Commit e327ce06 authored Feb 24, 2018 by Chengguang Xu Committed by Ilya Dryomov Apr 02, 2018

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>

parent b884014a

fs/ceph/caps.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}