svn commit: r365810 - head/sys/fs/tmpfs
Konstantin Belousov
kib at FreeBSD.org
Wed Sep 16 21:28:20 UTC 2020
Author: kib
Date: Wed Sep 16 21:28:18 2020
New Revision: 365810
URL: https://svnweb.freebsd.org/changeset/base/365810
Log:
tmpfs: restore atime updates for reads from page cache.
Split TMPFS_NODE_ACCCESSED bit into dedicated byte that can be updated
atomically without locks or (locked) atomics.
tn_update_getattr() change also contains unrelated bug fix.
Reported by: lwhsu
PR: 249362
Reviewed by: markj (previous version)
Discussed with: mjg
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26451
Modified:
head/sys/fs/tmpfs/tmpfs.h
head/sys/fs/tmpfs/tmpfs_fifoops.c
head/sys/fs/tmpfs/tmpfs_subr.c
head/sys/fs/tmpfs/tmpfs_vnops.c
Modified: head/sys/fs/tmpfs/tmpfs.h
==============================================================================
--- head/sys/fs/tmpfs/tmpfs.h Wed Sep 16 21:24:34 2020 (r365809)
+++ head/sys/fs/tmpfs/tmpfs.h Wed Sep 16 21:28:18 2020 (r365810)
@@ -173,11 +173,13 @@ struct tmpfs_node {
* Node's internal status. This is used by several file system
* operations to do modifications to the node in a delayed
* fashion.
+ *
+ * tn_accessed has a dedicated byte to allow update by store without
+ * using atomics. This provides a micro-optimization to e.g.
+ * tmpfs_read_pgcache().
*/
- int tn_status; /* (vi) */
-#define TMPFS_NODE_ACCESSED (1 << 1)
-#define TMPFS_NODE_MODIFIED (1 << 2)
-#define TMPFS_NODE_CHANGED (1 << 3)
+ uint8_t tn_status; /* (vi) */
+ uint8_t tn_accessed; /* unlocked */
/*
* The node size. It does not necessarily match the real amount
@@ -317,11 +319,16 @@ LIST_HEAD(tmpfs_node_list, tmpfs_node);
#define TMPFS_ASSERT_LOCKED(node) (void)0
#endif
+/* tn_vpstate */
#define TMPFS_VNODE_ALLOCATING 1
#define TMPFS_VNODE_WANT 2
#define TMPFS_VNODE_DOOMED 4
#define TMPFS_VNODE_WRECLAIM 8
+/* tn_status */
+#define TMPFS_NODE_MODIFIED 0x01
+#define TMPFS_NODE_CHANGED 0x02
+
/*
* Internal representation of a tmpfs mount point.
*/
@@ -452,6 +459,7 @@ int tmpfs_chtimes(struct vnode *, struct vattr *, stru
void tmpfs_itimes(struct vnode *, const struct timespec *,
const struct timespec *);
+void tmpfs_set_accessed(struct tmpfs_mount *tm, struct tmpfs_node *node);
void tmpfs_set_status(struct tmpfs_mount *tm, struct tmpfs_node *node,
int status);
int tmpfs_truncate(struct vnode *, off_t);
@@ -551,12 +559,10 @@ static inline void
tmpfs_update_getattr(struct vnode *vp)
{
struct tmpfs_node *node;
- int update_flags;
- update_flags = TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED;
-
node = VP_TO_TMPFS_NODE(vp);
- if (__predict_false(node->tn_status & update_flags) != 0)
+ if (__predict_false((node->tn_status & (TMPFS_NODE_MODIFIED |
+ TMPFS_NODE_CHANGED)) != 0 || node->tn_accessed))
tmpfs_update(vp);
}
Modified: head/sys/fs/tmpfs/tmpfs_fifoops.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_fifoops.c Wed Sep 16 21:24:34 2020 (r365809)
+++ head/sys/fs/tmpfs/tmpfs_fifoops.c Wed Sep 16 21:28:18 2020 (r365810)
@@ -56,8 +56,7 @@ tmpfs_fifo_close(struct vop_close_args *v)
struct tmpfs_node *node;
node = VP_TO_TMPFS_NODE(v->a_vp);
- tmpfs_set_status(VFS_TO_TMPFS(v->a_vp->v_mount), node,
- TMPFS_NODE_ACCESSED);
+ tmpfs_set_accessed(VFS_TO_TMPFS(v->a_vp->v_mount), node);
tmpfs_update(v->a_vp);
return (fifo_specops.vop_close(v));
}
Modified: head/sys/fs/tmpfs/tmpfs_subr.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_subr.c Wed Sep 16 21:24:34 2020 (r365809)
+++ head/sys/fs/tmpfs/tmpfs_subr.c Wed Sep 16 21:28:18 2020 (r365810)
@@ -88,6 +88,7 @@ tmpfs_node_ctor(void *mem, int size, void *arg, int fl
node->tn_gen++;
node->tn_size = 0;
node->tn_status = 0;
+ node->tn_accessed = false;
node->tn_flags = 0;
node->tn_links = 0;
node->tn_vnode = NULL;
@@ -1098,8 +1099,8 @@ tmpfs_dir_attach(struct vnode *vp, struct tmpfs_dirent
tmpfs_dir_attach_dup(dnode, &xde->ud.td_duphead, de);
}
dnode->tn_size += sizeof(struct tmpfs_dirent);
- dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
- TMPFS_NODE_MODIFIED;
+ dnode->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
+ dnode->tn_accessed = true;
tmpfs_update(vp);
}
@@ -1145,8 +1146,8 @@ tmpfs_dir_detach(struct vnode *vp, struct tmpfs_dirent
RB_REMOVE(tmpfs_dir, head, de);
dnode->tn_size -= sizeof(struct tmpfs_dirent);
- dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
- TMPFS_NODE_MODIFIED;
+ dnode->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
+ dnode->tn_accessed = true;
tmpfs_update(vp);
}
@@ -1199,7 +1200,7 @@ tmpfs_dir_getdotdent(struct tmpfs_mount *tm, struct tm
else
error = uiomove(&dent, dent.d_reclen, uio);
- tmpfs_set_status(tm, node, TMPFS_NODE_ACCESSED);
+ tmpfs_set_accessed(tm, node);
return (error);
}
@@ -1246,7 +1247,7 @@ tmpfs_dir_getdotdotdent(struct tmpfs_mount *tm, struct
else
error = uiomove(&dent, dent.d_reclen, uio);
- tmpfs_set_status(tm, node, TMPFS_NODE_ACCESSED);
+ tmpfs_set_accessed(tm, node);
return (error);
}
@@ -1391,8 +1392,8 @@ tmpfs_dir_getdents(struct tmpfs_mount *tm, struct tmpf
node->tn_dir.tn_readdir_lastn = off;
node->tn_dir.tn_readdir_lastp = de;
- tmpfs_set_status(tm, node, TMPFS_NODE_ACCESSED);
- return error;
+ tmpfs_set_accessed(tm, node);
+ return (error);
}
int
@@ -1833,7 +1834,7 @@ tmpfs_chtimes(struct vnode *vp, struct vattr *vap,
return (error);
if (vap->va_atime.tv_sec != VNOVAL)
- node->tn_status |= TMPFS_NODE_ACCESSED;
+ node->tn_accessed = true;
if (vap->va_mtime.tv_sec != VNOVAL)
node->tn_status |= TMPFS_NODE_MODIFIED;
@@ -1861,6 +1862,14 @@ tmpfs_set_status(struct tmpfs_mount *tm, struct tmpfs_
TMPFS_NODE_UNLOCK(node);
}
+void
+tmpfs_set_accessed(struct tmpfs_mount *tm, struct tmpfs_node *node)
+{
+ if (node->tn_accessed || tm->tm_ronly)
+ return;
+ atomic_store_8(&node->tn_accessed, true);
+}
+
/* Sync timestamps */
void
tmpfs_itimes(struct vnode *vp, const struct timespec *acc,
@@ -1872,13 +1881,13 @@ tmpfs_itimes(struct vnode *vp, const struct timespec *
ASSERT_VOP_LOCKED(vp, "tmpfs_itimes");
node = VP_TO_TMPFS_NODE(vp);
- if ((node->tn_status & (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED |
- TMPFS_NODE_CHANGED)) == 0)
+ if (!node->tn_accessed &&
+ (node->tn_status & (TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED)) == 0)
return;
vfs_timestamp(&now);
TMPFS_NODE_LOCK(node);
- if (node->tn_status & TMPFS_NODE_ACCESSED) {
+ if (node->tn_accessed) {
if (acc == NULL)
acc = &now;
node->tn_atime = *acc;
@@ -1890,8 +1899,8 @@ tmpfs_itimes(struct vnode *vp, const struct timespec *
}
if (node->tn_status & TMPFS_NODE_CHANGED)
node->tn_ctime = now;
- node->tn_status &= ~(TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED |
- TMPFS_NODE_CHANGED);
+ node->tn_status &= ~(TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED);
+ node->tn_accessed = false;
TMPFS_NODE_UNLOCK(node);
/* XXX: FIX? The entropy here is desirable, but the harvesting may be expensive */
Modified: head/sys/fs/tmpfs/tmpfs_vnops.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_vnops.c Wed Sep 16 21:24:34 2020 (r365809)
+++ head/sys/fs/tmpfs/tmpfs_vnops.c Wed Sep 16 21:28:18 2020 (r365810)
@@ -586,7 +586,7 @@ tmpfs_read(struct vop_read_args *v)
if (uio->uio_offset < 0)
return (EINVAL);
node = VP_TO_TMPFS_NODE(vp);
- tmpfs_set_status(VFS_TO_TMPFS(vp->v_mount), node, TMPFS_NODE_ACCESSED);
+ tmpfs_set_accessed(VFS_TO_TMPFS(vp->v_mount), node);
return (uiomove_object(node->tn_reg.tn_aobj, node->tn_size, uio));
}
@@ -622,6 +622,7 @@ tmpfs_read_pgcache(struct vop_read_pgcache_args *v)
if (!VN_IS_DOOMED(vp)) {
/* size cannot become shorter due to rangelock. */
size = node->tn_size;
+ tmpfs_set_accessed(node->tn_reg.tn_tmp, node);
vfs_smr_exit();
error = uiomove_object(object, size, v->a_uio);
return (error);
@@ -667,8 +668,8 @@ tmpfs_write(struct vop_write_args *v)
}
error = uiomove_object(node->tn_reg.tn_aobj, node->tn_size, uio);
- node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED |
- TMPFS_NODE_CHANGED;
+ node->tn_status |= TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED;
+ node->tn_accessed = true;
if (node->tn_mode & (S_ISUID | S_ISGID)) {
if (priv_check_cred(v->a_cred, PRIV_VFS_RETAINSUGID)) {
newmode = node->tn_mode & ~(S_ISUID | S_ISGID);
@@ -744,7 +745,8 @@ tmpfs_remove(struct vop_remove_args *v)
* reclaimed. */
tmpfs_free_dirent(tmp, de);
- node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED;
+ node->tn_status |= TMPFS_NODE_CHANGED;
+ node->tn_accessed = true;
error = 0;
out:
@@ -1317,15 +1319,15 @@ tmpfs_rmdir(struct vop_rmdir_args *v)
TMPFS_NODE_LOCK(node);
node->tn_links--;
node->tn_dir.tn_parent = NULL;
- node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
- TMPFS_NODE_MODIFIED;
+ node->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
+ node->tn_accessed = true;
TMPFS_NODE_UNLOCK(node);
TMPFS_NODE_LOCK(dnode);
dnode->tn_links--;
- dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
- TMPFS_NODE_MODIFIED;
+ dnode->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
+ dnode->tn_accessed = true;
TMPFS_NODE_UNLOCK(dnode);
if (tmpfs_use_nc(dvp)) {
@@ -1444,7 +1446,7 @@ tmpfs_readlink(struct vop_readlink_args *v)
error = uiomove(node->tn_link, MIN(node->tn_size, uio->uio_resid),
uio);
- tmpfs_set_status(VFS_TO_TMPFS(vp->v_mount), node, TMPFS_NODE_ACCESSED);
+ tmpfs_set_accessed(VFS_TO_TMPFS(vp->v_mount), node);
return (error);
}
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