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[109.81.17.247]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-482fbb28492sm20835619f8f.31.2026.08.31.02.09.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Aug 2026 02:09:41 -0700 (PDT) Date: Mon, 31 Aug 2026 11:09:40 +0200 From: Michal Hocko To: Andrew Morton Cc: Ye Liu , Ye Liu , David Rientjes , Shakeel Butt , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/oom_kill, proc: replace magic number 1000 with OOM_SCORE_ADJ_MAX Message-ID: References: <20260811033609.3992348-1-ye.liu@linux.dev> <20260829201310.648ed330984b91b1c135d8a3@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260829201310.648ed330984b91b1c135d8a3@linux-foundation.org> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 3FB0A140004 X-Stat-Signature: r8kddut9wgng7djrdreiomu7n44hnm3i X-Rspam-User: X-HE-Tag: 1788167383-881690 X-HE-Meta: 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 mWqrcNFK vi3bRKerjDeufpu4c2WNxEq2PxCCbibnAwy/GRErAGIAWGD1VKFd6tCSVEdZOWudIZ11U2dWLpcXV3E8vv1SGCpt8Hjfv/0rbRAKnWmJUIc7OiwJOU3pSXRBWuXEyJyOFBO8p04LP9IYa1kCVeJ3tU+Jc9qW4qcPIBeZ5F3L+F6HzSrI8v6yhtXD9JaqDE3vIakg9dMlHLfGHDWt2xhLmK+NnRcnV5HqDjMoiwRT2RInLeGU9G5s58NdkooDX0xVDTE8qy6NqpFrgOw5nuf9p/bBJZKK0sBwnRF6MnwwM4C92zDfAukpoiu1UH7Jj615gfy0+OZJaqdMmVorhLsaqh9npFWhpVrxFFHVylKn79GL+N1rSBLKd+bnI1tIo0iAPVOqUNyfSHoAd/0Bi/xNJV6SVR2TZTsXyvhpydiozgrQ02pEfhsRxgVZEH3uLaD4Jz3hVJRMJr0UV45I= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat 29-08-26 20:13:10, Andrew Morton wrote: > On Tue, 11 Aug 2026 11:36:08 +0800 Ye Liu wrote: > > > From: Ye Liu > > > > In oom_badness() and proc_oom_score(), the oom_score_adj normalization > > uses a hardcoded 1000, which is the value of OOM_SCORE_ADJ_MAX defined > > in include/uapi/linux/oom.h. Other code in the kernel (e.g. > > fs/proc/base.c oom_adj handling) already uses OOM_SCORE_ADJ_MAX for > > the same purpose. > > > > Replace the magic number with the macro for consistency and > > readability. No functional change. > > > > ... > > > > --- a/fs/proc/base.c > > +++ b/fs/proc/base.c > > @@ -594,7 +594,8 @@ static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns, > > * exporting for a long time so userspace might depend on it. > > */ > > if (badness != LONG_MIN) > > - points = (1000 + badness * 1000 / (long)totalpages) * 2 / 3; > > + points = (OOM_SCORE_ADJ_MAX + > > + badness * OOM_SCORE_ADJ_MAX / (long)totalpages) * 2 / 3; > > > > seq_printf(m, "%lu\n", points); > > > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > index 5f372f6e26fa..08bff7a55db8 100644 > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -230,7 +230,7 @@ long oom_badness(struct task_struct *p, unsigned long totalpages) > > task_unlock(p); > > > > /* Normalize to oom_score_adj units */ > > - adj *= totalpages / 1000; > > + adj *= totalpages / OOM_SCORE_ADJ_MAX; > > points += adj; > > > > return points; > > AI review suggests that this is a misinterpretation of "1000"? > > https://sashiko.dev/#/patchset/20260811033609.3992348-1-ye.liu@linux.dev Sashiko is trying to be clever and it is simply wrong here. The scaling fact is indeed the same as the OOM_SCORE_ADJ_MAX. -- Michal Hocko SUSE Labs