From: Petr Mladek <pmladek@suse.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
John Ogness <john.ogness@linutronix.de>,
Mike Galbraith <efault@gmx.de>,
Peter Zijlstra <peterz@infradead.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>, Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH v4 2/2] lib/vsprintf: Initialize vsprintf's pointer hash once the random core is ready.
Date: Thu, 29 Sep 2022 10:52:02 +0200 [thread overview]
Message-ID: <YzVcsvw3wv0FVOZO@alley> (raw)
In-Reply-To: <CAHmME9qzBRDfUh1vN6qW6BFuFz_qcuaEOR13Ojx2CzC_+CHxUw@mail.gmail.com>
On Wed 2022-09-28 11:21:05, Jason A. Donenfeld wrote:
> On 9/28/22, Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:
> >
> >> I could replace "system_unbound_wq" with "system_wq" when
> >> pushing. Is anybody against it, please?
> >
> > so schedule_delayed_work() then?
yup.
> > I don't mind at all. I used that one just because serialisation is not
> > needed and neither is the CPU important.
>
> Indeed, given that this very much is unbound, I think Sebastian's
> original patch makes most sense.
Yes, the work does not need any specific CPU. The thing is that the
normal system_wq is the preferred one. Any other workqueues should
be used only when there is a particular reason for it.
The unbound_wq should be used only when:
+ the work needs a lot of CPU time.
+ there are waves on related (sleeping) work items that might be
triggered from different CPUs.
In our case, the work is only one and short. The preferred
system_wq is perfectly fine.
Best Regards,
Petr
PS: It is not obvious. Tejun told me this when I converted a kthread
into the workqueue API. Also I spent quite some time understanding
the workqueue code recently.
next prev parent reply other threads:[~2022-09-29 8:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 10:49 [PATCH 0/2 v4] Init the hashed pointer from a worker Sebastian Andrzej Siewior
2022-09-27 10:49 ` [PATCH v4 1/2] lib/vsprintf: Remove static_branch_likely() from __ptr_to_hashval() Sebastian Andrzej Siewior
2022-09-27 14:49 ` Petr Mladek
2022-09-30 10:27 ` Sergey Senozhatsky
2022-09-27 10:49 ` [PATCH v4 2/2] lib/vsprintf: Initialize vsprintf's pointer hash once the random core is ready Sebastian Andrzej Siewior
2022-09-27 11:20 ` Jason A. Donenfeld
2022-09-27 16:40 ` Petr Mladek
2022-09-28 9:11 ` Sebastian Andrzej Siewior
2022-09-28 9:21 ` Jason A. Donenfeld
2022-09-29 8:52 ` Petr Mladek [this message]
2022-09-30 10:31 ` Sergey Senozhatsky
2022-09-29 12:43 ` [PATCH 0/2 v4] Init the hashed pointer from a worker Petr Mladek
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