linux-kernel - Re: [PATCH] Documentation: locking: update libc support status of PI futexes

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Message-ID: <20250107153121.wAL-TfKG@linutronix.de>
Date: Tue, 7 Jan 2025 16:31:21 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: alison@...-devel.com
Cc: corbet@....net, gratian.crisan@...com, triegel@...hat.com,
	rostedt@...dmis.org, linux-kernel@...r.kernel.org,
	linux-rt-users@...r.kernel.org, achaiken@...ora.tech
Subject: Re: [PATCH] Documentation: locking: update libc support status of PI
 futexes

On 2024-12-28 10:15:46 [-0800], alison@...-devel.com wrote:
> From: Alison Chaiken <alison@...-devel.com>
> 
> Update the text of futex-requeue-pi.rst to explain that, because of a
> conflict between POSIX requirements and ABI constraints, glibc does
> not support requeueing of PI futexes.  Add some information about
> librtpi, a library which provides an implementation of condition
> variables which supports priority inheritance.

Are you sure? My memory is that glibc avoided using the internal mutex.
The old problem should be gone and pthread_cond_signal() and
pthread_cond_wait() should work.

> Signed-off-by: Alison Chaiken <alison@...-devel.com>

Sebastian