Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753205AbYK0Q7t (ORCPT ); Thu, 27 Nov 2008 11:59:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751272AbYK0Q7g (ORCPT ); Thu, 27 Nov 2008 11:59:36 -0500 Received: from cavan.codon.org.uk ([93.93.128.6]:47674 "EHLO vavatch.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbYK0Q7g (ORCPT ); Thu, 27 Nov 2008 11:59:36 -0500 Date: Thu, 27 Nov 2008 16:59:29 +0000 From: Matthew Garrett To: Alan Cox Cc: Randy Dunlap , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, mingo@redhat.com, val.henson@gmail.com, matthew@wil.cx Subject: [PATCH v3] relatime: Make relatime smarter Message-ID: <20081127165929.GA23366@srcf.ucam.org> References: <20081126195457.GA3541@srcf.ucam.org> <20081126195824.GB3541@srcf.ucam.org> <492DD035.5020705@oracle.com> <20081127150126.GA20941@srcf.ucam.org> <20081127150341.GB20941@srcf.ucam.org> <20081127163535.775729bf@lxorguk.ukuu.org.uk> <20081127164754.GC22963@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081127164754.GC22963@srcf.ucam.org> User-Agent: Mutt/1.5.12-2006-07-14 X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@codon.org.uk X-SA-Exim-Scanned: No (on vavatch.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4878 Lines: 161 Make relatime smarter Allow atime to be updated once per day even with relatime. This lets utilities like tmpreaper (which delete files based on last access time) continue working. The time between atime updates can be configured at boot with the relatime_interval kernel argument, or at runtime through /proc Signed-off-by: Matthew Garrett --- Drop the default behaviour section - as Alan suggests, it can be handled in userspace. Merge the configuration code into the change in behaviour patch. Documentation/kernel-parameters.txt | 4 ++ fs/inode.c | 59 +++++++++++++++++++++++++++++----- include/linux/mount.h | 2 + kernel/sysctl.c | 9 +++++ 4 files changed, 65 insertions(+), 9 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e0f346d..6d0dc0a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1847,6 +1847,10 @@ and is between 256 and 4096 characters. It is defined in the file [KNL, SMP] Set scheduler's default relax_domain_level. See Documentation/cpusets.txt. + relatime_interval= + [FS] relative atime update frequency, in seconds. + (default: 1 day: 86400 seconds) + reserve= [KNL,BUGS] Force the kernel to ignore some iomem area reservetop= [X86-32] diff --git a/fs/inode.c b/fs/inode.c index 0487ddb..51e9ae1 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1179,6 +1179,52 @@ sector_t bmap(struct inode * inode, sector_t block) } EXPORT_SYMBOL(bmap); +/* + * Relative atime updates frequency (default: 1 day): + */ +int relatime_interval __read_mostly = 24*60*60; + +/* + * Allow overriding the default relatime value on the kernel command line + */ +static int __init set_relatime_interval(char *str) +{ + get_option(&str, &relatime_interval); + + return 1; +} +__setup("relatime_interval=", set_relatime_interval); + +/* + * With relative atime, only update atime if the + * previous atime is earlier than either the ctime or + * mtime. + */ +static int relatime_need_update(struct inode *inode, struct timespec now) +{ + /* + * Is mtime younger than atime? If yes, update atime: + */ + if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) + return 1; + /* + * Is ctime younger than atime? If yes, update atime: + */ + if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) + return 1; + + /* + * Is the previous atime value older than the update interval? + * If yes, update atime: + */ + if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= relatime_interval) + return 1; + /* + * Good, we can skip the atime update: + */ + return 0; +} + /** * touch_atime - update the access time * @mnt: mount the inode is accessed on @@ -1206,17 +1252,12 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry) goto out; if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) goto out; - if (mnt->mnt_flags & MNT_RELATIME) { - /* - * With relative atime, only update atime if the previous - * atime is earlier than either the ctime or mtime. - */ - if (timespec_compare(&inode->i_mtime, &inode->i_atime) < 0 && - timespec_compare(&inode->i_ctime, &inode->i_atime) < 0) - goto out; - } now = current_fs_time(inode->i_sb); + + if (mnt->mnt_flags & MNT_RELATIME) + if (!relatime_need_update(inode, now)) + goto out; if (timespec_equal(&inode->i_atime, &now)) goto out; diff --git a/include/linux/mount.h b/include/linux/mount.h index cab2a85..978fb10 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -112,4 +112,6 @@ extern void mark_mounts_for_expiry(struct list_head *mounts); extern spinlock_t vfsmount_lock; extern dev_t name_to_dev_t(char *name); +extern int relatime_interval; + #endif /* _LINUX_MOUNT_H */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 9d048fa..f085ad6 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -1334,6 +1335,14 @@ static struct ctl_table fs_table[] = { .mode = 0644, .proc_handler = &proc_dointvec, }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "relatime_interval", + .data = &relatime_interval, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE) { .ctl_name = CTL_UNNUMBERED, -- Matthew Garrett | mjg59@srcf.ucam.org -- 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/