From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH 4/5] linux: Optimize posix_spawn spurious sigaction calls
Date: Thu, 29 Aug 2019 11:26:00 -0000 [thread overview]
Message-ID: <4266b563-5433-8bb9-78a2-af0ff14cab59@linaro.org> (raw)
In-Reply-To: <875zmg9xjr.fsf@oldenburg2.str.redhat.com>
On 29/08/2019 05:38, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>> * include/atomic.h (atomic_fetch_or_seq_cst, atomic_fetch_or_seq_cst):
>> New macros.
>
> Why isn't a regular release store/acquire load synchronization
> sufficient here?
It should works, my understanding is a weaker store barrier might incur in
a slight more false positive in a highly concurrent sigaction call scenario.
But I assume that this is not a common scenario, so I used the strongest
barrier just to avoid the extra false positives.
>
> I wonder if we can get kernel support for this in the new clone system
> call with more flags. Then we don't have to complicate the sigaction
> implementation.
Maybe a CLONE_RESET_SIGNALS where the cloned process sets its signal
disposition to default SIG_IGN/SIG_DFL values may help us here. However
afaik clone now is out of space on 'flags' for newer ones (it already
defines 24 flags plus it reserve 8 bits for signal to be sent at process
exit) and it would take time to use this feature on glibc.
next prev parent reply other threads:[~2019-08-29 11:26 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 18:31 [PATCH v2 1/5] mips: Do not malloc on getdents64 fallback Adhemerval Zanella
2019-07-31 18:31 ` [PATCH 4/5] linux: Optimize posix_spawn spurious sigaction calls Adhemerval Zanella
2019-08-28 14:09 ` Adhemerval Zanella
2019-08-29 8:38 ` Florian Weimer
2019-08-29 11:26 ` Adhemerval Zanella [this message]
2019-08-30 10:07 ` Florian Weimer
2019-08-30 13:05 ` Adhemerval Zanella
2019-09-02 13:14 ` Florian Weimer
2019-09-02 19:47 ` Adhemerval Zanella
2019-10-07 17:51 ` Adhemerval Zanella
2019-10-07 18:25 ` Christian Brauner
2019-10-07 18:32 ` Florian Weimer
2019-10-07 21:08 ` Christian Brauner
2019-10-07 18:35 ` Adhemerval Zanella
2019-10-07 18:40 ` Florian Weimer
2019-10-07 19:20 ` Adhemerval Zanella
2019-10-09 9:37 ` Florian Weimer
2019-10-09 10:25 ` Christian Brauner
2019-10-09 12:17 ` Adhemerval Zanella
2019-10-09 19:16 ` Florian Weimer
2019-10-07 21:00 ` Joseph Myers
2019-10-07 18:41 ` Florian Weimer
2019-07-31 18:31 ` [PATCH v2 3/5] posix: Optimize stack Linux posix_spawn Adhemerval Zanella
2019-08-28 14:09 ` Adhemerval Zanella
2019-10-07 17:50 ` Adhemerval Zanella
2019-07-31 18:31 ` [PATCH v2 2/5] posix: Add posix_spawn_file_actions_closefrom Adhemerval Zanella
2019-08-28 14:09 ` Adhemerval Zanella
2019-08-28 17:22 ` Joseph Myers
2019-08-28 21:03 ` Adhemerval Zanella
2019-07-31 18:31 ` [PATCH v2 5/5] posix: Use posix_spawn for wordexp Adhemerval Zanella
2019-08-28 14:10 ` Adhemerval Zanella
2019-10-07 17:51 ` Adhemerval Zanella
2019-10-07 19:33 ` Florian Weimer
2019-10-07 21:04 ` Carlos O'Donell
2019-10-08 9:58 ` Florian Weimer
2019-10-08 17:41 ` Adhemerval Zanella
2019-10-09 9:11 ` Florian Weimer
2019-10-09 12:18 ` Adhemerval Zanella
2019-08-28 14:09 ` [PATCH v2 1/5] mips: Do not malloc on getdents64 fallback Adhemerval Zanella
2019-08-28 14:35 ` Andreas Schwab
2019-08-28 17:01 ` Adhemerval Zanella
2019-08-28 14:42 ` Florian Weimer
2019-08-28 21:02 ` Adhemerval Zanella
2019-08-28 21:23 ` Florian Weimer
2019-08-29 11:04 ` Adhemerval Zanella
2019-08-30 9:53 ` Florian Weimer
2019-08-30 12:53 ` Adhemerval Zanella
2019-09-02 12:59 ` Florian Weimer
2019-09-02 17:38 ` Adhemerval Zanella
2019-10-07 17:49 ` Adhemerval Zanella
2019-10-07 18:29 ` Florian Weimer
2019-10-08 17:38 ` Adhemerval Zanella
2019-10-08 18:52 ` Florian Weimer
2019-10-08 19:52 ` Adhemerval Zanella
2019-10-08 19:59 ` Florian Weimer
2019-10-09 13:02 ` Adhemerval Zanella
2020-11-02 19:51 ` Joseph Myers
2020-11-02 22:10 ` Adhemerval Zanella
2020-11-03 10:27 ` Florian Weimer
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