From mboxrd@z Thu Jan 1 00:00:00 1970 From: brookxu Subject: [PATCH 2/2] mem_cgroup: introduce foreign_writeback_in_process() function Date: Fri, 24 Sep 2021 14:46:23 +0800 Message-ID: <1632465983-30525-2-git-send-email-brookxu.cn@gmail.com> References: <1632465983-30525-1-git-send-email-brookxu.cn@gmail.com> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=f0GxVaNbVW0DvbjS40nByrp5JbLVkqcqCJ/2Z3nsHrQ=; b=KumeSPyep1PPko2skk0eqpAVVSFetiWqeAAclpxM6br9aBNY8UZ8HoRNhWJt6dq4l7 DRGK4F0m1dv7vyCNkpWdtUDJyDW+hkyAAlj3zMFof7bL81tqd8GDGjD90+ALVa+4UYUf 6FMs2h5X4jYNZ3iPHrGfooduiRDtrbu/taZ/wFQWushFmSxXf0ZsHKUup+5eZnOsl0KB 1VSbhX833c7Iy64o+my5fT3ImlXC9hJ88ZWfrLkL0CEcTzp2SMYINwUi4srGg4hk6KZ9 kfjY4T8MD/aNuc51L+/6neQbOOfxq9CcLzOxvs1HIpwVUOJ2DKNRd40CaSm1ws8GpnJw Euew== In-Reply-To: <1632465983-30525-1-git-send-email-brookxu.cn-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org From: Chunguang Xu Directly use atomic_read(&frn->done.cnt) == 1 to check whether frn is issued, which makes the code a bit obscure. Maybe we should replace it with a more understandable function. Signed-off-by: Chunguang Xu --- mm/memcontrol.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3e1384a6..464745b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4542,6 +4542,12 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, * As being wrong occasionally doesn't matter, updates and accesses to the * records are lockless and racy. */ + +static inline bool foreign_writeback_in_process(struct memcg_cgwb_frn *frn) +{ + return atomic_read(&frn->done.cnt) != 1; +} + void mem_cgroup_track_foreign_dirty_slowpath(struct page *page, struct bdi_writeback *wb) { @@ -4565,7 +4571,7 @@ void mem_cgroup_track_foreign_dirty_slowpath(struct page *page, frn->memcg_id == wb->memcg_css->id) break; if (time_before64(frn->at, oldest_at) && - atomic_read(&frn->done.cnt) == 1) { + !foreign_writeback_in_process(frn)) { oldest = i; oldest_at = frn->at; } @@ -4612,7 +4618,7 @@ void mem_cgroup_flush_foreign(struct bdi_writeback *wb) * already one in flight. */ if (time_after64(frn->at, now - intv) && - atomic_read(&frn->done.cnt) == 1) { + !foreign_writeback_in_process(frn)) { frn->at = 0; trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id); cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, -- 1.8.3.1