Module Name: src
Committed By: hannken
Date: Thu Feb 17 14:38:06 UTC 2022
Modified Files:
src/sys/kern: vfs_vnode.c
Log Message:
If the vnode to vrelel() is already reclaimed there is no need
to lock or defer it. Jump straight to decrement usecount and requeue.
To generate a diff of this commit:
cvs rdiff -u -r1.130 -r1.131 src/sys/kern/vfs_vnode.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_vnode.c
diff -u src/sys/kern/vfs_vnode.c:1.130 src/sys/kern/vfs_vnode.c:1.131
--- src/sys/kern/vfs_vnode.c:1.130 Sat Feb 12 15:51:29 2022
+++ src/sys/kern/vfs_vnode.c Thu Feb 17 14:38:06 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_vnode.c,v 1.130 2022/02/12 15:51:29 thorpej Exp $ */
+/* $NetBSD: vfs_vnode.c,v 1.131 2022/02/17 14:38:06 hannken Exp $ */
/*-
* Copyright (c) 1997-2011, 2019, 2020 The NetBSD Foundation, Inc.
@@ -148,7 +148,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.130 2022/02/12 15:51:29 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.131 2022/02/17 14:38:06 hannken Exp $");
#ifdef _KERNEL_OPT
#include "opt_pax.h"
@@ -811,6 +811,20 @@ vrelel(vnode_t *vp, int flags, int lktyp
#endif
/*
+ * If already clean there is no need to lock, defer or
+ * deactivate this node.
+ */
+ if (VSTATE_GET(vp) == VS_RECLAIMED) {
+ if (lktype != LK_NONE) {
+ mutex_exit(vp->v_interlock);
+ lktype = LK_NONE;
+ VOP_UNLOCK(vp);
+ mutex_enter(vp->v_interlock);
+ }
+ goto out;
+ }
+
+ /*
* First try to get the vnode locked for VOP_INACTIVE().
* Defer vnode release to vdrain_thread if caller requests
* it explicitly, is the pagedaemon or the lock failed.
@@ -820,8 +834,7 @@ vrelel(vnode_t *vp, int flags, int lktyp
defer = true;
} else if (lktype == LK_SHARED) {
/* Excellent chance of getting, if the last ref. */
- error = vn_lock(vp, LK_UPGRADE | LK_RETRY |
- LK_NOWAIT);
+ error = vn_lock(vp, LK_UPGRADE | LK_RETRY | LK_NOWAIT);
if (error != 0) {
defer = true;
} else {
@@ -829,8 +842,7 @@ vrelel(vnode_t *vp, int flags, int lktyp
}
} else if (lktype == LK_NONE) {
/* Excellent chance of getting, if the last ref. */
- error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY |
- LK_NOWAIT);
+ error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWAIT);
if (error != 0) {
defer = true;
} else {
@@ -853,74 +865,69 @@ vrelel(vnode_t *vp, int flags, int lktyp
KASSERT(lktype == LK_EXCLUSIVE);
/*
- * If not clean, deactivate the vnode, but preserve
- * our reference across the call to VOP_INACTIVE().
+ * Deactivate the vnode, but preserve our reference across
+ * the call to VOP_INACTIVE().
+ *
+ * If VOP_INACTIVE() indicates that the file has been
+ * deleted, then recycle the vnode.
+ *
+ * Note that VOP_INACTIVE() will not drop the vnode lock.
*/
- if (VSTATE_GET(vp) == VS_RECLAIMED) {
- VOP_UNLOCK(vp);
- } else {
+ mutex_exit(vp->v_interlock);
+ recycle = false;
+ VOP_INACTIVE(vp, &recycle);
+ rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
+ mutex_enter(vp->v_interlock);
+
+ for (;;) {
/*
- * If VOP_INACTIVE() indicates that the file has been
- * deleted, then recycle the vnode.
- *
- * Note that VOP_INACTIVE() will not drop the vnode lock.
+ * If no longer the last reference, try to shed it.
+ * On success, drop the interlock last thereby
+ * preventing the vnode being freed behind us.
*/
- mutex_exit(vp->v_interlock);
- recycle = false;
- VOP_INACTIVE(vp, &recycle);
- rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
- mutex_enter(vp->v_interlock);
-
- for (;;) {
- /*
- * If no longer the last reference, try to shed it.
- * On success, drop the interlock last thereby
- * preventing the vnode being freed behind us.
- */
- if (vtryrele(vp)) {
- VOP_UNLOCK(vp);
- rw_exit(vp->v_uobj.vmobjlock);
- mutex_exit(vp->v_interlock);
- return;
- }
- /*
- * Block new references then check again to see if a
- * new reference was acquired in the meantime. If
- * it was, restore the vnode state and try again.
- */
- if (recycle) {
- VSTATE_CHANGE(vp, VS_LOADED, VS_BLOCKED);
- if (vrefcnt(vp) != 1) {
- VSTATE_CHANGE(vp, VS_BLOCKED,
- VS_LOADED);
- continue;
- }
- }
- break;
- }
-
- /* Take care of space accounting. */
- if ((vp->v_iflag & VI_EXECMAP) != 0) {
- cpu_count(CPU_COUNT_EXECPAGES, -vp->v_uobj.uo_npages);
- }
- vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP);
- vp->v_vflag &= ~VV_MAPPED;
- rw_exit(vp->v_uobj.vmobjlock);
-
+ if (vtryrele(vp)) {
+ VOP_UNLOCK(vp);
+ rw_exit(vp->v_uobj.vmobjlock);
+ mutex_exit(vp->v_interlock);
+ return;
+ }
/*
- * Recycle the vnode if the file is now unused (unlinked),
- * otherwise just free it.
+ * Block new references then check again to see if a
+ * new reference was acquired in the meantime. If
+ * it was, restore the vnode state and try again.
*/
if (recycle) {
- VSTATE_ASSERT(vp, VS_BLOCKED);
- /* vcache_reclaim drops the lock. */
- vcache_reclaim(vp);
- } else {
- VOP_UNLOCK(vp);
+ VSTATE_CHANGE(vp, VS_LOADED, VS_BLOCKED);
+ if (vrefcnt(vp) != 1) {
+ VSTATE_CHANGE(vp, VS_BLOCKED, VS_LOADED);
+ continue;
+ }
}
- KASSERT(vrefcnt(vp) > 0);
+ break;
+ }
+
+ /* Take care of space accounting. */
+ if ((vp->v_iflag & VI_EXECMAP) != 0) {
+ cpu_count(CPU_COUNT_EXECPAGES, -vp->v_uobj.uo_npages);
+ }
+ vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP);
+ vp->v_vflag &= ~VV_MAPPED;
+ rw_exit(vp->v_uobj.vmobjlock);
+
+ /*
+ * Recycle the vnode if the file is now unused (unlinked),
+ * otherwise just free it.
+ */
+ if (recycle) {
+ VSTATE_ASSERT(vp, VS_BLOCKED);
+ /* vcache_reclaim drops the lock. */
+ vcache_reclaim(vp);
+ } else {
+ VOP_UNLOCK(vp);
}
+ KASSERT(vrefcnt(vp) > 0);
+out:
if ((atomic_dec_uint_nv(&vp->v_usecount) & VUSECOUNT_MASK) != 0) {
/* Gained another reference while being reclaimed. */
mutex_exit(vp->v_interlock);
