linux-kernel - [PATCH] mm/mempool: Use non-atomic '__set

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Message-Id: <e52476da5cee57151745c5c3c934a69798dc6fa4.1638132190.git.christophe.jaillet@wanadoo.fr>
Date:   Sun, 28 Nov 2021 21:52:28 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     konrad.wilk@...cle.com, akpm@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] mm/mempool: Use non-atomic '__set_bit()' when possible

the 'a' and 'b' bitmap are local to this function, so no concurrent access
can occur.
So, the non-atomic '__set_bit()' can be used to save a few cycles.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 mm/frontswap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/frontswap.c b/mm/frontswap.c
index 130e301c5ac0..6bed12260dea 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -127,7 +127,7 @@ void frontswap_register_ops(struct frontswap_ops *ops)
 	spin_lock(&swap_lock);
 	plist_for_each_entry(si, &swap_active_head, list) {
 		if (!WARN_ON(!si->frontswap_map))
-			set_bit(si->type, a);
+			__set_bit(si->type, a);
 	}
 	spin_unlock(&swap_lock);
 
@@ -149,7 +149,7 @@ void frontswap_register_ops(struct frontswap_ops *ops)
 	spin_lock(&swap_lock);
 	plist_for_each_entry(si, &swap_active_head, list) {
 		if (si->frontswap_map)
-			set_bit(si->type, b);
+			__set_bit(si->type, b);
 	}
 	spin_unlock(&swap_lock);
 
-- 
2.30.2