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Release 4.12 include/linux/writeback.h

Directory: include/linux
 * include/linux/writeback.h


#include <linux/sched.h>
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/flex_proportions.h>
#include <linux/backing-dev-defs.h>
#include <linux/blk_types.h>

struct bio;

DECLARE_PER_CPU(int, dirty_throttle_leaks);

 * The 1/4 region under the global dirty thresh is for smooth dirty throttling:
 *      (thresh - thresh/DIRTY_FULL_SCOPE, thresh)
 * Further beyond, all dirtier tasks will enter a loop waiting (possibly long
 * time) for the dirty pages to drop, unless written enough pages.
 * The global dirty threshold is normally equal to the global dirty limit,
 * except when the system suddenly allocates a lot of anonymous memory and
 * knocks down the global dirty threshold quickly, in which case the global
 * dirty limit will follow down slowly to prevent livelocking all dirtier tasks.

#define DIRTY_SCOPE		8


struct backing_dev_info;

 * fs/fs-writeback.c

enum writeback_sync_modes {
WB_SYNC_NONE,	/* Don't wait on anything */
WB_SYNC_ALL,	/* Wait on every mapping */

 * why some writeback work was initiated

enum wb_reason {
         * There is no bdi forker thread any more and works are done
         * by emergency worker, however, this is TPs userland visible
         * and we'll be exposing exactly the same information,
         * so it has a mismatch name.


 * A control structure which tells the writeback code what to do.  These are
 * always on the stack, and hence need no locking.  They are always initialised
 * in a manner such that unspecified fields are set to zero.

struct writeback_control {
long nr_to_write;		/* Write this many pages, and decrement
                                           this for each page written */
long pages_skipped;		/* Pages which were not written */

         * For a_ops->writepages(): if start or end are non-zero then this is
         * a hint that the filesystem need only write out the pages inside that
         * byterange.  The byte at `end' is included in the writeout request.
loff_t range_start;
loff_t range_end;

enum writeback_sync_modes sync_mode;

unsigned for_kupdate:1;		/* A kupdate writeback */
unsigned for_background:1;	/* A background writeback */
unsigned tagged_writepages:1;	/* tag-and-write to avoid livelock */
unsigned for_reclaim:1;		/* Invoked from the page allocator */
unsigned range_cyclic:1;	/* range_start is cyclic */
unsigned for_sync:1;		/* sync(2) WB_SYNC_ALL writeback */
struct bdi_writeback *wb;	/* wb this writeback is issued under */
struct inode *inode;		/* inode being written out */

	/* foreign inode detection, see wbc_detach_inode() */
int wb_id;			/* current wb id */
int wb_lcand_id;		/* last foreign candidate wb id */
int wb_tcand_id;		/* this foreign candidate wb id */
size_t wb_bytes;		/* bytes written by current wb */
size_t wb_lcand_bytes;		/* bytes written by last candidate */
size_t wb_tcand_bytes;		/* bytes written by this candidate */

static inline int wbc_to_write_flags(struct writeback_control *wbc) { if (wbc->sync_mode == WB_SYNC_ALL) return REQ_SYNC; else if (wbc->for_kupdate || wbc->for_background) return REQ_BACKGROUND; return 0; }


Jens Axboe40100.00%2100.00%

/* * A wb_domain represents a domain that wb's (bdi_writeback's) belong to * and are measured against each other in. There always is one global * domain, global_wb_domain, that every wb in the system is a member of. * This allows measuring the relative bandwidth of each wb to distribute * dirtyable memory accordingly. */ struct wb_domain { spinlock_t lock; /* * Scale the writeback cache size proportional to the relative * writeout speed. * * We do this by keeping a floating proportion between BDIs, based * on page writeback completions [end_page_writeback()]. Those * devices that write out pages fastest will get the larger share, * while the slower will get a smaller share. * * We use page writeout completions because we are interested in * getting rid of dirty pages. Having them written out is the * primary goal. * * We introduce a concept of time, a period over which we measure * these events, because demand can/will vary over time. The length * of this period itself is measured in page writeback completions. */ struct fprop_global completions; struct timer_list period_timer; /* timer for aging of completions */ unsigned long period_time; /* * The dirtyable memory and dirty threshold could be suddenly * knocked down by a large amount (eg. on the startup of KVM in a * swapless system). This may throw the system into deep dirty * exceeded state and throttle heavy/light dirtiers alike. To * retain good responsiveness, maintain global_dirty_limit for * tracking slowly down to the knocked down dirty threshold. * * Both fields are protected by ->lock. */ unsigned long dirty_limit_tstamp; unsigned long dirty_limit; }; /** * wb_domain_size_changed - memory available to a wb_domain has changed * @dom: wb_domain of interest * * This function should be called when the amount of memory available to * @dom has changed. It resets @dom's dirty limit parameters to prevent * the past values which don't match the current configuration from skewing * dirty throttling. Without this, when memory size of a wb_domain is * greatly reduced, the dirty throttling logic may allow too many pages to * be dirtied leading to consecutive unnecessary OOMs and may get stuck in * that situation. */
static inline void wb_domain_size_changed(struct wb_domain *dom) { spin_lock(&dom->lock); dom->dirty_limit_tstamp = jiffies; dom->dirty_limit = 0; spin_unlock(&dom->lock); }


Tejun Heo40100.00%1100.00%

/* * fs/fs-writeback.c */ struct bdi_writeback; void writeback_inodes_sb(struct super_block *, enum wb_reason reason); void writeback_inodes_sb_nr(struct super_block *, unsigned long nr, enum wb_reason reason); bool try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason); bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr, enum wb_reason reason); void sync_inodes_sb(struct super_block *); void wakeup_flusher_threads(long nr_pages, enum wb_reason reason); void inode_wait_for_writeback(struct inode *inode); /* writeback.h requires fs.h; it, too, is not included from here. */
static inline void wait_on_inode(struct inode *inode) { might_sleep(); wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE); }


Jörn Engel2592.59%150.00%
Jan Kara27.41%150.00%

#ifdef CONFIG_CGROUP_WRITEBACK #include <linux/cgroup.h> #include <linux/bio.h> void __inode_attach_wb(struct inode *inode, struct page *page); void wbc_attach_and_unlock_inode(struct writeback_control *wbc, struct inode *inode) __releases(&inode->i_lock); void wbc_detach_inode(struct writeback_control *wbc); void wbc_account_io(struct writeback_control *wbc, struct page *page, size_t bytes); void cgroup_writeback_umount(void); /** * inode_attach_wb - associate an inode with its wb * @inode: inode of interest * @page: page being dirtied (may be NULL) * * If @inode doesn't have its wb, associate it with the wb matching the * memcg of @page or, if @page is NULL, %current. May be called w/ or w/o * @inode->i_lock. */
static inline void inode_attach_wb(struct inode *inode, struct page *page) { if (!inode->i_wb) __inode_attach_wb(inode, page); }


Tejun Heo31100.00%1100.00%

/** * inode_detach_wb - disassociate an inode from its wb * @inode: inode of interest * * @inode is being freed. Detach from its wb. */
static inline void inode_detach_wb(struct inode *inode) { if (inode->i_wb) { WARN_ON_ONCE(!(inode->i_state & I_CLEAR)); wb_put(inode->i_wb); inode->i_wb = NULL; } }


Tejun Heo3373.33%150.00%
Jan Kara1226.67%150.00%

/** * wbc_attach_fdatawrite_inode - associate wbc and inode for fdatawrite * @wbc: writeback_control of interest * @inode: target inode * * This function is to be used by __filemap_fdatawrite_range(), which is an * alternative entry point into writeback code, and first ensures @inode is * associated with a bdi_writeback and attaches it to @wbc. */
static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc, struct inode *inode) { spin_lock(&inode->i_lock); inode_attach_wb(inode, NULL); wbc_attach_and_unlock_inode(wbc, inode); }


Tejun Heo39100.00%1100.00%

/** * wbc_init_bio - writeback specific initializtion of bio * @wbc: writeback_control for the writeback in progress * @bio: bio to be initialized * * @bio is a part of the writeback in progress controlled by @wbc. Perform * writeback specific initialization. This is used to apply the cgroup * writeback context. */
static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio) { /* * pageout() path doesn't attach @wbc to the inode being written * out. This is intentional as we don't want the function to block * behind a slow cgroup. Ultimately, we want pageout() to kick off * regular writeback instead of writing things out itself. */ if (wbc->wb) bio_associate_blkcg(bio, wbc->wb->blkcg_css); }


Tejun Heo35100.00%1100.00%

static inline void inode_attach_wb(struct inode *inode, struct page *page) { }


Tejun Heo16100.00%1100.00%

static inline void inode_detach_wb(struct inode *inode) { }


Tejun Heo11100.00%1100.00%

static inline void wbc_attach_and_unlock_inode(struct writeback_control *wbc, struct inode *inode) __releases(&inode->i_lock


Tejun Heo18100.00%1100.00%

) { spin_unlock(&inode->i_lock); }
static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc, struct inode *inode) { }


Tejun Heo16100.00%1100.00%

static inline void wbc_detach_inode(struct writeback_control *wbc) { }


Tejun Heo11100.00%1100.00%

static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio) { }


Tejun Heo16100.00%1100.00%

static inline void wbc_account_io(struct writeback_control *wbc, struct page *page, size_t bytes) { }


Tejun Heo19100.00%1100.00%

static inline void cgroup_writeback_umount(void) { }


Tejun Heo8100.00%1100.00%

#endif /* CONFIG_CGROUP_WRITEBACK */ /* * mm/page-writeback.c */ #ifdef CONFIG_BLOCK void laptop_io_completion(struct backing_dev_info *info); void laptop_sync_completion(void); void laptop_mode_sync(struct work_struct *work); void laptop_mode_timer_fn(unsigned long data); #else
static inline void laptop_sync_completion(void) { }


Jens Axboe8100.00%1100.00%

#endif bool node_dirty_ok(struct pglist_data *pgdat); int wb_domain_init(struct wb_domain *dom, gfp_t gfp); #ifdef CONFIG_CGROUP_WRITEBACK void wb_domain_exit(struct wb_domain *dom); #endif extern struct wb_domain global_wb_domain; /* These are exported to sysctl. */ extern int dirty_background_ratio; extern unsigned long dirty_background_bytes; extern int vm_dirty_ratio; extern unsigned long vm_dirty_bytes; extern unsigned int dirty_writeback_interval; extern unsigned int dirty_expire_interval; extern unsigned int dirtytime_expire_interval; extern int vm_highmem_is_dirtyable; extern int block_dump; extern int laptop_mode; extern int dirty_background_ratio_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); extern int dirty_background_bytes_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); extern int dirty_ratio_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); extern int dirty_bytes_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); int dirtytime_interval_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); struct ctl_table; int dirty_writeback_centisecs_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh); void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time); void balance_dirty_pages_ratelimited(struct address_space *mapping); bool wb_over_bg_thresh(struct bdi_writeback *wb); typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc, void *data); int generic_writepages(struct address_space *mapping, struct writeback_control *wbc); void tag_pages_for_writeback(struct address_space *mapping, pgoff_t start, pgoff_t end); int write_cache_pages(struct address_space *mapping, struct writeback_control *wbc, writepage_t writepage, void *data); int do_writepages(struct address_space *mapping, struct writeback_control *wbc); void writeback_set_ratelimit(void); void tag_pages_for_writeback(struct address_space *mapping, pgoff_t start, pgoff_t end); void account_page_redirty(struct page *page); void sb_mark_inode_writeback(struct inode *inode); void sb_clear_inode_writeback(struct inode *inode); #endif /* WRITEBACK_H */

Overall Contributors

Tejun Heo51541.00%1315.29%
Andrew Morton14311.39%1720.00%
David Rientjes917.25%22.35%
Jens Axboe806.37%78.24%
Fengguang Wu564.46%910.59%
Miklos Szeredi433.42%11.18%
Curt Wohlgemuth423.34%11.18%
Peter Zijlstra413.26%33.53%
Theodore Y. Ts'o302.39%11.18%
Jörn Engel251.99%11.18%
Dave Chinner241.91%22.35%
Chris Mason221.75%11.18%
Eric Sandeen211.67%22.35%
Matthew Garrett201.59%11.18%
Jan Kara171.35%22.35%
Namhyung Kim151.19%11.18%
David Howells131.04%11.18%
Hirofumi Ogawa80.64%11.18%
Johannes Weiner70.56%22.35%
Linus Torvalds50.40%22.35%
Alexey Dobriyan50.40%22.35%
Chandra Seetharaman50.40%11.18%
Bron Gondwana40.32%11.18%
Richard Kennedy40.32%11.18%
Marcelo Tosatti30.24%11.18%
Kent Overstreet30.24%11.18%
Christoph Hellwig30.24%11.18%
Mel Gorman30.24%11.18%
Miao Xie20.16%11.18%
Bart Samwel20.16%11.18%
Namjae Jeon10.08%11.18%
Andries E. Brouwer10.08%11.18%
Uwe Zeisberger10.08%11.18%
Wanpeng Li10.08%11.18%
Directory: include/linux
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