d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

tmpfs: restore atime updates for reads from page cache.

Browse Source 
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
This commit is contained in:
Konstantin Belousov 2020-09-16 21:28:18 +00:00
parent 23f9071466
commit 016b7c7e39
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=365810
4 changed files with 49 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
sys/fs/tmpfs/tmpfs.h
View File

@ -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 *, struct ucred *cred,
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);
}

3
sys/fs/tmpfs/tmpfs_fifoops.c
View File

@ -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));
}

37
sys/fs/tmpfs/tmpfs_subr.c
View File

@ -88,6 +88,7 @@ tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
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 *de)
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 *de)
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 tmpfs_node *node,
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 tmpfs_node *node,
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 tmpfs_node *node,
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_node *node, int status)
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 *acc,
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 *acc,
}
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 */

20
sys/fs/tmpfs/tmpfs_vnops.c
View File

@ -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);
}