Author: ps
Date: Thu Jun 4 16:18:07 2009
New Revision: 193440
URL: http://svn.freebsd.org/changeset/base/193440
Log:
Support shared vnode locks for write operations when the offset is
provided on filesystems that support it. This really improves mysql
+ innodb performance on ZFS.
Reviewed by: jhb, kmacy, jeffr
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
head/sys/kern/vfs_vnops.c
head/sys/sys/mount.h
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c Thu Jun
4 15:57:38 2009 (r193439)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c Thu Jun
4 16:18:07 2009 (r193440)
@@ -573,6 +573,7 @@ zfs_domount(vfs_t *vfsp, char *osname)
vfsp->mnt_flag |= MNT_LOCAL;
vfsp->mnt_kern_flag |= MNTK_MPSAFE;
vfsp->mnt_kern_flag |= MNTK_LOOKUP_SHARED;
+ vfsp->mnt_kern_flag |= MNTK_SHARED_WRITES;
if (error = dsl_prop_get_integer(osname, "readonly", &readonly, NULL))
goto out;
Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c Thu Jun 4 15:57:38 2009 (r193439)
+++ head/sys/kern/vfs_vnops.c Thu Jun 4 16:18:07 2009 (r193440)
@@ -367,7 +367,7 @@ vn_rdwr(rw, vp, base, len, offset, segfl
struct iovec aiov;
struct mount *mp;
struct ucred *cred;
- int error;
+ int error, lock_flags;
VFS_ASSERT_GIANT(vp->v_mount);
@@ -378,7 +378,13 @@ vn_rdwr(rw, vp, base, len, offset, segfl
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
!= 0)
return (error);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+ if (mp != NULL &&
+ (mp->mnt_kern_flag & MNTK_SHARED_WRITES)) {
+ lock_flags = LK_SHARED;
+ } else {
+ lock_flags = LK_EXCLUSIVE;
+ }
+ vn_lock(vp, lock_flags | LK_RETRY);
} else
vn_lock(vp, LK_SHARED | LK_RETRY);
@@ -564,7 +570,7 @@ vn_write(fp, uio, active_cred, flags, td
{
struct vnode *vp;
struct mount *mp;
- int error, ioflag;
+ int error, ioflag, lock_flags;
int vfslocked;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
@@ -587,7 +593,16 @@ vn_write(fp, uio, active_cred, flags, td
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
goto unlock;
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+
+ if (vp->v_mount != NULL &&
+ (vp->v_mount->mnt_kern_flag & MNTK_SHARED_WRITES) &&
+ (flags & FOF_OFFSET) != 0) {
+ lock_flags = LK_SHARED;
+ } else {
+ lock_flags = LK_EXCLUSIVE;
+ }
+
+ vn_lock(vp, lock_flags | LK_RETRY);
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
ioflag |= sequential_heuristic(uio, fp);
Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h Thu Jun 4 15:57:38 2009 (r193439)
+++ head/sys/sys/mount.h Thu Jun 4 16:18:07 2009 (r193440)
@@ -326,6 +326,7 @@ void __mnt_vnode_markerfree(str
#define MNTK_DRAINING 0x00000010 /* lock draining is happening */
#define MNTK_REFEXPIRE 0x00000020 /* refcount expiring is
happening */
#define MNTK_EXTENDED_SHARED 0x00000040 /* Allow shared locking for more ops
*/
+#define MNTK_SHARED_WRITES 0x00000080 /* Allow shared locking for
writes */
#define MNTK_UNMOUNT 0x01000000 /* unmount in progress */
#define MNTK_MWAIT 0x02000000 /* waiting for unmount to
finish */
#define MNTK_SUSPEND 0x08000000 /* request write suspension */
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