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cache: batch updates to numcache in case of mass removal

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This commit is contained in:
Mateusz Guzik 2020-10-24 01:14:52 +00:00
parent 208cb7c4b6
commit acb41008f3
1 changed files with 35 additions and 15 deletions
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50
sys/kern/vfs_cache.c
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@ -110,6 +110,7 @@ SDT_PROBE_DEFINE2(vfs, namecache, removecnp, hit, "struct vnode *",
SDT_PROBE_DEFINE2(vfs, namecache, removecnp, miss, "struct vnode *",
"struct componentname *");
SDT_PROBE_DEFINE1(vfs, namecache, purge, done, "struct vnode *");
SDT_PROBE_DEFINE1(vfs, namecache, purge, batch, "int");
SDT_PROBE_DEFINE1(vfs, namecache, purge_negative, done, "struct vnode *");
SDT_PROBE_DEFINE1(vfs, namecache, purgevfs, done, "struct mount *");
SDT_PROBE_DEFINE3(vfs, namecache, zap, done, "struct vnode *", "char *",
@ -166,6 +167,8 @@ struct namecache_ts {
struct namecache nc_nc;
};
TAILQ_HEAD(cache_freebatch, namecache);
/*
* At least mips n32 performs 64-bit accesses to timespec as found
* in namecache_ts and requires them to be aligned. Since others
@ -626,6 +629,27 @@ cache_free(struct namecache *ncp)
atomic_subtract_long(&numcache, 1);
}
static void
cache_free_batch(struct cache_freebatch *batch)
{
struct namecache *ncp, *nnp;
int i;
i = 0;
if (TAILQ_EMPTY(batch))
goto out;
TAILQ_FOREACH_SAFE(ncp, batch, nc_dst, nnp) {
if ((ncp->nc_flag & NCF_DVDROP) != 0) {
cache_drop_vnode(ncp->nc_dvp);
}
cache_free_uma(ncp);
i++;
}
atomic_subtract_long(&numcache, i);
out:
SDT_PROBE1(vfs, namecache, purge, batch, i);
}
/*
* TODO: With the value stored we can do better than computing the hash based
* on the address. The choice of FNV should also be revisited.
@ -2524,11 +2548,11 @@ cache_changesize(u_long newmaxvnodes)
static void
cache_purge_impl(struct vnode *vp)
{
TAILQ_HEAD(, namecache) ncps;
struct namecache *ncp, *nnp;
struct cache_freebatch batch;
struct namecache *ncp;
struct mtx *vlp, *vlp2;
TAILQ_INIT(&ncps);
TAILQ_INIT(&batch);
vlp = VP2VNODELOCK(vp);
vlp2 = NULL;
mtx_lock(vlp);
@ -2537,13 +2561,13 @@ cache_purge_impl(struct vnode *vp)
ncp = LIST_FIRST(&vp->v_cache_src);
if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
goto retry;
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
TAILQ_INSERT_TAIL(&batch, ncp, nc_dst);
}
while (!TAILQ_EMPTY(&vp->v_cache_dst)) {
ncp = TAILQ_FIRST(&vp->v_cache_dst);
if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
goto retry;
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
TAILQ_INSERT_TAIL(&batch, ncp, nc_dst);
}
ncp = vp->v_cache_dd;
if (ncp != NULL) {
@ -2551,15 +2575,13 @@ cache_purge_impl(struct vnode *vp)
("lost dotdot link"));
if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
goto retry;
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
TAILQ_INSERT_TAIL(&batch, ncp, nc_dst);
}
KASSERT(vp->v_cache_dd == NULL, ("incomplete purge"));
mtx_unlock(vlp);
if (vlp2 != NULL)
mtx_unlock(vlp2);
TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
cache_free(ncp);
}
cache_free_batch(&batch);
}
/*
@ -2617,26 +2639,24 @@ cache_purge_vgone(struct vnode *vp)
void
cache_purge_negative(struct vnode *vp)
{
TAILQ_HEAD(, namecache) ncps;
struct cache_freebatch batch;
struct namecache *ncp, *nnp;
struct mtx *vlp;
SDT_PROBE1(vfs, namecache, purge_negative, done, vp);
if (LIST_EMPTY(&vp->v_cache_src))
return;
TAILQ_INIT(&ncps);
TAILQ_INIT(&batch);
vlp = VP2VNODELOCK(vp);
mtx_lock(vlp);
LIST_FOREACH_SAFE(ncp, &vp->v_cache_src, nc_src, nnp) {
if (!(ncp->nc_flag & NCF_NEGATIVE))
continue;
cache_zap_negative_locked_vnode_kl(ncp, vp);
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
TAILQ_INSERT_TAIL(&batch, ncp, nc_dst);
}
mtx_unlock(vlp);
TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
cache_free(ncp);
}
cache_free_batch(&batch);
}
void