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From: David Howells <dhowells@redhat.com>
To: James Bottomley <James.Bottomley@steeleye.com>
Cc: David Howells <dhowells@redhat.com>,
	Andrew Morton <akpm@osdl.org>,
	torvalds@osdl.org, davem@davemloft.com, wli@holomorphy.com,
	matthew@wil.cx, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org
Subject: Re: [PATCH 3/3] WorkStruct: Use direct assignment rather than cmpxchg()
Date: Thu, 07 Dec 2006 21:16:03 +0000	[thread overview]
Message-ID: <10660.1165526163@redhat.com> (raw)
In-Reply-To: <1165525597.4698.46.camel@mulgrave.il.steeleye.com>

James Bottomley <James.Bottomley@SteelEye.com> wrote:

> That we'd have to put a conditional jump in there is an incorrect
> assumption on risc machines.

I didn't say we would *have* to put a conditional jump in there.  But I don't
know that I it can be avoided on all archs.

I don't know that sparc32 can do conditional instructions for example.  If we
force this assumption it becomes a potential limitation on the archs we can
support.  OTOH, it may be that every arch that supports SMP and has to emulate
bitops with spinlocks also supports conditional stores; but I don't know that.

David

  reply	other threads:[~2006-12-07 21:16 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-07 15:31 [PATCH 1/3] WorkStruct: Fix up some PA-RISC work items David Howells
2006-12-07 15:31 ` [PATCH 2/3] WorkStruct: Add assign_bits() to give an atomic-bitops safe assignment David Howells
2006-12-07 15:31 ` [PATCH 3/3] WorkStruct: Use direct assignment rather than cmpxchg() David Howells
2006-12-07 16:54   ` Andrew Morton
2006-12-07 20:06     ` David Howells
2006-12-07 21:06       ` Andrew Morton
2006-12-07 21:06       ` James Bottomley
2006-12-07 21:16         ` David Howells [this message]
2006-12-07 22:11           ` David Miller
2006-12-07 23:42       ` Russell King
2006-12-07 23:58         ` David Howells
2006-12-08 11:14           ` Russell King
2006-12-08 13:57             ` David Howells
2006-12-08  3:42 ` [PATCH 1/3] WorkStruct: Fix up some PA-RISC work items Kyle McMartin

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