diff options
author | Shakeel Butt <shakeelb@google.com> | 2021-09-02 23:53:27 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-03 18:58:10 +0200 |
commit | 7490a2d248145d8694e1e9828801b496250fd697 (patch) | |
tree | e05981fc7f52b23fc02ba12b8a058734baa0ba18 /fs/fs-writeback.c | |
parent | fs: inode: count invalidated shadow pages in pginodesteal (diff) | |
download | linux-7490a2d248145d8694e1e9828801b496250fd697.tar.xz linux-7490a2d248145d8694e1e9828801b496250fd697.zip |
writeback: memcg: simplify cgroup_writeback_by_id
Currently cgroup_writeback_by_id calls mem_cgroup_wb_stats() to get dirty
pages for a memcg. However mem_cgroup_wb_stats() does a lot more than
just get the number of dirty pages. Just directly get the number of dirty
pages instead of calling mem_cgroup_wb_stats(). Also
cgroup_writeback_by_id() is only called for best-effort dirty flushing, so
remove the unused 'nr' parameter and no need to explicitly flush memcg
stats.
Link: https://lkml.kernel.org/r/20210722182627.2267368-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r-- | fs/fs-writeback.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 867984e778c3..35894a2dba75 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1039,20 +1039,20 @@ restart: * cgroup_writeback_by_id - initiate cgroup writeback from bdi and memcg IDs * @bdi_id: target bdi id * @memcg_id: target memcg css id - * @nr: number of pages to write, 0 for best-effort dirty flushing * @reason: reason why some writeback work initiated * @done: target wb_completion * * Initiate flush of the bdi_writeback identified by @bdi_id and @memcg_id * with the specified parameters. */ -int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr, +int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, enum wb_reason reason, struct wb_completion *done) { struct backing_dev_info *bdi; struct cgroup_subsys_state *memcg_css; struct bdi_writeback *wb; struct wb_writeback_work *work; + unsigned long dirty; int ret; /* lookup bdi and memcg */ @@ -1081,24 +1081,22 @@ int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr, } /* - * If @nr is zero, the caller is attempting to write out most of + * The caller is attempting to write out most of * the currently dirty pages. Let's take the current dirty page * count and inflate it by 25% which should be large enough to * flush out most dirty pages while avoiding getting livelocked by * concurrent dirtiers. + * + * BTW the memcg stats are flushed periodically and this is best-effort + * estimation, so some potential error is ok. */ - if (!nr) { - unsigned long filepages, headroom, dirty, writeback; - - mem_cgroup_wb_stats(wb, &filepages, &headroom, &dirty, - &writeback); - nr = dirty * 10 / 8; - } + dirty = memcg_page_state(mem_cgroup_from_css(memcg_css), NR_FILE_DIRTY); + dirty = dirty * 10 / 8; /* issue the writeback work */ work = kzalloc(sizeof(*work), GFP_NOWAIT | __GFP_NOWARN); if (work) { - work->nr_pages = nr; + work->nr_pages = dirty; work->sync_mode = WB_SYNC_NONE; work->range_cyclic = 1; work->reason = reason; |