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From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: bogus barriers in sym53c8xx_2?
Date: Tue, 19 Aug 2003 23:49:53 +0000	[thread overview]
Message-ID: <marc-linux-ia64-106133886310517@msgid-missing> (raw)

In drivers/scsi/sym53c8xx_2/sym_misc.h we find:

#elif	defined	__ia64__
#define __READ_BARRIER()	__asm__ volatile("mf.a; mf" : : : "memory")
#define __WRITE_BARRIER()	__asm__ volatile("mf.a; mf" : : : "memory")

based on the comments and the other implementations, these barriers
are bogus and the "mf.a" should be dropped.

Anyone know who wrote this code originally and why the mf.a was added?

mf.a is very slow and should be avoided except were truly needed.

	--david

             reply	other threads:[~2003-08-19 23:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-08-19 23:49 David Mosberger [this message]
2003-08-20  3:26 ` bogus barriers in sym53c8xx_2? Matthew Wilcox
2003-08-20  3:43 ` Anton Blanchard
2003-08-21 19:34 ` David Mosberger

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