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Tue, 28 Oct 2025 00:28:11 -0700 (PDT) From: Akinobu Mita To: akinobu.mita@gmail.com Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, hannes@cmpxchg.org, david@redhat.com, mhocko@kernel.org, zhengqi.arch@bytedance.com, shakeel.butt@linux.dev, lorenzo.stoakes@oracle.com Subject: Re: oom-killer not invoked on systems with multiple memory-tiers Date: Tue, 28 Oct 2025 16:27:36 +0900 Message-ID: <20251028072736.10455-1-akinobu.mita@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251022135735.246203-1-akinobu.mita@gmail.com> References: <20251022135735.246203-1-akinobu.mita@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1E84E18000A X-Stat-Signature: ruy71arwxph7u3t8pbrzbqyykfukx7f5 X-HE-Tag: 1761636492-897074 X-HE-Meta: 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 f7h5ZnwF 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: lru_gen_age_node() checks the reclaimability of a node using lruvec_is_reclaimable() when min_ttl_ms is non-zero, but if min_ttl_ms is zero, it unconditionally determines that the node is reclaimable. I think we should still call lruvec_is_reclaimable() to check reclaimability even if min_ttl_ms is zero. Otherwise, we'll miss the opportunity to trigger an OOM kill in lru_gen_age_node(), which will cause the problem I reported. https://lore.kernel.org/linux-mm/20251022135735.246203-1-akinobu.mita@gmail.com/ The attached patch made the changes mentioned above and worked around the problem. --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index c922bad2b8fd..e1a88ed4e0b0 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4148,7 +4148,7 @@ static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) { struct mem_cgroup *memcg; unsigned long min_ttl = READ_ONCE(lru_gen_min_ttl); - bool reclaimable = !min_ttl; + bool reclaimable = false; VM_WARN_ON_ONCE(!current_is_kswapd()); -- 2.43.0