ceph: optimizing cap allocation

When setting high volume of caps_min_count or having many
unreserved caps, unused caps may always keep in the ->caps_list
even can't get new cap from kmem_cache_alloc because lack of
maximum limitation of caps_avail_count. Hence reuse caps in
->caps_list if available, it's maybe better than setting max
limitation of caps_avail_count and releasing unused caps when
reaching the limit.

Signed-off-by: Chengguang Xu <cgxu519@icloud.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Chengguang Xu 2018-02-24 18:35:29 +08:00 committed by Ilya Dryomov
parent b884014a91
commit e327ce0685

View File

@ -285,7 +285,23 @@ struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
mdsc->caps_use_count++;
mdsc->caps_total_count++;
spin_unlock(&mdsc->caps_list_lock);
} else {
spin_lock(&mdsc->caps_list_lock);
if (mdsc->caps_avail_count) {
BUG_ON(list_empty(&mdsc->caps_list));
mdsc->caps_avail_count--;
mdsc->caps_use_count++;
cap = list_first_entry(&mdsc->caps_list,
struct ceph_cap, caps_item);
list_del(&cap->caps_item);
BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
mdsc->caps_reserve_count + mdsc->caps_avail_count);
}
spin_unlock(&mdsc->caps_list_lock);
}
return cap;
}