diff options
| author | Chao Yu <yuchao0@huawei.com> | 2018-01-08 18:48:33 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2018-01-16 15:40:00 -0800 |
| commit | 49c60c67d235647c0bec7c68982539f3a6e8bbcd (patch) | |
| tree | 73ff723b4158094dcab5c70403fa83411dab9977 /fs/f2fs | |
| parent | 94b1e10e745424fe6183023ff5a525bf7d12f779 (diff) | |
f2fs: avoid high cpu usage in discard thread
We take very long time to finish generic/476, this is because we will
check consistence of all discard entries in global rb tree while
traversing all different granularity pending lists, even when the list
is empty, in order to avoid that unneeded overhead, we have to skip
the check when coming up an empty list.
generic/476 time consumption:
cost
Before patch & w/o consistence check 57s
Before patch & w/ consistence check 1426s
After patch 78s
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
| -rw-r--r-- | fs/f2fs/segment.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index b4b90980dc7b..35009dbacd46 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1204,6 +1204,8 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, pend_list = &dcc->pend_list[i]; mutex_lock(&dcc->cmd_lock); + if (list_empty(pend_list)) + goto next; f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root)); blk_start_plug(&plug); list_for_each_entry_safe(dc, tmp, pend_list, list) { @@ -1222,6 +1224,7 @@ skip: break; } blk_finish_plug(&plug); +next: mutex_unlock(&dcc->cmd_lock); if (iter >= dpolicy->max_requests) |