[PATCH v3] mm, oom: OOM sysrq should always kill a process

From: Jann Horn <jannh@google.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org, Jann Horn <jannh@google.com>,
	Michal Hocko <mhocko@suse.com>
Subject: [PATCH v3] mm, oom: OOM sysrq should always kill a process
Date: Thu,  6 Jan 2022 11:26:05 +0100	[thread overview]
Message-ID: <20220106102605.635656-1-jannh@google.com> (raw)

The OOM kill sysrq (alt+sysrq+F) should allow the user to kill the
process with the highest OOM badness with a single execution.

However, at the moment, the OOM kill can bail out if an OOM notifier
(e.g. the i915 one) says that it reclaimed a tiny amount of memory
from somewhere. That's probably not what the user wants, so skip the
bailout if the OOM was triggered via sysrq.

Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Jann Horn <jannh@google.com>
---
 mm/oom_kill.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1ddabefcfb5a..3c480b24a93c 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -1057,7 +1057,7 @@ bool out_of_memory(struct oom_control *oc)
 
 	if (!is_memcg_oom(oc)) {
 		blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
-		if (freed > 0)
+		if (freed > 0 && !is_sysrq_oom(oc))
 			/* Got some memory back in the last second. */
 			return true;
 	}

base-commit: c9e6606c7fe92b50a02ce51dda82586ebdf99b48
-- 
2.34.1.448.ga2b2bfdf31-goog

