svn commit: r268852 - in vendor-sys/illumos/dist/uts/common/fs/zfs: . sys
Xin LI
delphij at FreeBSD.org
Fri Jul 18 18:09:22 UTC 2014
Author: delphij
Date: Fri Jul 18 18:09:20 2014
New Revision: 268852
URL: http://svnweb.freebsd.org/changeset/base/268852
Log:
5008 lock contention (rrw_exit) while running a read only load
Reviewed by: Matthew Ahrens <matthew.ahrens at delphix.com>
Reviewed by: George Wilson <george.wilson at delphix.com>
Reviewed by: Alex Reece <alex.reece at delphix.com>
Reviewed by: Christopher Siden <christopher.siden at delphix.com>
Reviewed by: Richard Yao <ryao at gentoo.org>
Reviewed by: Saso Kiselkov <skiselkov.ml at gmail.com>
Approved by: Garrett D'Amore <garrett at damore.org>
illumos/illumos-gate at c9030f6c93613fe30ee0c16f92b96da7816ac052
Modified:
vendor-sys/illumos/dist/uts/common/fs/zfs/rrwlock.c
vendor-sys/illumos/dist/uts/common/fs/zfs/sys/rrwlock.h
vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_vfsops.h
vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_znode.h
vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_ioctl.c
vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_vfsops.c
vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_znode.c
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/rrwlock.c
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/rrwlock.c Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/rrwlock.c Fri Jul 18 18:09:20 2014 (r268852)
@@ -286,3 +286,91 @@ rrw_tsd_destroy(void *arg)
(void *)curthread, (void *)rn->rn_rrl);
}
}
+
+/*
+ * A reader-mostly lock implementation, tuning above reader-writer locks
+ * for hightly parallel read acquisitions, while pessimizing writes.
+ *
+ * The idea is to split single busy lock into array of locks, so that
+ * each reader can lock only one of them for read, depending on result
+ * of simple hash function. That proportionally reduces lock congestion.
+ * Writer same time has to sequentially aquire write on all the locks.
+ * That makes write aquisition proportionally slower, but in places where
+ * it is used (filesystem unmount) performance is not critical.
+ *
+ * All the functions below are direct wrappers around functions above.
+ */
+void
+rrm_init(rrmlock_t *rrl, boolean_t track_all)
+{
+ int i;
+
+ for (i = 0; i < RRM_NUM_LOCKS; i++)
+ rrw_init(&rrl->locks[i], track_all);
+}
+
+void
+rrm_destroy(rrmlock_t *rrl)
+{
+ int i;
+
+ for (i = 0; i < RRM_NUM_LOCKS; i++)
+ rrw_destroy(&rrl->locks[i]);
+}
+
+void
+rrm_enter(rrmlock_t *rrl, krw_t rw, void *tag)
+{
+ if (rw == RW_READER)
+ rrm_enter_read(rrl, tag);
+ else
+ rrm_enter_write(rrl);
+}
+
+/*
+ * This maps the current thread to a specific lock. Note that the lock
+ * must be released by the same thread that acquired it. We do this
+ * mapping by taking the thread pointer mod a prime number. We examine
+ * only the low 32 bits of the thread pointer, because 32-bit division
+ * is faster than 64-bit division, and the high 32 bits have little
+ * entropy anyway.
+ */
+#define RRM_TD_LOCK() (((uint32_t)(uintptr_t)(curthread)) % RRM_NUM_LOCKS)
+
+void
+rrm_enter_read(rrmlock_t *rrl, void *tag)
+{
+ rrw_enter_read(&rrl->locks[RRM_TD_LOCK()], tag);
+}
+
+void
+rrm_enter_write(rrmlock_t *rrl)
+{
+ int i;
+
+ for (i = 0; i < RRM_NUM_LOCKS; i++)
+ rrw_enter_write(&rrl->locks[i]);
+}
+
+void
+rrm_exit(rrmlock_t *rrl, void *tag)
+{
+ int i;
+
+ if (rrl->locks[0].rr_writer == curthread) {
+ for (i = 0; i < RRM_NUM_LOCKS; i++)
+ rrw_exit(&rrl->locks[i], tag);
+ } else {
+ rrw_exit(&rrl->locks[RRM_TD_LOCK()], tag);
+ }
+}
+
+boolean_t
+rrm_held(rrmlock_t *rrl, krw_t rw)
+{
+ if (rw == RW_WRITER) {
+ return (rrw_held(&rrl->locks[0], rw));
+ } else {
+ return (rrw_held(&rrl->locks[RRM_TD_LOCK()], rw));
+ }
+}
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/sys/rrwlock.h
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/sys/rrwlock.h Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/sys/rrwlock.h Fri Jul 18 18:09:20 2014 (r268852)
@@ -80,6 +80,31 @@ void rrw_tsd_destroy(void *arg);
#define RRW_LOCK_HELD(x) \
(rrw_held(x, RW_WRITER) || rrw_held(x, RW_READER))
+/*
+ * A reader-mostly lock implementation, tuning above reader-writer locks
+ * for hightly parallel read acquisitions, pessimizing write acquisitions.
+ *
+ * This should be a prime number. See comment in rrwlock.c near
+ * RRM_TD_LOCK() for details.
+ */
+#define RRM_NUM_LOCKS 17
+typedef struct rrmlock {
+ rrwlock_t locks[RRM_NUM_LOCKS];
+} rrmlock_t;
+
+void rrm_init(rrmlock_t *rrl, boolean_t track_all);
+void rrm_destroy(rrmlock_t *rrl);
+void rrm_enter(rrmlock_t *rrl, krw_t rw, void *tag);
+void rrm_enter_read(rrmlock_t *rrl, void *tag);
+void rrm_enter_write(rrmlock_t *rrl);
+void rrm_exit(rrmlock_t *rrl, void *tag);
+boolean_t rrm_held(rrmlock_t *rrl, krw_t rw);
+
+#define RRM_READ_HELD(x) rrm_held(x, RW_READER)
+#define RRM_WRITE_HELD(x) rrm_held(x, RW_WRITER)
+#define RRM_LOCK_HELD(x) \
+ (rrm_held(x, RW_WRITER) || rrm_held(x, RW_READER))
+
#ifdef __cplusplus
}
#endif
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_vfsops.h
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_vfsops.h Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_vfsops.h Fri Jul 18 18:09:20 2014 (r268852)
@@ -64,7 +64,7 @@ struct zfsvfs {
int z_norm; /* normalization flags */
boolean_t z_atime; /* enable atimes mount option */
boolean_t z_unmounted; /* unmounted */
- rrwlock_t z_teardown_lock;
+ rrmlock_t z_teardown_lock;
krwlock_t z_teardown_inactive_lock;
list_t z_all_znodes; /* all vnodes in the fs */
kmutex_t z_znodes_lock; /* lock for z_all_znodes */
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_znode.h
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_znode.h Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/sys/zfs_znode.h Fri Jul 18 18:09:20 2014 (r268852)
@@ -238,7 +238,7 @@ typedef struct znode {
/* Called on entry to each ZFS vnode and vfs operation */
#define ZFS_ENTER(zfsvfs) \
{ \
- rrw_enter_read(&(zfsvfs)->z_teardown_lock, FTAG); \
+ rrm_enter_read(&(zfsvfs)->z_teardown_lock, FTAG); \
if ((zfsvfs)->z_unmounted) { \
ZFS_EXIT(zfsvfs); \
return (EIO); \
@@ -246,7 +246,7 @@ typedef struct znode {
}
/* Must be called before exiting the vop */
-#define ZFS_EXIT(zfsvfs) rrw_exit(&(zfsvfs)->z_teardown_lock, FTAG)
+#define ZFS_EXIT(zfsvfs) rrm_exit(&(zfsvfs)->z_teardown_lock, FTAG)
/* Verifies the znode is valid */
#define ZFS_VERIFY_ZP(zp) \
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_ioctl.c
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_ioctl.c Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_ioctl.c Fri Jul 18 18:09:20 2014 (r268852)
@@ -1420,7 +1420,7 @@ zfsvfs_hold(const char *name, void *tag,
if (getzfsvfs(name, zfvp) != 0)
error = zfsvfs_create(name, zfvp);
if (error == 0) {
- rrw_enter(&(*zfvp)->z_teardown_lock, (writer) ? RW_WRITER :
+ rrm_enter(&(*zfvp)->z_teardown_lock, (writer) ? RW_WRITER :
RW_READER, tag);
if ((*zfvp)->z_unmounted) {
/*
@@ -1428,7 +1428,7 @@ zfsvfs_hold(const char *name, void *tag,
* thread should be just about to disassociate the
* objset from the zfsvfs.
*/
- rrw_exit(&(*zfvp)->z_teardown_lock, tag);
+ rrm_exit(&(*zfvp)->z_teardown_lock, tag);
return (SET_ERROR(EBUSY));
}
}
@@ -1438,7 +1438,7 @@ zfsvfs_hold(const char *name, void *tag,
static void
zfsvfs_rele(zfsvfs_t *zfsvfs, void *tag)
{
- rrw_exit(&zfsvfs->z_teardown_lock, tag);
+ rrm_exit(&zfsvfs->z_teardown_lock, tag);
if (zfsvfs->z_vfs) {
VFS_RELE(zfsvfs->z_vfs);
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_vfsops.c
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_vfsops.c Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_vfsops.c Fri Jul 18 18:09:20 2014 (r268852)
@@ -1004,7 +1004,7 @@ zfsvfs_create(const char *osname, zfsvfs
mutex_init(&zfsvfs->z_lock, NULL, MUTEX_DEFAULT, NULL);
list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
offsetof(znode_t, z_link_node));
- rrw_init(&zfsvfs->z_teardown_lock, B_FALSE);
+ rrm_init(&zfsvfs->z_teardown_lock, B_FALSE);
rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
@@ -1119,7 +1119,7 @@ zfsvfs_free(zfsvfs_t *zfsvfs)
mutex_destroy(&zfsvfs->z_znodes_lock);
mutex_destroy(&zfsvfs->z_lock);
list_destroy(&zfsvfs->z_all_znodes);
- rrw_destroy(&zfsvfs->z_teardown_lock);
+ rrm_destroy(&zfsvfs->z_teardown_lock);
rw_destroy(&zfsvfs->z_teardown_inactive_lock);
rw_destroy(&zfsvfs->z_fuid_lock);
for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
@@ -1784,7 +1784,7 @@ zfsvfs_teardown(zfsvfs_t *zfsvfs, boolea
{
znode_t *zp;
- rrw_enter(&zfsvfs->z_teardown_lock, RW_WRITER, FTAG);
+ rrm_enter(&zfsvfs->z_teardown_lock, RW_WRITER, FTAG);
if (!unmounting) {
/*
@@ -1814,7 +1814,7 @@ zfsvfs_teardown(zfsvfs_t *zfsvfs, boolea
*/
if (!unmounting && (zfsvfs->z_unmounted || zfsvfs->z_os == NULL)) {
rw_exit(&zfsvfs->z_teardown_inactive_lock);
- rrw_exit(&zfsvfs->z_teardown_lock, FTAG);
+ rrm_exit(&zfsvfs->z_teardown_lock, FTAG);
return (SET_ERROR(EIO));
}
@@ -1841,7 +1841,7 @@ zfsvfs_teardown(zfsvfs_t *zfsvfs, boolea
*/
if (unmounting) {
zfsvfs->z_unmounted = B_TRUE;
- rrw_exit(&zfsvfs->z_teardown_lock, FTAG);
+ rrm_exit(&zfsvfs->z_teardown_lock, FTAG);
rw_exit(&zfsvfs->z_teardown_inactive_lock);
}
@@ -2073,7 +2073,7 @@ zfs_resume_fs(zfsvfs_t *zfsvfs, const ch
znode_t *zp;
uint64_t sa_obj = 0;
- ASSERT(RRW_WRITE_HELD(&zfsvfs->z_teardown_lock));
+ ASSERT(RRM_WRITE_HELD(&zfsvfs->z_teardown_lock));
ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
/*
@@ -2129,7 +2129,7 @@ zfs_resume_fs(zfsvfs_t *zfsvfs, const ch
bail:
/* release the VOPs */
rw_exit(&zfsvfs->z_teardown_inactive_lock);
- rrw_exit(&zfsvfs->z_teardown_lock, FTAG);
+ rrm_exit(&zfsvfs->z_teardown_lock, FTAG);
if (err) {
/*
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_znode.c
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_znode.c Fri Jul 18 18:05:09 2014 (r268851)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/zfs_znode.c Fri Jul 18 18:09:20 2014 (r268852)
@@ -276,7 +276,7 @@ zfs_znode_move(void *buf, void *newbuf,
* can safely ensure that the filesystem is not and will not be
* unmounted. The next statement is equivalent to ZFS_ENTER().
*/
- rrw_enter(&zfsvfs->z_teardown_lock, RW_READER, FTAG);
+ rrm_enter(&zfsvfs->z_teardown_lock, RW_READER, FTAG);
if (zfsvfs->z_unmounted) {
ZFS_EXIT(zfsvfs);
rw_exit(&zfsvfs_lock);
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