From: David Howells <dhowells@redhat.com>
To: "Brian J. Watson" <Brian.J.Watson@compaq.com>
Cc: bcrl@redhat.com, Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] read/write semaphore trylock routines - 2.4.6
Date: Tue, 10 Jul 2001 08:32:54 +0100 [thread overview]
Message-ID: <16572.994750374@warthog.cambridge.redhat.com> (raw)
In-Reply-To: Your message of "Mon, 09 Jul 2001 20:32:13 PDT." <3B4A773D.50632896@compaq.com>
> A caveat for these trylock routines is that they use the cmpxchg
> instruction, which limits their usefulness on x86 to 486 and above.
Given that the implementation in that asm-i386/rwsem.h is based around usage
of the XADD instruction which exists everywhere the CMPXCHG instruction does
(I believe), you don't really need to put the #if clause around it.
You should also add spinlock versions too, which will cover most other archs.
David
next prev parent reply other threads:[~2001-07-10 7:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-10 3:32 [PATCH] read/write semaphore trylock routines - 2.4.6 Brian J. Watson
2001-07-10 7:32 ` David Howells [this message]
2001-07-11 3:20 ` Brian J. Watson
2001-07-18 23:22 ` Brian J. Watson
2001-07-19 7:41 ` David Howells
2001-07-25 17:56 ` [BUG 2.4.7] enabling RWSEM_DEBUG Brian J. Watson
2001-07-26 13:28 ` David Howells
2001-07-26 16:13 ` David Howells
2001-07-26 21:21 ` Brian J. Watson
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