diff options
| author | Wu Fengguang <fengguang.wu@intel.com> | 2009-09-23 20:33:40 +0800 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-09-25 18:08:24 +0200 |
| commit | d3ddec7635b6fb37cb49e3553bdeea59642be653 (patch) | |
| tree | 662a1ea9c0eac6aa9bb07d4f67b6aad84709600c | |
| parent | 3a2e9a5a2afc1a2d2c548b8987f133235cebe933 (diff) | |
writeback: stop background writeback when below background threshold
Treat bdi_start_writeback(0) as a special request to do background write,
and stop such work when we are below the background dirty threshold.
Also simplify the (nr_pages <= 0) checks. Since we already pass in
nr_pages=LONG_MAX for WB_SYNC_ALL and background writes, we don't
need to worry about it being decreased to zero.
Reported-by: Richard Kennedy <richard@rsk.demon.co.uk>
CC: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| -rw-r--r-- | fs/fs-writeback.c | 28 | ||||
| -rw-r--r-- | mm/page-writeback.c | 6 |
2 files changed, 20 insertions, 14 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index c59d6737036..476be9b1088 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -41,8 +41,9 @@ struct wb_writeback_args { long nr_pages; struct super_block *sb; enum writeback_sync_modes sync_mode; - int for_kupdate; - int range_cyclic; + int for_kupdate:1; + int range_cyclic:1; + int for_background:1; }; /* @@ -257,6 +258,15 @@ void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages) .range_cyclic = 1, }; + /* + * We treat @nr_pages=0 as the special case to do background writeback, + * ie. to sync pages until the background dirty threshold is reached. + */ + if (!nr_pages) { + args.nr_pages = LONG_MAX; + args.for_background = 1; + } + bdi_alloc_queue_work(bdi, &args); } @@ -720,20 +730,16 @@ static long wb_writeback(struct bdi_writeback *wb, for (;;) { /* - * Don't flush anything for non-integrity writeback where - * no nr_pages was given + * Stop writeback when nr_pages has been consumed */ - if (!args->for_kupdate && args->nr_pages <= 0 && - args->sync_mode == WB_SYNC_NONE) + if (args->nr_pages <= 0) break; /* - * If no specific pages were given and this is just a - * periodic background writeout and we are below the - * background dirty threshold, don't do anything + * For background writeout, stop when we are below the + * background dirty threshold */ - if (args->for_kupdate && args->nr_pages <= 0 && - !over_bground_thresh()) + if (args->for_background && !over_bground_thresh()) break; wbc.more_io = 0; diff --git a/mm/page-writeback.c b/mm/page-writeback.c index cbd4cba468b..3c78fc31620 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -593,10 +593,10 @@ static void balance_dirty_pages(struct address_space *mapping, * background_thresh, to keep the amount of dirty memory low. */ if ((laptop_mode && pages_written) || - (!laptop_mode && ((nr_writeback = global_page_state(NR_FILE_DIRTY) - + global_page_state(NR_UNSTABLE_NFS)) + (!laptop_mode && ((global_page_state(NR_FILE_DIRTY) + + global_page_state(NR_UNSTABLE_NFS)) > background_thresh))) - bdi_start_writeback(bdi, nr_writeback); + bdi_start_writeback(bdi, 0); } void set_page_dirty_balance(struct page *page, int page_mkwrite) |