From: David Miller <davem@davemloft.net>
To: rostedt@goodmis.org
Cc: peterz@infradead.org, will.newton@gmail.com, jbaron@redhat.com,
mathieu.desnoyers@polymtl.ca, hpa@zytor.com, mingo@elte.hu,
tglx@linutronix.de, andi@firstfloor.org, roland@redhat.com,
rth@redhat.com, masami.hiramatsu.pt@hitachi.com,
fweisbec@gmail.com, avi@redhat.com, sam@ravnborg.org,
ddaney@caviumnetworks.com, michael@ellerman.id.au,
linux-kernel@vger.kernel.org, vapier@gentoo.org,
cmetcalf@tilera.com, dhowells@redhat.com, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, benh@kernel.crashing.org
Subject: Re: [PATCH 0/2] jump label: 2.6.38 updates
Date: Mon, 14 Feb 2011 14:33:06 -0800 (PST) [thread overview]
Message-ID: <20110214.143306.193725652.davem@davemloft.net> (raw)
In-Reply-To: <1297722030.23343.86.camel@gandalf.stny.rr.com>
From: Steven Rostedt <rostedt@goodmis.org>
Date: Mon, 14 Feb 2011 17:20:30 -0500
> On Mon, 2011-02-14 at 13:46 -0800, David Miller wrote:
>> From: Steven Rostedt <rostedt@goodmis.org>
>> Date: Mon, 14 Feb 2011 16:39:36 -0500
>>
>> > Thus it is not about global, as global is updated by normal means and
>> > will update the caches. atomic_t is updated via the ll/sc that ignores
>> > the cache and causes all this to break down. IOW... broken hardware ;)
>>
>> I don't see how cache coherency can possibly work if the hardware
>> behaves this way.
>>
>> In cache aliasing situations, yes I can understand a L1 cache visibility
>> issue being present, but with kernel only stuff that should never happen
>> otherwise we have a bug in the arch cache flushing support.
>
> I guess the issue is, if you use ll/sc on memory, you must always use
> ll/sc on that memory, otherwise any normal read won't read the proper
> cache.
That also makes no sense at all.
Any update to the L2 cache must be snooped by the L1 cache and cause
an update, otherwise nothing can work correctly.
So every object we use cmpxchg() on in the kernel cannot work on this
architecture? Is that what you're saying?
If so, a lot of things we do will not work.
.
next prev parent reply other threads:[~2011-02-14 22:32 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-05 15:43 Jason Baron
2011-01-05 15:43 ` [PATCH 1/2] jump label: make enable/disable o(1) Jason Baron
2011-01-05 17:31 ` Steven Rostedt
2011-01-05 21:19 ` Jason Baron
2011-01-05 15:43 ` [PATCH 2/2] jump label: introduce static_branch() Jason Baron
2011-01-05 17:15 ` Frederic Weisbecker
2011-01-05 17:46 ` Steven Rostedt
2011-01-05 18:52 ` H. Peter Anvin
2011-01-05 21:19 ` Jason Baron
2011-01-05 21:14 ` Jason Baron
2011-01-05 17:32 ` David Daney
2011-01-05 17:43 ` Steven Rostedt
2011-01-05 18:44 ` David Miller
2011-01-05 20:04 ` Steven Rostedt
2011-01-05 18:56 ` H. Peter Anvin
2011-01-05 19:14 ` Ingo Molnar
2011-01-05 19:32 ` David Daney
2011-01-05 19:50 ` Ingo Molnar
2011-01-05 20:07 ` David Daney
2011-01-05 20:08 ` H. Peter Anvin
2011-01-05 20:18 ` Ingo Molnar
2011-01-05 21:16 ` Jason Baron
2011-01-05 17:41 ` Steven Rostedt
2011-01-09 18:48 ` Mathieu Desnoyers
2011-02-11 19:25 ` [PATCH 0/2] jump label: 2.6.38 updates Peter Zijlstra
2011-02-11 21:13 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP101B686C32E10BA346B15F896EF0@phx.gbl>
2011-02-11 21:38 ` Peter Zijlstra
2011-02-11 22:15 ` Jason Baron
2011-02-11 22:19 ` H. Peter Anvin
2011-02-11 22:30 ` Mathieu Desnoyers
2011-02-11 22:20 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP8562BA758CF8AAE5323AE296EF0@phx.gbl>
2011-02-11 22:27 ` Jason Baron
2011-02-11 22:32 ` Mathieu Desnoyers
2011-02-12 18:47 ` Peter Zijlstra
2011-02-14 12:27 ` Ingo Molnar
2011-02-14 15:51 ` Jason Baron
2011-02-14 15:57 ` Peter Zijlstra
2011-02-14 16:04 ` Jason Baron
2011-02-14 16:14 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP4069A1A89F06CDFF9B28F896D00@phx.gbl>
2011-02-14 16:25 ` Peter Zijlstra
2011-02-14 16:29 ` Jason Baron
2011-02-14 16:37 ` Peter Zijlstra
2011-02-14 16:43 ` Mathieu Desnoyers
2011-02-14 16:46 ` Steven Rostedt
2011-02-14 16:53 ` Peter Zijlstra
2011-02-14 17:18 ` Steven Rostedt
2011-02-14 17:23 ` Mike Frysinger
2011-02-14 17:27 ` Peter Zijlstra
2011-02-14 17:29 ` Mike Frysinger
2011-02-14 17:38 ` Peter Zijlstra
2011-02-14 17:45 ` Mike Frysinger
2011-02-14 17:38 ` Will Newton
2011-02-14 17:43 ` Peter Zijlstra
2011-02-14 17:50 ` Will Newton
2011-02-14 18:04 ` Peter Zijlstra
2011-02-14 18:24 ` Peter Zijlstra
2011-02-14 18:53 ` Mathieu Desnoyers
2011-02-14 21:29 ` Steven Rostedt
2011-02-14 21:39 ` Steven Rostedt
2011-02-14 21:46 ` David Miller
2011-02-14 22:20 ` Steven Rostedt
2011-02-14 22:21 ` Steven Rostedt
2011-02-14 22:21 ` H. Peter Anvin
2011-02-14 22:29 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP98BFCC52FD41661DD9CC1E96D00@phx.gbl>
2011-02-14 22:33 ` David Miller
2011-02-14 22:33 ` David Miller [this message]
2011-02-14 22:37 ` Matt Fleming
2011-02-14 23:03 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP166A8555C791786059B0FF96D00@phx.gbl>
2011-02-14 23:09 ` Paul E. McKenney
2011-02-14 23:29 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP4599FAAD7330498472B87396D00@phx.gbl>
2011-02-15 0:19 ` Segher Boessenkool
2011-02-15 0:48 ` Mathieu Desnoyers
2011-02-15 1:29 ` Steven Rostedt
[not found] ` <BLU0-SMTP984E876DBDFBC13F4C86F896D00@phx.gbl>
2011-02-15 0:42 ` Paul E. McKenney
2011-02-15 0:51 ` Mathieu Desnoyers
2011-02-15 11:53 ` Will Newton
2011-02-18 19:03 ` Paul E. McKenney
2011-02-14 23:19 ` H. Peter Anvin
2011-02-15 11:01 ` Will Newton
2011-02-15 13:31 ` H. Peter Anvin
2011-02-15 13:49 ` Steven Rostedt
2011-02-15 14:04 ` Will Newton
2011-02-15 21:11 ` Will Simoneau
2011-02-15 21:27 ` David Miller
2011-02-15 21:56 ` Will Simoneau
2011-02-16 10:15 ` Will Newton
2011-02-16 12:18 ` Steven Rostedt
2011-02-16 12:41 ` Will Newton
2011-02-16 13:24 ` Mathieu Desnoyers
2011-02-16 22:51 ` Will Simoneau
2011-02-17 0:53 ` Please watch your cc lists Andi Kleen
2011-02-17 0:56 ` David Miller
2011-02-17 1:04 ` Michael Witten
2011-02-17 10:55 ` [PATCH 0/2] jump label: 2.6.38 updates Will Newton
[not found] ` <BLU0-SMTP80F56386E7E060A3B2020B96D20@phx.gbl>
2011-02-17 1:55 ` Masami Hiramatsu
2011-02-17 3:19 ` H. Peter Anvin
2011-02-17 16:03 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP71BCB155CBAE79997EE08D96D20@phx.gbl>
2011-02-17 3:36 ` Steven Rostedt
2011-02-17 16:13 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP51D40A5B1DACA8883D6AB596D50@phx.gbl>
2011-02-17 20:09 ` Steven Rostedt
2011-02-15 22:20 ` Benjamin Herrenschmidt
2011-02-16 8:35 ` Ingo Molnar
2011-02-17 1:04 ` H. Peter Anvin
2011-02-17 12:51 ` Ingo Molnar
[not found] ` <BLU0-SMTP637B2E9372CFBF3A0B5B0996D00@phx.gbl>
2011-02-14 23:25 ` David Miller
2011-02-14 23:34 ` Mathieu Desnoyers
[not found] ` <20110214233405.GC17432@Krystal>
2011-02-14 23:52 ` Mathieu Desnoyers
2011-02-14 22:15 ` Matt Fleming
2011-02-15 15:20 ` Heiko Carstens
[not found] ` <BLU0-SMTP64371A838030ED92A7CCB696D00@phx.gbl>
2011-02-14 18:54 ` Jason Baron
2011-02-14 19:20 ` Peter Zijlstra
2011-02-14 19:48 ` Mathieu Desnoyers
2011-02-14 16:11 ` Mathieu Desnoyers
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