From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: "André Almeida" <andrealmeid@collabora.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Darren Hart <dvhart@infradead.org>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
kernel@collabora.com, pgriffais@valvesoftware.com,
z.figura12@gmail.com, joel@joelfernandes.org,
malteskarupke@fastmail.fm, linux-api@vger.kernel.org,
fweimer@redhat.com, libc-alpha@sourceware.org,
linux-kselftest@vger.kernel.org, shuah@kernel.org,
acme@kernel.org, corbet@lwn.net
Subject: Re: [RFC PATCH 01/13] futex2: Implement wait and wake functions
Date: Thu, 18 Feb 2021 10:48:50 -0500 [thread overview]
Message-ID: <87y2fltlzx.fsf@collabora.com> (raw)
In-Reply-To: <74e321d5-2cf5-f3a6-6a7a-49e1ed2fda07@collabora.com> (=?utf-8?Q?=22Andr=C3=A9?= Almeida"'s message of "Thu, 18 Feb 2021 10:29:46 -0300")
André Almeida <andrealmeid@collabora.com> writes:
>>> + if (unlikely(ret)) {
>>> + spin_unlock(&bucket->lock);
>>> +
>>> + bucket_dec_waiters(bucket);
>>> + __set_current_state(TASK_RUNNING);
>>> + *awakened = futex_dequeue_multiple(futexv, i);
>>> +
>>> + if (__get_user(uval, uaddr))
>>> + return -EFAULT;
>>> +
>>> + if (*awakened >= 0)
>>> + return 1;
>> If you are awakened, you don't need to waste time with trying to get
>> the
>> next key.
>>
>
> Yes, and this is what this return is supposed to do. What I'm missing?
you don't need to do that __get_user if some other key was already awoke.
[...]
if (*awakened >= 0)
return 1;
if (__get_user(uval, uaddr))
return -EFAULT;
[...]
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2021-02-18 18:16 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-15 15:23 [RFC PATCH 00/13] Add futex2 syscalls André Almeida
2021-02-15 15:23 ` [RFC PATCH 01/13] futex2: Implement wait and wake functions André Almeida
2021-02-15 19:59 ` Gabriel Krisman Bertazi
2021-02-18 13:29 ` André Almeida
2021-02-18 15:48 ` Gabriel Krisman Bertazi [this message]
2021-02-16 9:02 ` Peter Zijlstra
2021-02-18 20:09 ` André Almeida
2021-02-16 9:35 ` Peter Zijlstra
2021-02-16 9:56 ` Peter Zijlstra
2021-02-16 10:20 ` Sebastian Andrzej Siewior
2021-02-16 12:42 ` Peter Zijlstra
2021-02-16 22:12 ` Gabriel Krisman Bertazi
2021-02-15 15:23 ` [RFC PATCH 02/13] futex2: Add support for shared futexes André Almeida
2021-02-15 15:23 ` [RFC PATCH 03/13] futex2: Implement vectorized wait André Almeida
2021-02-15 20:03 ` Gabriel Krisman Bertazi
2021-02-15 20:06 ` Zebediah Figura
2021-02-15 20:08 ` Gabriel Krisman Bertazi
2021-02-15 15:23 ` [RFC PATCH 04/13] futex2: Implement requeue operation André Almeida
2021-02-15 15:23 ` [RFC PATCH 05/13] futex2: Add compatibility entry point for x86_x32 ABI André Almeida
2021-02-15 15:23 ` [RFC PATCH 06/13] docs: locking: futex2: Add documentation André Almeida
2021-02-16 18:34 ` Randy Dunlap
2021-02-18 19:12 ` André Almeida
2021-02-15 15:23 ` [RFC PATCH 07/13] selftests: futex2: Add wake/wait test André Almeida
2021-02-15 15:23 ` [RFC PATCH 08/13] selftests: futex2: Add timeout test André Almeida
2021-02-15 15:24 ` [RFC PATCH 09/13] selftests: futex2: Add wouldblock test André Almeida
2021-02-15 15:24 ` [RFC PATCH 10/13] selftests: futex2: Add waitv test André Almeida
2021-02-15 15:24 ` [RFC PATCH 11/13] selftests: futex2: Add requeue test André Almeida
2021-02-15 15:24 ` [RFC PATCH 12/13] perf bench: Add futex2 benchmark tests André Almeida
2021-02-15 15:24 ` [RFC PATCH 13/13] kernel: Enable waitpid() for futex2 André Almeida
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 \
--in-reply-to=87y2fltlzx.fsf@collabora.com \
--to=krisman@collabora.com \
--cc=acme@kernel.org \
--cc=andrealmeid@collabora.com \
--cc=bigeasy@linutronix.de \
--cc=corbet@lwn.net \
--cc=dvhart@infradead.org \
--cc=fweimer@redhat.com \
--cc=joel@joelfernandes.org \
--cc=kernel@collabora.com \
--cc=libc-alpha@sourceware.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=malteskarupke@fastmail.fm \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pgriffais@valvesoftware.com \
--cc=rostedt@goodmis.org \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=z.figura12@gmail.com \
/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;
as well as URLs for NNTP newsgroup(s).