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[109.81.29.60]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49981b03e70sm68907325e9.3.2026.08.13.04.29.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Aug 2026 04:29:36 -0700 (PDT) Date: Thu, 13 Aug 2026 13:29:35 +0200 From: Michal Hocko To: Ye Liu Cc: Andrew Morton , Ye Liu , David Rientjes , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/oom_kill: remove unreachable __GFP_THISNODE check in constrained_alloc() Message-ID: References: <20260813093810.573302-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260813093810.573302-1-ye.liu@linux.dev> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: E60F340008 X-Stat-Signature: q3axffxkzryarifkg8ezbidage9btisi X-Rspam-User: X-HE-Tag: 1786620577-522674 X-HE-Meta: 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 P7jHRVJm 2/V5bJtWYWcH7nF+T4LyCVom+qIvO1Bi9gseO1ti2EJUzqwJbDwfKTQHg26onudm5rS/k23zvh0PvJZCuddM7/dnQW7iVWTDZ4nC/hvRgpcklx4tu5wKNbqgyXyazeUjJCPz/qftQJ1kYNiviyajxSifTl25SepZ+JIrQvA4k0ZfHKzf+31bv+1IKc4ZAbcMAkNVscTfZ6n5bKO3Ir+vfgEUajVpbaal9ORhhg8n7x7sxOmk04yHKp7EbnFrwIpP4CZ1vy10aZe24CFc41NnV87cq3gD6TIERO5RtqQWc/w8krq0wNLHnpRPdgCnqGyAyKh3sDumqCkUToIaG5qw+jAiMnGsUP9RX5JAvAsVXeEEuUXv+byjmUwSB7DKCXGwD13uVcM2KBTbvAIlcyCYEAKoaIKdLJsMvSmVbYtXRskFJBfxkEkziztb417FlcY3eP5U2aecemXE2XMExuUf/lcQWEq+8KdWtsEC4y6PabIZjnGg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu 13-08-26 17:38:09, Ye Liu wrote: > From: Ye Liu > > The __GFP_THISNODE check in constrained_alloc() is dead code: global > OOM is never triggered with __GFP_THISNODE (blocked in > __alloc_pages_may_oom before out_of_memory() is called), and memcg OOM > returns CONSTRAINT_MEMCG at the top of the function before reaching > this point. Remove the check, its stale comment, and update the > following comment that referenced __GFP_THISNODE. > > Signed-off-by: Ye Liu Acked-by: Michal Hocko Thanks! > --- > v2: > - Remove the dead code directly. > - Link: https://lore.kernel.org/all/20260813030654.320269-1-ye.liu@linux.dev/ > > mm/oom_kill.c | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 5f372f6e26fa..fd3c476846a3 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -267,18 +267,11 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc) > > if (!oc->zonelist) > return CONSTRAINT_NONE; > - /* > - * Reach here only when __GFP_NOFAIL is used. So, we should avoid > - * to kill current.We have to random task kill in this case. > - * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now. > - */ > - if (oc->gfp_mask & __GFP_THISNODE) > - return CONSTRAINT_NONE; > > /* > - * This is not a __GFP_THISNODE allocation, so a truncated nodemask in > - * the page allocator means a mempolicy is in effect. Cpuset policy > - * is enforced in get_page_from_freelist(). > + * A truncated nodemask in the page allocator means a mempolicy > + * is in effect. Cpuset policy is enforced in > + * get_page_from_freelist(). > */ > if (oc->nodemask && > !nodes_subset(node_states[N_MEMORY], *oc->nodemask)) { > -- > 2.25.1 -- Michal Hocko SUSE Labs