| /* |
| * include/linux/backing-dev.h |
| * |
| * low-level device information and state which is propagated up through |
| * to high-level code. |
| */ |
| |
| #ifndef _LINUX_BACKING_DEV_H |
| #define _LINUX_BACKING_DEV_H |
| |
| #include <linux/percpu_counter.h> |
| #include <linux/log2.h> |
| #include <linux/proportions.h> |
| #include <linux/kernel.h> |
| #include <linux/fs.h> |
| #include <asm/atomic.h> |
| |
| struct page; |
| struct device; |
| struct dentry; |
| |
| /* |
| * Bits in backing_dev_info.state |
| */ |
| enum bdi_state { |
| BDI_pdflush, /* A pdflush thread is working this device */ |
| BDI_async_congested, /* The async (write) queue is getting full */ |
| BDI_sync_congested, /* The sync queue is getting full */ |
| BDI_unused, /* Available bits start here */ |
| }; |
| |
| typedef int (congested_fn)(void *, int); |
| |
| enum bdi_stat_item { |
| BDI_RECLAIMABLE, |
| BDI_WRITEBACK, |
| NR_BDI_STAT_ITEMS |
| }; |
| |
| #define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) |
| |
| struct backing_dev_info { |
| struct list_head bdi_list; |
| |
| unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ |
| unsigned long state; /* Always use atomic bitops on this */ |
| unsigned int capabilities; /* Device capabilities */ |
| congested_fn *congested_fn; /* Function pointer if device is md/dm */ |
| void *congested_data; /* Pointer to aux data for congested func */ |
| void (*unplug_io_fn)(struct backing_dev_info *, struct page *); |
| void *unplug_io_data; |
| |
| struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; |
| |
| struct prop_local_percpu completions; |
| int dirty_exceeded; |
| |
| unsigned int min_ratio; |
| unsigned int max_ratio, max_prop_frac; |
| |
| struct device *dev; |
| |
| struct list_head b_dirty; /* dirty inodes */ |
| struct list_head b_io; /* parked for writeback */ |
| struct list_head b_more_io; /* parked for more writeback */ |
| |
| #ifdef CONFIG_DEBUG_FS |
| struct dentry *debug_dir; |
| struct dentry *debug_stats; |
| #endif |
| }; |
| |
| int bdi_init(struct backing_dev_info *bdi); |
| void bdi_destroy(struct backing_dev_info *bdi); |
| |
| int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| const char *fmt, ...); |
| int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); |
| void bdi_unregister(struct backing_dev_info *bdi); |
| |
| extern struct mutex bdi_lock; |
| extern struct list_head bdi_list; |
| |
| static inline void __add_bdi_stat(struct backing_dev_info *bdi, |
| enum bdi_stat_item item, s64 amount) |
| { |
| __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); |
| } |
| |
| static inline void __inc_bdi_stat(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| __add_bdi_stat(bdi, item, 1); |
| } |
| |
| static inline void inc_bdi_stat(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| __inc_bdi_stat(bdi, item); |
| local_irq_restore(flags); |
| } |
| |
| static inline void __dec_bdi_stat(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| __add_bdi_stat(bdi, item, -1); |
| } |
| |
| static inline void dec_bdi_stat(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| __dec_bdi_stat(bdi, item); |
| local_irq_restore(flags); |
| } |
| |
| static inline s64 bdi_stat(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| return percpu_counter_read_positive(&bdi->bdi_stat[item]); |
| } |
| |
| static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| return percpu_counter_sum_positive(&bdi->bdi_stat[item]); |
| } |
| |
| static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, |
| enum bdi_stat_item item) |
| { |
| s64 sum; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| sum = __bdi_stat_sum(bdi, item); |
| local_irq_restore(flags); |
| |
| return sum; |
| } |
| |
| extern void bdi_writeout_inc(struct backing_dev_info *bdi); |
| |
| /* |
| * maximal error of a stat counter. |
| */ |
| static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) |
| { |
| #ifdef CONFIG_SMP |
| return nr_cpu_ids * BDI_STAT_BATCH; |
| #else |
| return 1; |
| #endif |
| } |
| |
| int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
| int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
| |
| /* |
| * Flags in backing_dev_info::capability |
| * |
| * The first three flags control whether dirty pages will contribute to the |
| * VM's accounting and whether writepages() should be called for dirty pages |
| * (something that would not, for example, be appropriate for ramfs) |
| * |
| * WARNING: these flags are closely related and should not normally be |
| * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these |
| * three flags into a single convenience macro. |
| * |
| * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting |
| * BDI_CAP_NO_WRITEBACK: Don't write pages back |
| * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages |
| * |
| * These flags let !MMU mmap() govern direct device mapping vs immediate |
| * copying more easily for MAP_PRIVATE, especially for ROM filesystems. |
| * |
| * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE) |
| * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED) |
| * BDI_CAP_READ_MAP: Can be mapped for reading |
| * BDI_CAP_WRITE_MAP: Can be mapped for writing |
| * BDI_CAP_EXEC_MAP: Can be mapped for execution |
| * |
| * BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed. |
| */ |
| #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
| #define BDI_CAP_NO_WRITEBACK 0x00000002 |
| #define BDI_CAP_MAP_COPY 0x00000004 |
| #define BDI_CAP_MAP_DIRECT 0x00000008 |
| #define BDI_CAP_READ_MAP 0x00000010 |
| #define BDI_CAP_WRITE_MAP 0x00000020 |
| #define BDI_CAP_EXEC_MAP 0x00000040 |
| #define BDI_CAP_NO_ACCT_WB 0x00000080 |
| #define BDI_CAP_SWAP_BACKED 0x00000100 |
| |
| #define BDI_CAP_VMFLAGS \ |
| (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) |
| |
| #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
| (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) |
| |
| #if defined(VM_MAYREAD) && \ |
| (BDI_CAP_READ_MAP != VM_MAYREAD || \ |
| BDI_CAP_WRITE_MAP != VM_MAYWRITE || \ |
| BDI_CAP_EXEC_MAP != VM_MAYEXEC) |
| #error please change backing_dev_info::capabilities flags |
| #endif |
| |
| extern struct backing_dev_info default_backing_dev_info; |
| void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page); |
| |
| int writeback_in_progress(struct backing_dev_info *bdi); |
| |
| static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) |
| { |
| if (bdi->congested_fn) |
| return bdi->congested_fn(bdi->congested_data, bdi_bits); |
| return (bdi->state & bdi_bits); |
| } |
| |
| static inline int bdi_read_congested(struct backing_dev_info *bdi) |
| { |
| return bdi_congested(bdi, 1 << BDI_sync_congested); |
| } |
| |
| static inline int bdi_write_congested(struct backing_dev_info *bdi) |
| { |
| return bdi_congested(bdi, 1 << BDI_async_congested); |
| } |
| |
| static inline int bdi_rw_congested(struct backing_dev_info *bdi) |
| { |
| return bdi_congested(bdi, (1 << BDI_sync_congested) | |
| (1 << BDI_async_congested)); |
| } |
| |
| enum { |
| BLK_RW_ASYNC = 0, |
| BLK_RW_SYNC = 1, |
| }; |
| |
| void clear_bdi_congested(struct backing_dev_info *bdi, int sync); |
| void set_bdi_congested(struct backing_dev_info *bdi, int sync); |
| long congestion_wait(int sync, long timeout); |
| |
| |
| static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
| { |
| return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); |
| } |
| |
| static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) |
| { |
| return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); |
| } |
| |
| static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
| { |
| /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ |
| return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | |
| BDI_CAP_NO_WRITEBACK)); |
| } |
| |
| static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi) |
| { |
| return bdi->capabilities & BDI_CAP_SWAP_BACKED; |
| } |
| |
| static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
| { |
| return bdi_cap_writeback_dirty(mapping->backing_dev_info); |
| } |
| |
| static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
| { |
| return bdi_cap_account_dirty(mapping->backing_dev_info); |
| } |
| |
| static inline bool mapping_cap_swap_backed(struct address_space *mapping) |
| { |
| return bdi_cap_swap_backed(mapping->backing_dev_info); |
| } |
| |
| #endif /* _LINUX_BACKING_DEV_H */ |