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Thu, 13 Aug 2026 09:38:19 +0000 X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Michal Hocko , Andrew Morton Cc: Ye Liu , David Rientjes , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] mm/oom_kill: remove unreachable __GFP_THISNODE check in constrained_alloc() Date: Thu, 13 Aug 2026 17:38:09 +0800 Message-Id: <20260813093810.573302-1-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 98370140006 X-Stat-Signature: 5jawt1b6bx4baw8dp6sqccnba9x36ar1 X-HE-Tag: 1786613900-415350 X-HE-Meta: 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 p8ekqcJO SRAi4FyYh8GKXvKDxXHcHvFdkQBLfQC9tVki6ES2B2F4uHiBxfHHUNjzzM+atJPCKUvvlbLhT1PxVJJWoyYnFdfI3D9APiJViJavCrLVaGqdCWHPmDGvIUoH83PlBUnh/cIRpMQ2s2dZY4XXEN4O1h0Mifspv0xDMhjF/kyAKiyxjy8fEbd5Jjkzc2k4Y+jw4DRLCzY2470SspHAJS63K6IALxXCVmm7Xjzw2IcBXiOkE9iBKNlZYjOHQZawlC8shyLAfuKsj/cWVNfWtqYdBxUXief/Mx3ofb3QOjM1iH/UlSSU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 --- 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