From: Oleg Nesterov <oleg@redhat.com>
To: Zihuan Zhang <zhangzihuan@kylinos.cn>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
David Hildenbrand <david@redhat.com>,
Michal Hocko <mhocko@suse.com>, Jonathan Corbet <corbet@lwn.net>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
len brown <len.brown@intel.com>, pavel machek <pavel@kernel.org>,
Kees Cook <kees@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Nico Pache <npache@redhat.com>, xu xin <xu.xin16@zte.com.cn>,
wangfushuai <wangfushuai@baidu.com>,
Andrii Nakryiko <andrii@kernel.org>,
Christian Brauner <brauner@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Jeff Layton <jlayton@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Adrian Ratiu <adrian.ratiu@collabora.com>,
linux-pm@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v1 6/9] freezer: Set default freeze priority for zombie tasks
Date: Mon, 11 Aug 2025 11:42:53 +0200 [thread overview]
Message-ID: <20250811094252.GC11928@redhat.com> (raw)
In-Reply-To: <393a4509-9b05-45b8-8496-699ace9a5438@kylinos.cn>
On 08/11, Zihuan Zhang wrote:
>
> 在 2025/8/8 22:29, Oleg Nesterov 写道:
> >On 08/07, Zihuan Zhang wrote:
> >>@@ -6980,6 +6981,7 @@ void __noreturn do_task_dead(void)
> >> current->flags |= PF_NOFREEZE;
> >>
> >> __schedule(SM_NONE);
> >>+ freeze_set_default_priority(current, FREEZE_PRIORITY_NEVER);
> >> BUG();
> >But this change has no effect?
> >
> >Firstly, this last __schedule() should not return, note the BUG() we have.
> >
> >Secondly, this zombie is already PF_NOFREEZE, freeze_task() will return
> >false anyway.
> Sorry, but in our tests with a large number of zombie tasks, returning early
> reduced the overhead. Even though freeze_task() would return false for
> PF_NOFREEZE, skipping the extra path still saved time in our suspend/freezer
https://lore.kernel.org/all/20250707084214.GD1613200@noisy.programming.kicks-ass.net/
Anyway the patch makes no sense in its current form, see my note
about __schedule() above.
Oleg.
next prev parent reply other threads:[~2025-08-11 9:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-07 12:14 [RFC PATCH v1 0/9] freezer: Introduce freeze priority model to address process dependency issues Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 1/9] freezer: Introduce freeze_priority field in task_struct Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 2/9] freezer: Introduce API to set per-task freeze priority Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 3/9] freezer: Add per-priority layered freeze logic Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 4/9] freezer: Set default freeze priority for userspace tasks Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 5/9] freezer: set default freeze priority for PF_SUSPEND_TASK processes Zihuan Zhang
2025-08-08 14:39 ` Oleg Nesterov
2025-08-11 9:25 ` Zihuan Zhang
2025-08-11 9:32 ` Oleg Nesterov
2025-08-11 9:42 ` Zihuan Zhang
2025-08-11 9:46 ` Oleg Nesterov
2025-08-11 9:54 ` Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 6/9] freezer: Set default freeze priority for zombie tasks Zihuan Zhang
2025-08-08 14:29 ` Oleg Nesterov
2025-08-11 9:29 ` Zihuan Zhang
2025-08-11 9:42 ` Oleg Nesterov [this message]
2025-08-12 8:07 ` Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 7/9] freezer: raise freeze priority of tasks failed to freeze last time Zihuan Zhang
2025-08-08 14:53 ` Oleg Nesterov
2025-08-11 9:31 ` Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 8/9] freezer: Add retry count statistics for freeze pass iterations Zihuan Zhang
2025-08-07 12:14 ` [RFC PATCH v1 9/9] proc: Add /proc/<pid>/freeze_priority interface Zihuan Zhang
2025-08-07 13:25 ` [RFC PATCH v1 0/9] freezer: Introduce freeze priority model to address process dependency issues Michal Hocko
2025-08-08 1:13 ` Zihuan Zhang
2025-08-08 7:00 ` Michal Hocko
2025-08-08 7:52 ` Zihuan Zhang
2025-08-08 8:58 ` Michal Hocko
2025-08-11 9:13 ` Zihuan Zhang
2025-08-11 10:58 ` Michal Hocko
2025-08-12 5:57 ` Zihuan Zhang
2025-08-12 17:26 ` Darrick J. Wong
2025-08-13 5:48 ` Zihuan Zhang
2025-08-14 16:43 ` Darrick J. Wong
2025-08-15 8:17 ` Zihuan Zhang
2025-08-08 7:57 ` Oleg Nesterov
2025-08-08 8:40 ` Zihuan Zhang
2025-08-14 14:37 ` Peter Zijlstra
2025-08-15 8:27 ` Zihuan Zhang
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