From: Jens Axboe <[email protected]>
To: Thomas Gleixner <[email protected]>,
[email protected], [email protected]
Cc: [email protected], [email protected],
Roman Gershman <[email protected]>
Subject: Re: [PATCH 4/4] task_work: use TIF_NOTIFY_SIGNAL if available
Date: Tue, 13 Oct 2020 17:55:07 -0600 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 10/13/20 5:50 PM, Thomas Gleixner wrote:
> On Thu, Oct 08 2020 at 09:27, Jens Axboe wrote:
>> +/*
>> + * TWA_SIGNAL signaling - use TIF_NOTIFY_SIGNAL, if available, as it's faster
>> + * than TIF_SIGPENDING as there's no dependency on ->sighand. The latter is
>> + * shared for threads, and can cause contention on sighand->lock. Even for
>> + * the non-threaded case TIF_NOTIFY_SIGNAL is more efficient, as no locking
>> + * or IRQ disabling is involved for notification (or running) purposes.
>> + */
>> +static void task_work_notify_signal(struct task_struct *task)
>> +{
>> +#ifdef TIF_NOTIFY_SIGNAL
>> + set_notify_signal(task);
>> +#else
>> + unsigned long flags;
>> +
>> + /*
>> + * Only grab the sighand lock if we don't already have some
>> + * task_work pending. This pairs with the smp_store_mb()
>> + * in get_signal(), see comment there.
>> + */
>> + if (!(READ_ONCE(task->jobctl) & JOBCTL_TASK_WORK) &&
>> + lock_task_sighand(task, &flags)) {
>> + task->jobctl |= JOBCTL_TASK_WORK;
>> + signal_wake_up(task, 0);
>> + unlock_task_sighand(task, &flags);
>> + }
>> +#endif
>
> Same #ifdeffery comment as before.
Fixed up.
--
Jens Axboe
next prev parent reply other threads:[~2020-10-14 9:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 15:27 [PATCHSET v4] Add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-08 15:27 ` [PATCH 1/4] tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() Jens Axboe
2020-10-13 23:35 ` Thomas Gleixner
2020-10-14 1:13 ` Jens Axboe
2020-10-08 15:27 ` [PATCH 2/4] kernel: add task_sigpending() helper Jens Axboe
2020-10-13 23:36 ` Thomas Gleixner
2020-10-08 15:27 ` [PATCH 3/4] kernel: add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-09 14:43 ` Oleg Nesterov
2020-10-09 15:13 ` Jens Axboe
2020-10-13 23:45 ` Thomas Gleixner
2020-10-13 23:54 ` Jens Axboe
2020-10-13 23:42 ` Thomas Gleixner
2020-10-13 23:45 ` Jens Axboe
2020-10-08 15:27 ` [PATCH 4/4] task_work: use TIF_NOTIFY_SIGNAL if available Jens Axboe
2020-10-13 23:50 ` Thomas Gleixner
2020-10-13 23:55 ` Jens Axboe [this message]
2020-10-09 14:30 ` [PATCHSET v4] Add support for TIF_NOTIFY_SIGNAL Oleg Nesterov
2020-10-09 15:16 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2020-10-16 15:45 [PATCHSET v6] " Jens Axboe
2020-10-16 15:45 ` [PATCH 4/4] task_work: use TIF_NOTIFY_SIGNAL if available Jens Axboe
2020-10-26 20:32 [PATCHSET v6a 0/4] Add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-26 20:32 ` [PATCH 4/4] task_work: use TIF_NOTIFY_SIGNAL if available Jens Axboe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
[email protected] \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox