From: Valdis.Kletnieks@vt.edu
To: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ben Hutchings <bhutchings@solarflare.com>,
Mikulas Patocka <mpatocka@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@vger.kernel.org
Subject: Re: [PATCH] documentation: explain memory barriers
Date: Wed, 08 Oct 2008 21:50:03 -0400 [thread overview]
Message-ID: <8119.1223517003@turing-police.cc.vt.edu> (raw)
In-Reply-To: Your message of "Wed, 08 Oct 2008 18:12:23 PDT." <20081008181223.6954c7b2.randy.dunlap@oracle.com>
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On Wed, 08 Oct 2008 18:12:23 PDT, Randy Dunlap said:
> +
> +24: All memory barriers {e.g., barrier(), rmb(), wmb()} need a comment in the
> + source code that explains the logic of what they are doing and why.
"what they are doing" will almost always be "flush value to RAM" or similar.
How about this instead:
+ 24: All memory barriers ({e.g., barrier(), rmb(), wmb()} need a comment in the
+ source code that explains the race condition being prevented, and states
+ the location of the other code or hardware feature that races with this.
+
+ An example comment:
+
+ /*
+ * If we don't do a wmb() here, the RBFROBNIZ register on the XU293
+ * card will get confused and wedge the hardware...
+ */
+ wmb();
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next prev parent reply other threads:[~2008-10-09 1:52 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20080911101616.GA24064@agk.fab.redhat.com>
2008-09-22 21:10 ` [PATCH] Memory management livelock Mikulas Patocka
2008-09-23 0:48 ` Andrew Morton
2008-09-23 22:34 ` Mikulas Patocka
2008-09-23 22:49 ` Andrew Morton
2008-09-23 23:11 ` Mikulas Patocka
2008-09-23 23:46 ` Andrew Morton
2008-09-24 18:50 ` Mikulas Patocka
2008-09-24 18:51 ` [PATCH 1/3] " Mikulas Patocka
2008-09-24 18:52 ` [PATCH 2/3] " Mikulas Patocka
2008-10-02 5:54 ` Andrew Morton
2008-10-05 22:11 ` RFC: one-bit mutexes (was: Re: [PATCH 2/3] Memory management livelock) Mikulas Patocka
2008-10-11 12:06 ` Nick Piggin
2008-10-20 20:14 ` Mikulas Patocka
2008-10-21 1:51 ` Nick Piggin
2008-10-05 22:14 ` [PATCH 1/3] bit mutexes Mikulas Patocka
2008-10-05 22:14 ` [PATCH 2/3] Fix fsync livelock Mikulas Patocka
2008-10-05 22:33 ` Arjan van de Ven
2008-10-05 23:02 ` Mikulas Patocka
2008-10-05 23:07 ` Arjan van de Ven
2008-10-05 23:18 ` Mikulas Patocka
2008-10-05 23:28 ` Arjan van de Ven
2008-10-06 0:01 ` Mikulas Patocka
2008-10-06 0:30 ` Arjan van de Ven
2008-10-06 3:30 ` Mikulas Patocka
2008-10-06 4:20 ` Arjan van de Ven
2008-10-06 13:00 ` Mikulas Patocka
2008-10-06 13:50 ` Arjan van de Ven
2008-10-06 20:44 ` Mikulas Patocka
2008-10-08 10:56 ` Pavel Machek
2008-10-06 2:51 ` Dave Chinner
2008-10-05 22:16 ` [PATCH 3/3] Fix fsync-vs-write misbehavior Mikulas Patocka
2008-10-09 1:12 ` [PATCH] documentation: explain memory barriers Randy Dunlap
2008-10-09 1:17 ` Chris Snook
2008-10-09 1:31 ` Andrew Morton
2008-10-09 5:51 ` Chris Snook
2008-10-09 9:58 ` Ben Hutchings
2008-10-09 21:27 ` Nick Piggin
2008-10-09 17:29 ` Nick Piggin
2008-10-09 1:50 ` Valdis.Kletnieks [this message]
2008-10-09 17:35 ` Nick Piggin
2008-10-09 6:52 ` Valdis.Kletnieks
2008-09-24 18:53 ` [PATCH 3/3] Memory management livelock Mikulas Patocka
2008-10-03 2:32 ` [PATCH] " Nick Piggin
2008-10-03 2:40 ` Andrew Morton
2008-10-03 2:59 ` Nick Piggin
2008-10-03 3:14 ` Andrew Morton
2008-10-03 3:47 ` Nick Piggin
2008-10-03 3:56 ` Andrew Morton
2008-10-03 4:07 ` Nick Piggin
2008-10-03 4:17 ` Andrew Morton
2008-10-03 4:29 ` Nick Piggin
2008-10-03 11:43 ` Mikulas Patocka
2008-10-03 12:27 ` Nick Piggin
2008-10-03 13:53 ` Mikulas Patocka
2008-10-03 2:54 ` Nick Piggin
2008-10-03 11:26 ` Mikulas Patocka
2008-10-03 12:31 ` Nick Piggin
2008-10-03 13:50 ` Mikulas Patocka
2008-10-03 14:50 ` Alasdair G Kergon
2008-10-03 14:36 ` Alasdair G Kergon
2008-10-03 15:52 ` application syncing options (was Re: [PATCH] Memory management livelock) david
2008-10-06 0:04 ` Mikulas Patocka
2008-10-06 0:19 ` david
2008-10-06 3:42 ` Mikulas Patocka
2008-10-07 3:37 ` david
2008-10-07 15:44 ` Mikulas Patocka
2008-10-07 17:16 ` david
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