diff options
Diffstat (limited to 'include/linux/backing-dev.h')
| -rw-r--r-- | include/linux/backing-dev.h | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h new file mode 100644 index 00000000..b1038bd6 --- /dev/null +++ b/include/linux/backing-dev.h @@ -0,0 +1,356 @@ +/* + * 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 <linux/sched.h> +#include <linux/timer.h> +#include <linux/writeback.h> +#include <linux/atomic.h> + +struct page; +struct device; +struct dentry; + +/* + * Bits in backing_dev_info.state + */ +enum bdi_state { + BDI_pending, /* On its way to being activated */ + BDI_wb_alloc, /* Default embedded wb allocated */ + BDI_async_congested, /* The async (write) queue is getting full */ + BDI_sync_congested, /* The sync queue is getting full */ + BDI_registered, /* bdi_register() was done */ + BDI_writeback_running, /* Writeback is in progress */ + BDI_unused, /* Available bits start here */ +}; + +typedef int (congested_fn)(void *, int); + +enum bdi_stat_item { + BDI_RECLAIMABLE, + BDI_WRITEBACK, + BDI_DIRTIED, + BDI_WRITTEN, + NR_BDI_STAT_ITEMS +}; + +#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) + +struct bdi_writeback { + struct backing_dev_info *bdi; /* our parent bdi */ + unsigned int nr; + + unsigned long last_old_flush; /* last old data flush */ + unsigned long last_active; /* last time bdi thread was active */ + + struct task_struct *task; /* writeback thread */ + struct timer_list wakeup_timer; /* used for delayed bdi thread wakeup */ + 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 */ + spinlock_t list_lock; /* protects the b_* lists */ +}; + +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 */ + + char *name; + + struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; + + unsigned long bw_time_stamp; /* last time write bw is updated */ + unsigned long dirtied_stamp; + unsigned long written_stamp; /* pages written at bw_time_stamp */ + unsigned long write_bandwidth; /* the estimated write bandwidth */ + unsigned long avg_write_bandwidth; /* further smoothed write bw */ + + /* + * The base dirty throttle rate, re-calculated on every 200ms. + * All the bdi tasks' dirty rate will be curbed under it. + * @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit + * in small steps and is much more smooth/stable than the latter. + */ + unsigned long dirty_ratelimit; + unsigned long balanced_dirty_ratelimit; + + struct prop_local_percpu completions; + int dirty_exceeded; + + unsigned int min_ratio; + unsigned int max_ratio, max_prop_frac; + + struct bdi_writeback wb; /* default writeback info for this bdi */ + spinlock_t wb_lock; /* protects work_list */ + + struct list_head work_list; + + struct device *dev; + + struct timer_list laptop_mode_wb_timer; + +#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); +int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int); +void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, + enum wb_reason reason); +void bdi_start_background_writeback(struct backing_dev_info *bdi); +int bdi_writeback_thread(void *data); +int bdi_has_dirty_io(struct backing_dev_info *bdi); +void bdi_arm_supers_timer(void); +void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi); +void bdi_lock_two(struct bdi_writeback *wb1, struct bdi_writeback *wb2); + +extern spinlock_t bdi_lock; +extern struct list_head bdi_list; +extern struct list_head bdi_pending_list; + +static inline int wb_has_dirty_io(struct bdi_writeback *wb) +{ + return !list_empty(&wb->b_dirty) || + !list_empty(&wb->b_io) || + !list_empty(&wb->b_more_io); +} + +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; +extern struct backing_dev_info noop_backing_dev_info; + +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); +long wait_iff_congested(struct zone *zone, 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 bdi_cap_flush_forker(struct backing_dev_info *bdi) +{ + return bdi == &default_backing_dev_info; +} + +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); +} + +static inline int bdi_sched_wait(void *word) +{ + schedule(); + return 0; +} + +#endif /* _LINUX_BACKING_DEV_H */ |