Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.programming.threads > #1028
| Date | 2012-08-25 16:47 -0700 |
|---|---|
| From | Patricia Shanahan <pats@acm.org> |
| Newsgroups | comp.programming.threads, comp.programming |
| Subject | Re: Distributed Reader-Writer Mutex by Dmitry Vyukov |
| References | <k1bkhs$uk8$1@dont-email.me> |
| Message-ID | <eImdnZsJT9u4-aTNnZ2dnUVZ_rqdnZ2d@earthlink.com> (permalink) |
Cross-posted to 2 groups.
On 8/25/2012 4:45 PM, aminer wrote:
> Hello all;
>
> I have loolked at the Distributed Reader-Writer Mutex by Dmitry Vyukov, look
> at
>
> http://www.1024cores.net/home/lock-free-algorithms/reader-writer-problem/distributed-reader-writer-mutex
>
>
> and i have looked at it and i think there is a problem with this method,
> cause look
> at the write lock function:
>
> int distr_rw_mutex_wrlock (distr_rw_mutex_t* mtx)
> {
> int i;
> for (i = 0; i != mtx->proc_count; i += 1)
> pthread_rwlock_wrlock(&mtx->cell[i].mtx);
> return 0;
> }
>
>
> What is wrong with it ? suppose two or more writers wants to lock this
> distributed rwlock
> there is a possibility of a deadlock.
>
> So i think you have to use a critical section around the for loop to be able
> to lock
> all the rwlocks at the same time to avoid the deadlock problem..
>
>
> Am i correct or not ?
The text explanation on the referenced web page says 'No additional
synchronization between writers is required, writers acquire the mutexes
in the same order (from 0 to P-1), so ownership over mutex 0 basically
determines who is the "current" writer (all other potential writers are
parked on mutex 0).'
Do you disagree with that explanation? If so, could you describe a
deadlock scenario that takes into account the fixed order of acquisition?
Patricia
Back to comp.programming.threads | Previous | Next — Previous in thread | Next in thread | Find similar
Distributed Reader-Writer Mutex by Dmitry Vyukov "aminer" <aminer@videotron.ca> - 2012-08-25 18:45 -0500
Re: Distributed Reader-Writer Mutex by Dmitry Vyukov "aminer" <aminer@videotron.ca> - 2012-08-25 19:19 -0500
Re: Distributed Reader-Writer Mutex by Dmitry Vyukov "aminer" <aminer@videotron.ca> - 2012-08-25 19:23 -0500
Re: Distributed Reader-Writer Mutex by Dmitry Vyukov Patricia Shanahan <pats@acm.org> - 2012-08-25 16:47 -0700
Re: Distributed Reader-Writer Mutex by Dmitry Vyukov "aminer" <aminer@videotron.ca> - 2012-08-25 19:56 -0500
csiph-web