From: Eric Dumazet <dada1@cosmosbay.com>
To: Andi Kleen <ak@suse.de>
Cc: Ravikiran G Thirumalai <kiran@scalex86.org>,
"Shai Fultheim (Shai@scalex86.org)" <shai@scalex86.org>,
pravin b shelar <pravin.shelar@calsoftinc.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC] NUMA futex hashing
Date: Tue, 8 Aug 2006 14:29:44 +0200 [thread overview]
Message-ID: <200608081429.44497.dada1@cosmosbay.com> (raw)
In-Reply-To: <200608081236.15823.ak@suse.de>
On Tuesday 08 August 2006 12:36, Andi Kleen wrote:
> > We may have special case for PRIVATE futexes (they dont need to be
> > chained in a global table, but a process private table)
>
> What do you mean with PRIVATE futex?
>
> Even if the futex mapping is only visible by a single MM mmap_sem is still
> needed to protect against other threads doing mmap.
Hum... I would call that a user error.
If a thread is munmap()ing the vma that contains active futexes, result is
undefined. Same as today I think (a thread blocked in a FUTEX_WAIT should
stay blocked)
The point is that private futexes could be managed using virtual addresses,
and no call to find_extend_vma(), hence no mmap_sem contention.
There could be problem if the same futex (32 bits integer) could be mapped at
different virtual addresses in the same process.
Eric
next prev parent reply other threads:[~2006-08-08 12:29 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-08 7:07 [RFC] NUMA futex hashing Ravikiran G Thirumalai
2006-08-08 9:14 ` Eric Dumazet
2006-08-08 20:31 ` Ravikiran G Thirumalai
2006-08-08 9:37 ` Jes Sorensen
2006-08-08 9:58 ` Andi Kleen
2006-08-08 10:07 ` Jes Sorensen
2006-08-08 9:57 ` Andi Kleen
2006-08-08 10:10 ` Eric Dumazet
2006-08-08 10:36 ` Andi Kleen
2006-08-08 12:29 ` Eric Dumazet [this message]
2006-08-08 12:47 ` Andi Kleen
2006-08-08 12:57 ` Eric Dumazet
2006-08-08 14:39 ` Ulrich Drepper
2006-08-08 15:11 ` Nick Piggin
2006-08-08 15:36 ` Ulrich Drepper
2006-08-08 16:22 ` Nick Piggin
2006-08-08 16:26 ` Nick Piggin
2006-08-08 16:49 ` Ulrich Drepper
2006-08-08 16:08 ` Eric Dumazet
2006-08-08 16:34 ` Nick Piggin
2006-08-08 16:49 ` Eric Dumazet
2006-08-08 16:59 ` Eric Dumazet
2006-08-09 1:56 ` Nick Piggin
2006-08-08 16:58 ` Ulrich Drepper
2006-08-08 17:08 ` Eric Dumazet
2006-08-09 1:58 ` Nick Piggin
2006-08-09 6:26 ` Eric Dumazet
2006-08-09 6:43 ` Eric Dumazet
2007-03-15 19:10 ` [PATCH 0/3] FUTEX : new PRIVATE futexes, SMP and NUMA improvements Eric Dumazet
2007-03-15 20:15 ` Nick Piggin
2007-03-16 8:05 ` Peter Zijlstra
2007-03-16 9:30 ` Eric Dumazet
2007-03-16 10:10 ` Peter Zijlstra
2007-03-16 10:30 ` Eric Dumazet
2007-03-16 10:36 ` Peter Zijlstra
2007-04-04 7:16 ` Ulrich Drepper
2007-04-05 17:49 ` [PATCH] FUTEX : new PRIVATE futexes Eric Dumazet
2007-04-05 20:43 ` Ulrich Drepper
2007-04-06 1:19 ` Nick Piggin
2007-04-06 5:53 ` Eric Dumazet
2007-04-06 11:50 ` Nick Piggin
2007-04-06 6:05 ` Hugh Dickins
2007-04-06 17:41 ` Jan Engelhardt
2007-04-06 12:26 ` Shared futexes (was [PATCH] FUTEX : new PRIVATE futexes) Peter Zijlstra
2007-04-06 13:02 ` Hugh Dickins
2007-04-06 13:15 ` Peter Zijlstra
2007-04-06 13:15 ` Nick Piggin
2007-04-06 13:22 ` Peter Zijlstra
2007-04-06 13:40 ` Nick Piggin
2007-04-06 12:31 ` [PATCH] FUTEX : new PRIVATE futexes Peter Zijlstra
2007-04-07 8:43 ` [PATCH, take4] " Eric Dumazet
2007-04-07 9:30 ` Nick Piggin
2007-04-07 10:00 ` Eric Dumazet
2007-04-11 7:22 ` Nick Piggin
2007-04-11 8:14 ` Eric Dumazet
2007-04-11 9:23 ` Nick Piggin
2007-04-11 9:30 ` Pierre Peiffer
2007-04-11 9:39 ` Nick Piggin
2007-04-11 9:40 ` Nick Piggin
2007-04-11 9:35 ` Eric Dumazet
2007-04-12 1:57 ` Nick Piggin
2007-04-07 11:18 ` Jakub Jelinek
2007-04-07 11:54 ` Eric Dumazet
2007-04-07 16:40 ` Ulrich Drepper
2007-04-07 22:15 ` Andrew Morton
2007-04-10 9:21 ` Eric Dumazet
2007-04-11 9:19 ` [PATCH, take5] " Eric Dumazet
2007-04-11 12:23 ` Rusty Russell
2007-04-26 12:55 ` [PATCH, take6] " Eric Dumazet
2007-04-26 13:35 ` Pierre Peiffer
2007-03-15 19:13 ` [PATCH 1/3] FUTEX : introduce PROCESS_PRIVATE semantic Eric Dumazet
2007-03-15 19:16 ` [PATCH 2/3] FUTEX : introduce private hashtables Eric Dumazet
2007-03-15 20:25 ` Nick Piggin
2007-03-15 21:09 ` Ulrich Drepper
2007-03-15 21:29 ` Nick Piggin
2007-03-15 22:59 ` William Lee Irwin III
2007-03-15 19:20 ` [PATCH 3/3] FUTEX : NUMA friendly global hashtable Eric Dumazet
2006-08-09 0:13 ` [RFC] NUMA futex hashing Ravikiran G Thirumalai
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