diff options
| author | Jan Kara <jack@suse.cz> | 2013-09-11 14:22:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:57:55 -0700 |
| commit | 47df3ddedd22c3f8e68aff831edb7921937674a2 (patch) | |
| tree | 3a8b82782ef6c90e7974063b642e5bbab04fd55e | |
| parent | 7cb2ef56e6a8b7b368b2e883a0a47d02fed66911 (diff) | |
| download | blackbird-obmc-linux-47df3ddedd22c3f8e68aff831edb7921937674a2.tar.gz blackbird-obmc-linux-47df3ddedd22c3f8e68aff831edb7921937674a2.zip | |
writeback: fix occasional slow sync(1)
In case when system contains no dirty pages, wakeup_flusher_threads() will
submit WB_SYNC_NONE writeback for 0 pages so wb_writeback() exits
immediately without doing anything, even though there are dirty inodes in
the system. Thus sync(1) will write all the dirty inodes from a
WB_SYNC_ALL writeback pass which is slow.
Fix the problem by using get_nr_dirty_pages() in wakeup_flusher_threads()
instead of calculating number of dirty pages manually. That function also
takes number of dirty inodes into account.
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Paul Taysom <taysom@chromium.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/fs-writeback.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 68851ff2fd41..87d778118027 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1049,10 +1049,8 @@ void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) { struct backing_dev_info *bdi; - if (!nr_pages) { - nr_pages = global_page_state(NR_FILE_DIRTY) + - global_page_state(NR_UNSTABLE_NFS); - } + if (!nr_pages) + nr_pages = get_nr_dirty_pages(); rcu_read_lock(); list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
