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[109.81.25.183]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48de0ac35dfsm10313855f8f.33.2026.10.14.00.50.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Oct 2026 00:50:31 -0700 (PDT) Date: Wed, 14 Oct 2026 09:50:30 +0200 From: Michal Hocko To: BouziguesAlexis@johndeere.com Cc: Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: nommu: set MMF_OOM_SKIP in exit_mmap() Message-ID: References: <20261013-fix-nommu-exit-mmap-oom-skip-v1-1-cb957cdbfcc3@JohnDeere.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261013-fix-nommu-exit-mmap-oom-skip-v1-1-cb957cdbfcc3@JohnDeere.com> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6FCB24000A X-Rspam-User: X-Stat-Signature: s9xuudu4pqoown6g69c5c3bidbptoebn X-HE-Tag: 1791964234-311326 X-HE-Meta: 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 aPxntJN3 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue 13-10-26 17:56:19, Alexis Bouzigues via B4 Relay wrote: > From: Alexis Bouzigues > > Commit 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run > concurrently") moved setting MMF_OOM_SKIP from __mmput() into the MMU > exit_mmap(), so it is no longer set when a NOMMU mm is torn down. > > As a result, a NOMMU OOM victim that has exited and freed its memory > keeps the OOM killer from selecting another victim until it is reaped. > > Set MMF_OOM_SKIP in the NOMMU exit_mmap() once the VMAs are freed, as > the MMU version does. Is this a real problem that you can actually hit? > Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") > Assisted-by: LLM > Signed-off-by: Alexis Bouzigues > --- > Restore MMF_OOM_SKIP on NOMMU mm teardown, which was lost when it moved > into the MMU-only exit_mmap(). > --- > mm/nommu.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/nommu.c b/mm/nommu.c > index 498e01ee40b0..913b2a1b5b3b 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -1555,6 +1555,7 @@ void exit_mmap(struct mm_struct *mm) > delete_vma(mm, vma); > cond_resched(); > } > + mm_flags_set(MMF_OOM_SKIP, mm); > __mt_destroy(&mm->mm_mt); > mmap_write_unlock(mm); > } > > --- > base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907 > change-id: 20261013-fix-nommu-exit-mmap-oom-skip-b8e68bf34b6d > > Best regards, > -- > Alexis Bouzigues > > -- Michal Hocko SUSE Labs