Commit 0e175a18 authored by Curt Wohlgemuth's avatar Curt Wohlgemuth Committed by Wu Fengguang
Browse files

writeback: Add a 'reason' to wb_writeback_work 



This creates a new 'reason' field in a wb_writeback_work
structure, which unambiguously identifies who initiates
writeback activity.  A 'wb_reason' enumeration has been
added to writeback.h, to enumerate the possible reasons.

The 'writeback_work_class' and tracepoint event class and
'writeback_queue_io' tracepoints are updated to include the
symbolic 'reason' in all trace events.

And the 'writeback_inodes_sbXXX' family of routines has had
a wb_stats parameter added to them, so callers can specify
why writeback is being started.

Acked-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarCurt Wohlgemuth <curtw@google.com>
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
parent ad4e38dd

fs/btrfs/extent-tree.c

+2 −1
Original line number Diff line number Diff line
@@ -3340,7 +3340,8 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans, 
		smp_mb();

		nr_pages = min_t(unsigned long, nr_pages,

		       root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);

		writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);

		writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,

						WB_REASON_FS_FREE_SPACE);



		spin_lock(&space_info->lock);

		if (reserved > space_info->bytes_reserved)

fs/buffer.c

+1 −1
Original line number Diff line number Diff line
@@ -285,7 +285,7 @@ static void free_more_memory(void) 
	struct zone *zone;

	int nid;



	wakeup_flusher_threads(1024);

	wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM);

	yield();



	for_each_online_node(nid) {

fs/ext4/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -2241,7 +2241,7 @@ static int ext4_nonda_switch(struct super_block *sb) 
	 * start pushing delalloc when 1/2 of free blocks are dirty.

	 */

	if (free_blocks < 2 * dirty_blocks)

		writeback_inodes_sb_if_idle(sb);

		writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE);



	return 0;

}

fs/fs-writeback.c

+36 −13
Original line number Diff line number Diff line
@@ -41,11 +41,23 @@ struct wb_writeback_work { 
	unsigned int for_kupdate:1;

	unsigned int range_cyclic:1;

	unsigned int for_background:1;

	enum wb_reason reason;		/* why was writeback initiated? */



	struct list_head list;		/* pending work list */

	struct completion *done;	/* set if the caller waits */

};



const char *wb_reason_name[] = {

	[WB_REASON_BACKGROUND]		= "background",

	[WB_REASON_TRY_TO_FREE_PAGES]	= "try_to_free_pages",

	[WB_REASON_SYNC]		= "sync",

	[WB_REASON_PERIODIC]		= "periodic",

	[WB_REASON_LAPTOP_TIMER]	= "laptop_timer",

	[WB_REASON_FREE_MORE_MEM]	= "free_more_memory",

	[WB_REASON_FS_FREE_SPACE]	= "fs_free_space",

	[WB_REASON_FORKER_THREAD]	= "forker_thread"

};



/*

 * Include the creation of the trace points after defining the

 * wb_writeback_work structure so that the definition remains local to this
@@ -115,7 +127,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi, 


static void

__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,

		      bool range_cyclic)

		      bool range_cyclic, enum wb_reason reason)

{

	struct wb_writeback_work *work;
@@ -135,6 +147,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, 
	work->sync_mode	= WB_SYNC_NONE;

	work->nr_pages	= nr_pages;

	work->range_cyclic = range_cyclic;

	work->reason	= reason;



	bdi_queue_work(bdi, work);

}
@@ -150,9 +163,10 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, 
 *   completion. Caller need not hold sb s_umount semaphore.

 *

 */

void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)

void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,

			enum wb_reason reason)

{

	__bdi_start_writeback(bdi, nr_pages, true);

	__bdi_start_writeback(bdi, nr_pages, true, reason);

}



/**
@@ -641,12 +655,14 @@ static long __writeback_inodes_wb(struct bdi_writeback *wb, 
	return wrote;

}



long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages)

long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,

				enum wb_reason reason)

{

	struct wb_writeback_work work = {

		.nr_pages	= nr_pages,

		.sync_mode	= WB_SYNC_NONE,

		.range_cyclic	= 1,

		.reason		= reason,

	};



	spin_lock(&wb->list_lock);
@@ -825,6 +841,7 @@ static long wb_check_background_flush(struct bdi_writeback *wb) 
			.sync_mode	= WB_SYNC_NONE,

			.for_background	= 1,

			.range_cyclic	= 1,

			.reason		= WB_REASON_BACKGROUND,

		};



		return wb_writeback(wb, &work);
@@ -858,6 +875,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb) 
			.sync_mode	= WB_SYNC_NONE,

			.for_kupdate	= 1,

			.range_cyclic	= 1,

			.reason		= WB_REASON_PERIODIC,

		};



		return wb_writeback(wb, &work);
@@ -976,7 +994,7 @@ int bdi_writeback_thread(void *data) 
 * Start writeback of `nr_pages' pages.  If `nr_pages' is zero, write back

 * the whole world.

 */

void wakeup_flusher_threads(long nr_pages)

void wakeup_flusher_threads(long nr_pages, enum wb_reason reason)

{

	struct backing_dev_info *bdi;
@@ -989,7 +1007,7 @@ void wakeup_flusher_threads(long nr_pages) 
	list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {

		if (!bdi_has_dirty_io(bdi))

			continue;

		__bdi_start_writeback(bdi, nr_pages, false);

		__bdi_start_writeback(bdi, nr_pages, false, reason);

	}

	rcu_read_unlock();

}
@@ -1210,7 +1228,9 @@ static void wait_sb_inodes(struct super_block *sb) 
 * on how many (if any) will be written, and this function does not wait

 * for IO completion of submitted IO.

 */

void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)

void writeback_inodes_sb_nr(struct super_block *sb,

			    unsigned long nr,

			    enum wb_reason reason)

{

	DECLARE_COMPLETION_ONSTACK(done);

	struct wb_writeback_work work = {
@@ -1219,6 +1239,7 @@ void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr) 
		.tagged_writepages	= 1,

		.done			= &done,

		.nr_pages		= nr,

		.reason			= reason,

	};



	WARN_ON(!rwsem_is_locked(&sb->s_umount));
@@ -1235,9 +1256,9 @@ EXPORT_SYMBOL(writeback_inodes_sb_nr); 
 * on how many (if any) will be written, and this function does not wait

 * for IO completion of submitted IO.

 */

void writeback_inodes_sb(struct super_block *sb)

void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)

{

	return writeback_inodes_sb_nr(sb, get_nr_dirty_pages());

	return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);

}

EXPORT_SYMBOL(writeback_inodes_sb);
@@ -1248,11 +1269,11 @@ EXPORT_SYMBOL(writeback_inodes_sb); 
 * Invoke writeback_inodes_sb if no writeback is currently underway.

 * Returns 1 if writeback was started, 0 if not.

 */

int writeback_inodes_sb_if_idle(struct super_block *sb)

int writeback_inodes_sb_if_idle(struct super_block *sb, enum wb_reason reason)

{

	if (!writeback_in_progress(sb->s_bdi)) {

		down_read(&sb->s_umount);

		writeback_inodes_sb(sb);

		writeback_inodes_sb(sb, reason);

		up_read(&sb->s_umount);

		return 1;

	} else
@@ -1269,11 +1290,12 @@ EXPORT_SYMBOL(writeback_inodes_sb_if_idle); 
 * Returns 1 if writeback was started, 0 if not.

 */

int writeback_inodes_sb_nr_if_idle(struct super_block *sb,

				   unsigned long nr)

				   unsigned long nr,

				   enum wb_reason reason)

{

	if (!writeback_in_progress(sb->s_bdi)) {

		down_read(&sb->s_umount);

		writeback_inodes_sb_nr(sb, nr);

		writeback_inodes_sb_nr(sb, nr, reason);

		up_read(&sb->s_umount);

		return 1;

	} else
@@ -1297,6 +1319,7 @@ void sync_inodes_sb(struct super_block *sb) 
		.nr_pages	= LONG_MAX,

		.range_cyclic	= 0,

		.done		= &done,

		.reason		= WB_REASON_SYNC,

	};



	WARN_ON(!rwsem_is_locked(&sb->s_umount));

fs/quota/quota.c

+1 −1
Original line number Diff line number Diff line
@@ -286,7 +286,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, 
		/* caller already holds s_umount */

		if (sb->s_flags & MS_RDONLY)

			return -EROFS;

		writeback_inodes_sb(sb);

		writeback_inodes_sb(sb, WB_REASON_SYNC);

		return 0;

	default:

		return -EINVAL;

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