linux-kernel - [PATCH] mm/memcg: reorder retry checks for clarity in try_charge

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Message-ID: <20251215145419.3097-1-kdipendra88@gmail.com>
Date: Mon, 15 Dec 2025 14:54:19 +0000
From: Dipendra Khadka <kdipendra88@...il.com>
To: akpm@...ux-foundation.org
Cc: hannes@...xchg.org,
	mhocko@...nel.org,
	roman.gushchin@...ux.dev,
	shakeel.butt@...ux.dev,
	muchun.song@...ux.dev,
	cgroups@...r.kernel.org,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] mm/memcg: reorder retry checks for clarity in try_charge_memcg

In try_charge_memcg(), reorder the retry logic checks to follow the
early-exit pattern by testing for dying task before decrementing the
retry counter:

Before:
    if (nr_retries--)
        goto retry;
    
    if (passed_oom && task_is_dying())
        goto nomem;

After:
    if (passed_oom && task_is_dying())
        goto nomem;
    
    if (nr_retries--)
        goto retry;

This makes the control flow more obvious: check exit conditions first,
then decide whether to retry. When current task is dying (e.g., has
received SIGKILL or is exiting), we should exit immediately rather than
consuming a retry count first.

No functional change for the common case where task is not dying.

Signed-off-by: Dipendra Khadka <kdipendra88@...il.com>
---
 mm/memcontrol.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index be810c1fbfc3..7c9145538683 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2412,16 +2412,16 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
 	if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
 		goto retry;

+	/* Avoid endless loop for tasks bypassed by the oom killer */
+	if (passed_oom && task_is_dying())
+		goto nomem;
+
 	if (nr_retries--)
 		goto retry;
 
 	if (gfp_mask & __GFP_RETRY_MAYFAIL)
 		goto nomem;
 
-	/* Avoid endless loop for tasks bypassed by the oom killer */
-	if (passed_oom && task_is_dying())
-		goto nomem;
-
 	/*
 	 * keep retrying as long as the memcg oom killer is able to make
 	 * a forward progress or bypass the charge if the oom killer
-- 
2.43.0