[v5,2/5] memcg: flush stats non-atomically in mem_cgroup_wb_stats()

Commit Message

Yosry Ahmed April 21, 2023, 5:40 p.m. UTC

The previous patch moved the wb_over_bg_thresh()->mem_cgroup_wb_stats()
code path in wb_writeback() outside the lock section. We no longer need
to flush the stats atomically. Flush the stats non-atomically.

Signed-off-by: Yosry Ahmed <[e-mail]>
Reviewed-by: Michal Koutný <[e-mail]>
Acked-by: Shakeel Butt <[e-mail]>
---
 mm/memcontrol.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

Comments

Tejun Heo May 5, 2023, 3:19 p.m. UTC | #1

On Fri, Apr 21, 2023 at 05:40:17PM +0000, Yosry Ahmed wrote:
> The previous patch moved the wb_over_bg_thresh()->mem_cgroup_wb_stats()
> code path in wb_writeback() outside the lock section. We no longer need
> to flush the stats atomically. Flush the stats non-atomically.
> 
> Signed-off-by: Yosry Ahmed <[e-mail]>
> Reviewed-by: Michal Koutný <[e-mail]>
> Acked-by: Shakeel Butt <[e-mail]>

Acked-by: Tejun Heo <[e-mail]>

Thanks.

Patch

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4b27e245a055..5e79fdf8442b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4648,11 +4648,7 @@  void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
 	struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
 	struct mem_cgroup *parent;
 
-	/*
-	 * wb_writeback() takes a spinlock and calls
-	 * wb_over_bg_thresh()->mem_cgroup_wb_stats(). Do not sleep.
-	 */
-	mem_cgroup_flush_stats_atomic();
+	mem_cgroup_flush_stats();
 
 	*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
 	*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);