dlm: avoid scanning unchanged toss lists
Keep track of whether a toss list contains any
shrinkable rsbs. If not, dlm_scand can avoid
scanning the list for rsbs to shrink. Unnecessary
scanning can otherwise waste a lot of time because
the toss lists can contain a large number of rsbs
that are non-shrinkable (directory records).
Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 77c0f70..e7665c3 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -96,10 +96,13 @@
}
+#define DLM_RTF_SHRINK 0x00000001
+
struct dlm_rsbtable {
struct rb_root keep;
struct rb_root toss;
spinlock_t lock;
+ uint32_t flags;
};
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index a579f30..f750165 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1132,6 +1132,7 @@
rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[r->res_bucket].keep);
rsb_insert(r, &ls->ls_rsbtbl[r->res_bucket].toss);
r->res_toss_time = jiffies;
+ ls->ls_rsbtbl[r->res_bucket].flags |= DLM_RTF_SHRINK;
if (r->res_lvbptr) {
dlm_free_lvb(r->res_lvbptr);
r->res_lvbptr = NULL;
@@ -1659,11 +1660,18 @@
char *name;
int our_nodeid = dlm_our_nodeid();
int remote_count = 0;
+ int need_shrink = 0;
int i, len, rv;
memset(&ls->ls_remove_lens, 0, sizeof(int) * DLM_REMOVE_NAMES_MAX);
spin_lock(&ls->ls_rsbtbl[b].lock);
+
+ if (!(ls->ls_rsbtbl[b].flags & DLM_RTF_SHRINK)) {
+ spin_unlock(&ls->ls_rsbtbl[b].lock);
+ return;
+ }
+
for (n = rb_first(&ls->ls_rsbtbl[b].toss); n; n = next) {
next = rb_next(n);
r = rb_entry(n, struct dlm_rsb, res_hashnode);
@@ -1679,6 +1687,8 @@
continue;
}
+ need_shrink = 1;
+
if (!time_after_eq(jiffies, r->res_toss_time +
dlm_config.ci_toss_secs * HZ)) {
continue;
@@ -1710,6 +1720,11 @@
rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
dlm_free_rsb(r);
}
+
+ if (need_shrink)
+ ls->ls_rsbtbl[b].flags |= DLM_RTF_SHRINK;
+ else
+ ls->ls_rsbtbl[b].flags &= ~DLM_RTF_SHRINK;
spin_unlock(&ls->ls_rsbtbl[b].lock);
/*