Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751748AbWADLp4 (ORCPT ); Wed, 4 Jan 2006 06:45:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751752AbWADLp4 (ORCPT ); Wed, 4 Jan 2006 06:45:56 -0500 Received: from smtp.osdl.org ([65.172.181.4]:40168 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751747AbWADLpz (ORCPT ); Wed, 4 Jan 2006 06:45:55 -0500 Date: Wed, 4 Jan 2006 03:45:34 -0800 From: Andrew Morton To: Eric Dumazet Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Shrinks sizeof(files_struct) and better layout Message-Id: <20060104034534.45d9c18a.akpm@osdl.org> In-Reply-To: <43BB1178.7020409@cosmosbay.com> References: <20051108185349.6e86cec3.akpm@osdl.org> <437226B1.4040901@cosmosbay.com> <20051109220742.067c5f3a.akpm@osdl.org> <4373698F.9010608@cosmosbay.com> <43BB1178.7020409@cosmosbay.com> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3759 Lines: 92 Eric Dumazet wrote: > > [PATCH] shrink the fdset and reorder fields to give better multi-threaded > performance. Boy, this is going to need some elaborate performance testing.. We can't have that `8 * sizeof(embedded_fd_set)' splattered all over the tree. This? fs/file.c | 6 +++--- include/linux/file.h | 5 +++++ include/linux/init_task.h | 2 +- kernel/fork.c | 2 +- 4 files changed, 10 insertions(+), 5 deletions(-) diff -puN fs/file.c~shrinks-sizeoffiles_struct-and-better-layout-tidy fs/file.c --- devel/fs/file.c~shrinks-sizeoffiles_struct-and-better-layout-tidy 2006-01-04 03:45:10.000000000 -0800 +++ devel-akpm/fs/file.c 2006-01-04 03:45:10.000000000 -0800 @@ -125,7 +125,7 @@ static void free_fdtable_rcu(struct rcu_ kmem_cache_free(files_cachep, fdt->free_files); return; } - if (fdt->max_fdset <= 8 * sizeof(embedded_fd_set) && + if (fdt->max_fdset <= EMBEDDED_FD_SET_SIZE && fdt->max_fds <= NR_OPEN_DEFAULT) { /* * The fdtable was embedded @@ -157,7 +157,7 @@ static void free_fdtable_rcu(struct rcu_ void free_fdtable(struct fdtable *fdt) { if (fdt->free_files || - fdt->max_fdset > 8 * sizeof(embedded_fd_set) || + fdt->max_fdset > EMBEDDED_FD_SET_SIZE || fdt->max_fds > NR_OPEN_DEFAULT) call_rcu(&fdt->rcu, free_fdtable_rcu); } @@ -221,7 +221,7 @@ fd_set * alloc_fdset(int num) void free_fdset(fd_set *array, int num) { - if (num <= 8 * sizeof(embedded_fd_set)) /* Don't free an embedded fdset */ + if (num <= EMBEDDED_FD_SET_SIZE) /* Don't free an embedded fdset */ return; else if (num <= 8 * PAGE_SIZE) kfree(array); diff -puN include/linux/file.h~shrinks-sizeoffiles_struct-and-better-layout-tidy include/linux/file.h --- devel/include/linux/file.h~shrinks-sizeoffiles_struct-and-better-layout-tidy 2006-01-04 03:45:10.000000000 -0800 +++ devel-akpm/include/linux/file.h 2006-01-04 03:45:10.000000000 -0800 @@ -25,6 +25,11 @@ typedef struct { unsigned long fds_bits[1]; } embedded_fd_set; +/* + * More than this number of fds: we use a separately allocated fd_set + */ +#define EMBEDDED_FD_SET_SIZE (8 * sizeof(struct embedded_fd_set)) + struct fdtable { unsigned int max_fds; int max_fdset; diff -puN include/linux/init_task.h~shrinks-sizeoffiles_struct-and-better-layout-tidy include/linux/init_task.h --- devel/include/linux/init_task.h~shrinks-sizeoffiles_struct-and-better-layout-tidy 2006-01-04 03:45:10.000000000 -0800 +++ devel-akpm/include/linux/init_task.h 2006-01-04 03:45:10.000000000 -0800 @@ -7,7 +7,7 @@ #define INIT_FDTABLE \ { \ .max_fds = NR_OPEN_DEFAULT, \ - .max_fdset = 8 * sizeof(embedded_fd_set), \ + .max_fdset = EMBEDDED_FD_SET_SIZE, \ .fd = &init_files.fd_array[0], \ .close_on_exec = (fd_set *)&init_files.close_on_exec_init, \ .open_fds = (fd_set *)&init_files.open_fds_init, \ diff -puN kernel/fork.c~shrinks-sizeoffiles_struct-and-better-layout-tidy kernel/fork.c --- devel/kernel/fork.c~shrinks-sizeoffiles_struct-and-better-layout-tidy 2006-01-04 03:45:10.000000000 -0800 +++ devel-akpm/kernel/fork.c 2006-01-04 03:45:10.000000000 -0800 @@ -584,7 +584,7 @@ static struct files_struct *alloc_files( newf->next_fd = 0; fdt = &newf->fdtab; fdt->max_fds = NR_OPEN_DEFAULT; - fdt->max_fdset = 8 * sizeof(embedded_fd_set); + fdt->max_fdset = EMBEDDED_FD_SET_SIZE; fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init; fdt->open_fds = (fd_set *)&newf->open_fds_init; fdt->fd = &newf->fd_array[0]; _ - 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/