linux-kernel - [PATCH] mm: vmscan: avoid a unnecessary reschedule in shrink

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Message-ID: <20201016033952.1924-1-tian.xianting@h3c.com>
Date:   Fri, 16 Oct 2020 11:39:52 +0800
From:   Xianting Tian <tian.xianting@....com>
To:     <akpm@...ux-foundation.org>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        Xianting Tian <tian.xianting@....com>
Subject: [PATCH] mm: vmscan: avoid a unnecessary reschedule in shrink_slab()

In shrink_slab(), it directly goes to 'out' label only when it
can't get the lock of shrinker_rwsew. In this case, it doesn't
do the real work of shrinking slab, so we don't need trigger a
reschedule by cond_resched().

Signed-off-by: Xianting Tian <tian.xianting@....com>
---
 mm/vmscan.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 466fc3144..676e97b28 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -687,8 +687,9 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
 	}
 
 	up_read(&shrinker_rwsem);
-out:
+
 	cond_resched();
+out:
 	return freed;
 }
 
-- 
2.17.1