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>
This commit is contained in:
David Teigland 2013-01-07 11:03:42 -06:00
parent 2318aa2720
commit f117228346
2 changed files with 18 additions and 0 deletions

View file

@ -96,10 +96,13 @@ do { \
}
#define DLM_RTF_SHRINK 0x00000001
struct dlm_rsbtable {
struct rb_root keep;
struct rb_root toss;
spinlock_t lock;
uint32_t flags;
};

View file

@ -1132,6 +1132,7 @@ static void toss_rsb(struct kref *kref)
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 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
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 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
continue;
}
need_shrink = 1;
if (!time_after_eq(jiffies, r->res_toss_time +
dlm_config.ci_toss_secs * HZ)) {
continue;
@ -1710,6 +1720,11 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
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);
/*