From: Peter Zijlstra <peterz@infradead.org>
To: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Jason Low <jason.low2@hp.com>, Davidlohr Bueso <davidlohr@hp.com>,
Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Alex Shi <alex.shi@linaro.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] checkpatch: Make the memory barrier test noisier
Date: Fri, 27 Sep 2013 16:50:07 +0200 [thread overview]
Message-ID: <20130927145007.GD15690@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <1380292495.17366.106.camel@joe-AO722>
On Fri, Sep 27, 2013 at 07:34:55AM -0700, Joe Perches wrote:
> That would make it seem as if all barriers are SMP no?
I would think any memory barrier is ordering against someone else; if
not smp then a device/hardware -- like for instance the hardware page
table walker.
Barriers are fundamentally about order; and order only makes sense if
there's more than 1 party to the game.
> Maybe just refer to Documentation/memory-barriers.txt
> and/or say something like "please document appropriately"
Documentation/memory-barriers.txt is always good; appropriately doesn't
seem to quantify anything much at all. Someone might think:
/* */
smp_mb();
appropriate...
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Jason Low <jason.low2@hp.com>, Davidlohr Bueso <davidlohr@hp.com>,
Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Alex Shi <alex.shi@linaro.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] checkpatch: Make the memory barrier test noisier
Date: Fri, 27 Sep 2013 16:50:07 +0200 [thread overview]
Message-ID: <20130927145007.GD15690@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <1380292495.17366.106.camel@joe-AO722>
On Fri, Sep 27, 2013 at 07:34:55AM -0700, Joe Perches wrote:
> That would make it seem as if all barriers are SMP no?
I would think any memory barrier is ordering against someone else; if
not smp then a device/hardware -- like for instance the hardware page
table walker.
Barriers are fundamentally about order; and order only makes sense if
there's more than 1 party to the game.
> Maybe just refer to Documentation/memory-barriers.txt
> and/or say something like "please document appropriately"
Documentation/memory-barriers.txt is always good; appropriately doesn't
seem to quantify anything much at all. Someone might think:
/* */
smp_mb();
appropriate...
next prev parent reply other threads:[~2013-09-27 14:50 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1380144003.git.tim.c.chen@linux.intel.com>
2013-09-25 22:10 ` [PATCH v6 0/6] rwsem: performance optimizations Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 1/6] rwsem: check the lock before cpmxchg in down_write_trylock Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 2/6] rwsem: remove 'out' label in do_wake Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 3/6] rwsem: remove try_reader_grant label do_wake Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 4/6] rwsem/wake: check lock before do atomic update Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 5/6] MCS Lock: Restructure the MCS lock defines and locking code into its own file Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-26 6:46 ` Ingo Molnar
2013-09-26 6:46 ` Ingo Molnar
2013-09-26 8:40 ` Peter Zijlstra
2013-09-26 8:40 ` Peter Zijlstra
2013-09-26 9:37 ` Ingo Molnar
2013-09-26 9:37 ` Ingo Molnar
2013-09-26 18:18 ` Tim Chen
2013-09-26 18:18 ` Tim Chen
2013-09-26 19:27 ` Jason Low
2013-09-26 19:27 ` Jason Low
2013-09-26 20:06 ` Davidlohr Bueso
2013-09-26 20:06 ` Davidlohr Bueso
2013-09-26 20:23 ` Jason Low
2013-09-26 20:23 ` Jason Low
2013-09-26 20:40 ` Davidlohr Bueso
2013-09-26 20:40 ` Davidlohr Bueso
2013-09-26 21:09 ` Jason Low
2013-09-26 21:09 ` Jason Low
2013-09-26 21:41 ` Tim Chen
2013-09-26 21:41 ` Tim Chen
2013-09-26 22:42 ` Jason Low
2013-09-26 22:42 ` Jason Low
2013-09-26 22:57 ` Tim Chen
2013-09-26 22:57 ` Tim Chen
2013-09-27 6:02 ` Ingo Molnar
2013-09-27 6:02 ` Ingo Molnar
2013-09-27 6:26 ` Jason Low
2013-09-27 6:26 ` Jason Low
2013-09-27 11:23 ` Peter Zijlstra
2013-09-27 11:23 ` Peter Zijlstra
2013-09-27 13:44 ` Joe Perches
2013-09-27 13:44 ` Joe Perches
2013-09-27 13:48 ` Peter Zijlstra
2013-09-27 13:48 ` Peter Zijlstra
2013-09-27 14:05 ` Joe Perches
2013-09-27 14:05 ` Joe Perches
2013-09-27 14:18 ` Peter Zijlstra
2013-09-27 14:18 ` Peter Zijlstra
2013-09-27 14:14 ` [PATCH] checkpatch: Make the memory barrier test noisier Joe Perches
2013-09-27 14:14 ` Joe Perches
2013-09-27 14:26 ` Peter Zijlstra
2013-09-27 14:26 ` Peter Zijlstra
2013-09-27 14:34 ` Joe Perches
2013-09-27 14:34 ` Joe Perches
2013-09-27 14:50 ` Peter Zijlstra [this message]
2013-09-27 14:50 ` Peter Zijlstra
2013-09-27 15:17 ` Paul E. McKenney
2013-09-27 15:17 ` Paul E. McKenney
2013-09-27 15:34 ` Peter Zijlstra
2013-09-27 15:34 ` Peter Zijlstra
2013-09-27 16:04 ` Paul E. McKenney
2013-09-27 16:04 ` Paul E. McKenney
2013-09-27 16:04 ` Paul E. McKenney
2013-09-27 23:40 ` Oliver Neukum
2013-09-27 23:40 ` Oliver Neukum
2013-09-28 7:54 ` Peter Zijlstra
2013-09-28 7:54 ` Peter Zijlstra
2013-09-27 16:12 ` [PATCH v6 5/6] MCS Lock: Restructure the MCS lock defines and locking code into its own file Jason Low
2013-09-27 16:12 ` Jason Low
2013-09-27 16:19 ` Tim Chen
2013-09-27 16:19 ` Tim Chen
2013-10-02 19:19 ` Waiman Long
2013-10-02 19:19 ` Waiman Long
2013-10-02 19:30 ` Jason Low
2013-10-02 19:30 ` Jason Low
2013-10-02 19:37 ` Waiman Long
2013-10-02 19:37 ` Waiman Long
2013-09-26 22:22 ` Davidlohr Bueso
2013-09-26 22:22 ` Davidlohr Bueso
2013-09-27 15:29 ` Paul E. McKenney
2013-09-27 15:29 ` Paul E. McKenney
2013-09-27 18:09 ` Tim Chen
2013-09-27 18:09 ` Tim Chen
2013-09-28 2:58 ` Waiman Long
2013-09-28 2:58 ` Waiman Long
2013-09-27 19:38 ` Tim Chen
2013-09-27 19:38 ` Tim Chen
2013-09-27 20:16 ` Jason Low
2013-09-27 20:16 ` Jason Low
2013-09-27 20:38 ` Paul E. McKenney
2013-09-27 20:38 ` Paul E. McKenney
2013-09-27 22:46 ` Tim Chen
2013-09-27 22:46 ` Tim Chen
2013-09-27 23:01 ` Paul E. McKenney
2013-09-27 23:01 ` Paul E. McKenney
2013-09-27 23:54 ` Jason Low
2013-09-27 23:54 ` Jason Low
2013-09-28 0:02 ` Davidlohr Bueso
2013-09-28 0:02 ` Davidlohr Bueso
2013-09-28 2:19 ` Paul E. McKenney
2013-09-28 2:19 ` Paul E. McKenney
2013-09-28 4:34 ` Jason Low
2013-09-28 4:34 ` Jason Low
2013-09-30 15:51 ` Waiman Long
2013-09-30 15:51 ` Waiman Long
2013-09-30 16:10 ` Jason Low
2013-09-30 16:10 ` Jason Low
2013-09-30 16:36 ` Waiman Long
2013-09-30 16:36 ` Waiman Long
2013-10-01 16:48 ` Tim Chen
2013-10-01 16:48 ` Tim Chen
2013-10-01 20:01 ` Waiman Long
2013-10-01 20:01 ` Waiman Long
2013-10-01 21:16 ` Tim Chen
2013-10-01 21:16 ` Tim Chen
2013-10-02 1:25 ` Waiman Long
2013-10-02 1:25 ` Waiman Long
2013-10-02 18:43 ` Tim Chen
2013-10-02 18:43 ` Tim Chen
2013-10-02 19:32 ` Waiman Long
2013-10-02 19:32 ` Waiman Long
2013-09-30 16:28 ` Tim Chen
2013-09-30 16:28 ` Tim Chen
2013-09-25 22:10 ` [PATCH v6 6/6] rwsem: do optimistic spinning for writer lock acquisition Tim Chen
2013-09-25 22:10 ` Tim Chen
2013-09-26 6:53 ` Ingo Molnar
2013-09-26 6:53 ` Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130927145007.GD15690@laptop.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=alex.shi@linaro.org \
--cc=andi@firstfloor.org \
--cc=dave.hansen@intel.com \
--cc=davidlohr.bueso@hp.com \
--cc=davidlohr@hp.com \
--cc=jason.low2@hp.com \
--cc=joe@perches.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=matthew.r.wilcox@intel.com \
--cc=mingo@elte.hu \
--cc=mingo@kernel.org \
--cc=peter@hurleysoftware.com \
--cc=riel@redhat.com \
--cc=tim.c.chen@linux.intel.com \
--cc=walken@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.