From: James Bottomley <James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
To: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Jens Axboe <jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
npiggin-l3A5Bk7waGM@public.gmane.org,
torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org,
sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org,
"Paul E. McKenney"
<paulmck-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 1/11] Add generic helpers for arch IPI function calls
Date: Mon, 28 Apr 2008 10:43:32 -0400 [thread overview]
Message-ID: <1209393812.3367.24.camel@localhost.localdomain> (raw)
In-Reply-To: <18470.1209392727-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
On Mon, 2008-04-28 at 15:25 +0100, David Howells wrote:
> We could use a GOT, but I believe that would add an extra memory
> access to any
> memory access or jump - which I'd prefer to avoid.
Not necessarily; this is how we work on PARISC with a GOT as the ELF
spec defines. The point is that the GOT is linker constructed, so we
only lay down GOT entries when the linker sees that relative
displacements fail, so they don't consume memory (or even get brought
into existence) in the ordinary case. The flip side of this is that we
do double jump (relative to jump through got) for the long displacements
we can't reach.
James
WARNING: multiple messages have this Message-ID (diff)
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <jens.axboe@oracle.com>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
npiggin@suse.de, torvalds@linux-foundation.org,
peterz@infradead.org, sam@ravnborg.org,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: [PATCH 1/11] Add generic helpers for arch IPI function calls
Date: Mon, 28 Apr 2008 10:43:32 -0400 [thread overview]
Message-ID: <1209393812.3367.24.camel@localhost.localdomain> (raw)
Message-ID: <20080428144332.wDnFRGeUBZjTsaVzyY8bIB9n3CqKdPcrhLK8dfYFAx0@z> (raw)
In-Reply-To: <18470.1209392727@redhat.com>
On Mon, 2008-04-28 at 15:25 +0100, David Howells wrote:
> We could use a GOT, but I believe that would add an extra memory
> access to any
> memory access or jump - which I'd prefer to avoid.
Not necessarily; this is how we work on PARISC with a GOT as the ELF
spec defines. The point is that the GOT is linker constructed, so we
only lay down GOT entries when the linker sees that relative
displacements fail, so they don't consume memory (or even get brought
into existence) in the ordinary case. The flip side of this is that we
do double jump (relative to jump through got) for the long displacements
we can't reach.
James
next prev parent reply other threads:[~2008-04-28 14:43 UTC|newest]
Thread overview: 169+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-22 18:50 [PATCH 0/11] Generic smp_call_function() #2 Jens Axboe
2008-04-22 18:50 ` Jens Axboe
[not found] ` <1208890227-24808-1-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-22 18:50 ` [PATCH 1/11] Add generic helpers for arch IPI function calls Jens Axboe
2008-04-22 18:50 ` Jens Axboe
[not found] ` <1208890227-24808-2-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-22 20:17 ` Peter Zijlstra
2008-04-22 20:17 ` Peter Zijlstra
2008-04-23 6:07 ` Jens Axboe
2008-04-23 6:07 ` Jens Axboe
[not found] ` <20080423060725.GT12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-23 6:32 ` Peter Zijlstra
2008-04-23 6:32 ` Peter Zijlstra
2008-04-23 7:49 ` Jens Axboe
2008-04-23 7:49 ` Jens Axboe
[not found] ` <20080423074933.GB12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-23 7:50 ` Peter Zijlstra
2008-04-23 7:50 ` Peter Zijlstra
2008-04-24 22:01 ` Russell King
2008-04-24 22:01 ` Russell King
[not found] ` <20080424220157.GA26179-f404yB8NqCZvn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2008-04-25 7:18 ` Jens Axboe
2008-04-25 7:18 ` Jens Axboe
[not found] ` <20080425071823.GF12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-26 6:28 ` Jeremy Fitzhardinge
2008-04-26 6:28 ` Jeremy Fitzhardinge
[not found] ` <4812CB99.1070600-TSDbQ3PG+2Y@public.gmane.org>
2008-04-28 7:38 ` Jes Sorensen
2008-04-28 7:38 ` Jes Sorensen
2008-04-26 6:11 ` Andrew Morton
2008-04-26 6:11 ` Andrew Morton
[not found] ` <20080425231100.b93a1601.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2008-04-26 14:13 ` James Bottomley
2008-04-26 14:13 ` James Bottomley
2008-04-27 0:58 ` Paul E. McKenney
2008-04-27 0:58 ` Paul E. McKenney
[not found] ` <20080427005816.GB21687-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2008-04-27 10:36 ` Jens Axboe
2008-04-27 10:36 ` Jens Axboe
2008-04-27 10:30 ` Jens Axboe
2008-04-27 10:30 ` Jens Axboe
[not found] ` <1209219236.3113.6.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2008-04-28 14:25 ` David Howells
2008-04-28 14:25 ` David Howells
[not found] ` <18470.1209392727-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2008-04-28 14:43 ` James Bottomley [this message]
2008-04-28 14:43 ` James Bottomley
2008-04-22 18:50 ` [PATCH 2/11] x86: convert to generic helpers for " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 19:03 ` Linus Torvalds
2008-04-22 19:03 ` Linus Torvalds
[not found] ` <alpine.LFD.1.10.0804221157220.2779-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2008-04-22 19:12 ` Ingo Molnar
2008-04-22 19:12 ` Ingo Molnar
[not found] ` <20080422191213.GA6370-X9Un+BFzKDI@public.gmane.org>
2008-04-22 19:22 ` Linus Torvalds
2008-04-22 19:22 ` Linus Torvalds
2008-04-22 19:26 ` Ingo Molnar
2008-04-22 19:26 ` Ingo Molnar
[not found] ` <20080422192601.GB12588-X9Un+BFzKDI@public.gmane.org>
2008-04-22 19:50 ` Linus Torvalds
2008-04-22 19:50 ` Linus Torvalds
[not found] ` <alpine.LFD.1.10.0804221244350.2779-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2008-04-23 1:11 ` Nick Piggin
2008-04-23 1:11 ` Nick Piggin
[not found] ` <20080423011153.GB17572-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2008-04-23 1:22 ` Linus Torvalds
2008-04-23 1:22 ` Linus Torvalds
[not found] ` <alpine.LFD.1.10.0804221817050.2779-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2008-04-23 1:36 ` Nick Piggin
2008-04-23 1:36 ` Nick Piggin
2008-04-23 7:08 ` Jens Axboe
2008-04-23 7:08 ` Jens Axboe
2008-04-23 12:54 ` Jens Axboe
2008-04-23 12:54 ` Jens Axboe
[not found] ` <1208890227-24808-3-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-26 6:44 ` Jeremy Fitzhardinge
2008-04-26 6:44 ` Jeremy Fitzhardinge
[not found] ` <4812CF5B.4080902-TSDbQ3PG+2Y@public.gmane.org>
2008-04-27 10:23 ` Jens Axboe
2008-04-27 10:23 ` Jens Axboe
[not found] ` <20080427102335.GS12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-27 15:18 ` Jeremy Fitzhardinge
2008-04-27 15:18 ` Jeremy Fitzhardinge
2008-04-22 18:50 ` [PATCH 3/11] powerpc: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 4/11] ia64: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 5/11] alpha: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 6/11] arm: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 7/11] m32r: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 8/11] mips: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 23:18 ` Ralf Baechle
2008-04-22 23:18 ` Ralf Baechle
2008-04-23 7:18 ` Jens Axboe
2008-04-23 7:18 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 9/11] parisc: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 10/11] sh: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
[not found] ` <1208890227-24808-11-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-25 8:56 ` Paul Mundt
2008-04-25 8:56 ` Paul Mundt
[not found] ` <20080425085637.GA30569-M7jkjyW5wf5g9hUCZPvPmw@public.gmane.org>
2008-04-25 9:16 ` Jens Axboe
2008-04-25 9:16 ` Jens Axboe
2008-04-22 18:50 ` [PATCH 11/11] s390: " Jens Axboe
2008-04-22 18:50 ` Jens Axboe
[not found] ` <1208890227-24808-12-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-23 7:58 ` Heiko Carstens
2008-04-23 7:58 ` Heiko Carstens
[not found] ` <20080423075831.GB15850-Pmgahw53EmNLmI7Nx2oIsGnsbthNF6/HVpNB7YpNyf8@public.gmane.org>
2008-04-23 8:11 ` Jens Axboe
2008-04-23 8:11 ` Jens Axboe
[not found] ` <20080423081147.GC12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-23 11:21 ` Jens Axboe
2008-04-23 11:21 ` Jens Axboe
[not found] ` <20080423112124.GJ12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-23 11:47 ` Heiko Carstens
2008-04-23 11:47 ` Heiko Carstens
[not found] ` <20080423114744.GA29422-Pmgahw53EmNLmI7Nx2oIsGnsbthNF6/HVpNB7YpNyf8@public.gmane.org>
2008-04-23 11:54 ` Jens Axboe
2008-04-23 11:54 ` Jens Axboe
2008-04-23 12:42 ` Martin Schwidefsky
2008-04-23 12:42 ` Martin Schwidefsky
2008-04-23 15:56 ` Rusty Russell
2008-04-23 15:56 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2008-04-22 7:57 [PATCH 0/11] Generic smp_call_function() and friends Jens Axboe
[not found] ` <1208851058-8500-1-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-22 7:57 ` [PATCH 1/11] Add generic helpers for arch IPI function calls Jens Axboe
2008-04-22 7:57 ` Jens Axboe
[not found] ` <1208851058-8500-2-git-send-email-jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2008-04-22 9:16 ` Avi Kivity
2008-04-22 9:16 ` Avi Kivity
[not found] ` <480DACDD.7040108-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-04-22 9:22 ` Jens Axboe
2008-04-22 9:22 ` Jens Axboe
[not found] ` <20080422092230.GW12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-22 11:14 ` Jens Axboe
2008-04-22 11:14 ` Jens Axboe
2008-04-22 13:00 ` Peter Zijlstra
2008-04-22 13:00 ` Peter Zijlstra
2008-04-22 14:25 ` Jens Axboe
2008-04-22 14:25 ` Jens Axboe
[not found] ` <20080422142543.GG12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-22 14:38 ` Avi Kivity
2008-04-22 14:38 ` Avi Kivity
[not found] ` <480DF861.6000705-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2008-04-22 14:43 ` Peter Zijlstra
2008-04-22 14:43 ` Peter Zijlstra
2008-04-22 14:47 ` Avi Kivity
2008-04-22 14:47 ` Avi Kivity
2008-04-22 14:53 ` Jens Axboe
2008-04-22 14:53 ` Jens Axboe
2008-04-22 14:43 ` Linus Torvalds
2008-04-22 14:43 ` Linus Torvalds
[not found] ` <alpine.LFD.1.10.0804220735350.2779-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2008-04-22 14:51 ` Jens Axboe
2008-04-22 14:51 ` Jens Axboe
2008-04-22 15:01 ` Linus Torvalds
2008-04-22 15:01 ` Linus Torvalds
2008-04-22 16:49 ` Jens Axboe
2008-04-22 16:49 ` Jens Axboe
[not found] ` <20080422164947.GN12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-22 17:04 ` Jens Axboe
2008-04-22 17:04 ` Jens Axboe
[not found] ` <20080422170405.GO12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-22 17:13 ` Jens Axboe
2008-04-22 17:13 ` Jens Axboe
[not found] ` <20080422171324.GP12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-22 17:29 ` Linus Torvalds
2008-04-22 17:29 ` Linus Torvalds
[not found] ` <alpine.LFD.1.10.0804221027210.2779-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2008-04-22 18:23 ` Jens Axboe
2008-04-22 18:23 ` Jens Axboe
[not found] ` <20080422182337.GQ12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-22 18:39 ` Linus Torvalds
2008-04-22 18:39 ` Linus Torvalds
2008-04-22 14:58 ` Linus Torvalds
2008-04-22 14:58 ` Linus Torvalds
[not found] ` <alpine.LFD.1.10.0804220749450.2779-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2008-04-22 15:07 ` Jens Axboe
2008-04-22 15:07 ` Jens Axboe
2008-04-22 23:12 ` Mark Lord
2008-04-22 23:12 ` Mark Lord
[not found] ` <480E70ED.3030701-gsilrlXbHYg@public.gmane.org>
2008-04-23 7:24 ` Jens Axboe
2008-04-23 7:24 ` Jens Axboe
[not found] ` <20080423072432.GX12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-23 13:42 ` Mark Lord
2008-04-23 13:42 ` Mark Lord
[not found] ` <480F3CBC.60305-gsilrlXbHYg@public.gmane.org>
2008-04-23 13:51 ` Jens Axboe
2008-04-23 13:51 ` Jens Axboe
2008-04-23 14:46 ` Mark Lord
2008-04-23 14:46 ` Mark Lord
[not found] ` <480F4BD9.8090003-gsilrlXbHYg@public.gmane.org>
2008-04-24 10:59 ` Jens Axboe
2008-04-24 10:59 ` Jens Axboe
[not found] ` <20080424105908.GW12774-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2008-04-24 12:44 ` Mark Lord
2008-04-24 12:44 ` Mark Lord
[not found] ` <481080A0.9050804-gsilrlXbHYg@public.gmane.org>
2008-04-24 21:30 ` Rafael J. Wysocki
2008-04-24 21:30 ` Rafael J. Wysocki
2008-04-25 11:08 ` Pavel Machek
2008-04-25 11:08 ` Pavel Machek
2008-04-26 8:04 ` Pavel Machek
2008-04-26 8:04 ` Pavel Machek
2008-04-28 15:13 ` Mark Lord
2008-04-28 15:13 ` Mark Lord
2008-05-01 16:23 ` Pavel Machek
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