From: Ingo Molnar <mingo@elte.hu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>,
simoneau@ele.uri.edu, will.newton@gmail.com, hpa@zytor.com,
matt@console-pimps.org, rostedt@goodmis.org,
peterz@infradead.org, jbaron@redhat.com,
mathieu.desnoyers@polymtl.ca, 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
Subject: Re: [PATCH 0/2] jump label: 2.6.38 updates
Date: Wed, 16 Feb 2011 09:35:42 +0100 [thread overview]
Message-ID: <20110216083542.GE16529@elte.hu> (raw)
In-Reply-To: <1297808418.2460.9.camel@pasglop>
* Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> On Tue, 2011-02-15 at 13:27 -0800, David Miller wrote:
> > From: Will Simoneau <simoneau@ele.uri.edu>
> > Date: Tue, 15 Feb 2011 16:11:23 -0500
> >
> > > Note how the cache and cache coherence protocol are fundamental parts of this
> > > operation; if these instructions simply bypassed the cache, they *could not*
> > > work correctly - how do you detect when the underlying memory has been
> > > modified?
> >
> > The issue here isn't L2 cache bypassing, it's local L1 cache bypassing.
> >
> > The chips in question aparently do not consult the local L1 cache on
> > "ll" instructions.
> >
> > Therefore you must only ever access such atomic data using "ll"
> > instructions.
>
> Note that it's actually a reasonable design choice to not consult the L1
> in these case .... as long as you invalidate it on the way. That's how
> current powerpcs do it afaik, they send a kill to any matching L1 line
> along as reading from the L2. (Of course, L1 has to be write-through for
> that to work).
Just curious: how does this work if there's an interrupt (or NMI) right after the
invalidate instruction but before the 'll' instruction? The IRQ/NMI may refill the
L1. Or are the two instructions coupled by hw (they form a single instruction in
essence) and irqs/NMIs are inhibited inbetween?
Thanks,
Ingo
next prev parent reply other threads:[~2011-02-16 8:36 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-05 15:43 [PATCH 0/2] jump label: 2.6.38 updates 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
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 [this message]
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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