From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Nick Piggin <npiggin@suse.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
Rusty Russell <rusty@rustcorp.com.au>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org
Subject: Re: Q: smp.c && barriers (Was: [PATCH 1/4] generic-smp: remove single ipi fallback for smp_call_function_many())
Date: Tue, 17 Feb 2009 13:40:55 +0100 [thread overview]
Message-ID: <1234874455.4744.96.camel@laptop> (raw)
In-Reply-To: <1234862974.4744.31.camel@laptop>
On Tue, 2009-02-17 at 10:29 +0100, Peter Zijlstra wrote:
> > It would be nice to have a comment which explains how can we miss the
> > first addition without read_barrier_depends(). And why only on alpha.
>
> Paul, care to once again enlighten us? The best I can remember is that
> alpha has split caches, and the rmb is needed for them to become
> coherent -- no other arch is crazy in exactly that way.
>
> But note that read_barrier_depends() is not quite a NOP for !alpha, it
> does that ACCESS_ONCE() thing, which very much makes a difference, even
> on x86.
I've been saying crazy stuff, read_barrier_depends() is a NOP, I got
confused with rcu_dereference(). My bad.
next prev parent reply other threads:[~2009-02-17 12:41 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-16 16:38 [PATCH 0/4] generic smp helpers vs kmalloc Peter Zijlstra
2009-02-16 16:38 ` [PATCH 1/4] generic-smp: remove single ipi fallback for smp_call_function_many() Peter Zijlstra
2009-02-16 19:10 ` Oleg Nesterov
2009-02-16 19:41 ` Peter Zijlstra
2009-02-16 20:30 ` Oleg Nesterov
2009-02-16 20:55 ` Peter Zijlstra
2009-02-16 21:22 ` Oleg Nesterov
2009-02-17 12:25 ` Oleg Nesterov
2009-02-16 20:49 ` Q: smp.c && barriers (Was: [PATCH 1/4] generic-smp: remove single ipi fallback for smp_call_function_many()) Oleg Nesterov
2009-02-16 21:03 ` Peter Zijlstra
2009-02-16 21:32 ` Oleg Nesterov
2009-02-16 21:45 ` Peter Zijlstra
2009-02-16 22:02 ` Oleg Nesterov
2009-02-16 22:24 ` Peter Zijlstra
2009-02-16 23:19 ` Oleg Nesterov
2009-02-17 9:29 ` Peter Zijlstra
2009-02-17 10:11 ` Nick Piggin
2009-02-17 10:27 ` Peter Zijlstra
2009-02-17 10:39 ` Nick Piggin
2009-02-17 11:26 ` Nick Piggin
2009-02-17 11:48 ` Peter Zijlstra
2009-02-17 15:51 ` Paul E. McKenney
2009-02-18 2:15 ` Suresh Siddha
2009-02-18 2:40 ` Paul E. McKenney
2009-02-17 19:28 ` Q: " Oleg Nesterov
2009-02-17 21:32 ` Paul E. McKenney
2009-02-17 21:45 ` Oleg Nesterov
2009-02-17 22:39 ` Paul E. McKenney
2009-02-18 13:52 ` Nick Piggin
2009-02-18 16:09 ` Linus Torvalds
2009-02-18 16:21 ` Ingo Molnar
2009-02-18 16:21 ` Ingo Molnar
2009-02-18 16:21 ` Ingo Molnar
2009-02-18 16:33 ` Linus Torvalds
2009-02-18 16:58 ` Ingo Molnar
2009-02-18 17:05 ` Ingo Molnar
2009-02-18 17:10 ` Ingo Molnar
2009-02-18 17:17 ` Linus Torvalds
2009-02-18 17:23 ` Ingo Molnar
2009-02-18 17:14 ` Linus Torvalds
2009-02-18 17:47 ` Ingo Molnar
2009-02-18 18:33 ` Suresh Siddha
2009-02-18 16:37 ` Gleb Natapov
2009-02-19 0:12 ` Nick Piggin
2009-02-19 6:47 ` Benjamin Herrenschmidt
2009-02-19 13:11 ` Nick Piggin
2009-02-19 15:06 ` Ingo Molnar
2009-02-19 21:49 ` Benjamin Herrenschmidt
2009-02-18 2:21 ` Suresh Siddha
2009-02-18 13:59 ` Nick Piggin
2009-02-18 16:19 ` Linus Torvalds
2009-02-18 16:23 ` Ingo Molnar
2009-02-18 18:43 ` Suresh Siddha
2009-02-18 19:17 ` Ingo Molnar
2009-02-18 23:55 ` Suresh Siddha
2009-02-19 12:20 ` Ingo Molnar
2009-02-19 12:29 ` Nick Piggin
2009-02-19 12:45 ` Ingo Molnar
2009-02-19 22:00 ` Suresh Siddha
2009-02-20 10:56 ` Ingo Molnar
2009-02-20 18:56 ` Suresh Siddha
2009-02-20 19:40 ` Ingo Molnar
2009-02-20 23:28 ` Jack Steiner
2009-02-25 3:32 ` Nick Piggin
2009-02-25 12:47 ` Ingo Molnar
2009-02-25 18:25 ` Luck, Tony
2009-03-17 18:16 ` Suresh Siddha
2009-03-18 8:51 ` [tip:x86/x2apic] x86: add x2apic_wrmsr_fence() to x2apic flush tlb paths Suresh Siddha
2009-02-17 12:40 ` Peter Zijlstra [this message]
2009-02-17 15:43 ` Q: smp.c && barriers (Was: [PATCH 1/4] generic-smp: remove single ipi fallback for smp_call_function_many()) Paul E. McKenney
2009-02-17 15:40 ` [PATCH] generic-smp: remove kmalloc() Peter Zijlstra
2009-02-17 17:21 ` Oleg Nesterov
2009-02-17 17:40 ` Peter Zijlstra
2009-02-17 17:46 ` Peter Zijlstra
2009-02-17 18:30 ` Oleg Nesterov
2009-02-17 19:29 ` [PATCH -v4] generic-ipi: " Peter Zijlstra
2009-02-17 20:02 ` Oleg Nesterov
2009-02-17 20:11 ` Peter Zijlstra
2009-02-17 20:16 ` Peter Zijlstra
2009-02-17 20:44 ` Oleg Nesterov
2009-02-17 20:49 ` Peter Zijlstra
2009-02-17 22:09 ` Oleg Nesterov
2009-02-17 22:15 ` Peter Zijlstra
2009-02-17 21:30 ` Paul E. McKenney
2009-02-17 21:38 ` Peter Zijlstra
2009-02-16 16:38 ` [PATCH 2/4] generic-smp: remove kmalloc usage Peter Zijlstra
2009-02-17 0:40 ` Linus Torvalds
2009-02-17 8:24 ` Peter Zijlstra
2009-02-17 9:43 ` Ingo Molnar
2009-02-17 9:49 ` Peter Zijlstra
2009-02-17 10:56 ` Ingo Molnar
2009-02-18 4:50 ` Rusty Russell
2009-02-18 16:05 ` Ingo Molnar
2009-02-19 0:00 ` Jeremy Fitzhardinge
2009-02-19 12:21 ` Ingo Molnar
2009-02-19 4:31 ` Rusty Russell
2009-02-19 9:10 ` Peter Zijlstra
2009-02-19 11:04 ` Jens Axboe
2009-02-19 16:52 ` Linus Torvalds
2009-02-17 15:44 ` Linus Torvalds
2009-02-16 16:38 ` [PATCH 3/4] generic-smp: properly allocate the cpumasks Peter Zijlstra
2009-02-16 23:17 ` Rusty Russell
2009-02-16 16:38 ` [PATCH 4/4] generic-smp: clean up some of the csd->flags fiddling Peter Zijlstra
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=1234874455.4744.96.camel@laptop \
--to=peterz@infradead.org \
--cc=jens.axboe@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=npiggin@suse.de \
--cc=oleg@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=rostedt@goodmis.org \
--cc=rusty@rustcorp.com.au \
--cc=suresh.b.siddha@intel.com \
--cc=torvalds@linux-foundation.org \
/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.