mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
* Cheap lock for user mode processes release when process exits
@ 2007-04-13  1:54 mchu
  2007-04-13  2:43 ` Andrew Morton
  0 siblings, 1 reply; 2+ messages in thread
From: mchu @ 2007-04-13  1:54 UTC (permalink / raw)
  To: linux-kernel

Hi all,

Maybe someone here knows better.

I have several user-mode processes using shared mmap.  There can be several reader processes and only one writer.  Readers access the shared region frequently, writer seldom.

Naturally, multi-reader/single-writer locks works best.  I tried this with futex on 2.6.9-42.EL.  However, if one of the processes is killed/exits, the lock doesn't get released.

I can trap the signal to release the lock, but not all signals like kill.

Anyway I can achieve this without a potential deadlock?

Thanks,
Michael

^ permalink raw reply	[flat|nested] 2+ messages in thread
* Re: Cheap lock for user mode processes release when process exits
  2007-04-13  1:54 Cheap lock for user mode processes release when process exits mchu
@ 2007-04-13  2:43 ` Andrew Morton
  0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2007-04-13  2:43 UTC (permalink / raw)
  To: mchu; +Cc: linux-kernel

On Fri, 13 Apr 2007 01:54:28 +0000 (GMT) <mchu@mirapoint.com> wrote:

> Hi all,
> 
> Maybe someone here knows better.
> 
> I have several user-mode processes using shared mmap.  There can be several reader processes and only one writer.  Readers access the shared region frequently, writer seldom.
> 
> Naturally, multi-reader/single-writer locks works best.  I tried this with futex on 2.6.9-42.EL.  However, if one of the processes is killed/exits, the lock doesn't get released.
> 
> I can trap the signal to release the lock, but not all signals like kill.
> 
> Anyway I can achieve this without a potential deadlock?
> 

Robust futexes: http://lwn.net/Articles/172149/

But I don't know whether RH backported them into RHEL4.

^ permalink raw reply	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2007-04-13  2:44 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-04-13  1:54 Cheap lock for user mode processes release when process exits mchu
2007-04-13  2:43 ` Andrew Morton

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome