From e327ce068518e38c0182739e879b9dce477c8d85 Mon Sep 17 00:00:00 2001 From: Chengguang Xu Date: Sat, 24 Feb 2018 18:35:29 +0800 Subject: [PATCH] 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 Reviewed-by: "Yan, Zheng" Signed-off-by: Ilya Dryomov --- fs/ceph/caps.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 1d02648788e3..421cdce71fb0 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -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; }