Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753231AbYGXDpv (ORCPT ); Wed, 23 Jul 2008 23:45:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752493AbYGXDpL (ORCPT ); Wed, 23 Jul 2008 23:45:11 -0400 Received: from ozlabs.org ([203.10.76.45]:46501 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752300AbYGXDpJ (ORCPT ); Wed, 23 Jul 2008 23:45:09 -0400 From: Rusty Russell To: Mike Travis Subject: Re: [PATCH 1/1] cpumask: Change cpumask_of_cpu to use cpumask_of_cpu_map Date: Thu, 24 Jul 2008 12:45:15 +1000 User-Agent: KMail/1.9.9 Cc: Ingo Molnar , Andrew Morton , "H. Peter Anvin" , Jack Steiner , Christoph Lameter , linux-kernel@vger.kernel.org, Len Brown , Lennert Buytenhek , Dave Jones , Paul Jackson , Tony Luck , Tigran Aivazian , Paul Mackerras , Benjamin Herrenschmidt , Robert Richter , Martin Schwidefsky , Heiko Carstens , Sam Creasey , Greg Banks , "Eric W. Biederman" , Adrian Bunk , Thomas Gleixner , Andreas Schwab , Johannes Weiner References: <20080723171841.815234000@polaris-admin.engr.sgi.com> <20080723171841.997896000@polaris-admin.engr.sgi.com> In-Reply-To: <20080723171841.997896000@polaris-admin.engr.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200807241245.17239.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6421 Lines: 194 On Thursday 24 July 2008 03:18:42 Mike Travis wrote: > Note that the declaration of cpumask_of_cpu_map[] is initialized > so that cpumask_of_cpu(0) is defined early. This assumes that > cpu 0 is the boot cpu. Hi Mike, Make this statically initialized please. That almost guarantees there'll be no problems. It's a little tricky to do, but possible. Patch below tested on 32 bit x86 only. > Based on linux-2.6.tip/master at the following commit: > > commit a099a9b18ab434594bb01ed920e8c58574203fa9 > Merge: 9b4ae4d... f3b51d7... > Author: Ingo Molnar > Date: Tue Jul 22 15:43:36 2008 +0200 > > Merge branch 'out-of-tree' This is two-steps forward one step back. Have Ingo drop the original patches, and roll together into a single change. That should be much clearer. I know it's a PITA. Thanks, Rusty. Make cpumask_of_cpu_map generic If an arch doesn't define cpumask_of_cpu_map, create a generic statically-initialized one for them. This allows removal of the buggy cpumask_of_cpu() macro (&cpumask_of_cpu() gives address of out-of-scope var). An arch with NR_CPUS of 4096 probably wants to allocate this itself based on the actual number of CPUs, since otherwise they're using 2MB of rodata (1024 cpus means 128k). That's what CONFIG_HAVE_CPUMASK_OF_CPU_MAP is for (only x86/64 does so at the moment). In future as we support more CPUs, we'll need to resort to a get_cpu_map()/put_cpu_map() allocation scheme. Signed-off-by: Rusty Russell diff -r 95e128369c3c include/linux/cpumask.h --- a/include/linux/cpumask.h Thu Jul 24 11:16:27 2008 +1000 +++ b/include/linux/cpumask.h Thu Jul 24 12:33:45 2008 +1000 @@ -226,23 +226,8 @@ int __next_cpu(int n, const cpumask_t *s #define next_cpu(n, src) ({ (void)(src); 1; }) #endif -#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP -extern cpumask_t *cpumask_of_cpu_map; +extern const cpumask_t *cpumask_of_cpu_map; #define cpumask_of_cpu(cpu) (cpumask_of_cpu_map[cpu]) - -#else -#define cpumask_of_cpu(cpu) \ -(*({ \ - typeof(_unused_cpumask_arg_) m; \ - if (sizeof(m) == sizeof(unsigned long)) { \ - m.bits[0] = 1UL<<(cpu); \ - } else { \ - cpus_clear(m); \ - cpu_set((cpu), m); \ - } \ - &m; \ -})) -#endif #define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS) diff -r 95e128369c3c kernel/cpu.c --- a/kernel/cpu.c Thu Jul 24 11:16:27 2008 +1000 +++ b/kernel/cpu.c Thu Jul 24 12:33:45 2008 +1000 @@ -428,3 +428,112 @@ out: #endif /* CONFIG_PM_SLEEP_SMP */ #endif /* CONFIG_SMP */ + +#ifndef CONFIG_HAVE_CPUMASK_OF_CPU_MAP +/* 64 bits of zeros, for initializers. */ +#if BITS_PER_LONG == 32 +#define Z64 0, 0 +#else +#define Z64 0 +#endif + +/* Initializer macros. */ +#define CMI0(n) { .bits = { 1UL << (n) } } +#define CMI(n, ...) { .bits = { __VA_ARGS__, 1UL << ((n) % BITS_PER_LONG) } } + +#define CMI8(n, ...) \ + CMI((n), __VA_ARGS__), CMI((n)+1, __VA_ARGS__), \ + CMI((n)+2, __VA_ARGS__), CMI((n)+3, __VA_ARGS__), \ + CMI((n)+4, __VA_ARGS__), CMI((n)+5, __VA_ARGS__), \ + CMI((n)+6, __VA_ARGS__), CMI((n)+7, __VA_ARGS__) + +#if BITS_PER_LONG == 32 +#define CMI64(n, ...) \ + CMI8((n), __VA_ARGS__), CMI8((n)+8, __VA_ARGS__), \ + CMI8((n)+16, __VA_ARGS__), CMI8((n)+24, __VA_ARGS__), \ + CMI8((n)+32, 0, __VA_ARGS__), CMI8((n)+40, 0, __VA_ARGS__), \ + CMI8((n)+48, 0, __VA_ARGS__), CMI8((n)+56, 0, __VA_ARGS__) +#else +#define CMI64(n, ...) \ + CMI8((n), __VA_ARGS__), CMI8((n)+8, __VA_ARGS__), \ + CMI8((n)+16, __VA_ARGS__), CMI8((n)+24, __VA_ARGS__), \ + CMI8((n)+32, __VA_ARGS__), CMI8((n)+40, __VA_ARGS__), \ + CMI8((n)+48, __VA_ARGS__), CMI8((n)+56, __VA_ARGS__) +#endif + +#define CMI256(n, ...) \ + CMI64((n), __VA_ARGS__), CMI64((n)+64, Z64, __VA_ARGS__), \ + CMI64((n)+128, Z64, Z64, __VA_ARGS__), \ + CMI64((n)+192, Z64, Z64, Z64, __VA_ARGS__) +#define Z256 Z64, Z64, Z64, Z64 + +#define CMI1024(n, ...) \ + CMI256((n), __VA_ARGS__), \ + CMI256((n)+256, Z256, __VA_ARGS__), \ + CMI256((n)+512, Z256, Z256, __VA_ARGS__), \ + CMI256((n)+768, Z256, Z256, Z256, __VA_ARGS__) +#define Z1024 Z256, Z256, Z256, Z256 + +/* We want this statically initialized, just to be safe. We try not + * to waste too much space, either. */ +static const cpumask_t cpumask_map[] = { + CMI0(0), CMI0(1), CMI0(2), CMI0(3), +#if NR_CPUS > 4 + CMI0(4), CMI0(5), CMI0(6), CMI0(7), +#endif +#if NR_CPUS > 8 + CMI0(8), CMI0(9), CMI0(10), CMI0(11), + CMI0(12), CMI0(13), CMI0(14), CMI0(15), +#endif +#if NR_CPUS > 16 + CMI0(16), CMI0(17), CMI0(18), CMI0(19), + CMI0(20), CMI0(21), CMI0(22), CMI0(23), + CMI0(24), CMI0(25), CMI0(26), CMI0(27), + CMI0(28), CMI0(29), CMI0(30), CMI0(31), +#endif +#if NR_CPUS > 32 +#if BITS_PER_LONG == 32 + CMI(32, 0), CMI(33, 0), CMI(34, 0), CMI(35, 0), + CMI(36, 0), CMI(37, 0), CMI(38, 0), CMI(39, 0), + CMI(40, 0), CMI(41, 0), CMI(42, 0), CMI(43, 0), + CMI(44, 0), CMI(45, 0), CMI(46, 0), CMI(47, 0), + CMI(48, 0), CMI(49, 0), CMI(50, 0), CMI(51, 0), + CMI(52, 0), CMI(53, 0), CMI(54, 0), CMI(55, 0), + CMI(56, 0), CMI(57, 0), CMI(58, 0), CMI(59, 0), + CMI(60, 0), CMI(61, 0), CMI(62, 0), CMI(63, 0), +#else + CMI0(32), CMI0(33), CMI0(34), CMI0(35), + CMI0(36), CMI0(37), CMI0(38), CMI0(39), + CMI0(40), CMI0(41), CMI0(42), CMI0(43), + CMI0(44), CMI0(45), CMI0(46), CMI0(47), + CMI0(48), CMI0(49), CMI0(50), CMI0(51), + CMI0(52), CMI0(53), CMI0(54), CMI0(55), + CMI0(56), CMI0(57), CMI0(58), CMI0(59), + CMI0(60), CMI0(61), CMI0(62), CMI0(63), +#endif /* BITS_PER_LONG == 64 */ +#endif +#if NR_CPUS > 64 + CMI64(64, Z64), +#endif +#if NR_CPUS > 128 + CMI64(128, Z64, Z64), CMI64(192, Z64, Z64, Z64), +#endif +#if NR_CPUS > 256 + CMI256(256, Z256), +#endif +#if NR_CPUS > 512 + CMI256(512, Z256, Z256), CMI256(768, Z256, Z256, Z256), +#endif +#if NR_CPUS > 1024 + CMI1024(1024, Z1024), +#endif +#if NR_CPUS > 2048 + CMI1024(2048, Z1024, Z1024), CMI1024(3072, Z1024, Z1024, Z1024), +#endif +#if NR_CPUS > 4096 +#error NR_CPUS too big. Fix initializers or set CONFIG_HAVE_CPUMASK_OF_CPU_MAP +#endif +}; + +const cpumask_t *cpumask_of_cpu_map = cpumask_map; +#endif /* !CONFIG_HAVE_CPUMASK_OF_CPU_MAP */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/