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Wysocki" , pavel@kernel.org, len.brown@intel.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/1] PM / Freezer: Skip zombie/dead processes to Message-ID: <20250716161624.GD16401@redhat.com> References: <20250611101247.15522-1-zhangzihuan@kylinos.cn> <20250611101247.15522-2-zhangzihuan@kylinos.cn> <20250703164021.GY1613200@noisy.programming.kicks-ass.net> <20250704081941.GC2001818@noisy.programming.kicks-ass.net> <67997bdd-d00a-413a-a565-188c4b06f385@kylinos.cn> <20250704092144.GH2001818@noisy.programming.kicks-ass.net> <20250707084214.GD1613200@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-pm@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: <20250707084214.GD1613200@noisy.programming.kicks-ass.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 I don't like the patch Zihuan, but On 07/07, Peter Zijlstra wrote: > > Anyway, this seems to suggest something relatively simple like this here > should do: > > diff --git a/kernel/freezer.c b/kernel/freezer.c > index 8d530d0949ff..8b7cecd17564 100644 > --- a/kernel/freezer.c > +++ b/kernel/freezer.c > @@ -162,20 +162,22 @@ static bool __freeze_task(struct task_struct *p) > */ > bool freeze_task(struct task_struct *p) > { > - unsigned long flags; > - > - spin_lock_irqsave(&freezer_lock, flags); > - if (!freezing(p) || frozen(p) || __freeze_task(p)) { > - spin_unlock_irqrestore(&freezer_lock, flags); > + /* > + * User tasks get NOFREEZE in do_task_dead(). > + */ > + if ((p->flags & (PF_NOFREEZE | PF_KTHREAD)) == PF_NOFREEZE) > return false; > - } I don't understand your change... It probably makes sense to avoid freezer_lock when PF_NOFREEZE is set but it can't change the current behaciour, freezing() -> freezing_slow_path() checks PF_NOFREEZE too and returns false in this case. Oleg.