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| author | kib <kib@FreeBSD.org> | 2012-02-06 11:04:36 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2012-02-06 11:04:36 +0000 |
| commit | 52c17430bc70cd8c1e6dc2ff5c7786cc3f4871e4 (patch) | |
| tree | fae5558858b305702b78be385893645701a55d02 /sys/kern | |
| parent | 8b885b79f5441a9ccaf7101ad3dab74016626fe6 (diff) | |
| download | FreeBSD-src-52c17430bc70cd8c1e6dc2ff5c7786cc3f4871e4.zip FreeBSD-src-52c17430bc70cd8c1e6dc2ff5c7786cc3f4871e4.tar.gz | |
Current implementations of sync(2) and syncer vnode fsync() VOP uses
mnt_noasync counter to temporary remove MNTK_ASYNC mount option, which
is needed to guarantee a synchronous completion of the initiated i/o
before syscall or VOP return. Global removal of MNTK_ASYNC option is
harmful because not only i/o started from corresponding thread becomes
synchronous, but all i/o is synchronous on the filesystem which is
initiated during sync(2) or syncer activity.
Instead of removing MNTK_ASYNC from mnt_kern_flag, provide a local
thread flag to disable async i/o for current thread only. Use the
opportunity to move DOINGASYNC() macro into sys/vnode.h and
consistently use it through places which tested for MNTK_ASYNC.
Some testing demonstrated 60-70% improvements in run time for the
metadata-intensive operations on async-mounted UFS volumes, but still
with great deviation due to other reasons.
Reviewed by: mckusick
Tested by: scottl
MFC after: 2 weeks
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/vfs_subr.c | 13 | ||||
| -rw-r--r-- | sys/kern/vfs_syscalls.c | 14 |
2 files changed, 6 insertions, 21 deletions
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c index 6cdd372..28562e6 100644 --- a/sys/kern/vfs_subr.c +++ b/sys/kern/vfs_subr.c @@ -3521,7 +3521,7 @@ sync_fsync(struct vop_fsync_args *ap) { struct vnode *syncvp = ap->a_vp; struct mount *mp = syncvp->v_mount; - int error; + int error, save; struct bufobj *bo; /* @@ -3551,17 +3551,10 @@ sync_fsync(struct vop_fsync_args *ap) vfs_unbusy(mp); return (0); } - MNT_ILOCK(mp); - mp->mnt_noasync++; - mp->mnt_kern_flag &= ~MNTK_ASYNC; - MNT_IUNLOCK(mp); + save = curthread_pflags_set(TDP_SYNCIO); vfs_msync(mp, MNT_NOWAIT); error = VFS_SYNC(mp, MNT_LAZY); - MNT_ILOCK(mp); - mp->mnt_noasync--; - if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0) - mp->mnt_kern_flag |= MNTK_ASYNC; - MNT_IUNLOCK(mp); + curthread_pflags_restore(save); vn_finished_write(mp); vfs_unbusy(mp); return (error); diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c index 31ad276..e460570 100644 --- a/sys/kern/vfs_syscalls.c +++ b/sys/kern/vfs_syscalls.c @@ -134,7 +134,7 @@ sys_sync(td, uap) struct sync_args *uap; { struct mount *mp, *nmp; - int vfslocked; + int save, vfslocked; mtx_lock(&mountlist_mtx); for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) { @@ -145,18 +145,10 @@ sys_sync(td, uap) vfslocked = VFS_LOCK_GIANT(mp); if ((mp->mnt_flag & MNT_RDONLY) == 0 && vn_start_write(NULL, &mp, V_NOWAIT) == 0) { - MNT_ILOCK(mp); - mp->mnt_noasync++; - mp->mnt_kern_flag &= ~MNTK_ASYNC; - MNT_IUNLOCK(mp); + save = curthread_pflags_set(TDP_SYNCIO); vfs_msync(mp, MNT_NOWAIT); VFS_SYNC(mp, MNT_NOWAIT); - MNT_ILOCK(mp); - mp->mnt_noasync--; - if ((mp->mnt_flag & MNT_ASYNC) != 0 && - mp->mnt_noasync == 0) - mp->mnt_kern_flag |= MNTK_ASYNC; - MNT_IUNLOCK(mp); + curthread_pflags_restore(save); vn_finished_write(mp); } VFS_UNLOCK_GIANT(vfslocked); |
