Re: [patch 2/5] mutex subsystem: add architecture specific mutex primitives

• To: Nicolas Pitre <[email protected]>
• Subject: Re: [patch 2/5] mutex subsystem: add architecture specific mutex primitives
• From: Nick Piggin <[email protected]>
• Date: Thu, 22 Dec 2005 19:03:32 +1100
• Cc: Ingo Molnar <[email protected]>, Linus Torvalds <[email protected]>, lkml <[email protected]>, Andrew Morton <[email protected]>, Arjan van de Ven <[email protected]>, Jes Sorensen <[email protected]>, Zwane Mwaikambo <[email protected]>, Oleg Nesterov <[email protected]>, David Howells <[email protected]>, Alan Cox <[email protected]>, Benjamin LaHaise <[email protected]>, Steven Rostedt <[email protected]>, Christoph Hellwig <[email protected]>, Andi Kleen <[email protected]>, Russell King <[email protected]>
• Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=Udf2hm4gxayh3AsExt/8vNsQKeUG3OLyIoWerHTEwCWr6iaAxjfm0dXGsf05x8pbEKkR7S/4IJmJzGvV7rVlep7YJzd71D6TEW6/TCHz/EsCdjGaVAevhIX5N0Sg1OQfmTCs5a0J2WtpSELr+SezrfIqCmX4wF48h+slFJ2fYUQ= ;
• In-reply-to: <[email protected]>
• References: <[email protected]> <[email protected]> <[email protected]> <[email protected]> <[email protected]>
• Sender: [email protected]
• User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1

Nick Piggin wrote:

I think ARMv6 has a decent atomic_cmpxchg implementation but does
not define __HAVE_ARCH_CMPXCHG. It might be useful to try to use this
for ARMv6 SMP for a slightly better trylock.

And on UP builds, it may simply be best to open code an interrupt unsafe
cmpxchg and use atomic_cmpxchg unconditionally on SMP builds (which I
think generates half decent code on all SMP architectures).

Just something to think about. Of course this will require the dreaded
preempt_disable() which might make it a showstopper.

--
SUSE Labs, Novell Inc.

Send instant messages to your online friends http://au.messenger.yahoo.com -

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• References:
  • [patch 0/8] mutex subsystem, ANNOUNCE
    • From: Ingo Molnar <[email protected]>
  • [patch 3/3] mutex subsystem: move the core to the new atomic helpers
    • From: Nicolas Pitre <[email protected]>
  • Re: [patch 3/3] mutex subsystem: move the core to the new atomic helpers
    • From: Ingo Molnar <[email protected]>
  • [patch 2/5] mutex subsystem: add architecture specific mutex primitives
    • From: Nicolas Pitre <[email protected]>
  • Re: [patch 2/5] mutex subsystem: add architecture specific mutex primitives
    • From: Nick Piggin <[email protected]>

• Prev by Date: Re: [patch 0/8] mutex subsystem, ANNOUNCE
• Next by Date: Re: [patch 0/8] mutex subsystem, ANNOUNCE
• Previous by thread: Re: [patch 2/5] mutex subsystem: add architecture specific mutex primitives
• Next by thread: [patch 1/5] mutex subsystem: fix asm-arm/atomic.h
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]