RELEASE, cs, buffer);
1330 break;
Paul Jackson45b07ef2006-01-08 01:00:56 -08001331 case FILE_MEMORY_MIGRATE:
1332 retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
1333 break;
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001334 case FILE_MEMORY_PRESSURE_ENABLED:
1335 retval = update_memory_pressure_enabled(cs, buffer);
1336 break;
1337 case FILE_MEMORY_PRESSURE:
1338 retval = -EACCES;
1339 break;
Paul Jackson825a46a2006-03-24 03:16:03 -08001340 case FILE_SPREAD_PAGE:
1341 retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
Paul Jackson151a4422006-03-24 03:16:11 -08001342 cs->mems_generation = cpuset_mems_generation++;
Paul Jackson825a46a2006-03-24 03:16:03 -08001343 break;
1344 case FILE_SPREAD_SLAB:
1345 retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
Paul Jackson151a4422006-03-24 03:16:11 -08001346 cs->mems_generation = cpuset_mems_generation++;
Paul Jackson825a46a2006-03-24 03:16:03 -08001347 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 case FILE_TASKLIST:
Paul Jackson3077a262005-08-09 10:07:59 -07001349 retval = attach_task(cs, buffer, &pathbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 break;
1351 default:
1352 retval = -EINVAL;
1353 goto out2;
1354 }
1355
1356 if (retval == 0)
1357 retval = nbytes;
1358out2:
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001359 mutex_unlock(&manage_mutex);
Paul Jackson3077a262005-08-09 10:07:59 -07001360 cpuset_release_agent(pathbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361out1:
1362 kfree(buffer);
1363 return retval;
1364}
1365
1366static ssize_t cpuset_file_write(struct file *file, const char __user *buf,
1367 size_t nbytes, loff_t *ppos)
1368{
1369 ssize_t retval = 0;
1370 struct cftype *cft = __d_cft(file->f_dentry);
1371 if (!cft)
1372 return -ENODEV;
1373
1374 /* special function ? */
1375 if (cft->write)
1376 retval = cft->write(file, buf, nbytes, ppos);
1377 else
1378 retval = cpuset_common_file_write(file, buf, nbytes, ppos);
1379
1380 return retval;
1381}
1382
1383/*
1384 * These ascii lists should be read in a single call, by using a user
1385 * buffer large enough to hold the entire map. If read in smaller
1386 * chunks, there is no guarantee of atomicity. Since the display format
1387 * used, list of ranges of sequential numbers, is variable length,
1388 * and since these maps can change value dynamically, one could read
1389 * gibberish by doing partial reads while a list was changing.
1390 * A single large read to a buffer that crosses a page boundary is
1391 * ok, because the result being copied to user land is not recomputed
1392 * across a page fault.
1393 */
1394
1395static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
1396{
1397 cpumask_t mask;
1398
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001399 mutex_lock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400 mask = cs->cpus_allowed;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001401 mutex_unlock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402
1403 return cpulist_scnprintf(page, PAGE_SIZE, mask);
1404}
1405
1406static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
1407{
1408 nodemask_t mask;
1409
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001410 mutex_lock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 mask = cs->mems_allowed;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001412 mutex_unlock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413
1414 return nodelist_scnprintf(page, PAGE_SIZE, mask);
1415}
1416
1417static ssize_t cpuset_common_file_read(struct file *file, char __user *buf,
1418 size_t nbytes, loff_t *ppos)
1419{
1420 struct cftype *cft = __d_cft(file->f_dentry);
1421 struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
1422 cpuset_filetype_t type = cft->private;
1423 char *page;
1424 ssize_t retval = 0;
1425 char *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426
1427 if (!(page = (char *)__get_free_page(GFP_KERNEL)))
1428 return -ENOMEM;
1429
1430 s = page;
1431
1432 switch (type) {
1433 case FILE_CPULIST:
1434 s += cpuset_sprintf_cpulist(s, cs);
1435 break;
1436 case FILE_MEMLIST:
1437 s += cpuset_sprintf_memlist(s, cs);
1438 break;
1439 case FILE_CPU_EXCLUSIVE:
1440 *s++ = is_cpu_exclusive(cs) ? '1' : '0';
1441 break;
1442 case FILE_MEM_EXCLUSIVE:
1443 *s++ = is_mem_exclusive(cs) ? '1' : '0';
1444 break;
1445 case FILE_NOTIFY_ON_RELEASE:
1446 *s++ = notify_on_release(cs) ? '1' : '0';
1447 break;
Paul Jackson45b07ef2006-01-08 01:00:56 -08001448 case FILE_MEMORY_MIGRATE:
1449 *s++ = is_memory_migrate(cs) ? '1' : '0';
1450 break;
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001451 case FILE_MEMORY_PRESSURE_ENABLED:
1452 *s++ = cpuset_memory_pressure_enabled ? '1' : '0';
1453 break;
1454 case FILE_MEMORY_PRESSURE:
1455 s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter));
1456 break;
Paul Jackson825a46a2006-03-24 03:16:03 -08001457 case FILE_SPREAD_PAGE:
1458 *s++ = is_spread_page(cs) ? '1' : '0';
1459 break;
1460 case FILE_SPREAD_SLAB:
1461 *s++ = is_spread_slab(cs) ? '1' : '0';
1462 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463 default:
1464 retval = -EINVAL;
1465 goto out;
1466 }
1467 *s++ = '\n';
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468
Al Viroeacaa1f2005-09-30 03:26:43 +01001469 retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470out:
1471 free_page((unsigned long)page);
1472 return retval;
1473}
1474
1475static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes,
1476 loff_t *ppos)
1477{
1478 ssize_t retval = 0;
1479 struct cftype *cft = __d_cft(file->f_dentry);
1480 if (!cft)
1481 return -ENODEV;
1482
1483 /* special function ? */
1484 if (cft->read)
1485 retval = cft->read(file, buf, nbytes, ppos);
1486 else
1487 retval = cpuset_common_file_read(file, buf, nbytes, ppos);
1488
1489 return retval;
1490}
1491
1492static int cpuset_file_open(struct inode *inode, struct file *file)
1493{
1494 int err;
1495 struct cftype *cft;
1496
1497 err = generic_file_open(inode, file);
1498 if (err)
1499 return err;
1500
1501 cft = __d_cft(file->f_dentry);
1502 if (!cft)
1503 return -ENODEV;
1504 if (cft->open)
1505 err = cft->open(inode, file);
1506 else
1507 err = 0;
1508
1509 return err;
1510}
1511
1512static int cpuset_file_release(struct inode *inode, struct file *file)
1513{
1514 struct cftype *cft = __d_cft(file->f_dentry);
1515 if (cft->release)
1516 return cft->release(inode, file);
1517 return 0;
1518}
1519
Paul Jackson18a19cb2005-10-30 15:02:31 -08001520/*
1521 * cpuset_rename - Only allow simple rename of directories in place.
1522 */
1523static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry,
1524 struct inode *new_dir, struct dentry *new_dentry)
1525{
1526 if (!S_ISDIR(old_dentry->d_inode->i_mode))
1527 return -ENOTDIR;
1528 if (new_dentry->d_inode)
1529 return -EEXIST;
1530 if (old_dir != new_dir)
1531 return -EIO;
1532 return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
1533}
1534
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535static struct file_operations cpuset_file_operations = {
1536 .read = cpuset_file_read,
1537 .write = cpuset_file_write,
1538 .llseek = generic_file_llseek,
1539 .open = cpuset_file_open,
1540 .release = cpuset_file_release,
1541};
1542
1543static struct inode_operations cpuset_dir_inode_operations = {
1544 .lookup = simple_lookup,
1545 .mkdir = cpuset_mkdir,
1546 .rmdir = cpuset_rmdir,
Paul Jackson18a19cb2005-10-30 15:02:31 -08001547 .rename = cpuset_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548};
1549
1550static int cpuset_create_file(struct dentry *dentry, int mode)
1551{
1552 struct inode *inode;
1553
1554 if (!dentry)
1555 return -ENOENT;
1556 if (dentry->d_inode)
1557 return -EEXIST;
1558
1559 inode = cpuset_new_inode(mode);
1560 if (!inode)
1561 return -ENOMEM;
1562
1563 if (S_ISDIR(mode)) {
1564 inode->i_op = &cpuset_dir_inode_operations;
1565 inode->i_fop = &simple_dir_operations;
1566
1567 /* start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -07001568 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 } else if (S_ISREG(mode)) {
1570 inode->i_size = 0;
1571 inode->i_fop = &cpuset_file_operations;
1572 }
1573
1574 d_instantiate(dentry, inode);
1575 dget(dentry); /* Extra count - pin the dentry in core */
1576 return 0;
1577}
1578
1579/*
1580 * cpuset_create_dir - create a directory for an object.
Paul Jacksonc5b2aff2006-01-08 01:01:51 -08001581 * cs: the cpuset we create the directory for.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582 * It must have a valid ->parent field
1583 * And we are going to fill its ->dentry field.
1584 * name: The name to give to the cpuset directory. Will be copied.
1585 * mode: mode to set on new directory.
1586 */
1587
1588static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode)
1589{
1590 struct dentry *dentry = NULL;
1591 struct dentry *parent;
1592 int error = 0;
1593
1594 parent = cs->parent->dentry;
1595 dentry = cpuset_get_dentry(parent, name);
1596 if (IS_ERR(dentry))
1597 return PTR_ERR(dentry);
1598 error = cpuset_create_file(dentry, S_IFDIR | mode);
1599 if (!error) {
1600 dentry->d_fsdata = cs;
Dave Hansend8c76e62006-09-30 23:29:04 -07001601 inc_nlink(parent->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001602 cs->dentry = dentry;
1603 }
1604 dput(dentry);
1605
1606 return error;
1607}
1608
1609static int cpuset_add_file(struct dentry *dir, const struct cftype *cft)
1610{
1611 struct dentry *dentry;
1612 int error;
1613
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001614 mutex_lock(&dir->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615 dentry = cpuset_get_dentry(dir, cft->name);
1616 if (!IS_ERR(dentry)) {
1617 error = cpuset_create_file(dentry, 0644 | S_IFREG);
1618 if (!error)
1619 dentry->d_fsdata = (void *)cft;
1620 dput(dentry);
1621 } else
1622 error = PTR_ERR(dentry);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001623 mutex_unlock(&dir->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624 return error;
1625}
1626
1627/*
1628 * Stuff for reading the 'tasks' file.
1629 *
1630 * Reading this file can return large amounts of data if a cpuset has
1631 * *lots* of attached tasks. So it may need several calls to read(),
1632 * but we cannot guarantee that the information we produce is correct
1633 * unless we produce it entirely atomically.
1634 *
1635 * Upon tasks file open(), a struct ctr_struct is allocated, that
1636 * will have a pointer to an array (also allocated here). The struct
1637 * ctr_struct * is stored in file->private_data. Its resources will
1638 * be freed by release() when the file is closed. The array is used
1639 * to sprintf the PIDs and then used by read().
1640 */
1641
1642/* cpusets_tasks_read array */
1643
1644struct ctr_struct {
1645 char *buf;
1646 int bufsz;
1647};
1648
1649/*
1650 * Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'.
Paul Jackson053199e2005-10-30 15:02:30 -08001651 * Return actual number of pids loaded. No need to task_lock(p)
1652 * when reading out p->cpuset, as we don't really care if it changes
1653 * on the next cycle, and we are not going to try to dereference it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654 */
Arjan van de Ven858119e2006-01-14 13:20:43 -08001655static int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656{
1657 int n = 0;
1658 struct task_struct *g, *p;
1659
1660 read_lock(&tasklist_lock);
1661
1662 do_each_thread(g, p) {
1663 if (p->cpuset == cs) {
1664 pidarray[n++] = p->pid;
1665 if (unlikely(n == npids))
1666 goto array_full;
1667 }
1668 } while_each_thread(g, p);
1669
1670array_full:
1671 read_unlock(&tasklist_lock);
1672 return n;
1673}
1674
1675static int cmppid(const void *a, const void *b)
1676{
1677 return *(pid_t *)a - *(pid_t *)b;
1678}
1679
1680/*
1681 * Convert array 'a' of 'npids' pid_t's to a string of newline separated
1682 * decimal pids in 'buf'. Don't write more than 'sz' chars, but return
1683 * count 'cnt' of how many chars would be written if buf were large enough.
1684 */
1685static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
1686{
1687 int cnt = 0;
1688 int i;
1689
1690 for (i = 0; i < npids; i++)
1691 cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
1692 return cnt;
1693}
1694
Paul Jackson053199e2005-10-30 15:02:30 -08001695/*
1696 * Handle an open on 'tasks' file. Prepare a buffer listing the
1697 * process id's of tasks currently attached to the cpuset being opened.
1698 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001699 * Does not require any specific cpuset mutexes, and does not take any.
Paul Jackson053199e2005-10-30 15:02:30 -08001700 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701static int cpuset_tasks_open(struct inode *unused, struct file *file)
1702{
1703 struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
1704 struct ctr_struct *ctr;
1705 pid_t *pidarray;
1706 int npids;
1707 char c;
1708
1709 if (!(file->f_mode & FMODE_READ))
1710 return 0;
1711
1712 ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
1713 if (!ctr)
1714 goto err0;
1715
1716 /*
1717 * If cpuset gets more users after we read count, we won't have
1718 * enough space - tough. This race is indistinguishable to the
1719 * caller from the case that the additional cpuset users didn't
1720 * show up until sometime later on.
1721 */
1722 npids = atomic_read(&cs->count);
1723 pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
1724 if (!pidarray)
1725 goto err1;
1726
1727 npids = pid_array_load(pidarray, npids, cs);
1728 sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
1729
1730 /* Call pid_array_to_buf() twice, first just to get bufsz */
1731 ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
1732 ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
1733 if (!ctr->buf)
1734 goto err2;
1735 ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
1736
1737 kfree(pidarray);
1738 file->private_data = ctr;
1739 return 0;
1740
1741err2:
1742 kfree(pidarray);
1743err1:
1744 kfree(ctr);
1745err0:
1746 return -ENOMEM;
1747}
1748
1749static ssize_t cpuset_tasks_read(struct file *file, char __user *buf,
1750 size_t nbytes, loff_t *ppos)
1751{
1752 struct ctr_struct *ctr = file->private_data;
1753
1754 if (*ppos + nbytes > ctr->bufsz)
1755 nbytes = ctr->bufsz - *ppos;
1756 if (copy_to_user(buf, ctr->buf + *ppos, nbytes))
1757 return -EFAULT;
1758 *ppos += nbytes;
1759 return nbytes;
1760}
1761
1762static int cpuset_tasks_release(struct inode *unused_inode, struct file *file)
1763{
1764 struct ctr_struct *ctr;
1765
1766 if (file->f_mode & FMODE_READ) {
1767 ctr = file->private_data;
1768 kfree(ctr->buf);
1769 kfree(ctr);
1770 }
1771 return 0;
1772}
1773
1774/*
1775 * for the common functions, 'private' gives the type of file
1776 */
1777
1778static struct cftype cft_tasks = {
1779 .name = "tasks",
1780 .open = cpuset_tasks_open,
1781 .read = cpuset_tasks_read,
1782 .release = cpuset_tasks_release,
1783 .private = FILE_TASKLIST,
1784};
1785
1786static struct cftype cft_cpus = {
1787 .name = "cpus",
1788 .private = FILE_CPULIST,
1789};
1790
1791static struct cftype cft_mems = {
1792 .name = "mems",
1793 .private = FILE_MEMLIST,
1794};
1795
1796static struct cftype cft_cpu_exclusive = {
1797 .name = "cpu_exclusive",
1798 .private = FILE_CPU_EXCLUSIVE,
1799};
1800
1801static struct cftype cft_mem_exclusive = {
1802 .name = "mem_exclusive",
1803 .private = FILE_MEM_EXCLUSIVE,
1804};
1805
1806static struct cftype cft_notify_on_release = {
1807 .name = "notify_on_release",
1808 .private = FILE_NOTIFY_ON_RELEASE,
1809};
1810
Paul Jackson45b07ef2006-01-08 01:00:56 -08001811static struct cftype cft_memory_migrate = {
1812 .name = "memory_migrate",
1813 .private = FILE_MEMORY_MIGRATE,
1814};
1815
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001816static struct cftype cft_memory_pressure_enabled = {
1817 .name = "memory_pressure_enabled",
1818 .private = FILE_MEMORY_PRESSURE_ENABLED,
1819};
1820
1821static struct cftype cft_memory_pressure = {
1822 .name = "memory_pressure",
1823 .private = FILE_MEMORY_PRESSURE,
1824};
1825
Paul Jackson825a46a2006-03-24 03:16:03 -08001826static struct cftype cft_spread_page = {
1827 .name = "memory_spread_page",
1828 .private = FILE_SPREAD_PAGE,
1829};
1830
1831static struct cftype cft_spread_slab = {
1832 .name = "memory_spread_slab",
1833 .private = FILE_SPREAD_SLAB,
1834};
1835
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836static int cpuset_populate_dir(struct dentry *cs_dentry)
1837{
1838 int err;
1839
1840 if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0)
1841 return err;
1842 if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0)
1843 return err;
1844 if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0)
1845 return err;
1846 if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0)
1847 return err;
1848 if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0)
1849 return err;
Paul Jackson45b07ef2006-01-08 01:00:56 -08001850 if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0)
1851 return err;
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001852 if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0)
1853 return err;
Paul Jackson825a46a2006-03-24 03:16:03 -08001854 if ((err = cpuset_add_file(cs_dentry, &cft_spread_page)) < 0)
1855 return err;
1856 if ((err = cpuset_add_file(cs_dentry, &cft_spread_slab)) < 0)
1857 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0)
1859 return err;
1860 return 0;
1861}
1862
1863/*
1864 * cpuset_create - create a cpuset
1865 * parent: cpuset that will be parent of the new cpuset.
1866 * name: name of the new cpuset. Will be strcpy'ed.
1867 * mode: mode to set on new inode
1868 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001869 * Must be called with the mutex on the parent inode held
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 */
1871
1872static long cpuset_create(struct cpuset *parent, const char *name, int mode)
1873{
1874 struct cpuset *cs;
1875 int err;
1876
1877 cs = kmalloc(sizeof(*cs), GFP_KERNEL);
1878 if (!cs)
1879 return -ENOMEM;
1880
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001881 mutex_lock(&manage_mutex);
Paul Jacksoncf2a473c2006-01-08 01:01:54 -08001882 cpuset_update_task_memory_state();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883 cs->flags = 0;
1884 if (notify_on_release(parent))
1885 set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
Paul Jackson825a46a2006-03-24 03:16:03 -08001886 if (is_spread_page(parent))
1887 set_bit(CS_SPREAD_PAGE, &cs->flags);
1888 if (is_spread_slab(parent))
1889 set_bit(CS_SPREAD_SLAB, &cs->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890 cs->cpus_allowed = CPU_MASK_NONE;
1891 cs->mems_allowed = NODE_MASK_NONE;
1892 atomic_set(&cs->count, 0);
1893 INIT_LIST_HEAD(&cs->sibling);
1894 INIT_LIST_HEAD(&cs->children);
Paul Jackson151a4422006-03-24 03:16:11 -08001895 cs->mems_generation = cpuset_mems_generation++;
Paul Jackson3e0d98b2006-01-08 01:01:49 -08001896 fmeter_init(&cs->fmeter);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897
1898 cs->parent = parent;
1899
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001900 mutex_lock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 list_add(&cs->sibling, &cs->parent->children);
Paul Jackson202f72d2006-01-08 01:01:57 -08001902 number_of_cpusets++;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001903 mutex_unlock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904
1905 err = cpuset_create_dir(cs, name, mode);
1906 if (err < 0)
1907 goto err;
1908
1909 /*
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001910 * Release manage_mutex before cpuset_populate_dir() because it
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001911 * will down() this new directory's i_mutex and if we race with
Linus Torvalds1da177e2005-04-16 15:20:36 -07001912 * another mkdir, we might deadlock.
1913 */
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001914 mutex_unlock(&manage_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915
1916 err = cpuset_populate_dir(cs->dentry);
1917 /* If err < 0, we have a half-filled directory - oh well ;) */
1918 return 0;
1919err:
1920 list_del(&cs->sibling);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001921 mutex_unlock(&manage_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 kfree(cs);
1923 return err;
1924}
1925
1926static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1927{
1928 struct cpuset *c_parent = dentry->d_parent->d_fsdata;
1929
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001930 /* the vfs holds inode->i_mutex already */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931 return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR);
1932}
1933
Paul Jacksonabb5a5c2006-07-23 11:36:08 -07001934/*
1935 * Locking note on the strange update_flag() call below:
1936 *
1937 * If the cpuset being removed is marked cpu_exclusive, then simulate
1938 * turning cpu_exclusive off, which will call update_cpu_domains().
1939 * The lock_cpu_hotplug() call in update_cpu_domains() must not be
1940 * made while holding callback_mutex. Elsewhere the kernel nests
1941 * callback_mutex inside lock_cpu_hotplug() calls. So the reverse
1942 * nesting would risk an ABBA deadlock.
1943 */
1944
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
1946{
1947 struct cpuset *cs = dentry->d_fsdata;
1948 struct dentry *d;
1949 struct cpuset *parent;
Paul Jackson3077a262005-08-09 10:07:59 -07001950 char *pathbuf = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001952 /* the vfs holds both inode->i_mutex already */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001954 mutex_lock(&manage_mutex);
Paul Jacksoncf2a473c2006-01-08 01:01:54 -08001955 cpuset_update_task_memory_state();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 if (atomic_read(&cs->count) > 0) {
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001957 mutex_unlock(&manage_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 return -EBUSY;
1959 }
1960 if (!list_empty(&cs->children)) {
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001961 mutex_unlock(&manage_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 return -EBUSY;
1963 }
Paul Jacksonabb5a5c2006-07-23 11:36:08 -07001964 if (is_cpu_exclusive(cs)) {
1965 int retval = update_flag(CS_CPU_EXCLUSIVE, cs, "0");
1966 if (retval < 0) {
1967 mutex_unlock(&manage_mutex);
1968 return retval;
1969 }
1970 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001971 parent = cs->parent;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001972 mutex_lock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 set_bit(CS_REMOVED, &cs->flags);
1974 list_del(&cs->sibling); /* delete my sibling from parent->children */
Dinakar Guniguntala85d7b942005-06-25 14:57:34 -07001975 spin_lock(&cs->dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976 d = dget(cs->dentry);
1977 cs->dentry = NULL;
1978 spin_unlock(&d->d_lock);
1979 cpuset_d_remove_dir(d);
1980 dput(d);
Paul Jackson202f72d2006-01-08 01:01:57 -08001981 number_of_cpusets--;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001982 mutex_unlock(&callback_mutex);
Paul Jackson053199e2005-10-30 15:02:30 -08001983 if (list_empty(&parent->children))
1984 check_for_release(parent, &pathbuf);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08001985 mutex_unlock(&manage_mutex);
Paul Jackson3077a262005-08-09 10:07:59 -07001986 cpuset_release_agent(pathbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987 return 0;
1988}
1989
Paul Jacksonc417f022006-01-08 01:02:01 -08001990/*
1991 * cpuset_init_early - just enough so that the calls to
1992 * cpuset_update_task_memory_state() in early init code
1993 * are harmless.
1994 */
1995
1996int __init cpuset_init_early(void)
1997{
1998 struct task_struct *tsk = current;
1999
2000 tsk->cpuset = &top_cpuset;
Paul Jackson151a4422006-03-24 03:16:11 -08002001 tsk->cpuset->mems_generation = cpuset_mems_generation++;
Paul Jacksonc417f022006-01-08 01:02:01 -08002002 return 0;
2003}
2004
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005/**
2006 * cpuset_init - initialize cpusets at system boot
2007 *
2008 * Description: Initialize top_cpuset and the cpuset internal file system,
2009 **/
2010
2011int __init cpuset_init(void)
2012{
2013 struct dentry *root;
2014 int err;
2015
2016 top_cpuset.cpus_allowed = CPU_MASK_ALL;
2017 top_cpuset.mems_allowed = NODE_MASK_ALL;
2018
Paul Jackson3e0d98b2006-01-08 01:01:49 -08002019 fmeter_init(&top_cpuset.fmeter);
Paul Jackson151a4422006-03-24 03:16:11 -08002020 top_cpuset.mems_generation = cpuset_mems_generation++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021
2022 init_task.cpuset = &top_cpuset;
2023
2024 err = register_filesystem(&cpuset_fs_type);
2025 if (err < 0)
2026 goto out;
2027 cpuset_mount = kern_mount(&cpuset_fs_type);
2028 if (IS_ERR(cpuset_mount)) {
2029 printk(KERN_ERR "cpuset: could not mount!\n");
2030 err = PTR_ERR(cpuset_mount);
2031 cpuset_mount = NULL;
2032 goto out;
2033 }
2034 root = cpuset_mount->mnt_sb->s_root;
2035 root->d_fsdata = &top_cpuset;
Dave Hansend8c76e62006-09-30 23:29:04 -07002036 inc_nlink(root->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 top_cpuset.dentry = root;
2038 root->d_inode->i_op = &cpuset_dir_inode_operations;
Paul Jackson202f72d2006-01-08 01:01:57 -08002039 number_of_cpusets = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002040 err = cpuset_populate_dir(root);
Paul Jackson3e0d98b2006-01-08 01:01:49 -08002041 /* memory_pressure_enabled is in root cpuset only */
2042 if (err == 0)
2043 err = cpuset_add_file(root, &cft_memory_pressure_enabled);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044out:
2045 return err;
2046}
2047
Paul Jacksonb1aac8b2006-09-29 02:01:17 -07002048#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_MEMORY_HOTPLUG)
2049/*
2050 * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
2051 * or memory nodes, we need to walk over the cpuset hierarchy,
2052 * removing that CPU or node from all cpusets. If this removes the
2053 * last CPU or node from a cpuset, then the guarantee_online_cpus()
2054 * or guarantee_online_mems() code will use that emptied cpusets
2055 * parent online CPUs or nodes. Cpusets that were already empty of
2056 * CPUs or nodes are left empty.
2057 *
2058 * This routine is intentionally inefficient in a couple of regards.
2059 * It will check all cpusets in a subtree even if the top cpuset of
2060 * the subtree has no offline CPUs or nodes. It checks both CPUs and
2061 * nodes, even though the caller could have been coded to know that
2062 * only one of CPUs or nodes needed to be checked on a given call.
2063 * This was done to minimize text size rather than cpu cycles.
2064 *
2065 * Call with both manage_mutex and callback_mutex held.
2066 *
2067 * Recursive, on depth of cpuset subtree.
2068 */
2069
2070static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
2071{
2072 struct cpuset *c;
2073
2074 /* Each of our child cpusets mems must be online */
2075 list_for_each_entry(c, &cur->children, sibling) {
2076 guarantee_online_cpus_mems_in_subtree(c);
2077 if (!cpus_empty(c->cpus_allowed))
2078 guarantee_online_cpus(c, &c->cpus_allowed);
2079 if (!nodes_empty(c->mems_allowed))
2080 guarantee_online_mems(c, &c->mems_allowed);
2081 }
2082}
2083
2084/*
2085 * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
2086 * cpu_online_map and node_online_map. Force the top cpuset to track
2087 * whats online after any CPU or memory node hotplug or unplug event.
2088 *
2089 * To ensure that we don't remove a CPU or node from the top cpuset
2090 * that is currently in use by a child cpuset (which would violate
2091 * the rule that cpusets must be subsets of their parent), we first
2092 * call the recursive routine guarantee_online_cpus_mems_in_subtree().
2093 *
2094 * Since there are two callers of this routine, one for CPU hotplug
2095 * events and one for memory node hotplug events, we could have coded
2096 * two separate routines here. We code it as a single common routine
2097 * in order to minimize text size.
2098 */
2099
2100static void common_cpu_mem_hotplug_unplug(void)
2101{
2102 mutex_lock(&manage_mutex);
2103 mutex_lock(&callback_mutex);
2104
2105 guarantee_online_cpus_mems_in_subtree(&top_cpuset);
2106 top_cpuset.cpus_allowed = cpu_online_map;
2107 top_cpuset.mems_allowed = node_online_map;
2108
2109 mutex_unlock(&callback_mutex);
2110 mutex_unlock(&manage_mutex);
2111}
2112#endif
2113
2114#ifdef CONFIG_HOTPLUG_CPU
Paul Jackson4c4d50f2006-08-27 01:23:51 -07002115/*
2116 * The top_cpuset tracks what CPUs and Memory Nodes are online,
2117 * period. This is necessary in order to make cpusets transparent
2118 * (of no affect) on systems that are actively using CPU hotplug
2119 * but making no active use of cpusets.
2120 *
Paul Jackson38837fc2006-09-29 02:01:16 -07002121 * This routine ensures that top_cpuset.cpus_allowed tracks
2122 * cpu_online_map on each CPU hotplug (cpuhp) event.
Paul Jackson4c4d50f2006-08-27 01:23:51 -07002123 */
2124
Paul Jackson4c4d50f2006-08-27 01:23:51 -07002125static int cpuset_handle_cpuhp(struct notifier_block *nb,
2126 unsigned long phase, void *cpu)
2127{
Paul Jacksonb1aac8b2006-09-29 02:01:17 -07002128 common_cpu_mem_hotplug_unplug();
Paul Jackson4c4d50f2006-08-27 01:23:51 -07002129 return 0;
2130}
2131#endif
2132
Paul Jacksonb1aac8b2006-09-29 02:01:17 -07002133#ifdef CONFIG_MEMORY_HOTPLUG
Paul Jackson38837fc2006-09-29 02:01:16 -07002134/*
2135 * Keep top_cpuset.mems_allowed tracking node_online_map.
2136 * Call this routine anytime after you change node_online_map.
2137 * See also the previous routine cpuset_handle_cpuhp().
2138 */
2139
Al Viro1af98922006-10-10 22:48:57 +01002140void cpuset_track_online_nodes(void)
Paul Jackson38837fc2006-09-29 02:01:16 -07002141{
Paul Jacksonb1aac8b2006-09-29 02:01:17 -07002142 common_cpu_mem_hotplug_unplug();
Paul Jackson38837fc2006-09-29 02:01:16 -07002143}
2144#endif
2145
Linus Torvalds1da177e2005-04-16 15:20:36 -07002146/**
2147 * cpuset_init_smp - initialize cpus_allowed
2148 *
2149 * Description: Finish top cpuset after cpu, node maps are initialized
2150 **/
2151
2152void __init cpuset_init_smp(void)
2153{
2154 top_cpuset.cpus_allowed = cpu_online_map;
2155 top_cpuset.mems_allowed = node_online_map;
Paul Jackson4c4d50f2006-08-27 01:23:51 -07002156
2157 hotcpu_notifier(cpuset_handle_cpuhp, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158}
2159
2160/**
2161 * cpuset_fork - attach newly forked task to its parents cpuset.
Randy Dunlapd9fd8a62005-07-27 11:45:11 -07002162 * @tsk: pointer to task_struct of forking parent process.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002163 *
Paul Jackson053199e2005-10-30 15:02:30 -08002164 * Description: A task inherits its parent's cpuset at fork().
2165 *
2166 * A pointer to the shared cpuset was automatically copied in fork.c
2167 * by dup_task_struct(). However, we ignore that copy, since it was
2168 * not made under the protection of task_lock(), so might no longer be
2169 * a valid cpuset pointer. attach_task() might have already changed
2170 * current->cpuset, allowing the previously referenced cpuset to
2171 * be removed and freed. Instead, we task_lock(current) and copy
2172 * its present value of current->cpuset for our freshly forked child.
2173 *
2174 * At the point that cpuset_fork() is called, 'current' is the parent
2175 * task, and the passed argument 'child' points to the child task.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002176 **/
2177
Paul Jackson053199e2005-10-30 15:02:30 -08002178void cpuset_fork(struct task_struct *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179{
Paul Jackson053199e2005-10-30 15:02:30 -08002180 task_lock(current);
2181 child->cpuset = current->cpuset;
2182 atomic_inc(&child->cpuset->count);
2183 task_unlock(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184}
2185
2186/**
2187 * cpuset_exit - detach cpuset from exiting task
2188 * @tsk: pointer to task_struct of exiting process
2189 *
2190 * Description: Detach cpuset from @tsk and release it.
2191 *
Paul Jackson053199e2005-10-30 15:02:30 -08002192 * Note that cpusets marked notify_on_release force every task in
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002193 * them to take the global manage_mutex mutex when exiting.
Paul Jackson053199e2005-10-30 15:02:30 -08002194 * This could impact scaling on very large systems. Be reluctant to
2195 * use notify_on_release cpusets where very high task exit scaling
2196 * is required on large systems.
Paul Jackson2efe86b2005-05-27 02:02:43 -07002197 *
Paul Jackson053199e2005-10-30 15:02:30 -08002198 * Don't even think about derefencing 'cs' after the cpuset use count
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002199 * goes to zero, except inside a critical section guarded by manage_mutex
2200 * or callback_mutex. Otherwise a zero cpuset use count is a license to
Paul Jackson053199e2005-10-30 15:02:30 -08002201 * any other task to nuke the cpuset immediately, via cpuset_rmdir().
2202 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002203 * This routine has to take manage_mutex, not callback_mutex, because
2204 * it is holding that mutex while calling check_for_release(),
2205 * which calls kmalloc(), so can't be called holding callback_mutex().
Paul Jackson053199e2005-10-30 15:02:30 -08002206 *
2207 * We don't need to task_lock() this reference to tsk->cpuset,
2208 * because tsk is already marked PF_EXITING, so attach_task() won't
Paul Jacksonb4b26412006-01-08 01:01:53 -08002209 * mess with it, or task is a failed fork, never visible to attach_task.
Paul Jackson06fed332006-02-15 15:17:38 -08002210 *
Paul Jackson8488bc32006-03-24 03:16:10 -08002211 * the_top_cpuset_hack:
Paul Jackson06fed332006-02-15 15:17:38 -08002212 *
2213 * Set the exiting tasks cpuset to the root cpuset (top_cpuset).
2214 *
2215 * Don't leave a task unable to allocate memory, as that is an
2216 * accident waiting to happen should someone add a callout in
2217 * do_exit() after the cpuset_exit() call that might allocate.
2218 * If a task tries to allocate memory with an invalid cpuset,
2219 * it will oops in cpuset_update_task_memory_state().
2220 *
2221 * We call cpuset_exit() while the task is still competent to
2222 * handle notify_on_release(), then leave the task attached to
2223 * the root cpuset (top_cpuset) for the remainder of its exit.
2224 *
2225 * To do this properly, we would increment the reference count on
2226 * top_cpuset, and near the very end of the kernel/exit.c do_exit()
2227 * code we would add a second cpuset function call, to drop that
2228 * reference. This would just create an unnecessary hot spot on
2229 * the top_cpuset reference count, to no avail.
2230 *
2231 * Normally, holding a reference to a cpuset without bumping its
2232 * count is unsafe. The cpuset could go away, or someone could
2233 * attach us to a different cpuset, decrementing the count on
2234 * the first cpuset that we never incremented. But in this case,
2235 * top_cpuset isn't going away, and either task has PF_EXITING set,
2236 * which wards off any attach_task() attempts, or task is a failed
2237 * fork, never visible to attach_task.
2238 *
2239 * Another way to do this would be to set the cpuset pointer
2240 * to NULL here, and check in cpuset_update_task_memory_state()
2241 * for a NULL pointer. This hack avoids that NULL check, for no
2242 * cost (other than this way too long comment ;).
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243 **/
2244
2245void cpuset_exit(struct task_struct *tsk)
2246{
2247 struct cpuset *cs;
2248
Linus Torvalds1da177e2005-04-16 15:20:36 -07002249 cs = tsk->cpuset;
Paul Jackson8488bc32006-03-24 03:16:10 -08002250 tsk->cpuset = &top_cpuset; /* the_top_cpuset_hack - see above */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002251
Paul Jackson2efe86b2005-05-27 02:02:43 -07002252 if (notify_on_release(cs)) {
Paul Jackson3077a262005-08-09 10:07:59 -07002253 char *pathbuf = NULL;
2254
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002255 mutex_lock(&manage_mutex);
Paul Jackson2efe86b2005-05-27 02:02:43 -07002256 if (atomic_dec_and_test(&cs->count))
Paul Jackson3077a262005-08-09 10:07:59 -07002257 check_for_release(cs, &pathbuf);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002258 mutex_unlock(&manage_mutex);
Paul Jackson3077a262005-08-09 10:07:59 -07002259 cpuset_release_agent(pathbuf);
Paul Jackson2efe86b2005-05-27 02:02:43 -07002260 } else {
2261 atomic_dec(&cs->count);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 }
2263}
2264
2265/**
2266 * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
2267 * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
2268 *
2269 * Description: Returns the cpumask_t cpus_allowed of the cpuset
2270 * attached to the specified @tsk. Guaranteed to return some non-empty
2271 * subset of cpu_online_map, even if this means going outside the
2272 * tasks cpuset.
2273 **/
2274
Paul Jackson909d75a2006-01-08 01:01:55 -08002275cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276{
2277 cpumask_t mask;
2278
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002279 mutex_lock(&callback_mutex);
Paul Jackson909d75a2006-01-08 01:01:55 -08002280 task_lock(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281 guarantee_online_cpus(tsk->cpuset, &mask);
Paul Jackson909d75a2006-01-08 01:01:55 -08002282 task_unlock(tsk);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002283 mutex_unlock(&callback_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284
2285 return mask;
2286}
2287
2288void cpuset_init_current_mems_allowed(void)
2289{
2290 current->mems_allowed = NODE_MASK_ALL;
2291}
2292
Randy Dunlapd9fd8a62005-07-27 11:45:11 -07002293/**
Paul Jackson909d75a2006-01-08 01:01:55 -08002294 * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
2295 * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
2296 *
2297 * Description: Returns the nodemask_t mems_allowed of the cpuset
2298 * attached to the specified @tsk. Guaranteed to return some non-empty
2299 * subset of node_online_map, even if this means going outside the
2300 * tasks cpuset.
2301 **/
2302
2303nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
2304{
2305 nodemask_t mask;
2306
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002307 mutex_lock(&callback_mutex);
Paul Jackson909d75a2006-01-08 01:01:55 -08002308 task_lock(tsk);
2309 guarantee_online_mems(tsk->cpuset, &mask);
2310 task_unlock(tsk);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002311 mutex_unlock(&callback_mutex);
Paul Jackson909d75a2006-01-08 01:01:55 -08002312
2313 return mask;
2314}
2315
2316/**
Randy Dunlapd9fd8a62005-07-27 11:45:11 -07002317 * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed
2318 * @zl: the zonelist to be checked
2319 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320 * Are any of the nodes on zonelist zl allowed in current->mems_allowed?
2321 */
2322int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
2323{
2324 int i;
2325
2326 for (i = 0; zl->zones[i]; i++) {
Christoph Lameter89fa3022006-09-25 23:31:55 -07002327 int nid = zone_to_nid(zl->zones[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328
2329 if (node_isset(nid, current->mems_allowed))
2330 return 1;
2331 }
2332 return 0;
2333}
2334
Paul Jackson9bf22292005-09-06 15:18:12 -07002335/*
2336 * nearest_exclusive_ancestor() - Returns the nearest mem_exclusive
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002337 * ancestor to the specified cpuset. Call holding callback_mutex.
Paul Jackson9bf22292005-09-06 15:18:12 -07002338 * If no ancestor is mem_exclusive (an unusual configuration), then
2339 * returns the root cpuset.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002340 */
Paul Jackson9bf22292005-09-06 15:18:12 -07002341static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002342{
Paul Jackson9bf22292005-09-06 15:18:12 -07002343 while (!is_mem_exclusive(cs) && cs->parent)
2344 cs = cs->parent;
2345 return cs;
2346}
2347
2348/**
2349 * cpuset_zone_allowed - Can we allocate memory on zone z's memory node?
2350 * @z: is this zone on an allowed node?
2351 * @gfp_mask: memory allocation flags (we use __GFP_HARDWALL)
2352 *
2353 * If we're in interrupt, yes, we can always allocate. If zone
2354 * z's node is in our tasks mems_allowed, yes. If it's not a
2355 * __GFP_HARDWALL request and this zone's nodes is in the nearest
2356 * mem_exclusive cpuset ancestor to this tasks cpuset, yes.
2357 * Otherwise, no.
2358 *
2359 * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
2360 * and do not allow allocations outside the current tasks cpuset.
2361 * GFP_KERNEL allocations are not so marked, so can escape to the
2362 * nearest mem_exclusive ancestor cpuset.
2363 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002364 * Scanning up parent cpusets requires callback_mutex. The __alloc_pages()
Paul Jackson9bf22292005-09-06 15:18:12 -07002365 * routine only calls here with __GFP_HARDWALL bit _not_ set if
2366 * it's a GFP_KERNEL allocation, and all nodes in the current tasks
2367 * mems_allowed came up empty on the first pass over the zonelist.
2368 * So only GFP_KERNEL allocations, if all nodes in the cpuset are
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002369 * short of memory, might require taking the callback_mutex mutex.
Paul Jackson9bf22292005-09-06 15:18:12 -07002370 *
Paul Jackson36be57f2006-05-20 15:00:10 -07002371 * The first call here from mm/page_alloc:get_page_from_freelist()
2372 * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, so
2373 * no allocation on a node outside the cpuset is allowed (unless in
2374 * interrupt, of course).
Paul Jackson9bf22292005-09-06 15:18:12 -07002375 *
Paul Jackson36be57f2006-05-20 15:00:10 -07002376 * The second pass through get_page_from_freelist() doesn't even call
2377 * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
2378 * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
2379 * in alloc_flags. That logic and the checks below have the combined
2380 * affect that:
Paul Jackson9bf22292005-09-06 15:18:12 -07002381 * in_interrupt - any node ok (current task context irrelevant)
2382 * GFP_ATOMIC - any node ok
2383 * GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok
2384 * GFP_USER - only nodes in current tasks mems allowed ok.
Paul Jackson36be57f2006-05-20 15:00:10 -07002385 *
2386 * Rule:
2387 * Don't call cpuset_zone_allowed() if you can't sleep, unless you
2388 * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
2389 * the code that might scan up ancestor cpusets and sleep.
Paul Jackson9bf22292005-09-06 15:18:12 -07002390 **/
2391
Paul Jackson202f72d2006-01-08 01:01:57 -08002392int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
Paul Jackson9bf22292005-09-06 15:18:12 -07002393{
2394 int node; /* node that zone z is on */
2395 const struct cpuset *cs; /* current cpuset ancestors */
Paul Jackson29afd492006-03-24 03:16:12 -08002396 int allowed; /* is allocation in zone z allowed? */
Paul Jackson9bf22292005-09-06 15:18:12 -07002397
Christoph Lameter9b819d22006-09-25 23:31:40 -07002398 if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
Paul Jackson9bf22292005-09-06 15:18:12 -07002399 return 1;
Christoph Lameter89fa3022006-09-25 23:31:55 -07002400 node = zone_to_nid(z);
Paul Jackson92d1dbd2006-05-20 15:00:11 -07002401 might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
Paul Jackson9bf22292005-09-06 15:18:12 -07002402 if (node_isset(node, current->mems_allowed))
2403 return 1;
2404 if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
2405 return 0;
2406
Bob Picco5563e772005-11-13 16:06:35 -08002407 if (current->flags & PF_EXITING) /* Let dying task have memory */
2408 return 1;
2409
Paul Jackson9bf22292005-09-06 15:18:12 -07002410 /* Not hardwall and node outside mems_allowed: scan up cpusets */
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002411 mutex_lock(&callback_mutex);
Paul Jackson053199e2005-10-30 15:02:30 -08002412
Paul Jackson053199e2005-10-30 15:02:30 -08002413 task_lock(current);
2414 cs = nearest_exclusive_ancestor(current->cpuset);
2415 task_unlock(current);
2416
Paul Jackson9bf22292005-09-06 15:18:12 -07002417 allowed = node_isset(node, cs->mems_allowed);
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002418 mutex_unlock(&callback_mutex);
Paul Jackson9bf22292005-09-06 15:18:12 -07002419 return allowed;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002420}
2421
Paul Jacksonef08e3b2005-09-06 15:18:13 -07002422/**
Paul Jackson505970b2006-01-14 13:21:06 -08002423 * cpuset_lock - lock out any changes to cpuset structures
2424 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002425 * The out of memory (oom) code needs to mutex_lock cpusets
Paul Jackson505970b2006-01-14 13:21:06 -08002426 * from being changed while it scans the tasklist looking for a
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002427 * task in an overlapping cpuset. Expose callback_mutex via this
Paul Jackson505970b2006-01-14 13:21:06 -08002428 * cpuset_lock() routine, so the oom code can lock it, before
2429 * locking the task list. The tasklist_lock is a spinlock, so
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002430 * must be taken inside callback_mutex.
Paul Jackson505970b2006-01-14 13:21:06 -08002431 */
2432
2433void cpuset_lock(void)
2434{
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002435 mutex_lock(&callback_mutex);
Paul Jackson505970b2006-01-14 13:21:06 -08002436}
2437
2438/**
2439 * cpuset_unlock - release lock on cpuset changes
2440 *
2441 * Undo the lock taken in a previous cpuset_lock() call.
2442 */
2443
2444void cpuset_unlock(void)
2445{
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002446 mutex_unlock(&callback_mutex);
Paul Jackson505970b2006-01-14 13:21:06 -08002447}
2448
2449/**
Paul Jackson825a46a2006-03-24 03:16:03 -08002450 * cpuset_mem_spread_node() - On which node to begin search for a page
2451 *
2452 * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
2453 * tasks in a cpuset with is_spread_page or is_spread_slab set),
2454 * and if the memory allocation used cpuset_mem_spread_node()
2455 * to determine on which node to start looking, as it will for
2456 * certain page cache or slab cache pages such as used for file
2457 * system buffers and inode caches, then instead of starting on the
2458 * local node to look for a free page, rather spread the starting
2459 * node around the tasks mems_allowed nodes.
2460 *
2461 * We don't have to worry about the returned node being offline
2462 * because "it can't happen", and even if it did, it would be ok.
2463 *
2464 * The routines calling guarantee_online_mems() are careful to
2465 * only set nodes in task->mems_allowed that are online. So it
2466 * should not be possible for the following code to return an
2467 * offline node. But if it did, that would be ok, as this routine
2468 * is not returning the node where the allocation must be, only
2469 * the node where the search should start. The zonelist passed to
2470 * __alloc_pages() will include all nodes. If the slab allocator
2471 * is passed an offline node, it will fall back to the local node.
2472 * See kmem_cache_alloc_node().
2473 */
2474
2475int cpuset_mem_spread_node(void)
2476{
2477 int node;
2478
2479 node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
2480 if (node == MAX_NUMNODES)
2481 node = first_node(current->mems_allowed);
2482 current->cpuset_mem_spread_rotor = node;
2483 return node;
2484}
2485EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
2486
2487/**
Paul Jacksonef08e3b2005-09-06 15:18:13 -07002488 * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
2489 * @p: pointer to task_struct of some other task.
2490 *
2491 * Description: Return true if the nearest mem_exclusive ancestor
2492 * cpusets of tasks @p and current overlap. Used by oom killer to
2493 * determine if task @p's memory usage might impact the memory
2494 * available to the current task.
2495 *
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002496 * Call while holding callback_mutex.
Paul Jacksonef08e3b2005-09-06 15:18:13 -07002497 **/
2498
2499int cpuset_excl_nodes_overlap(const struct task_struct *p)
2500{
2501 const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */
Nick Piggin0d673a52006-08-27 01:23:54 -07002502 int overlap = 1; /* do cpusets overlap? */
Paul Jacksonef08e3b2005-09-06 15:18:13 -07002503
Paul Jackson053199e2005-10-30 15:02:30 -08002504 task_lock(current);
2505 if (current->flags & PF_EXITING) {
2506 task_unlock(current);
2507 goto done;
2508 }
2509 cs1 = nearest_exclusive_ancestor(current->cpuset);
2510 task_unlock(current);
2511
2512 task_lock((struct task_struct *)p);
2513 if (p->flags & PF_EXITING) {
2514 task_unlock((struct task_struct *)p);
2515 goto done;
2516 }
2517 cs2 = nearest_exclusive_ancestor(p->cpuset);
2518 task_unlock((struct task_struct *)p);
2519
Paul Jacksonef08e3b2005-09-06 15:18:13 -07002520 overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
2521done:
Paul Jacksonef08e3b2005-09-06 15:18:13 -07002522 return overlap;
2523}
2524
Linus Torvalds1da177e2005-04-16 15:20:36 -07002525/*
Paul Jackson3e0d98b2006-01-08 01:01:49 -08002526 * Collection of memory_pressure is suppressed unless
2527 * this flag is enabled by writing "1" to the special
2528 * cpuset file 'memory_pressure_enabled' in the root cpuset.
2529 */
2530
Paul Jacksonc5b2aff2006-01-08 01:01:51 -08002531int cpuset_memory_pressure_enabled __read_mostly;
Paul Jackson3e0d98b2006-01-08 01:01:49 -08002532
2533/**
2534 * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
2535 *
2536 * Keep a running average of the rate of synchronous (direct)
2537 * page reclaim efforts initiated by tasks in each cpuset.
2538 *
2539 * This represents the rate at which some task in the cpuset
2540 * ran low on memory on all nodes it was allowed to use, and
2541 * had to enter the kernels page reclaim code in an effort to
2542 * create more free memory by tossing clean pages or swapping
2543 * or writing dirty pages.
2544 *
2545 * Display to user space in the per-cpuset read-only file
2546 * "memory_pressure". Value displayed is an integer
2547 * representing the recent rate of entry into the synchronous
2548 * (direct) page reclaim by any task attached to the cpuset.
2549 **/
2550
2551void __cpuset_memory_pressure_bump(void)
2552{
2553 struct cpuset *cs;
2554
2555 task_lock(current);
2556 cs = current->cpuset;
2557 fmeter_markevent(&cs->fmeter);
2558 task_unlock(current);
2559}
2560
2561/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002562 * proc_cpuset_show()
2563 * - Print tasks cpuset path into seq_file.
2564 * - Used for /proc/<pid>/cpuset.
Paul Jackson053199e2005-10-30 15:02:30 -08002565 * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
2566 * doesn't really matter if tsk->cpuset changes after we read it,
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002567 * and we take manage_mutex, keeping attach_task() from changing it
Paul Jackson8488bc32006-03-24 03:16:10 -08002568 * anyway. No need to check that tsk->cpuset != NULL, thanks to
2569 * the_top_cpuset_hack in cpuset_exit(), which sets an exiting tasks
2570 * cpuset to top_cpuset.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002571 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002572static int proc_cpuset_show(struct seq_file *m, void *v)
2573{
Eric W. Biederman13b41b02006-06-26 00:25:56 -07002574 struct pid *pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002575 struct task_struct *tsk;
2576 char *buf;
Eric W. Biederman99f89552006-06-26 00:25:55 -07002577 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002578
Eric W. Biederman99f89552006-06-26 00:25:55 -07002579 retval = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002580 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
2581 if (!buf)
Eric W. Biederman99f89552006-06-26 00:25:55 -07002582 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002583
Eric W. Biederman99f89552006-06-26 00:25:55 -07002584 retval = -ESRCH;
Eric W. Biederman13b41b02006-06-26 00:25:56 -07002585 pid = m->private;
2586 tsk = get_pid_task(pid, PIDTYPE_PID);
Eric W. Biederman99f89552006-06-26 00:25:55 -07002587 if (!tsk)
2588 goto out_free;
2589
2590 retval = -EINVAL;
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002591 mutex_lock(&manage_mutex);
Eric W. Biederman99f89552006-06-26 00:25:55 -07002592
Paul Jackson8488bc32006-03-24 03:16:10 -08002593 retval = cpuset_path(tsk->cpuset, buf, PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594 if (retval < 0)
Eric W. Biederman99f89552006-06-26 00:25:55 -07002595 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002596 seq_puts(m, buf);
2597 seq_putc(m, '\n');
Eric W. Biederman99f89552006-06-26 00:25:55 -07002598out_unlock:
Ingo Molnar3d3f26a2006-03-23 03:00:18 -08002599 mutex_unlock(&manage_mutex);
Eric W. Biederman99f89552006-06-26 00:25:55 -07002600 put_task_struct(tsk);
2601out_free:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002602 kfree(buf);
Eric W. Biederman99f89552006-06-26 00:25:55 -07002603out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002604 return retval;
2605}
2606
2607static int cpuset_open(struct inode *inode, struct file *file)
2608{
Eric W. Biederman13b41b02006-06-26 00:25:56 -07002609 struct pid *pid = PROC_I(inode)->pid;
2610 return single_open(file, proc_cpuset_show, pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002611}
2612
2613struct file_operations proc_cpuset_operations = {
2614 .open = cpuset_open,
2615 .read = seq_read,
2616 .llseek = seq_lseek,
2617 .release = single_release,
2618};
2619
2620/* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
2621char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
2622{
2623 buffer += sprintf(buffer, "Cpus_allowed:\t");
2624 buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
2625 buffer += sprintf(buffer, "\n");
2626 buffer += sprintf(buffer, "Mems_allowed:\t");
2627 buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
2628 buffer += sprintf(buffer, "\n");
2629 return buffer;
2630}