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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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> 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