From: Oleg Nesterov <oleg@redhat.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Marco Elver <elver@google.com>,
linux-kernel@vger.kernel.org,
"Eric W . Biederman" <ebiederm@xmission.com>,
Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [PATCH v4] posix-timers: Prefer delivery of signals to the current thread
Date: Sat, 28 Jan 2023 21:15:22 +0100 [thread overview]
Message-ID: <20230128201520.GB14906@redhat.com> (raw)
In-Reply-To: <20230128195641.GA14906@redhat.com>
Forgot to mention ...
On 01/28, Oleg Nesterov wrote:
>
> Dmitry,
>
> I agree with what you said, just one note...
>
> On 01/27, Dmitry Vyukov wrote:
> >
> > After this change the test passes quickly (within a second for me).
>
> yet perhaps it makes sense to slightly change it? It does
>
> +static void *distribution_thr(void *arg) {
> + while (__atomic_load_n(&remain, __ATOMIC_RELAXED));
> + return NULL;
> +}
>
> so distribution_thr() eats CPU even after this thread gets a signal and thus
> (in theory) it can "steal" cpu_timer_fire() from other threads unpredictably
> long ? How about
>
> - while (__atomic_load_n(&remain, __ATOMIC_RELAXED));
> + while (__atomic_load_n(&got_signal, __ATOMIC_RELAXED));
>
> ?
Of course, in this case it also makes sense to change the main() function the
same way and add BUG_ON(remain) after the "for (...) pthread_join()" block.
Oleg.
next prev parent reply other threads:[~2023-01-28 20:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-16 17:18 [RFC PATCH] posix-timers: Support delivery of signals to the current thread Dmitry Vyukov
2023-01-11 15:49 ` Dmitry Vyukov
2023-01-11 21:28 ` Thomas Gleixner
2023-01-12 11:24 ` [RFC PATCH v2] " Dmitry Vyukov
2023-01-25 12:43 ` Oleg Nesterov
2023-01-25 15:17 ` Oleg Nesterov
2023-01-25 15:34 ` Dmitry Vyukov
2023-01-25 16:31 ` Oleg Nesterov
2023-01-25 16:45 ` Oleg Nesterov
2023-01-25 17:07 ` Oleg Nesterov
2023-01-26 10:58 ` Dmitry Vyukov
2023-01-26 10:56 ` Dmitry Vyukov
2023-01-26 10:51 ` [PATCH v3] posix-timers: Prefer " Dmitry Vyukov
2023-01-26 14:46 ` Oleg Nesterov
2023-01-26 15:41 ` [PATCH v4] " Dmitry Vyukov
2023-01-26 17:51 ` Marco Elver
2023-01-26 19:57 ` Thomas Gleixner
2023-01-27 6:58 ` Dmitry Vyukov
2023-01-28 19:56 ` Oleg Nesterov
2023-01-28 20:15 ` Oleg Nesterov [this message]
2023-01-30 9:00 ` Dmitry Vyukov
2023-01-30 16:49 ` Oleg Nesterov
2023-02-02 7:36 ` Dmitry Vyukov
2023-02-20 14:43 ` [PATCH v5] " Dmitry Vyukov
2023-02-22 15:19 ` Oleg Nesterov
2023-03-14 8:25 ` Dmitry Vyukov
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