Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932498AbVINSjp (ORCPT ); Wed, 14 Sep 2005 14:39:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932520AbVINSjp (ORCPT ); Wed, 14 Sep 2005 14:39:45 -0400 Received: from ams-iport-1.cisco.com ([144.254.224.140]:52362 "EHLO ams-iport-1.cisco.com") by vger.kernel.org with ESMTP id S932498AbVINSjo (ORCPT ); Wed, 14 Sep 2005 14:39:44 -0400 To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: [PATCH] Move GFP_KERNEL use out of line to shrink text X-Message-Flag: Warning: May contain useful information References: <20050913120707.74a19800.akpm@osdl.org> <52y8602zl7.fsf@cisco.com> <52acig2q37.fsf_-_@cisco.com> <20050913223511.141e78c1.akpm@osdl.org> From: Roland Dreier Date: Wed, 14 Sep 2005 11:39:34 -0700 In-Reply-To: <20050913223511.141e78c1.akpm@osdl.org> (Andrew Morton's message of "Tue, 13 Sep 2005 22:35:11 -0700") Message-ID: <52fys7ze6x.fsf_-_@cisco.com> User-Agent: Gnus/5.1006 (Gnus v5.10.6) XEmacs/21.4 (Jumbo Shrimp, linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 14 Sep 2005 18:39:36.0157 (UTC) FILETIME=[A7FE98D0:01C5B95B] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4942 Lines: 144 Andrew> It hardly seems worth it, really. Better savings would Andrew> come from doing the same trick to kmem_cache_alloc() then Andrew> tweaking kmalloc(). Yep, right as usual; here's an updated patch. Do with it as you will -- I won't be hurt if you dump it, since I had fun trying this out. Reduce kernel text by moving many uses of GFP_KERNEL out of line, by creating __kmem_cache_alloc_gfp_kernel(), __kmalloc_gfp_kernel() and __kzalloc_gfp_kernel() wrapper functions. Then kmem_cache_alloc(), kmalloc() and kzalloc() can be inline functions that just call their _gfp_kernel version if their flags parameter is a compile-time constant and is GFP_KERNEL, and call their ordinary version otherwise. On an x86_64 allyesconfig kernel, I see the following sizes: text data bss dec hex filename 24202272 7609162 1998512 33809946 203e61a vmlinux-before 24197561 7609474 1998512 33805547 203d4eb vmlinux-after for a net savings of 4711 bytes of text (at a cost of 312 bytes of data for some reason). With my usual config, the patched kernel boots and runs fine. Signed-off-by: Roland Dreier diff --git a/include/linux/slab.h b/include/linux/slab.h --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -61,7 +61,8 @@ extern kmem_cache_t *kmem_cache_create(c void (*)(void *, kmem_cache_t *, unsigned long)); extern int kmem_cache_destroy(kmem_cache_t *); extern int kmem_cache_shrink(kmem_cache_t *); -extern void *kmem_cache_alloc(kmem_cache_t *, unsigned int __nocast); +extern void *__kmem_cache_alloc(kmem_cache_t *, unsigned int __nocast); +extern void *__kmem_cache_alloc_gfp_kernel(kmem_cache_t *); extern void kmem_cache_free(kmem_cache_t *, void *); extern unsigned int kmem_cache_size(kmem_cache_t *); extern const char *kmem_cache_name(kmem_cache_t *); @@ -75,6 +76,15 @@ struct cache_sizes { }; extern struct cache_sizes malloc_sizes[]; extern void *__kmalloc(size_t, unsigned int __nocast); +extern void *__kmalloc_gfp_kernel(size_t); + +static inline void *kmem_cache_alloc(kmem_cache_t *cache, unsigned int __nocast flags) +{ + if (__builtin_constant_p(flags) && flags == GFP_KERNEL) + return __kmem_cache_alloc_gfp_kernel(cache); + + return __kmem_cache_alloc(cache, flags); +} static inline void *kmalloc(size_t size, unsigned int __nocast flags) { @@ -96,10 +106,22 @@ found: malloc_sizes[i].cs_dmacachep : malloc_sizes[i].cs_cachep, flags); } + + if (__builtin_constant_p(flags) && flags == GFP_KERNEL) + return __kmalloc_gfp_kernel(size); return __kmalloc(size, flags); } -extern void *kzalloc(size_t, unsigned int __nocast); +extern void *__kzalloc(size_t, unsigned int __nocast); +extern void *__kzalloc_gfp_kernel(size_t); + +static inline void *kzalloc(size_t size, unsigned int __nocast flags) +{ + if (__builtin_constant_p(flags) && flags == GFP_KERNEL) + return __kzalloc_gfp_kernel(size); + + return __kzalloc(size, flags); +} /** * kcalloc - allocate memory for an array. The memory is set to zero. diff --git a/mm/slab.c b/mm/slab.c --- a/mm/slab.c +++ b/mm/slab.c @@ -2778,11 +2778,17 @@ static inline void __cache_free(kmem_cac * Allocate an object from this cache. The flags are only relevant * if the cache has no available objects. */ -void *kmem_cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) +void *__kmem_cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) { return __cache_alloc(cachep, flags); } -EXPORT_SYMBOL(kmem_cache_alloc); +EXPORT_SYMBOL(__kmem_cache_alloc); + +void *__kmem_cache_alloc_gfp_kernel(kmem_cache_t *cachep) +{ + return __cache_alloc(cachep, GFP_KERNEL); +} +EXPORT_SYMBOL(__kmem_cache_alloc_gfp_kernel); /** * kmem_ptr_validate - check if an untrusted pointer might @@ -2912,6 +2918,12 @@ void *__kmalloc(size_t size, unsigned in } EXPORT_SYMBOL(__kmalloc); +void *__kmalloc_gfp_kernel(size_t size) +{ + return __kmalloc(size, GFP_KERNEL); +} +EXPORT_SYMBOL(__kmalloc_gfp_kernel); + #ifdef CONFIG_SMP /** * __alloc_percpu - allocate one copy of the object for every present @@ -2985,14 +2997,20 @@ EXPORT_SYMBOL(kmem_cache_free); * @size: how many bytes of memory are required. * @flags: the type of memory to allocate. */ -void *kzalloc(size_t size, unsigned int __nocast flags) +void *__kzalloc(size_t size, unsigned int __nocast flags) { void *ret = kmalloc(size, flags); if (ret) memset(ret, 0, size); return ret; } -EXPORT_SYMBOL(kzalloc); +EXPORT_SYMBOL(__kzalloc); + +void *__kzalloc_gfp_kernel(size_t size) +{ + return __kzalloc(size, GFP_KERNEL); +} +EXPORT_SYMBOL(__kzalloc_gfp_kernel); /** * kfree - free previously allocated memory - 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/