From: Andi Kleen <andi@firstfloor.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Eric Dumazet <eric.dumazet@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
mingo@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -tip] x86: atomic64: inline atomic64_read()
Date: Fri, 03 Jul 2009 20:24:22 +0200 [thread overview]
Message-ID: <87ocs1aall.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20090703111033.6e9627de@infradead.org> (Arjan van de Ven's message of "Fri, 3 Jul 2009 11:10:33 -0700")
Arjan van de Ven <arjan@infradead.org> writes:
> On Fri, 3 Jul 2009 20:04:50 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
>
>> > +static inline u64 atomic64_read(atomic64_t *ptr)
>> > +{
>> > + u64 res;
>> > +
>> > + asm volatile(
>> > + "mov %%ebx, %%eax\n\t"
>> > + "mov %%ecx, %%edx\n\t"
>> > + LOCK_PREFIX "cmpxchg8b %1\n"
>
> also afaik cmpxchg implies the lock prefix, so no need to make an
> explicit one... it just adds code size and alternatives-work
No it doesn't; LOCK is implied for "xchg", but not for cmpxchg
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-07-03 18:24 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-30 21:24 [PATCH] FRV: Wire up new syscalls David Howells
2009-06-30 21:34 ` Ingo Molnar
2009-06-30 21:41 ` Arnd Bergmann
2009-06-30 21:54 ` Ingo Molnar
2009-07-01 11:28 ` David Howells
2009-07-01 11:54 ` Ingo Molnar
2009-07-01 12:19 ` David Howells
2009-07-01 12:36 ` Paul Mackerras
2009-07-01 12:41 ` David Howells
2009-07-01 13:13 ` Ingo Molnar
2009-07-01 14:10 ` David Howells
2009-07-01 14:49 ` Ingo Molnar
2009-07-01 16:47 ` [PATCH 1/2] FRV: Implement atomic64_t David Howells
2009-07-01 17:20 ` Linus Torvalds
2009-07-01 21:11 ` Ingo Molnar
2009-07-01 22:57 ` [PATCH] x86: Code atomic(64)_read and atomic(64)_set in C not CPP [was Re: FRV: Implement atomic64_t] Paul Mackerras
2009-07-02 7:21 ` [tip:x86/urgent] x86: Code atomic(64)_read and atomic(64)_set in C not CPP tip-bot for Paul Mackerras
2009-07-02 7:21 ` [PATCH] x86: Code atomic(64)_read and atomic(64)_set in C not CPP [was Re: FRV: Implement atomic64_t] Ingo Molnar
2009-07-01 23:46 ` [PATCH 1/2] FRV: Implement atomic64_t [ver #2] David Howells
2009-07-01 23:46 ` [PATCH 2/2] FRV: Add basic performance counter support " David Howells
2009-07-02 21:10 ` [PATCH 1/2] FRV: Implement atomic64_t Eric Dumazet
2009-07-02 21:28 ` Linus Torvalds
2009-07-02 22:08 ` [PATCH] x86: atomic64_t should be 8 bytes aligned Eric Dumazet
2009-07-02 23:53 ` Linus Torvalds
2009-07-03 6:14 ` Ingo Molnar
2009-07-03 12:42 ` [tip:perfcounters/urgent] x86: atomic64: The atomic64_t data type should be 8 bytes aligned on 32-bit too tip-bot for Eric Dumazet
2009-07-03 16:58 ` Linus Torvalds
2009-07-03 17:49 ` H. Peter Anvin
2009-07-03 12:42 ` [tip:perfcounters/urgent] x86: atomic64: Move the 32-bit atomic64_t implementation to a .c file tip-bot for Ingo Molnar
2009-07-03 16:47 ` Linus Torvalds
2009-07-03 18:31 ` [tip:perfcounters/urgent] x86: atomic64: Clean up atomic64_sub_and_test() and atomic64_add_negative() tip-bot for Ingo Molnar
2009-07-03 19:18 ` tip-bot for Ingo Molnar
2009-07-04 0:05 ` [tip:perfcounters/urgent] x86: atomic64: Move the 32-bit atomic64_t implementation to a .c file Paul Mackerras
2009-07-05 11:25 ` Ingo Molnar
2009-07-03 12:43 ` [tip:perfcounters/urgent] x86: atomic64: Improve atomic64_read() tip-bot for Eric Dumazet
2009-07-03 12:43 ` [tip:perfcounters/urgent] x86: atomic64: Improve cmpxchg8b() tip-bot for Eric Dumazet
2009-07-03 12:43 ` [tip:perfcounters/urgent] x86: atomic64: Improve atomic64_add_return() tip-bot for Ingo Molnar
2009-07-03 12:43 ` [tip:perfcounters/urgent] x86: atomic64: Reduce size of functions tip-bot for Ingo Molnar
2009-07-03 12:44 ` [tip:perfcounters/urgent] x86: atomic64: Fix unclean type use in atomic64_xchg() tip-bot for Ingo Molnar
2009-07-03 17:02 ` Linus Torvalds
2009-07-03 18:00 ` Ingo Molnar
2009-07-03 12:44 ` [tip:perfcounters/urgent] x86: atomic64: Improve atomic64_read() tip-bot for Eric Dumazet
2009-07-03 14:50 ` [PATCH -tip] x86: atomic64: inline atomic64_read() Eric Dumazet
2009-07-03 18:04 ` Ingo Molnar
2009-07-03 18:10 ` Arjan van de Ven
2009-07-03 18:18 ` Ingo Molnar
2009-07-03 18:25 ` Andi Kleen
2009-07-03 18:30 ` Arjan van de Ven
2009-07-03 18:43 ` Ingo Molnar
2009-07-03 18:24 ` Andi Kleen [this message]
2009-07-03 18:31 ` [tip:perfcounters/urgent] x86: atomic64: Optimize CMPXCHG8B sequences to not use the LOCK prefix tip-bot for Ingo Molnar
2009-07-03 18:45 ` Ingo Molnar
2009-07-03 19:10 ` [PATCH -tip] x86: atomic64: inline atomic64_read() Linus Torvalds
2009-07-03 19:17 ` Ingo Molnar
2009-07-03 19:38 ` Linus Torvalds
2009-07-03 21:40 ` Ingo Molnar
2009-07-03 18:31 ` [tip:perfcounters/urgent] x86: atomic64: Inline atomic64_read() again tip-bot for Eric Dumazet
2009-07-03 19:18 ` tip-bot for Eric Dumazet
2009-07-04 9:49 ` tip-bot for Eric Dumazet
2009-07-03 12:44 ` [tip:perfcounters/urgent] x86: atomic64: Code atomic(64)_read and atomic(64)_set in C not CPP tip-bot for Paul Mackerras
2009-07-03 12:48 ` tip-bot for Paul Mackerras
2009-07-03 12:48 ` [tip:perfcounters/urgent] x86: atomic64: Improve atomic64_read() tip-bot for Eric Dumazet
2009-07-03 15:33 ` [tip:perfcounters/urgent] x86: atomic64: Export APIs to modules tip-bot for Ingo Molnar
2009-07-03 18:30 ` tip-bot for Ingo Molnar
2009-07-03 18:30 ` [tip:perfcounters/urgent] x86: atomic64: Improve atomic64_xchg() tip-bot for Ingo Molnar
2009-07-03 12:01 ` [patch] x86: atomic64_t: Improve atomic64_add_return() Ingo Molnar
2009-07-03 12:26 ` [PATCH] x86: atomic64_t: _cmpxchg() & _read() optimizations Eric Dumazet
2009-07-03 12:40 ` Ingo Molnar
2009-07-03 17:38 ` [patch] x86: atomic64_t: Improve atomic64_add_return() Linus Torvalds
2009-07-03 6:05 ` [PATCH 1/2] FRV: Implement atomic64_t Eric Dumazet
2009-07-03 12:27 ` Ingo Molnar
2009-07-03 12:39 ` Eric Dumazet
2009-07-03 11:17 ` Ingo Molnar
2009-07-03 11:26 ` Ingo Molnar
2009-07-01 17:33 ` David Howells
2009-07-01 23:48 ` David Howells
2009-07-01 16:47 ` [PATCH 2/2] FRV: Add basic performance counter support David Howells
2009-07-01 21:10 ` Ingo Molnar
2009-07-01 15:19 ` [PATCH] FRV: Wire up new syscalls David Howells
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