From: Luca Barbieri <luca@luca-barbieri.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@elte.hu, hpa@zytor.com, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/10] x86-32: support atomic64_t on 386/486 UP/SMP
Date: Thu, 18 Feb 2010 11:58:01 +0100 [thread overview]
Message-ID: <ff13bc9a1002180258h667a96b2s611140fc3e2492be@mail.gmail.com> (raw)
In-Reply-To: <1266488746.26719.120.camel@laptop>
> IIRC we dropped <i586 SMP support, and since we don't have a PMU on
> those chips atomic64_t doesn't need to be NMI safe, so a simple
> UP-IRQ-disable implementation should suffice.
We need the generic version with spinlocks for other architectures,
and reusing it is the cheapest way to support 386/486.
We thus get 386/486 SMP for free, and on UP the spinlocks simplify to
just IRQ disabling.
The only thing we could do is to #ifdef out the hashed spinlock array
in the generic implementation on UP builds, which would save about 1KB
of memory.
That is independent from this patch though.
next prev parent reply other threads:[~2010-02-18 10:58 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-17 11:42 [PATCH 0/10] x86-32: improve atomic64_t functions Luca Barbieri
2010-02-17 11:42 ` [PATCH 01/10] x86: add support for multiple choice alternatives Luca Barbieri
2010-02-17 12:47 ` Avi Kivity
2010-02-18 19:46 ` H. Peter Anvin
2010-02-17 11:42 ` [PATCH 02/10] x86: add support for relative CALL and JMP in alternatives Luca Barbieri
2010-02-18 19:40 ` H. Peter Anvin
2010-02-18 23:38 ` Luca Barbieri
2010-02-18 23:54 ` H. Peter Anvin
2010-02-19 14:27 ` Masami Hiramatsu
2010-02-17 11:42 ` [PATCH 03/10] x86: add support for lock prefix " Luca Barbieri
2010-02-17 11:42 ` [PATCH 04/10] x86-32: allow UP/SMP lock replacement in cmpxchg64 Luca Barbieri
2010-02-17 11:42 ` [PATCH 05/10] lib: add self-test for atomic64_t Luca Barbieri
2010-02-17 11:42 ` [PATCH 06/10] x86-32: rewrite 32-bit atomic64 functions in assembly Luca Barbieri
2010-02-17 11:42 ` [PATCH 07/10] lib: move generic atomic64 to atomic64-impl.h Luca Barbieri
2010-02-17 11:42 ` [PATCH 08/10] x86-32: support atomic64_t on 386/486 UP/SMP Luca Barbieri
2010-02-18 10:25 ` Peter Zijlstra
2010-02-18 10:58 ` Luca Barbieri [this message]
2010-02-18 15:20 ` H. Peter Anvin
2010-02-17 11:42 ` [PATCH 09/10] x86-32: use SSE for atomic64_read/set if available Luca Barbieri
2010-02-17 22:39 ` H. Peter Anvin
2010-02-18 0:41 ` Luca Barbieri
2010-02-18 0:47 ` H. Peter Anvin
2010-02-18 9:56 ` Avi Kivity
2010-02-18 10:07 ` Luca Barbieri
2010-02-18 8:23 ` Andi Kleen
2010-02-18 9:53 ` Luca Barbieri
2010-02-18 9:56 ` Luca Barbieri
2010-02-18 10:11 ` Andi Kleen
2010-02-18 10:27 ` Luca Barbieri
2010-02-18 15:24 ` H. Peter Anvin
2010-02-18 18:14 ` Luca Barbieri
2010-02-18 18:28 ` H. Peter Anvin
2010-02-18 18:42 ` Luca Barbieri
2010-02-18 19:07 ` H. Peter Anvin
2010-02-18 20:26 ` Andi Kleen
2010-02-18 16:52 ` H. Peter Anvin
2010-02-18 18:49 ` Luca Barbieri
2010-02-18 19:06 ` H. Peter Anvin
2010-02-18 19:43 ` Luca Barbieri
2010-02-18 19:45 ` Yuhong Bao
2010-02-18 10:24 ` Peter Zijlstra
2010-02-18 10:25 ` Peter Zijlstra
2010-02-18 10:50 ` Luca Barbieri
2010-02-18 11:00 ` Peter Zijlstra
2010-02-18 12:29 ` Luca Barbieri
2010-02-18 12:32 ` Peter Zijlstra
2010-02-18 13:45 ` Luca Barbieri
2010-02-17 11:42 ` [PATCH 10/10] x86-32: panic on !CX8 && XMM Luca Barbieri
2010-02-17 22:38 ` H. Peter Anvin
2010-02-17 23:00 ` Yuhong Bao
2010-02-17 23:41 ` H. Peter Anvin
2010-02-18 1:13 ` Yuhong Bao
2010-02-25 20:24 ` Yuhong Bao
2010-02-18 0:46 ` Luca Barbieri
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