| /* |
| * kernel/cpuset.c |
| * |
| * Processor and Memory placement constraints for sets of tasks. |
| * |
| * Copyright (C) 2003 BULL SA. |
| * Copyright (C) 2004-2007 Silicon Graphics, Inc. |
| * Copyright (C) 2006 Google, Inc |
| * |
| * Portions derived from Patrick Mochel's sysfs code. |
| * sysfs is Copyright (c) 2001-3 Patrick Mochel |
| * |
| * 2003-10-10 Written by Simon Derr. |
| * 2003-10-22 Updates by Stephen Hemminger. |
| * 2004 May-July Rework by Paul Jackson. |
| * 2006 Rework by Paul Menage to use generic cgroups |
| * 2008 Rework of the scheduler domains and CPU hotplug handling |
| * by Max Krasnyansky |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file COPYING in the main directory of the Linux |
| * distribution for more details. |
| */ |
| |
| #include <linux/cpu.h> |
| #include <linux/cpumask.h> |
| #include <linux/cpuset.h> |
| #include <linux/err.h> |
| #include <linux/errno.h> |
| #include <linux/file.h> |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| #include <linux/kernel.h> |
| #include <linux/kmod.h> |
| #include <linux/list.h> |
| #include <linux/mempolicy.h> |
| #include <linux/mm.h> |
| #include <linux/memory.h> |
| #include <linux/module.h> |
| #include <linux/mount.h> |
| #include <linux/namei.h> |
| #include <linux/pagemap.h> |
| #include <linux/proc_fs.h> |
| #include <linux/rcupdate.h> |
| #include <linux/sched.h> |
| #include <linux/seq_file.h> |
| #include <linux/security.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/stat.h> |
| #include <linux/string.h> |
| #include <linux/time.h> |
| #include <linux/backing-dev.h> |
| #include <linux/sort.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/atomic.h> |
| #include <linux/mutex.h> |
| #include <linux/workqueue.h> |
| #include <linux/cgroup.h> |
| |
| /* |
| * Workqueue for cpuset related tasks. |
| * |
| * Using kevent workqueue may cause deadlock when memory_migrate |
| * is set. So we create a separate workqueue thread for cpuset. |
| */ |
| static struct workqueue_struct *cpuset_wq; |
| |
| /* |
| * Tracks how many cpusets are currently defined in system. |
| * When there is only one cpuset (the root cpuset) we can |
| * short circuit some hooks. |
| */ |
| int number_of_cpusets __read_mostly; |
| |
| /* Forward declare cgroup structures */ |
| struct cgroup_subsys cpuset_subsys; |
| struct cpuset; |
| |
| /* See "Frequency meter" comments, below. */ |
| |
| struct fmeter { |
| int cnt; /* unprocessed events count */ |
| int val; /* most recent output value */ |
| time_t time; /* clock (secs) when val computed */ |
| spinlock_t lock; /* guards read or write of above */ |
| }; |
| |
| struct cpuset { |
| struct cgroup_subsys_state css; |
| |
| unsigned long flags; /* "unsigned long" so bitops work */ |
| cpumask_var_t cpus_allowed; /* CPUs allowed to tasks in cpuset */ |
| nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */ |
| |
| struct cpuset *parent; /* my parent */ |
| |
| struct fmeter fmeter; /* memory_pressure filter */ |
| |
| /* partition number for rebuild_sched_domains() */ |
| int pn; |
| |
| /* for custom sched domain */ |
| int relax_domain_level; |
| |
| /* used for walking a cpuset heirarchy */ |
| struct list_head stack_list; |
| }; |
| |
| /* Retrieve the cpuset for a cgroup */ |
| static inline struct cpuset *cgroup_cs(struct cgroup *cont) |
| { |
| return container_of(cgroup_subsys_state(cont, cpuset_subsys_id), |
| struct cpuset, css); |
| } |
| |
| /* Retrieve the cpuset for a task */ |
| static inline struct cpuset *task_cs(struct task_struct *task) |
| { |
| return container_of(task_subsys_state(task, cpuset_subsys_id), |
| struct cpuset, css); |
| } |
| |
| /* bits in struct cpuset flags field */ |
| typedef enum { |
| CS_CPU_EXCLUSIVE, |
| CS_MEM_EXCLUSIVE, |
| CS_MEM_HARDWALL, |
| CS_MEMORY_MIGRATE, |
| CS_SCHED_LOAD_BALANCE, |
| CS_SPREAD_PAGE, |
| CS_SPREAD_SLAB, |
| } cpuset_flagbits_t; |
| |
| /* convenient tests for these bits */ |
| static inline int is_cpu_exclusive(const struct cpuset *cs) |
| { |
| return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); |
| } |
| |
| static inline int is_mem_exclusive(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); |
| } |
| |
| static inline int is_mem_hardwall(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEM_HARDWALL, &cs->flags); |
| } |
| |
| static inline int is_sched_load_balance(const struct cpuset *cs) |
| { |
| return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
| } |
| |
| static inline int is_memory_migrate(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEMORY_MIGRATE, &cs->flags); |
| } |
| |
| static inline int is_spread_page(const struct cpuset *cs) |
| { |
| return test_bit(CS_SPREAD_PAGE, &cs->flags); |
| } |
| |
| static inline int is_spread_slab(const struct cpuset *cs) |
| { |
| return test_bit(CS_SPREAD_SLAB, &cs->flags); |
| } |
| |
| static struct cpuset top_cpuset = { |
| .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), |
| }; |
| |
| /* |
| * There are two global mutexes guarding cpuset structures. The first |
| * is the main control groups cgroup_mutex, accessed via |
| * cgroup_lock()/cgroup_unlock(). The second is the cpuset-specific |
| * callback_mutex, below. They can nest. It is ok to first take |
| * cgroup_mutex, then nest callback_mutex. We also require taking |
| * task_lock() when dereferencing a task's cpuset pointer. See "The |
| * task_lock() exception", at the end of this comment. |
| * |
| * A task must hold both mutexes to modify cpusets. If a task |
| * holds cgroup_mutex, then it blocks others wanting that mutex, |
| * ensuring that it is the only task able to also acquire callback_mutex |
| * and be able to modify cpusets. It can perform various checks on |
| * the cpuset structure first, knowing nothing will change. It can |
| * also allocate memory while just holding cgroup_mutex. While it is |
| * performing these checks, various callback routines can briefly |
| * acquire callback_mutex to query cpusets. Once it is ready to make |
| * the changes, it takes callback_mutex, blocking everyone else. |
| * |
| * Calls to the kernel memory allocator can not be made while holding |
| * callback_mutex, as that would risk double tripping on callback_mutex |
| * from one of the callbacks into the cpuset code from within |
| * __alloc_pages(). |
| * |
| * If a task is only holding callback_mutex, then it has read-only |
| * access to cpusets. |
| * |
| * Now, the task_struct fields mems_allowed and mempolicy may be changed |
| * by other task, we use alloc_lock in the task_struct fields to protect |
| * them. |
| * |
| * The cpuset_common_file_read() handlers only hold callback_mutex across |
| * small pieces of code, such as when reading out possibly multi-word |
| * cpumasks and nodemasks. |
| * |
| * Accessing a task's cpuset should be done in accordance with the |
| * guidelines for accessing subsystem state in kernel/cgroup.c |
| */ |
| |
| static DEFINE_MUTEX(callback_mutex); |
| |
| /* |
| * cpuset_buffer_lock protects both the cpuset_name and cpuset_nodelist |
| * buffers. They are statically allocated to prevent using excess stack |
| * when calling cpuset_print_task_mems_allowed(). |
| */ |
| #define CPUSET_NAME_LEN (128) |
| #define CPUSET_NODELIST_LEN (256) |
| static char cpuset_name[CPUSET_NAME_LEN]; |
| static char cpuset_nodelist[CPUSET_NODELIST_LEN]; |
| static DEFINE_SPINLOCK(cpuset_buffer_lock); |
| |
| /* |
| * This is ugly, but preserves the userspace API for existing cpuset |
| * users. If someone tries to mount the "cpuset" filesystem, we |
| * silently switch it to mount "cgroup" instead |
| */ |
| static int cpuset_get_sb(struct file_system_type *fs_type, |
| int flags, const char *unused_dev_name, |
| void *data, struct vfsmount *mnt) |
| { |
| struct file_system_type *cgroup_fs = get_fs_type("cgroup"); |
| int ret = -ENODEV; |
| if (cgroup_fs) { |
| char mountopts[] = |
| "cpuset,noprefix," |
| "release_agent=/sbin/cpuset_release_agent"; |
| ret = cgroup_fs->get_sb(cgroup_fs, flags, |
| unused_dev_name, mountopts, mnt); |
| put_filesystem(cgroup_fs); |
| } |
| return ret; |
| } |
| |
| static struct file_system_type cpuset_fs_type = { |
| .name = "cpuset", |
| .get_sb = cpuset_get_sb, |
| }; |
| |
| /* |
| * Return in pmask the portion of a cpusets's cpus_allowed that |
| * are online. If none are online, walk up the cpuset hierarchy |
| * until we find one that does have some online cpus. If we get |
| * all the way to the top and still haven't found any online cpus, |
| * return cpu_online_map. Or if passed a NULL cs from an exit'ing |
| * task, return cpu_online_map. |
| * |
| * One way or another, we guarantee to return some non-empty subset |
| * of cpu_online_map. |
| * |
| * Call with callback_mutex held. |
| */ |
| |
| static void guarantee_online_cpus(const struct cpuset *cs, |
| struct cpumask *pmask) |
| { |
| while (cs && !cpumask_intersects(cs->cpus_allowed, cpu_online_mask)) |
| cs = cs->parent; |
| if (cs) |
| cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask); |
| else |
| cpumask_copy(pmask, cpu_online_mask); |
| BUG_ON(!cpumask_intersects(pmask, cpu_online_mask)); |
| } |
| |
| /* |
| * Return in *pmask the portion of a cpusets's mems_allowed that |
| * are online, with memory. If none are online with memory, walk |
| * up the cpuset hierarchy until we find one that does have some |
| * online mems. If we get all the way to the top and still haven't |
| * found any online mems, return node_states[N_HIGH_MEMORY]. |
| * |
| * One way or another, we guarantee to return some non-empty subset |
| * of node_states[N_HIGH_MEMORY]. |
| * |
| * Call with callback_mutex held. |
| */ |
| |
| static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask) |
| { |
| while (cs && !nodes_intersects(cs->mems_allowed, |
| node_states[N_HIGH_MEMORY])) |
| cs = cs->parent; |
| if (cs) |
| nodes_and(*pmask, cs->mems_allowed, |
| node_states[N_HIGH_MEMORY]); |
| else |
| *pmask = node_states[N_HIGH_MEMORY]; |
| BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY])); |
| } |
| |
| /* |
| * update task's spread flag if cpuset's page/slab spread flag is set |
| * |
| * Called with callback_mutex/cgroup_mutex held |
| */ |
| static void cpuset_update_task_spread_flag(struct cpuset *cs, |
| struct task_struct *tsk) |
| { |
| if (is_spread_page(cs)) |
| tsk->flags |= PF_SPREAD_PAGE; |
| else |
| tsk->flags &= ~PF_SPREAD_PAGE; |
| if (is_spread_slab(cs)) |
| tsk->flags |= PF_SPREAD_SLAB; |
| else |
| tsk->flags &= ~PF_SPREAD_SLAB; |
| } |
| |
| /* |
| * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? |
| * |
| * One cpuset is a subset of another if all its allowed CPUs and |
| * Memory Nodes are a subset of the other, and its exclusive flags |
| * are only set if the other's are set. Call holding cgroup_mutex. |
| */ |
| |
| static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) |
| { |
| return cpumask_subset(p->cpus_allowed, q->cpus_allowed) && |
| nodes_subset(p->mems_allowed, q->mems_allowed) && |
| is_cpu_exclusive(p) <= is_cpu_exclusive(q) && |
| is_mem_exclusive(p) <= is_mem_exclusive(q); |
| } |
| |
| /** |
| * alloc_trial_cpuset - allocate a trial cpuset |
| * @cs: the cpuset that the trial cpuset duplicates |
| */ |
| static struct cpuset *alloc_trial_cpuset(const struct cpuset *cs) |
| { |
| struct cpuset *trial; |
| |
| trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL); |
| if (!trial) |
| return NULL; |
| |
| if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL)) { |
| kfree(trial); |
| return NULL; |
| } |
| cpumask_copy(trial->cpus_allowed, cs->cpus_allowed); |
| |
| return trial; |
| } |
| |
| /** |
| * free_trial_cpuset - free the trial cpuset |
| * @trial: the trial cpuset to be freed |
| */ |
| static void free_trial_cpuset(struct cpuset *trial) |
| { |
| free_cpumask_var(trial->cpus_allowed); |
| kfree(trial); |
| } |
| |
| /* |
| * validate_change() - Used to validate that any proposed cpuset change |
| * follows the structural rules for cpusets. |
| * |
| * If we replaced the flag and mask values of the current cpuset |
| * (cur) with those values in the trial cpuset (trial), would |
| * our various subset and exclusive rules still be valid? Presumes |
| * cgroup_mutex held. |
| * |
| * 'cur' is the address of an actual, in-use cpuset. Operations |
| * such as list traversal that depend on the actual address of the |
| * cpuset in the list must use cur below, not trial. |
| * |
| * 'trial' is the address of bulk structure copy of cur, with |
| * perhaps one or more of the fields cpus_allowed, mems_allowed, |
| * or flags changed to new, trial values. |
| * |
| * Return 0 if valid, -errno if not. |
| */ |
| |
| static int validate_change(const struct cpuset *cur, const struct cpuset *trial) |
| { |
| struct cgroup *cont; |
| struct cpuset *c, *par; |
| |
| /* Each of our child cpusets must be a subset of us */ |
| list_for_each_entry(cont, &cur->css.cgroup->children, sibling) { |
| if (!is_cpuset_subset(cgroup_cs(cont), trial)) |
| return -EBUSY; |
| } |
| |
| /* Remaining checks don't apply to root cpuset */ |
| if (cur == &top_cpuset) |
| return 0; |
| |
| par = cur->parent; |
| |
| /* We must be a subset of our parent cpuset */ |
| if (!is_cpuset_subset(trial, par)) |
| return -EACCES; |
| |
| /* |
| * If either I or some sibling (!= me) is exclusive, we can't |
| * overlap |
| */ |
| list_for_each_entry(cont, &par->css.cgroup->children, sibling) { |
| c = cgroup_cs(cont); |
| if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && |
| c != cur && |
| cpumask_intersects(trial->cpus_allowed, c->cpus_allowed)) |
| return -EINVAL; |
| if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && |
| c != cur && |
| nodes_intersects(trial->mems_allowed, c->mems_allowed)) |
| return -EINVAL; |
| } |
| |
| /* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */ |
| if (cgroup_task_count(cur->css.cgroup)) { |
| if (cpumask_empty(trial->cpus_allowed) || |
| nodes_empty(trial->mems_allowed)) { |
| return -ENOSPC; |
| } |
| } |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_SMP |
| /* |
| * Helper routine for generate_sched_domains(). |
| * Do cpusets a, b have overlapping cpus_allowed masks? |
| */ |
| static int cpusets_overlap(struct cpuset *a, struct cpuset *b) |
| { |
| return cpumask_intersects(a->cpus_allowed, b->cpus_allowed); |
| } |
| |
| static void |
| update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) |
| { |
| if (dattr->relax_domain_level < c->relax_domain_level) |
| dattr->relax_domain_level = c->relax_domain_level; |
| return; |
| } |
| |
| static void |
| update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c) |
| { |
| LIST_HEAD(q); |
| |
| list_add(&c->stack_list, &q); |
| while (!list_empty(&q)) { |
| struct cpuset *cp; |
| struct cgroup *cont; |
| struct cpuset *child; |
| |
| cp = list_first_entry(&q, struct cpuset, stack_list); |
| list_del(q.next); |
| |
| if (cpumask_empty(cp->cpus_allowed)) |
| continue; |
| |
| if (is_sched_load_balance(cp)) |
| update_domain_attr(dattr, cp); |
| |
| list_for_each_entry(cont, &cp->css.cgroup->children, sibling) { |
| child = cgroup_cs(cont); |
| list_add_tail(&child->stack_list, &q); |
| } |
| } |
| } |
| |
| /* |
| * generate_sched_domains() |
| * |
| * This function builds a partial partition of the systems CPUs |
| * A 'partial partition' is a set of non-overlapping subsets whose |
| * union is a subset of that set. |
| * The output of this function needs to be passed to kernel/sched.c |
| * partition_sched_domains() routine, which will rebuild the scheduler's |
| * load balancing domains (sched domains) as specified by that partial |
| * partition. |
| * |
| * See "What is sched_load_balance" in Documentation/cgroups/cpusets.txt |
| * for a background explanation of this. |
| * |
| * Does not return errors, on the theory that the callers of this |
| * routine would rather not worry about failures to rebuild sched |
| * domains when operating in the severe memory shortage situations |
| * that could cause allocation failures below. |
| * |
| * Must be called with cgroup_lock held. |
| * |
| * The three key local variables below are: |
| * q - a linked-list queue of cpuset pointers, used to implement a |
| * top-down scan of all cpusets. This scan loads a pointer |
| * to each cpuset marked is_sched_load_balance into the |
| * array 'csa'. For our purposes, rebuilding the schedulers |
| * sched domains, we can ignore !is_sched_load_balance cpusets. |
| * csa - (for CpuSet Array) Array of pointers to all the cpusets |
| * that need to be load balanced, for convenient iterative |
| * access by the subsequent code that finds the best partition, |
| * i.e the set of domains (subsets) of CPUs such that the |
| * cpus_allowed of every cpuset marked is_sched_load_balance |
| * is a subset of one of these domains, while there are as |
| * many such domains as possible, each as small as possible. |
| * doms - Conversion of 'csa' to an array of cpumasks, for passing to |
| * the kernel/sched.c routine partition_sched_domains() in a |
| * convenient format, that can be easily compared to the prior |
| * value to determine what partition elements (sched domains) |
| * were changed (added or removed.) |
| * |
| * Finding the best partition (set of domains): |
| * The triple nested loops below over i, j, k scan over the |
| * load balanced cpusets (using the array of cpuset pointers in |
| * csa[]) looking for pairs of cpusets that have overlapping |
| * cpus_allowed, but which don't have the same 'pn' partition |
| * number and gives them in the same partition number. It keeps |
| * looping on the 'restart' label until it can no longer find |
| * any such pairs. |
| * |
| * The union of the cpus_allowed masks from the set of |
| * all cpusets having the same 'pn' value then form the one |
| * element of the partition (one sched domain) to be passed to |
| * partition_sched_domains(). |
| */ |
| static int generate_sched_domains(cpumask_var_t **domains, |
| struct sched_domain_attr **attributes) |
| { |
| LIST_HEAD(q); /* queue of cpusets to be scanned */ |
| struct cpuset *cp; /* scans q */ |
| struct cpuset **csa; /* array of all cpuset ptrs */ |
| int csn; /* how many cpuset ptrs in csa so far */ |
| int i, j, k; /* indices for partition finding loops */ |
| cpumask_var_t *doms; /* resulting partition; i.e. sched domains */ |
| struct sched_domain_attr *dattr; /* attributes for custom domains */ |
| int ndoms = 0; /* number of sched domains in result */ |
| int nslot; /* next empty doms[] struct cpumask slot */ |
| |
| doms = NULL; |
| dattr = NULL; |
| csa = NULL; |
| |
| /* Special case for the 99% of systems with one, full, sched domain */ |
| if (is_sched_load_balance(&top_cpuset)) { |
| ndoms = 1; |
| doms = alloc_sched_domains(ndoms); |
| if (!doms) |
| goto done; |
| |
| dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); |
| if (dattr) { |
| *dattr = SD_ATTR_INIT; |
| update_domain_attr_tree(dattr, &top_cpuset); |
| } |
| cpumask_copy(doms[0], top_cpuset.cpus_allowed); |
| |
| goto done; |
| } |
| |
| csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL); |
| if (!csa) |
| goto done; |
| csn = 0; |
| |
| list_add(&top_cpuset.stack_list, &q); |
| while (!list_empty(&q)) { |
| struct cgroup *cont; |
| struct cpuset *child; /* scans child cpusets of cp */ |
| |
| cp = list_first_entry(&q, struct cpuset, stack_list); |
| list_del(q.next); |
| |
| if (cpumask_empty(cp->cpus_allowed)) |
| continue; |
| |
| /* |
| * All child cpusets contain a subset of the parent's cpus, so |
| * just skip them, and then we call update_domain_attr_tree() |
| * to calc relax_domain_level of the corresponding sched |
| * domain. |
| */ |
| if (is_sched_load_balance(cp)) { |
| csa[csn++] = cp; |
| continue; |
| } |
| |
| list_for_each_entry(cont, &cp->css.cgroup->children, sibling) { |
| child = cgroup_cs(cont); |
| list_add_tail(&child->stack_list, &q); |
| } |
| } |
| |
| for (i = 0; i < csn; i++) |
| csa[i]->pn = i; |
| ndoms = csn; |
| |
| restart: |
| /* Find the best partition (set of sched domains) */ |
| for (i = 0; i < csn; i++) { |
| struct cpuset *a = csa[i]; |
| int apn = a->pn; |
| |
| for (j = 0; j < csn; j++) { |
| struct cpuset *b = csa[j]; |
| int bpn = b->pn; |
| |
| if (apn != bpn && cpusets_overlap(a, b)) { |
| for (k = 0; k < csn; k++) { |
| struct cpuset *c = csa[k]; |
| |
| if (c->pn == bpn) |
| c->pn = apn; |
| } |
| ndoms--; /* one less element */ |
| goto restart; |
| } |
| } |
| } |
| |
| /* |
| * Now we know how many domains to create. |
| * Convert <csn, csa> to <ndoms, doms> and populate cpu masks. |
| */ |
| doms = alloc_sched_domains(ndoms); |
| if (!doms) |
| goto done; |
| |
| /* |
| * The rest of the code, including the scheduler, can deal with |
| * dattr==NULL case. No need to abort if alloc fails. |
| */ |
| dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL); |
| |
| for (nslot = 0, i = 0; i < csn; i++) { |
| struct cpuset *a = csa[i]; |
| struct cpumask *dp; |
| int apn = a->pn; |
| |
| if (apn < 0) { |
| /* Skip completed partitions */ |
| continue; |
| } |
| |
| dp = doms[nslot]; |
| |
| if (nslot == ndoms) { |
| static int warnings = 10; |
| if (warnings) { |
| printk(KERN_WARNING |
| "rebuild_sched_domains confused:" |
| " nslot %d, ndoms %d, csn %d, i %d," |
| " apn %d\n", |
| nslot, ndoms, csn, i, apn); |
| warnings--; |
| } |
| continue; |
| } |
| |
| cpumask_clear(dp); |
| if (dattr) |
| *(dattr + nslot) = SD_ATTR_INIT; |
| for (j = i; j < csn; j++) { |
| struct cpuset *b = csa[j]; |
| |
| if (apn == b->pn) { |
| cpumask_or(dp, dp, b->cpus_allowed); |
| if (dattr) |
| update_domain_attr_tree(dattr + nslot, b); |
| |
| /* Done with this partition */ |
| b->pn = -1; |
| } |
| } |
| nslot++; |
| } |
| BUG_ON(nslot != ndoms); |
| |
| done: |
| kfree(csa); |
| |
| /* |
| * Fallback to the default domain if kmalloc() failed. |
| * See comments in partition_sched_domains(). |
| */ |
| if (doms == NULL) |
| ndoms = 1; |
| |
| *domains = doms; |
| *attributes = dattr; |
| return ndoms; |
| } |
| |
| /* |
| * Rebuild scheduler domains. |
| * |
| * Call with neither cgroup_mutex held nor within get_online_cpus(). |
| * Takes both cgroup_mutex and get_online_cpus(). |
| * |
| * Cannot be directly called from cpuset code handling changes |
| * to the cpuset pseudo-filesystem, because it cannot be called |
| * from code that already holds cgroup_mutex. |
| */ |
| static void do_rebuild_sched_domains(struct work_struct *unused) |
| { |
| struct sched_domain_attr *attr; |
| cpumask_var_t *doms; |
| int ndoms; |
| |
| get_online_cpus(); |
| |
| /* Generate domain masks and attrs */ |
| cgroup_lock(); |
| ndoms = generate_sched_domains(&doms, &attr); |
| cgroup_unlock(); |
| |
| /* Have scheduler rebuild the domains */ |
| partition_sched_domains(ndoms, doms, attr); |
| |
| put_online_cpus(); |
| } |
| #else /* !CONFIG_SMP */ |
| static void do_rebuild_sched_domains(struct work_struct *unused) |
| { |
| } |
| |
| static int generate_sched_domains(cpumask_var_t **domains, |
| struct sched_domain_attr **attributes) |
| { |
| *domains = NULL; |
| return 1; |
| } |
| #endif /* CONFIG_SMP */ |
| |
| static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains); |
| |
| /* |
| * Rebuild scheduler domains, asynchronously via workqueue. |
| * |
| * If the flag 'sched_load_balance' of any cpuset with non-empty |
| * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset |
| * which has that flag enabled, or if any cpuset with a non-empty |
| * 'cpus' is removed, then call this routine to rebuild the |
| * scheduler's dynamic sched domains. |
| * |
| * The rebuild_sched_domains() and partition_sched_domains() |
| * routines must nest cgroup_lock() inside get_online_cpus(), |
| * but such cpuset changes as these must nest that locking the |
| * other way, holding cgroup_lock() for much of the code. |
| * |
| * So in order to avoid an ABBA deadlock, the cpuset code handling |
| * these user changes delegates the actual sched domain rebuilding |
| * to a separate workqueue thread, which ends up processing the |
| * above do_rebuild_sched_domains() function. |
| */ |
| static void async_rebuild_sched_domains(void) |
| { |
| queue_work(cpuset_wq, &rebuild_sched_domains_work); |
| } |
| |
| /* |
| * Accomplishes the same scheduler domain rebuild as the above |
| * async_rebuild_sched_domains(), however it directly calls the |
| * rebuild routine synchronously rather than calling it via an |
| * asynchronous work thread. |
| * |
| * This can only be called from code that is not holding |
| * cgroup_mutex (not nested in a cgroup_lock() call.) |
| */ |
| void rebuild_sched_domains(void) |
| { |
| do_rebuild_sched_domains(NULL); |
| } |
| |
| /** |
| * cpuset_test_cpumask - test a task's cpus_allowed versus its cpuset's |
| * @tsk: task to test |
| * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner |
| * |
| * Call with cgroup_mutex held. May take callback_mutex during call. |
| * Called for each task in a cgroup by cgroup_scan_tasks(). |
| * Return nonzero if this tasks's cpus_allowed mask should be changed (in other |
| * words, if its mask is not equal to its cpuset's mask). |
| */ |
| static int cpuset_test_cpumask(struct task_struct *tsk, |
| struct cgroup_scanner *scan) |
| { |
| return !cpumask_equal(&tsk->cpus_allowed, |
| (cgroup_cs(scan->cg))->cpus_allowed); |
| } |
| |
| /** |
| * cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's |
| * @tsk: task to test |
| * @scan: struct cgroup_scanner containing the cgroup of the task |
| * |
| * Called by cgroup_scan_tasks() for each task in a cgroup whose |
| * cpus_allowed mask needs to be changed. |
| * |
| * We don't need to re-check for the cgroup/cpuset membership, since we're |
| * holding cgroup_lock() at this point. |
| */ |
| static void cpuset_change_cpumask(struct task_struct *tsk, |
| struct cgroup_scanner *scan) |
| { |
| set_cpus_allowed_ptr(tsk, ((cgroup_cs(scan->cg))->cpus_allowed)); |
| } |
| |
| /** |
| * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. |
| * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed |
| * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks() |
| * |
| * Called with cgroup_mutex held |
| * |
| * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, |
| * calling callback functions for each. |
| * |
| * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0 |
| * if @heap != NULL. |
| */ |
| static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap) |
| { |
| struct cgroup_scanner scan; |
| |
| scan.cg = cs->css.cgroup; |
| scan.test_task = cpuset_test_cpumask; |
| scan.process_task = cpuset_change_cpumask; |
| scan.heap = heap; |
| cgroup_scan_tasks(&scan); |
| } |
| |
| /** |
| * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it |
| * @cs: the cpuset to consider |
| * @buf: buffer of cpu numbers written to this cpuset |
| */ |
| static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, |
| const char *buf) |
| { |
| struct ptr_heap heap; |
| int retval; |
| int is_load_balanced; |
| |
| /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */ |
| if (cs == &top_cpuset) |
| return -EACCES; |
| |
| /* |
| * An empty cpus_allowed is ok only if the cpuset has no tasks. |
| * Since cpulist_parse() fails on an empty mask, we special case |
| * that parsing. The validate_change() call ensures that cpusets |
| * with tasks have cpus. |
| */ |
| if (!*buf) { |
| cpumask_clear(trialcs->cpus_allowed); |
| } else { |
| retval = cpulist_parse(buf, trialcs->cpus_allowed); |
| if (retval < 0) |
| return retval; |
| |
| if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask)) |
| return -EINVAL; |
| } |
| retval = validate_change(cs, trialcs); |
| if (retval < 0) |
| return retval; |
| |
| /* Nothing to do if the cpus didn't change */ |
| if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) |
| return 0; |
| |
| retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); |
| if (retval) |
| return retval; |
| |
| is_load_balanced = is_sched_load_balance(trialcs); |
| |
| mutex_lock(&callback_mutex); |
| cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); |
| mutex_unlock(&callback_mutex); |
| |
| /* |
| * Scan tasks in the cpuset, and update the cpumasks of any |
| * that need an update. |
| */ |
| update_tasks_cpumask(cs, &heap); |
| |
| heap_free(&heap); |
| |
| if (is_load_balanced) |
| async_rebuild_sched_domains(); |
| return 0; |
| } |
| |
| /* |
| * cpuset_migrate_mm |
| * |
| * Migrate memory region from one set of nodes to another. |
| * |
| * Temporarilly set tasks mems_allowed to target nodes of migration, |
| * so that the migration code can allocate pages on these nodes. |
| * |
| * Call holding cgroup_mutex, so current's cpuset won't change |
| * during this call, as manage_mutex holds off any cpuset_attach() |
| * calls. Therefore we don't need to take task_lock around the |
| * call to guarantee_online_mems(), as we know no one is changing |
| * our task's cpuset. |
| * |
| * While the mm_struct we are migrating is typically from some |
| * other task, the task_struct mems_allowed that we are hacking |
| * is for our current task, which must allocate new pages for that |
| * migrating memory region. |
| */ |
| |
| static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, |
| const nodemask_t *to) |
| { |
| struct task_struct *tsk = current; |
| |
| tsk->mems_allowed = *to; |
| |
| do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL); |
| |
| guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed); |
| } |
| |
| /* |
| * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy |
| * @tsk: the task to change |
| * @newmems: new nodes that the task will be set |
| * |
| * In order to avoid seeing no nodes if the old and new nodes are disjoint, |
| * we structure updates as setting all new allowed nodes, then clearing newly |
| * disallowed ones. |
| */ |
| static void cpuset_change_task_nodemask(struct task_struct *tsk, |
| nodemask_t *newmems) |
| { |
| repeat: |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return; |
| if (current->flags & PF_EXITING) /* Let dying task have memory */ |
| return; |
| |
| task_lock(tsk); |
| nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); |
| mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1); |
| |
| |
| /* |
| * ensure checking ->mems_allowed_change_disable after setting all new |
| * allowed nodes. |
| * |
| * the read-side task can see an nodemask with new allowed nodes and |
| * old allowed nodes. and if it allocates page when cpuset clears newly |
| * disallowed ones continuous, it can see the new allowed bits. |
| * |
| * And if setting all new allowed nodes is after the checking, setting |
| * all new allowed nodes and clearing newly disallowed ones will be done |
| * continuous, and the read-side task may find no node to alloc page. |
| */ |
| smp_mb(); |
| |
| /* |
| * Allocation of memory is very fast, we needn't sleep when waiting |
| * for the read-side. |
| */ |
| while (ACCESS_ONCE(tsk->mems_allowed_change_disable)) { |
| task_unlock(tsk); |
| if (!task_curr(tsk)) |
| yield(); |
| goto repeat; |
| } |
| |
| /* |
| * ensure checking ->mems_allowed_change_disable before clearing all new |
| * disallowed nodes. |
| * |
| * if clearing newly disallowed bits before the checking, the read-side |
| * task may find no node to alloc page. |
| */ |
| smp_mb(); |
| |
| mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2); |
| tsk->mems_allowed = *newmems; |
| task_unlock(tsk); |
| } |
| |
| /* |
| * Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy |
| * of it to cpuset's new mems_allowed, and migrate pages to new nodes if |
| * memory_migrate flag is set. Called with cgroup_mutex held. |
| */ |
| static void cpuset_change_nodemask(struct task_struct *p, |
| struct cgroup_scanner *scan) |
| { |
| struct mm_struct *mm; |
| struct cpuset *cs; |
| int migrate; |
| const nodemask_t *oldmem = scan->data; |
| NODEMASK_ALLOC(nodemask_t, newmems, GFP_KERNEL); |
| |
| if (!newmems) |
| return; |
| |
| cs = cgroup_cs(scan->cg); |
| guarantee_online_mems(cs, newmems); |
| |
| cpuset_change_task_nodemask(p, newmems); |
| |
| NODEMASK_FREE(newmems); |
| |
| mm = get_task_mm(p); |
| if (!mm) |
| return; |
| |
| migrate = is_memory_migrate(cs); |
| |
| mpol_rebind_mm(mm, &cs->mems_allowed); |
| if (migrate) |
| cpuset_migrate_mm(mm, oldmem, &cs->mems_allowed); |
| mmput(mm); |
| } |
| |
| static void *cpuset_being_rebound; |
| |
| /** |
| * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset. |
| * @cs: the cpuset in which each task's mems_allowed mask needs to be changed |
| * @oldmem: old mems_allowed of cpuset cs |
| * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks() |
| * |
| * Called with cgroup_mutex held |
| * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0 |
| * if @heap != NULL. |
| */ |
| static void update_tasks_nodemask(struct cpuset *cs, const nodemask_t *oldmem, |
| struct ptr_heap *heap) |
| { |
| struct cgroup_scanner scan; |
| |
| cpuset_being_rebound = cs; /* causes mpol_dup() rebind */ |
| |
| scan.cg = cs->css.cgroup; |
| scan.test_task = NULL; |
| scan.process_task = cpuset_change_nodemask; |
| scan.heap = heap; |
| scan.data = (nodemask_t *)oldmem; |
| |
| /* |
| * The mpol_rebind_mm() call takes mmap_sem, which we couldn't |
| * take while holding tasklist_lock. Forks can happen - the |
| * mpol_dup() cpuset_being_rebound check will catch such forks, |
| * and rebind their vma mempolicies too. Because we still hold |
| * the global cgroup_mutex, we know that no other rebind effort |
| * will be contending for the global variable cpuset_being_rebound. |
| * It's ok if we rebind the same mm twice; mpol_rebind_mm() |
| * is idempotent. Also migrate pages in each mm to new nodes. |
| */ |
| cgroup_scan_tasks(&scan); |
| |
| /* We're done rebinding vmas to this cpuset's new mems_allowed. */ |
| cpuset_being_rebound = NULL; |
| } |
| |
| /* |
| * Handle user request to change the 'mems' memory placement |
| * of a cpuset. Needs to validate the request, update the |
| * cpusets mems_allowed, and for each task in the cpuset, |
| * update mems_allowed and rebind task's mempolicy and any vma |
| * mempolicies and if the cpuset is marked 'memory_migrate', |
| * migrate the tasks pages to the new memory. |
| * |
| * Call with cgroup_mutex held. May take callback_mutex during call. |
| * Will take tasklist_lock, scan tasklist for tasks in cpuset cs, |
| * lock each such tasks mm->mmap_sem, scan its vma's and rebind |
| * their mempolicies to the cpusets new mems_allowed. |
| */ |
| static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, |
| const char *buf) |
| { |
| NODEMASK_ALLOC(nodemask_t, oldmem, GFP_KERNEL); |
| int retval; |
| struct ptr_heap heap; |
| |
| if (!oldmem) |
| return -ENOMEM; |
| |
| /* |
| * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY]; |
| * it's read-only |
| */ |
| if (cs == &top_cpuset) { |
| retval = -EACCES; |
| goto done; |
| } |
| |
| /* |
| * An empty mems_allowed is ok iff there are no tasks in the cpuset. |
| * Since nodelist_parse() fails on an empty mask, we special case |
| * that parsing. The validate_change() call ensures that cpusets |
| * with tasks have memory. |
| */ |
| if (!*buf) { |
| nodes_clear(trialcs->mems_allowed); |
| } else { |
| retval = nodelist_parse(buf, trialcs->mems_allowed); |
| if (retval < 0) |
| goto done; |
| |
| if (!nodes_subset(trialcs->mems_allowed, |
| node_states[N_HIGH_MEMORY])) { |
| retval = -EINVAL; |
| goto done; |
| } |
| } |
| *oldmem = cs->mems_allowed; |
| if (nodes_equal(*oldmem, trialcs->mems_allowed)) { |
| retval = 0; /* Too easy - nothing to do */ |
| goto done; |
| } |
| retval = validate_change(cs, trialcs); |
| if (retval < 0) |
| goto done; |
| |
| retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); |
| if (retval < 0) |
| goto done; |
| |
| mutex_lock(&callback_mutex); |
| cs->mems_allowed = trialcs->mems_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| update_tasks_nodemask(cs, oldmem, &heap); |
| |
| heap_free(&heap); |
| done: |
| NODEMASK_FREE(oldmem); |
| return retval; |
| } |
| |
| int current_cpuset_is_being_rebound(void) |
| { |
| return task_cs(current) == cpuset_being_rebound; |
| } |
| |
| static int update_relax_domain_level(struct cpuset *cs, s64 val) |
| { |
| #ifdef CONFIG_SMP |
| if (val < -1 || val >= SD_LV_MAX) |
| return -EINVAL; |
| #endif |
| |
| if (val != cs->relax_domain_level) { |
| cs->relax_domain_level = val; |
| if (!cpumask_empty(cs->cpus_allowed) && |
| is_sched_load_balance(cs)) |
| async_rebuild_sched_domains(); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * cpuset_change_flag - make a task's spread flags the same as its cpuset's |
| * @tsk: task to be updated |
| * @scan: struct cgroup_scanner containing the cgroup of the task |
| * |
| * Called by cgroup_scan_tasks() for each task in a cgroup. |
| * |
| * We don't need to re-check for the cgroup/cpuset membership, since we're |
| * holding cgroup_lock() at this point. |
| */ |
| static void cpuset_change_flag(struct task_struct *tsk, |
| struct cgroup_scanner *scan) |
| { |
| cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk); |
| } |
| |
| /* |
| * update_tasks_flags - update the spread flags of tasks in the cpuset. |
| * @cs: the cpuset in which each task's spread flags needs to be changed |
| * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks() |
| * |
| * Called with cgroup_mutex held |
| * |
| * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, |
| * calling callback functions for each. |
| * |
| * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0 |
| * if @heap != NULL. |
| */ |
| static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap) |
| { |
| struct cgroup_scanner scan; |
| |
| scan.cg = cs->css.cgroup; |
| scan.test_task = NULL; |
| scan.process_task = cpuset_change_flag; |
| scan.heap = heap; |
| cgroup_scan_tasks(&scan); |
| } |
| |
| /* |
| * update_flag - read a 0 or a 1 in a file and update associated flag |
| * bit: the bit to update (see cpuset_flagbits_t) |
| * cs: the cpuset to update |
| * turning_on: whether the flag is being set or cleared |
| * |
| * Call with cgroup_mutex held. |
| */ |
| |
| static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, |
| int turning_on) |
| { |
| struct cpuset *trialcs; |
| int balance_flag_changed; |
| int spread_flag_changed; |
| struct ptr_heap heap; |
| int err; |
| |
| trialcs = alloc_trial_cpuset(cs); |
| if (!trialcs) |
| return -ENOMEM; |
| |
| if (turning_on) |
| set_bit(bit, &trialcs->flags); |
| else |
| clear_bit(bit, &trialcs->flags); |
| |
| err = validate_change(cs, trialcs); |
| if (err < 0) |
| goto out; |
| |
| err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); |
| if (err < 0) |
| goto out; |
| |
| balance_flag_changed = (is_sched_load_balance(cs) != |
| is_sched_load_balance(trialcs)); |
| |
| spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) |
| || (is_spread_page(cs) != is_spread_page(trialcs))); |
| |
| mutex_lock(&callback_mutex); |
| cs->flags = trialcs->flags; |
| mutex_unlock(&callback_mutex); |
| |
| if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) |
| async_rebuild_sched_domains(); |
| |
| if (spread_flag_changed) |
| update_tasks_flags(cs, &heap); |
| heap_free(&heap); |
| out: |
| free_trial_cpuset(trialcs); |
| return err; |
| } |
| |
| /* |
| * Frequency meter - How fast is some event occurring? |
| * |
| * These routines manage a digitally filtered, constant time based, |
| * event frequency meter. There are four routines: |
| * fmeter_init() - initialize a frequency meter. |
| * fmeter_markevent() - called each time the event happens. |
| * fmeter_getrate() - returns the recent rate of such events. |
| * fmeter_update() - internal routine used to update fmeter. |
| * |
| * A common data structure is passed to each of these routines, |
| * which is used to keep track of the state required to manage the |
| * frequency meter and its digital filter. |
| * |
| * The filter works on the number of events marked per unit time. |
| * The filter is single-pole low-pass recursive (IIR). The time unit |
| * is 1 second. Arithmetic is done using 32-bit integers scaled to |
| * simulate 3 decimal digits of precision (multiplied by 1000). |
| * |
| * With an FM_COEF of 933, and a time base of 1 second, the filter |
| * has a half-life of 10 seconds, meaning that if the events quit |
| * happening, then the rate returned from the fmeter_getrate() |
| * will be cut in half each 10 seconds, until it converges to zero. |
| * |
| * It is not worth doing a real infinitely recursive filter. If more |
| * than FM_MAXTICKS ticks have elapsed since the last filter event, |
| * just compute FM_MAXTICKS ticks worth, by which point the level |
| * will be stable. |
| * |
| * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid |
| * arithmetic overflow in the fmeter_update() routine. |
| * |
| * Given the simple 32 bit integer arithmetic used, this meter works |
| * best for reporting rates between one per millisecond (msec) and |
| * one per 32 (approx) seconds. At constant rates faster than one |
| * per msec it maxes out at values just under 1,000,000. At constant |
| * rates between one per msec, and one per second it will stabilize |
| * to a value N*1000, where N is the rate of events per second. |
| * At constant rates between one per second and one per 32 seconds, |
| * it will be choppy, moving up on the seconds that have an event, |
| * and then decaying until the next event. At rates slower than |
| * about one in 32 seconds, it decays all the way back to zero between |
| * each event. |
| */ |
| |
| #define FM_COEF 933 /* coefficient for half-life of 10 secs */ |
| #define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */ |
| #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ |
| #define FM_SCALE 1000 /* faux fixed point scale */ |
| |
| /* Initialize a frequency meter */ |
| static void fmeter_init(struct fmeter *fmp) |
| { |
| fmp->cnt = 0; |
| fmp->val = 0; |
| fmp->time = 0; |
| spin_lock_init(&fmp->lock); |
| } |
| |
| /* Internal meter update - process cnt events and update value */ |
| static void fmeter_update(struct fmeter *fmp) |
| { |
| time_t now = get_seconds(); |
| time_t ticks = now - fmp->time; |
| |
| if (ticks == 0) |
| return; |
| |
| ticks = min(FM_MAXTICKS, ticks); |
| while (ticks-- > 0) |
| fmp->val = (FM_COEF * fmp->val) / FM_SCALE; |
| fmp->time = now; |
| |
| fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; |
| fmp->cnt = 0; |
| } |
| |
| /* Process any previous ticks, then bump cnt by one (times scale). */ |
| static void fmeter_markevent(struct fmeter *fmp) |
| { |
| spin_lock(&fmp->lock); |
| fmeter_update(fmp); |
| fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); |
| spin_unlock(&fmp->lock); |
| } |
| |
| /* Process any previous ticks, then return current value. */ |
| static int fmeter_getrate(struct fmeter *fmp) |
| { |
| int val; |
| |
| spin_lock(&fmp->lock); |
| fmeter_update(fmp); |
| val = fmp->val; |
| spin_unlock(&fmp->lock); |
| return val; |
| } |
| |
| /* Protected by cgroup_lock */ |
| static cpumask_var_t cpus_attach; |
| |
| /* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */ |
| static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont, |
| struct task_struct *tsk, bool threadgroup) |
| { |
| int ret; |
| struct cpuset *cs = cgroup_cs(cont); |
| |
| if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)) |
| return -ENOSPC; |
| |
| /* |
| * Kthreads bound to specific cpus cannot be moved to a new cpuset; we |
| * cannot change their cpu affinity and isolating such threads by their |
| * set of allowed nodes is unnecessary. Thus, cpusets are not |
| * applicable for such threads. This prevents checking for success of |
| * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may |
| * be changed. |
| */ |
| if (tsk->flags & PF_THREAD_BOUND) |
| return -EINVAL; |
| |
| ret = security_task_setscheduler(tsk, 0, NULL); |
| if (ret) |
| return ret; |
| if (threadgroup) { |
| struct task_struct *c; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) { |
| ret = security_task_setscheduler(c, 0, NULL); |
| if (ret) { |
| rcu_read_unlock(); |
| return ret; |
| } |
| } |
| rcu_read_unlock(); |
| } |
| return 0; |
| } |
| |
| static void cpuset_attach_task(struct task_struct *tsk, nodemask_t *to, |
| struct cpuset *cs) |
| { |
| int err; |
| /* |
| * can_attach beforehand should guarantee that this doesn't fail. |
| * TODO: have a better way to handle failure here |
| */ |
| err = set_cpus_allowed_ptr(tsk, cpus_attach); |
| WARN_ON_ONCE(err); |
| |
| cpuset_change_task_nodemask(tsk, to); |
| cpuset_update_task_spread_flag(cs, tsk); |
| |
| } |
| |
| static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont, |
| struct cgroup *oldcont, struct task_struct *tsk, |
| bool threadgroup) |
| { |
| struct mm_struct *mm; |
| struct cpuset *cs = cgroup_cs(cont); |
| struct cpuset *oldcs = cgroup_cs(oldcont); |
| NODEMASK_ALLOC(nodemask_t, from, GFP_KERNEL); |
| NODEMASK_ALLOC(nodemask_t, to, GFP_KERNEL); |
| |
| if (from == NULL || to == NULL) |
| goto alloc_fail; |
| |
| if (cs == &top_cpuset) { |
| cpumask_copy(cpus_attach, cpu_possible_mask); |
| } else { |
| guarantee_online_cpus(cs, cpus_attach); |
| } |
| guarantee_online_mems(cs, to); |
| |
| /* do per-task migration stuff possibly for each in the threadgroup */ |
| cpuset_attach_task(tsk, to, cs); |
| if (threadgroup) { |
| struct task_struct *c; |
| rcu_read_lock(); |
| list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) { |
| cpuset_attach_task(c, to, cs); |
| } |
| rcu_read_unlock(); |
| } |
| |
| /* change mm; only needs to be done once even if threadgroup */ |
| *from = oldcs->mems_allowed; |
| *to = cs->mems_allowed; |
| mm = get_task_mm(tsk); |
| if (mm) { |
| mpol_rebind_mm(mm, to); |
| if (is_memory_migrate(cs)) |
| cpuset_migrate_mm(mm, from, to); |
| mmput(mm); |
| } |
| |
| alloc_fail: |
| NODEMASK_FREE(from); |
| NODEMASK_FREE(to); |
| } |
| |
| /* The various types of files and directories in a cpuset file system */ |
| |
| typedef enum { |
| FILE_MEMORY_MIGRATE, |
| FILE_CPULIST, |
| FILE_MEMLIST, |
| FILE_CPU_EXCLUSIVE, |
| FILE_MEM_EXCLUSIVE, |
| FILE_MEM_HARDWALL, |
| FILE_SCHED_LOAD_BALANCE, |
| FILE_SCHED_RELAX_DOMAIN_LEVEL, |
| FILE_MEMORY_PRESSURE_ENABLED, |
| FILE_MEMORY_PRESSURE, |
| FILE_SPREAD_PAGE, |
| FILE_SPREAD_SLAB, |
| } cpuset_filetype_t; |
| |
| static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val) |
| { |
| int retval = 0; |
| struct cpuset *cs = cgroup_cs(cgrp); |
| cpuset_filetype_t type = cft->private; |
| |
| if (!cgroup_lock_live_group(cgrp)) |
| return -ENODEV; |
| |
| switch (type) { |
| case FILE_CPU_EXCLUSIVE: |
| retval = update_flag(CS_CPU_EXCLUSIVE, cs, val); |
| break; |
| case FILE_MEM_EXCLUSIVE: |
| retval = update_flag(CS_MEM_EXCLUSIVE, cs, val); |
| break; |
| case FILE_MEM_HARDWALL: |
| retval = update_flag(CS_MEM_HARDWALL, cs, val); |
| break; |
| case FILE_SCHED_LOAD_BALANCE: |
| retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val); |
| break; |
| case FILE_MEMORY_MIGRATE: |
| retval = update_flag(CS_MEMORY_MIGRATE, cs, val); |
| break; |
| case FILE_MEMORY_PRESSURE_ENABLED: |
| cpuset_memory_pressure_enabled = !!val; |
| break; |
| case FILE_MEMORY_PRESSURE: |
| retval = -EACCES; |
| break; |
| case FILE_SPREAD_PAGE: |
| retval = update_flag(CS_SPREAD_PAGE, cs, val); |
| break; |
| case FILE_SPREAD_SLAB: |
| retval = update_flag(CS_SPREAD_SLAB, cs, val); |
| break; |
| default: |
| retval = -EINVAL; |
| break; |
| } |
| cgroup_unlock(); |
| return retval; |
| } |
| |
| static int cpuset_write_s64(struct cgroup *cgrp, struct cftype *cft, s64 val) |
| { |
| int retval = 0; |
| struct cpuset *cs = cgroup_cs(cgrp); |
| cpuset_filetype_t type = cft->private; |
| |
| if (!cgroup_lock_live_group(cgrp)) |
| return -ENODEV; |
| |
| switch (type) { |
| case FILE_SCHED_RELAX_DOMAIN_LEVEL: |
| retval = update_relax_domain_level(cs, val); |
| break; |
| default: |
| retval = -EINVAL; |
| break; |
| } |
| cgroup_unlock(); |
| return retval; |
| } |
| |
| /* |
| * Common handling for a write to a "cpus" or "mems" file. |
| */ |
| static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft, |
| const char *buf) |
| { |
| int retval = 0; |
| struct cpuset *cs = cgroup_cs(cgrp); |
| struct cpuset *trialcs; |
| |
| if (!cgroup_lock_live_group(cgrp)) |
| return -ENODEV; |
| |
| trialcs = alloc_trial_cpuset(cs); |
| if (!trialcs) |
| return -ENOMEM; |
| |
| switch (cft->private) { |
| case FILE_CPULIST: |
| retval = update_cpumask(cs, trialcs, buf); |
| break; |
| case FILE_MEMLIST: |
| retval = update_nodemask(cs, trialcs, buf); |
| break; |
| default: |
| retval = -EINVAL; |
| break; |
| } |
| |
| free_trial_cpuset(trialcs); |
| cgroup_unlock(); |
| return retval; |
| } |
| |
| /* |
| * These ascii lists should be read in a single call, by using a user |
| * buffer large enough to hold the entire map. If read in smaller |
| * chunks, there is no guarantee of atomicity. Since the display format |
| * used, list of ranges of sequential numbers, is variable length, |
| * and since these maps can change value dynamically, one could read |
| * gibberish by doing partial reads while a list was changing. |
| * A single large read to a buffer that crosses a page boundary is |
| * ok, because the result being copied to user land is not recomputed |
| * across a page fault. |
| */ |
| |
| static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs) |
| { |
| int ret; |
| |
| mutex_lock(&callback_mutex); |
| ret = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed); |
| mutex_unlock(&callback_mutex); |
| |
| return ret; |
| } |
| |
| static int cpuset_sprintf_memlist(char *page, struct cpuset *cs) |
| { |
| NODEMASK_ALLOC(nodemask_t, mask, GFP_KERNEL); |
| int retval; |
| |
| if (mask == NULL) |
| return -ENOMEM; |
| |
| mutex_lock(&callback_mutex); |
| *mask = cs->mems_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| retval = nodelist_scnprintf(page, PAGE_SIZE, *mask); |
| |
| NODEMASK_FREE(mask); |
| |
| return retval; |
| } |
| |
| static ssize_t cpuset_common_file_read(struct cgroup *cont, |
| struct cftype *cft, |
| struct file *file, |
| char __user *buf, |
| size_t nbytes, loff_t *ppos) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| cpuset_filetype_t type = cft->private; |
| char *page; |
| ssize_t retval = 0; |
| char *s; |
| |
| if (!(page = (char *)__get_free_page(GFP_TEMPORARY))) |
| return -ENOMEM; |
| |
| s = page; |
| |
| switch (type) { |
| case FILE_CPULIST: |
| s += cpuset_sprintf_cpulist(s, cs); |
| break; |
| case FILE_MEMLIST: |
| s += cpuset_sprintf_memlist(s, cs); |
| break; |
| default: |
| retval = -EINVAL; |
| goto out; |
| } |
| *s++ = '\n'; |
| |
| retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page); |
| out: |
| free_page((unsigned long)page); |
| return retval; |
| } |
| |
| static u64 cpuset_read_u64(struct cgroup *cont, struct cftype *cft) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| cpuset_filetype_t type = cft->private; |
| switch (type) { |
| case FILE_CPU_EXCLUSIVE: |
| return is_cpu_exclusive(cs); |
| case FILE_MEM_EXCLUSIVE: |
| return is_mem_exclusive(cs); |
| case FILE_MEM_HARDWALL: |
| return is_mem_hardwall(cs); |
| case FILE_SCHED_LOAD_BALANCE: |
| return is_sched_load_balance(cs); |
| case FILE_MEMORY_MIGRATE: |
| return is_memory_migrate(cs); |
| case FILE_MEMORY_PRESSURE_ENABLED: |
| return cpuset_memory_pressure_enabled; |
| case FILE_MEMORY_PRESSURE: |
| return fmeter_getrate(&cs->fmeter); |
| case FILE_SPREAD_PAGE: |
| return is_spread_page(cs); |
| case FILE_SPREAD_SLAB: |
| return is_spread_slab(cs); |
| default: |
| BUG(); |
| } |
| |
| /* Unreachable but makes gcc happy */ |
| return 0; |
| } |
| |
| static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| cpuset_filetype_t type = cft->private; |
| switch (type) { |
| case FILE_SCHED_RELAX_DOMAIN_LEVEL: |
| return cs->relax_domain_level; |
| default: |
| BUG(); |
| } |
| |
| /* Unrechable but makes gcc happy */ |
| return 0; |
| } |
| |
| |
| /* |
| * for the common functions, 'private' gives the type of file |
| */ |
| |
| static struct cftype files[] = { |
| { |
| .name = "cpus", |
| .read = cpuset_common_file_read, |
| .write_string = cpuset_write_resmask, |
| .max_write_len = (100U + 6 * NR_CPUS), |
| .private = FILE_CPULIST, |
| }, |
| |
| { |
| .name = "mems", |
| .read = cpuset_common_file_read, |
| .write_string = cpuset_write_resmask, |
| .max_write_len = (100U + 6 * MAX_NUMNODES), |
| .private = FILE_MEMLIST, |
| }, |
| |
| { |
| .name = "cpu_exclusive", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_CPU_EXCLUSIVE, |
| }, |
| |
| { |
| .name = "mem_exclusive", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_MEM_EXCLUSIVE, |
| }, |
| |
| { |
| .name = "mem_hardwall", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_MEM_HARDWALL, |
| }, |
| |
| { |
| .name = "sched_load_balance", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_SCHED_LOAD_BALANCE, |
| }, |
| |
| { |
| .name = "sched_relax_domain_level", |
| .read_s64 = cpuset_read_s64, |
| .write_s64 = cpuset_write_s64, |
| .private = FILE_SCHED_RELAX_DOMAIN_LEVEL, |
| }, |
| |
| { |
| .name = "memory_migrate", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_MEMORY_MIGRATE, |
| }, |
| |
| { |
| .name = "memory_pressure", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_MEMORY_PRESSURE, |
| .mode = S_IRUGO, |
| }, |
| |
| { |
| .name = "memory_spread_page", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_SPREAD_PAGE, |
| }, |
| |
| { |
| .name = "memory_spread_slab", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_SPREAD_SLAB, |
| }, |
| }; |
| |
| static struct cftype cft_memory_pressure_enabled = { |
| .name = "memory_pressure_enabled", |
| .read_u64 = cpuset_read_u64, |
| .write_u64 = cpuset_write_u64, |
| .private = FILE_MEMORY_PRESSURE_ENABLED, |
| }; |
| |
| static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont) |
| { |
| int err; |
| |
| err = cgroup_add_files(cont, ss, files, ARRAY_SIZE(files)); |
| if (err) |
| return err; |
| /* memory_pressure_enabled is in root cpuset only */ |
| if (!cont->parent) |
| err = cgroup_add_file(cont, ss, |
| &cft_memory_pressure_enabled); |
| return err; |
| } |
| |
| /* |
| * post_clone() is called at the end of cgroup_clone(). |
| * 'cgroup' was just created automatically as a result of |
| * a cgroup_clone(), and the current task is about to |
| * be moved into 'cgroup'. |
| * |
| * Currently we refuse to set up the cgroup - thereby |
| * refusing the task to be entered, and as a result refusing |
| * the sys_unshare() or clone() which initiated it - if any |
| * sibling cpusets have exclusive cpus or mem. |
| * |
| * If this becomes a problem for some users who wish to |
| * allow that scenario, then cpuset_post_clone() could be |
| * changed to grant parent->cpus_allowed-sibling_cpus_exclusive |
| * (and likewise for mems) to the new cgroup. Called with cgroup_mutex |
| * held. |
| */ |
| static void cpuset_post_clone(struct cgroup_subsys *ss, |
| struct cgroup *cgroup) |
| { |
| struct cgroup *parent, *child; |
| struct cpuset *cs, *parent_cs; |
| |
| parent = cgroup->parent; |
| list_for_each_entry(child, &parent->children, sibling) { |
| cs = cgroup_cs(child); |
| if (is_mem_exclusive(cs) || is_cpu_exclusive(cs)) |
| return; |
| } |
| cs = cgroup_cs(cgroup); |
| parent_cs = cgroup_cs(parent); |
| |
| cs->mems_allowed = parent_cs->mems_allowed; |
| cpumask_copy(cs->cpus_allowed, parent_cs->cpus_allowed); |
| return; |
| } |
| |
| /* |
| * cpuset_create - create a cpuset |
| * ss: cpuset cgroup subsystem |
| * cont: control group that the new cpuset will be part of |
| */ |
| |
| static struct cgroup_subsys_state *cpuset_create( |
| struct cgroup_subsys *ss, |
| struct cgroup *cont) |
| { |
| struct cpuset *cs; |
| struct cpuset *parent; |
| |
| if (!cont->parent) { |
| return &top_cpuset.css; |
| } |
| parent = cgroup_cs(cont->parent); |
| cs = kmalloc(sizeof(*cs), GFP_KERNEL); |
| if (!cs) |
| return ERR_PTR(-ENOMEM); |
| if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL)) { |
| kfree(cs); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| cs->flags = 0; |
| if (is_spread_page(parent)) |
| set_bit(CS_SPREAD_PAGE, &cs->flags); |
| if (is_spread_slab(parent)) |
| set_bit(CS_SPREAD_SLAB, &cs->flags); |
| set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
| cpumask_clear(cs->cpus_allowed); |
| nodes_clear(cs->mems_allowed); |
| fmeter_init(&cs->fmeter); |
| cs->relax_domain_level = -1; |
| |
| cs->parent = parent; |
| number_of_cpusets++; |
| return &cs->css ; |
| } |
| |
| /* |
| * If the cpuset being removed has its flag 'sched_load_balance' |
| * enabled, then simulate turning sched_load_balance off, which |
| * will call async_rebuild_sched_domains(). |
| */ |
| |
| static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| |
| if (is_sched_load_balance(cs)) |
| update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); |
| |
| number_of_cpusets--; |
| free_cpumask_var(cs->cpus_allowed); |
| kfree(cs); |
| } |
| |
| struct cgroup_subsys cpuset_subsys = { |
| .name = "cpuset", |
| .create = cpuset_create, |
| .destroy = cpuset_destroy, |
| .can_attach = cpuset_can_attach, |
| .attach = cpuset_attach, |
| .populate = cpuset_populate, |
| .post_clone = cpuset_post_clone, |
| .subsys_id = cpuset_subsys_id, |
| .early_init = 1, |
| }; |
| |
| /** |
| * cpuset_init - initialize cpusets at system boot |
| * |
| * Description: Initialize top_cpuset and the cpuset internal file system, |
| **/ |
| |
| int __init cpuset_init(void) |
| { |
| int err = 0; |
| |
| if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)) |
| BUG(); |
| |
| cpumask_setall(top_cpuset.cpus_allowed); |
| nodes_setall(top_cpuset.mems_allowed); |
| |
| fmeter_init(&top_cpuset.fmeter); |
| set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); |
| top_cpuset.relax_domain_level = -1; |
| |
| err = register_filesystem(&cpuset_fs_type); |
| if (err < 0) |
| return err; |
| |
| if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)) |
| BUG(); |
| |
| number_of_cpusets = 1; |
| return 0; |
| } |
| |
| /** |
| * cpuset_do_move_task - move a given task to another cpuset |
| * @tsk: pointer to task_struct the task to move |
| * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner |
| * |
| * Called by cgroup_scan_tasks() for each task in a cgroup. |
| * Return nonzero to stop the walk through the tasks. |
| */ |
| static void cpuset_do_move_task(struct task_struct *tsk, |
| struct cgroup_scanner *scan) |
| { |
| struct cgroup *new_cgroup = scan->data; |
| |
| cgroup_attach_task(new_cgroup, tsk); |
| } |
| |
| /** |
| * move_member_tasks_to_cpuset - move tasks from one cpuset to another |
| * @from: cpuset in which the tasks currently reside |
| * @to: cpuset to which the tasks will be moved |
| * |
| * Called with cgroup_mutex held |
| * callback_mutex must not be held, as cpuset_attach() will take it. |
| * |
| * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, |
| * calling callback functions for each. |
| */ |
| static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to) |
| { |
| struct cgroup_scanner scan; |
| |
| scan.cg = from->css.cgroup; |
| scan.test_task = NULL; /* select all tasks in cgroup */ |
| scan.process_task = cpuset_do_move_task; |
| scan.heap = NULL; |
| scan.data = to->css.cgroup; |
| |
| if (cgroup_scan_tasks(&scan)) |
| printk(KERN_ERR "move_member_tasks_to_cpuset: " |
| "cgroup_scan_tasks failed\n"); |
| } |
| |
| /* |
| * If CPU and/or memory hotplug handlers, below, unplug any CPUs |
| * or memory nodes, we need to walk over the cpuset hierarchy, |
| * removing that CPU or node from all cpusets. If this removes the |
| * last CPU or node from a cpuset, then move the tasks in the empty |
| * cpuset to its next-highest non-empty parent. |
| * |
| * Called with cgroup_mutex held |
| * callback_mutex must not be held, as cpuset_attach() will take it. |
| */ |
| static void remove_tasks_in_empty_cpuset(struct cpuset *cs) |
| { |
| struct cpuset *parent; |
| |
| /* |
| * The cgroup's css_sets list is in use if there are tasks |
| * in the cpuset; the list is empty if there are none; |
| * the cs->css.refcnt seems always 0. |
| */ |
| if (list_empty(&cs->css.cgroup->css_sets)) |
| return; |
| |
| /* |
| * Find its next-highest non-empty parent, (top cpuset |
| * has online cpus, so can't be empty). |
| */ |
| parent = cs->parent; |
| while (cpumask_empty(parent->cpus_allowed) || |
| nodes_empty(parent->mems_allowed)) |
| parent = parent->parent; |
| |
| move_member_tasks_to_cpuset(cs, parent); |
| } |
| |
| /* |
| * Walk the specified cpuset subtree and look for empty cpusets. |
| * The tasks of such cpuset must be moved to a parent cpuset. |
| * |
| * Called with cgroup_mutex held. We take callback_mutex to modify |
| * cpus_allowed and mems_allowed. |
| * |
| * This walk processes the tree from top to bottom, completing one layer |
| * before dropping down to the next. It always processes a node before |
| * any of its children. |
| * |
| * For now, since we lack memory hot unplug, we'll never see a cpuset |
| * that has tasks along with an empty 'mems'. But if we did see such |
| * a cpuset, we'd handle it just like we do if its 'cpus' was empty. |
| */ |
| static void scan_for_empty_cpusets(struct cpuset *root) |
| { |
| LIST_HEAD(queue); |
| struct cpuset *cp; /* scans cpusets being updated */ |
| struct cpuset *child; /* scans child cpusets of cp */ |
| struct cgroup *cont; |
| NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL); |
| |
| if (oldmems == NULL) |
| return; |
| |
| list_add_tail((struct list_head *)&root->stack_list, &queue); |
| |
| while (!list_empty(&queue)) { |
| cp = list_first_entry(&queue, struct cpuset, stack_list); |
| list_del(queue.next); |
| list_for_each_entry(cont, &cp->css.cgroup->children, sibling) { |
| child = cgroup_cs(cont); |
| list_add_tail(&child->stack_list, &queue); |
| } |
| |
| /* Continue past cpusets with all cpus, mems online */ |
| if (cpumask_subset(cp->cpus_allowed, cpu_active_mask) && |
| nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY])) |
| continue; |
| |
| *oldmems = cp->mems_allowed; |
| |
| /* Remove offline cpus and mems from this cpuset. */ |
| mutex_lock(&callback_mutex); |
| cpumask_and(cp->cpus_allowed, cp->cpus_allowed, |
| cpu_active_mask); |
| nodes_and(cp->mems_allowed, cp->mems_allowed, |
| node_states[N_HIGH_MEMORY]); |
| mutex_unlock(&callback_mutex); |
| |
| /* Move tasks from the empty cpuset to a parent */ |
| if (cpumask_empty(cp->cpus_allowed) || |
| nodes_empty(cp->mems_allowed)) |
| remove_tasks_in_empty_cpuset(cp); |
| else { |
| update_tasks_cpumask(cp, NULL); |
| update_tasks_nodemask(cp, oldmems, NULL); |
| } |
| } |
| NODEMASK_FREE(oldmems); |
| } |
| |
| /* |
| * The top_cpuset tracks what CPUs and Memory Nodes are online, |
| * period. This is necessary in order to make cpusets transparent |
| * (of no affect) on systems that are actively using CPU hotplug |
| * but making no active use of cpusets. |
| * |
| * This routine ensures that top_cpuset.cpus_allowed tracks |
| * cpu_online_map on each CPU hotplug (cpuhp) event. |
| * |
| * Called within get_online_cpus(). Needs to call cgroup_lock() |
| * before calling generate_sched_domains(). |
| */ |
| static int cpuset_track_online_cpus(struct notifier_block *unused_nb, |
| unsigned long phase, void *unused_cpu) |
| { |
| struct sched_domain_attr *attr; |
| cpumask_var_t *doms; |
| int ndoms; |
| |
| switch (phase) { |
| case CPU_ONLINE: |
| case CPU_ONLINE_FROZEN: |
| case CPU_DOWN_PREPARE: |
| case CPU_DOWN_PREPARE_FROZEN: |
| case CPU_DOWN_FAILED: |
| case CPU_DOWN_FAILED_FROZEN: |
| break; |
| |
| default: |
| return NOTIFY_DONE; |
| } |
| |
| cgroup_lock(); |
| mutex_lock(&callback_mutex); |
| cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); |
| mutex_unlock(&callback_mutex); |
| scan_for_empty_cpusets(&top_cpuset); |
| ndoms = generate_sched_domains(&doms, &attr); |
| cgroup_unlock(); |
| |
| /* Have scheduler rebuild the domains */ |
| partition_sched_domains(ndoms, doms, attr); |
| |
| return NOTIFY_OK; |
| } |
| |
| #ifdef CONFIG_MEMORY_HOTPLUG |
| /* |
| * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY]. |
| * Call this routine anytime after node_states[N_HIGH_MEMORY] changes. |
| * See also the previous routine cpuset_track_online_cpus(). |
| */ |
| static int cpuset_track_online_nodes(struct notifier_block *self, |
| unsigned long action, void *arg) |
| { |
| NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL); |
| |
| if (oldmems == NULL) |
| return NOTIFY_DONE; |
| |
| cgroup_lock(); |
| switch (action) { |
| case MEM_ONLINE: |
| *oldmems = top_cpuset.mems_allowed; |
| mutex_lock(&callback_mutex); |
| top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; |
| mutex_unlock(&callback_mutex); |
| update_tasks_nodemask(&top_cpuset, oldmems, NULL); |
| break; |
| case MEM_OFFLINE: |
| /* |
| * needn't update top_cpuset.mems_allowed explicitly because |
| * scan_for_empty_cpusets() will update it. |
| */ |
| scan_for_empty_cpusets(&top_cpuset); |
| break; |
| default: |
| break; |
| } |
| cgroup_unlock(); |
| |
| NODEMASK_FREE(oldmems); |
| return NOTIFY_OK; |
| } |
| #endif |
| |
| /** |
| * cpuset_init_smp - initialize cpus_allowed |
| * |
| * Description: Finish top cpuset after cpu, node maps are initialized |
| **/ |
| |
| void __init cpuset_init_smp(void) |
| { |
| cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); |
| top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; |
| |
| hotcpu_notifier(cpuset_track_online_cpus, 0); |
| hotplug_memory_notifier(cpuset_track_online_nodes, 10); |
| |
| cpuset_wq = create_singlethread_workqueue("cpuset"); |
| BUG_ON(!cpuset_wq); |
| } |
| |
| /** |
| * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. |
| * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. |
| * @pmask: pointer to struct cpumask variable to receive cpus_allowed set. |
| * |
| * Description: Returns the cpumask_var_t cpus_allowed of the cpuset |
| * attached to the specified @tsk. Guaranteed to return some non-empty |
| * subset of cpu_online_map, even if this means going outside the |
| * tasks cpuset. |
| **/ |
| |
| void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) |
| { |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| guarantee_online_cpus(task_cs(tsk), pmask); |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| } |
| |
| int cpuset_cpus_allowed_fallback(struct task_struct *tsk) |
| { |
| const struct cpuset *cs; |
| int cpu; |
| |
| rcu_read_lock(); |
| cs = task_cs(tsk); |
| if (cs) |
| cpumask_copy(&tsk->cpus_allowed, cs->cpus_allowed); |
| rcu_read_unlock(); |
| |
| /* |
| * We own tsk->cpus_allowed, nobody can change it under us. |
| * |
| * But we used cs && cs->cpus_allowed lockless and thus can |
| * race with cgroup_attach_task() or update_cpumask() and get |
| * the wrong tsk->cpus_allowed. However, both cases imply the |
| * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr() |
| * which takes task_rq_lock(). |
| * |
| * If we are called after it dropped the lock we must see all |
| * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary |
| * set any mask even if it is not right from task_cs() pov, |
| * the pending set_cpus_allowed_ptr() will fix things. |
| */ |
| |
| cpu = cpumask_any_and(&tsk->cpus_allowed, cpu_active_mask); |
| if (cpu >= nr_cpu_ids) { |
| /* |
| * Either tsk->cpus_allowed is wrong (see above) or it |
| * is actually empty. The latter case is only possible |
| * if we are racing with remove_tasks_in_empty_cpuset(). |
| * Like above we can temporary set any mask and rely on |
| * set_cpus_allowed_ptr() as synchronization point. |
| */ |
| cpumask_copy(&tsk->cpus_allowed, cpu_possible_mask); |
| cpu = cpumask_any(cpu_active_mask); |
| } |
| |
| return cpu; |
| } |
| |
| void cpuset_init_current_mems_allowed(void) |
| { |
| nodes_setall(current->mems_allowed); |
| } |
| |
| /** |
| * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. |
| * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. |
| * |
| * Description: Returns the nodemask_t mems_allowed of the cpuset |
| * attached to the specified @tsk. Guaranteed to return some non-empty |
| * subset of node_states[N_HIGH_MEMORY], even if this means going outside the |
| * tasks cpuset. |
| **/ |
| |
| nodemask_t cpuset_mems_allowed(struct task_struct *tsk) |
| { |
| nodemask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| guarantee_online_mems(task_cs(tsk), &mask); |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| |
| return mask; |
| } |
| |
| /** |
| * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed |
| * @nodemask: the nodemask to be checked |
| * |
| * Are any of the nodes in the nodemask allowed in current->mems_allowed? |
| */ |
| int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) |
| { |
| return nodes_intersects(*nodemask, current->mems_allowed); |
| } |
| |
| /* |
| * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or |
| * mem_hardwall ancestor to the specified cpuset. Call holding |
| * callback_mutex. If no ancestor is mem_exclusive or mem_hardwall |
| * (an unusual configuration), then returns the root cpuset. |
| */ |
| static const struct cpuset *nearest_hardwall_ancestor(const struct cpuset *cs) |
| { |
| while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && cs->parent) |
| cs = cs->parent; |
| return cs; |
| } |
| |
| /** |
| * cpuset_node_allowed_softwall - Can we allocate on a memory node? |
| * @node: is this an allowed node? |
| * @gfp_mask: memory allocation flags |
| * |
| * If we're in interrupt, yes, we can always allocate. If __GFP_THISNODE is |
| * set, yes, we can always allocate. If node is in our task's mems_allowed, |
| * yes. If it's not a __GFP_HARDWALL request and this node is in the nearest |
| * hardwalled cpuset ancestor to this task's cpuset, yes. If the task has been |
| * OOM killed and has access to memory reserves as specified by the TIF_MEMDIE |
| * flag, yes. |
| * Otherwise, no. |
| * |
| * If __GFP_HARDWALL is set, cpuset_node_allowed_softwall() reduces to |
| * cpuset_node_allowed_hardwall(). Otherwise, cpuset_node_allowed_softwall() |
| * might sleep, and might allow a node from an enclosing cpuset. |
| * |
| * cpuset_node_allowed_hardwall() only handles the simpler case of hardwall |
| * cpusets, and never sleeps. |
| * |
| * The __GFP_THISNODE placement logic is really handled elsewhere, |
| * by forcibly using a zonelist starting at a specified node, and by |
| * (in get_page_from_freelist()) refusing to consider the zones for |
| * any node on the zonelist except the first. By the time any such |
| * calls get to this routine, we should just shut up and say 'yes'. |
| * |
| * GFP_USER allocations are marked with the __GFP_HARDWALL bit, |
| * and do not allow allocations outside the current tasks cpuset |
| * unless the task has been OOM killed as is marked TIF_MEMDIE. |
| * GFP_KERNEL allocations are not so marked, so can escape to the |
| * nearest enclosing hardwalled ancestor cpuset. |
| * |
| * Scanning up parent cpusets requires callback_mutex. The |
| * __alloc_pages() routine only calls here with __GFP_HARDWALL bit |
| * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the |
| * current tasks mems_allowed came up empty on the first pass over |
| * the zonelist. So only GFP_KERNEL allocations, if all nodes in the |
| * cpuset are short of memory, might require taking the callback_mutex |
| * mutex. |
| * |
| * The first call here from mm/page_alloc:get_page_from_freelist() |
| * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, |
| * so no allocation on a node outside the cpuset is allowed (unless |
| * in interrupt, of course). |
| * |
| * The second pass through get_page_from_freelist() doesn't even call |
| * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() |
| * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set |
| * in alloc_flags. That logic and the checks below have the combined |
| * affect that: |
| * in_interrupt - any node ok (current task context irrelevant) |
| * GFP_ATOMIC - any node ok |
| * TIF_MEMDIE - any node ok |
| * GFP_KERNEL - any node in enclosing hardwalled cpuset ok |
| * GFP_USER - only nodes in current tasks mems allowed ok. |
| * |
| * Rule: |
| * Don't call cpuset_node_allowed_softwall if you can't sleep, unless you |
| * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables |
| * the code that might scan up ancestor cpusets and sleep. |
| */ |
| int __cpuset_node_allowed_softwall(int node, gfp_t gfp_mask) |
| { |
| const struct cpuset *cs; /* current cpuset ancestors */ |
| int allowed; /* is allocation in zone z allowed? */ |
| |
| if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
| return 1; |
| might_sleep_if(!(gfp_mask & __GFP_HARDWALL)); |
| if (node_isset(node, current->mems_allowed)) |
| return 1; |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return 1; |
| if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ |
| return 0; |
| |
| if (current->flags & PF_EXITING) /* Let dying task have memory */ |
| return 1; |
| |
| /* Not hardwall and node outside mems_allowed: scan up cpusets */ |
| mutex_lock(&callback_mutex); |
| |
| task_lock(current); |
| cs = nearest_hardwall_ancestor(task_cs(current)); |
| task_unlock(current); |
| |
| allowed = node_isset(node, cs->mems_allowed); |
| mutex_unlock(&callback_mutex); |
| return allowed; |
| } |
| |
| /* |
| * cpuset_node_allowed_hardwall - Can we allocate on a memory node? |
| * @node: is this an allowed node? |
| * @gfp_mask: memory allocation flags |
| * |
| * If we're in interrupt, yes, we can always allocate. If __GFP_THISNODE is |
| * set, yes, we can always allocate. If node is in our task's mems_allowed, |
| * yes. If the task has been OOM killed and has access to memory reserves as |
| * specified by the TIF_MEMDIE flag, yes. |
| * Otherwise, no. |
| * |
| * The __GFP_THISNODE placement logic is really handled elsewhere, |
| * by forcibly using a zonelist starting at a specified node, and by |
| * (in get_page_from_freelist()) refusing to consider the zones for |
| * any node on the zonelist except the first. By the time any such |
| * calls get to this routine, we should just shut up and say 'yes'. |
| * |
| * Unlike the cpuset_node_allowed_softwall() variant, above, |
| * this variant requires that the node be in the current task's |
| * mems_allowed or that we're in interrupt. It does not scan up the |
| * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset. |
| * It never sleeps. |
| */ |
| int __cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask) |
| { |
| if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
| return 1; |
| if (node_isset(node, current->mems_allowed)) |
| return 1; |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return 1; |
| return 0; |
| } |
| |
| /** |
| * cpuset_unlock - release lock on cpuset changes |
| * |
| * Undo the lock taken in a previous cpuset_lock() call. |
| */ |
| |
| void cpuset_unlock(void) |
| { |
| mutex_unlock(&callback_mutex); |
| } |
| |
| /** |
| * cpuset_mem_spread_node() - On which node to begin search for a file page |
| * cpuset_slab_spread_node() - On which node to begin search for a slab page |
| * |
| * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for |
| * tasks in a cpuset with is_spread_page or is_spread_slab set), |
| * and if the memory allocation used cpuset_mem_spread_node() |
| * to determine on which node to start looking, as it will for |
| * certain page cache or slab cache pages such as used for file |
| * system buffers and inode caches, then instead of starting on the |
| * local node to look for a free page, rather spread the starting |
| * node around the tasks mems_allowed nodes. |
| * |
| * We don't have to worry about the returned node being offline |
| * because "it can't happen", and even if it did, it would be ok. |
| * |
| * The routines calling guarantee_online_mems() are careful to |
| * only set nodes in task->mems_allowed that are online. So it |
| * should not be possible for the following code to return an |
| * offline node. But if it did, that would be ok, as this routine |
| * is not returning the node where the allocation must be, only |
| * the node where the search should start. The zonelist passed to |
| * __alloc_pages() will include all nodes. If the slab allocator |
| * is passed an offline node, it will fall back to the local node. |
| * See kmem_cache_alloc_node(). |
| */ |
| |
| static int cpuset_spread_node(int *rotor) |
| { |
| int node; |
| |
| node = next_node(*rotor, current->mems_allowed); |
| if (node == MAX_NUMNODES) |
| node = first_node(current->mems_allowed); |
| *rotor = node; |
| return node; |
| } |
| |
| int cpuset_mem_spread_node(void) |
| { |
| return cpuset_spread_node(¤t->cpuset_mem_spread_rotor); |
| } |
| |
| int cpuset_slab_spread_node(void) |
| { |
| return cpuset_spread_node(¤t->cpuset_slab_spread_rotor); |
| } |
| |
| EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); |
| |
| /** |
| * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? |
| * @tsk1: pointer to task_struct of some task. |
| * @tsk2: pointer to task_struct of some other task. |
| * |
| * Description: Return true if @tsk1's mems_allowed intersects the |
| * mems_allowed of @tsk2. Used by the OOM killer to determine if |
| * one of the task's memory usage might impact the memory available |
| * to the other. |
| **/ |
| |
| int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, |
| const struct task_struct *tsk2) |
| { |
| return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); |
| } |
| |
| /** |
| * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed |
| * @task: pointer to task_struct of some task. |
| * |
| * Description: Prints @task's name, cpuset name, and cached copy of its |
| * mems_allowed to the kernel log. Must hold task_lock(task) to allow |
| * dereferencing task_cs(task). |
| */ |
| void cpuset_print_task_mems_allowed(struct task_struct *tsk) |
| { |
| struct dentry *dentry; |
| |
| dentry = task_cs(tsk)->css.cgroup->dentry; |
| spin_lock(&cpuset_buffer_lock); |
| snprintf(cpuset_name, CPUSET_NAME_LEN, |
| dentry ? (const char *)dentry->d_name.name : "/"); |
| nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN, |
| tsk->mems_allowed); |
| printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n", |
| tsk->comm, cpuset_name, cpuset_nodelist); |
| spin_unlock(&cpuset_buffer_lock); |
| } |
| |
| /* |
| * Collection of memory_pressure is suppressed unless |
| * this flag is enabled by writing "1" to the special |
| * cpuset file 'memory_pressure_enabled' in the root cpuset. |
| */ |
| |
| int cpuset_memory_pressure_enabled __read_mostly; |
| |
| /** |
| * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. |
| * |
| * Keep a running average of the rate of synchronous (direct) |
| * page reclaim efforts initiated by tasks in each cpuset. |
| * |
| * This represents the rate at which some task in the cpuset |
| * ran low on memory on all nodes it was allowed to use, and |
| * had to enter the kernels page reclaim code in an effort to |
| * create more free memory by tossing clean pages or swapping |
| * or writing dirty pages. |
| * |
| * Display to user space in the per-cpuset read-only file |
| * "memory_pressure". Value displayed is an integer |
| * representing the recent rate of entry into the synchronous |
| * (direct) page reclaim by any task attached to the cpuset. |
| **/ |
| |
| void __cpuset_memory_pressure_bump(void) |
| { |
| task_lock(current); |
| fmeter_markevent(&task_cs(current)->fmeter); |
| task_unlock(current); |
| } |
| |
| #ifdef CONFIG_PROC_PID_CPUSET |
| /* |
| * proc_cpuset_show() |
| * - Print tasks cpuset path into seq_file. |
| * - Used for /proc/<pid>/cpuset. |
| * - No need to task_lock(tsk) on this tsk->cpuset reference, as it |
| * doesn't really matter if tsk->cpuset changes after we read it, |
| * and we take cgroup_mutex, keeping cpuset_attach() from changing it |
| * anyway. |
| */ |
| static int proc_cpuset_show(struct seq_file *m, void *unused_v) |
| { |
| struct pid *pid; |
| struct task_struct *tsk; |
| char *buf; |
| struct cgroup_subsys_state *css; |
| int retval; |
| |
| retval = -ENOMEM; |
| buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| if (!buf) |
| goto out; |
| |
| retval = -ESRCH; |
| pid = m->private; |
| tsk = get_pid_task(pid, PIDTYPE_PID); |
| if (!tsk) |
| goto out_free; |
| |
| retval = -EINVAL; |
| cgroup_lock(); |
| css = task_subsys_state(tsk, cpuset_subsys_id); |
| retval = cgroup_path(css->cgroup, buf, PAGE_SIZE); |
| if (retval < 0) |
| goto out_unlock; |
| seq_puts(m, buf); |
| seq_putc(m, '\n'); |
| out_unlock: |
| cgroup_unlock(); |
| put_task_struct(tsk); |
| out_free: |
| kfree(buf); |
| out: |
| return retval; |
| } |
| |
| static int cpuset_open(struct inode *inode, struct file *file) |
| { |
| struct pid *pid = PROC_I(inode)->pid; |
| return single_open(file, proc_cpuset_show, pid); |
| } |
| |
| const struct file_operations proc_cpuset_operations = { |
| .open = cpuset_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = single_release, |
| }; |
| #endif /* CONFIG_PROC_PID_CPUSET */ |
| |
| /* Display task mems_allowed in /proc/<pid>/status file. */ |
| void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task) |
| { |
| seq_printf(m, "Mems_allowed:\t"); |
| seq_nodemask(m, &task->mems_allowed); |
| seq_printf(m, "\n"); |
| seq_printf(m, "Mems_allowed_list:\t"); |
| seq_nodemask_list(m, &task->mems_allowed); |
| seq_printf(m, "\n"); |
| } |