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Re: [PATCH] Fix lost wake-up when pthread_rwlock_timedrwlock times out.
- From: Torvald Riegel <triegel at redhat dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: GLIBC Devel <libc-alpha at sourceware dot org>, "Carlos O'Donell" <carlos at redhat dot com>, Siddhesh Poyarekar <siddhesh at redhat dot com>
- Date: Wed, 13 May 2015 11:11:46 +0200
- Subject: Re: [PATCH] Fix lost wake-up when pthread_rwlock_timedrwlock times out.
- Authentication-results: sourceware.org; auth=none
- References: <1429715209 dot 17814 dot 38 dot camel at triegel dot csb> <alpine dot DEB dot 2 dot 10 dot 1504241752410 dot 30193 at digraph dot polyomino dot org dot uk> <1430324093 dot 4450 dot 96 dot camel at triegel dot csb>
Ping.
On Wed, 2015-04-29 at 18:14 +0200, Torvald Riegel wrote:
> On Fri, 2015-04-24 at 17:53 +0000, Joseph Myers wrote:
> > On Wed, 22 Apr 2015, Torvald Riegel wrote:
> >
> > > If we set up a rwlock to prefer writers (and disallow recursive rdlock
> > > acquisitions), then readers will block for writers that are blocked to
> > > acquire the lock (otherwise, readers could constantly enter and exit,
> > > and the writer would never get the lock). However, the existing
> > > implementation did not wake such readers when the writer timed out.
> > > This patch adds the missing wake-up.
> > > There's no similar case for writers being blocked on readers.
> > >
> > > Tested on x86_64-linux. OK?
> > >
> > > 2015-04-22 Torvald Riegel <triegel@redhat.com>
> > >
> > > * nptl/pthread_rwlock_timedwrlock.c (pthread_rwlock_timedwrlock): Add
> > > missing wake-up of readers.
> > > * nptl/tst-rwlock15.c: New file.
> > > * nptl/Makefile (tests): Add new test.
> >
> > If this was a bug that was user-visible in a release, there should be a
> > bug filed in Bugzilla for it and appropriate [BZ #N] used.
> >
>
> Thanks for the reminder, here's an updated version. I also added a
> small performance optimization.
>
> Tested on x86_64-linux. OK?
>
> 2015-04-28 Torvald Riegel <triegel@redhat.com>
>
> [BZ #18324]
> * nptl/pthread_rwlock_timedwrlock.c (pthread_rwlock_timedwrlock): Add
> missing wake-up of readers.
> * nptl/tst-rwlock15.c: New file.
> * nptl/Makefile (tests): Add new test.
>