ceph: don't pre-allocate space for cap release messages
Previously we pre-allocate cap release messages for each caps. This
wastes lots of memory when there are large amount of caps. This patch
make the code not pre-allocate the cap release messages. Instead,
we add the corresponding ceph_cap struct to a list when releasing a
cap. Later when flush cap releases is needed, we allocate the cap
release messages dynamically.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 2bb9264..76eb144 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -458,7 +458,6 @@
s->s_cap_reconnect = 0;
s->s_cap_iterator = NULL;
INIT_LIST_HEAD(&s->s_cap_releases);
- INIT_LIST_HEAD(&s->s_cap_releases_done);
INIT_LIST_HEAD(&s->s_cap_flushing);
INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
@@ -998,27 +997,25 @@
* session caps
*/
-/*
- * Free preallocated cap messages assigned to this session
- */
-static void cleanup_cap_releases(struct ceph_mds_session *session)
+/* caller holds s_cap_lock, we drop it */
+static void cleanup_cap_releases(struct ceph_mds_client *mdsc,
+ struct ceph_mds_session *session)
+ __releases(session->s_cap_lock)
{
- struct ceph_msg *msg;
-
- spin_lock(&session->s_cap_lock);
- while (!list_empty(&session->s_cap_releases)) {
- msg = list_first_entry(&session->s_cap_releases,
- struct ceph_msg, list_head);
- list_del_init(&msg->list_head);
- ceph_msg_put(msg);
- }
- while (!list_empty(&session->s_cap_releases_done)) {
- msg = list_first_entry(&session->s_cap_releases_done,
- struct ceph_msg, list_head);
- list_del_init(&msg->list_head);
- ceph_msg_put(msg);
- }
+ LIST_HEAD(tmp_list);
+ list_splice_init(&session->s_cap_releases, &tmp_list);
+ session->s_num_cap_releases = 0;
spin_unlock(&session->s_cap_lock);
+
+ dout("cleanup_cap_releases mds%d\n", session->s_mds);
+ while (!list_empty(&tmp_list)) {
+ struct ceph_cap *cap;
+ /* zero out the in-progress message */
+ cap = list_first_entry(&tmp_list,
+ struct ceph_cap, session_caps);
+ list_del(&cap->session_caps);
+ ceph_put_cap(mdsc, cap);
+ }
}
static void cleanup_session_requests(struct ceph_mds_client *mdsc,
@@ -1095,10 +1092,16 @@
dout("iterate_session_caps finishing cap %p removal\n",
cap);
BUG_ON(cap->session != session);
+ cap->session = NULL;
list_del_init(&cap->session_caps);
session->s_nr_caps--;
- cap->session = NULL;
- old_cap = cap; /* put_cap it w/o locks held */
+ if (cap->queue_release) {
+ list_add_tail(&cap->session_caps,
+ &session->s_cap_releases);
+ session->s_num_cap_releases++;
+ } else {
+ old_cap = cap; /* put_cap it w/o locks held */
+ }
}
if (ret < 0)
goto out;
@@ -1191,11 +1194,12 @@
spin_lock(&session->s_cap_lock);
}
}
- spin_unlock(&session->s_cap_lock);
+
+ // drop cap expires and unlock s_cap_lock
+ cleanup_cap_releases(session->s_mdsc, session);
BUG_ON(session->s_nr_caps > 0);
BUG_ON(!list_empty(&session->s_cap_flushing));
- cleanup_cap_releases(session);
}
/*
@@ -1418,76 +1422,10 @@
session->s_trim_caps = 0;
}
- ceph_add_cap_releases(mdsc, session);
ceph_send_cap_releases(mdsc, session);
return 0;
}
-/*
- * Allocate cap_release messages. If there is a partially full message
- * in the queue, try to allocate enough to cover it's remainder, so that
- * we can send it immediately.
- *
- * Called under s_mutex.
- */
-int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
- struct ceph_mds_session *session)
-{
- struct ceph_msg *msg, *partial = NULL;
- struct ceph_mds_cap_release *head;
- int err = -ENOMEM;
- int extra = mdsc->fsc->mount_options->cap_release_safety;
- int num;
-
- dout("add_cap_releases %p mds%d extra %d\n", session, session->s_mds,
- extra);
-
- spin_lock(&session->s_cap_lock);
-
- if (!list_empty(&session->s_cap_releases)) {
- msg = list_first_entry(&session->s_cap_releases,
- struct ceph_msg,
- list_head);
- head = msg->front.iov_base;
- num = le32_to_cpu(head->num);
- if (num) {
- dout(" partial %p with (%d/%d)\n", msg, num,
- (int)CEPH_CAPS_PER_RELEASE);
- extra += CEPH_CAPS_PER_RELEASE - num;
- partial = msg;
- }
- }
- while (session->s_num_cap_releases < session->s_nr_caps + extra) {
- spin_unlock(&session->s_cap_lock);
- msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
- GFP_NOFS, false);
- if (!msg)
- goto out_unlocked;
- dout("add_cap_releases %p msg %p now %d\n", session, msg,
- (int)msg->front.iov_len);
- head = msg->front.iov_base;
- head->num = cpu_to_le32(0);
- msg->front.iov_len = sizeof(*head);
- spin_lock(&session->s_cap_lock);
- list_add(&msg->list_head, &session->s_cap_releases);
- session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
- }
-
- if (partial) {
- head = partial->front.iov_base;
- num = le32_to_cpu(head->num);
- dout(" queueing partial %p with %d/%d\n", partial, num,
- (int)CEPH_CAPS_PER_RELEASE);
- list_move_tail(&partial->list_head,
- &session->s_cap_releases_done);
- session->s_num_cap_releases -= CEPH_CAPS_PER_RELEASE - num;
- }
- err = 0;
- spin_unlock(&session->s_cap_lock);
-out_unlocked:
- return err;
-}
-
static int check_cap_flush(struct ceph_inode_info *ci,
u64 want_flush_seq, u64 want_snap_seq)
{
@@ -1590,62 +1528,76 @@
void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session)
{
- struct ceph_msg *msg;
+ struct ceph_msg *msg = NULL;
+ struct ceph_mds_cap_release *head;
+ struct ceph_mds_cap_item *item;
+ struct ceph_cap *cap;
+ LIST_HEAD(tmp_list);
+ int num_cap_releases;
- dout("send_cap_releases mds%d\n", session->s_mds);
spin_lock(&session->s_cap_lock);
- while (!list_empty(&session->s_cap_releases_done)) {
- msg = list_first_entry(&session->s_cap_releases_done,
- struct ceph_msg, list_head);
- list_del_init(&msg->list_head);
- spin_unlock(&session->s_cap_lock);
+again:
+ list_splice_init(&session->s_cap_releases, &tmp_list);
+ num_cap_releases = session->s_num_cap_releases;
+ session->s_num_cap_releases = 0;
+ spin_unlock(&session->s_cap_lock);
+
+ while (!list_empty(&tmp_list)) {
+ if (!msg) {
+ msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE,
+ PAGE_CACHE_SIZE, GFP_NOFS, false);
+ if (!msg)
+ goto out_err;
+ head = msg->front.iov_base;
+ head->num = cpu_to_le32(0);
+ msg->front.iov_len = sizeof(*head);
+ }
+ cap = list_first_entry(&tmp_list, struct ceph_cap,
+ session_caps);
+ list_del(&cap->session_caps);
+ num_cap_releases--;
+
+ head = msg->front.iov_base;
+ le32_add_cpu(&head->num, 1);
+ item = msg->front.iov_base + msg->front.iov_len;
+ item->ino = cpu_to_le64(cap->cap_ino);
+ item->cap_id = cpu_to_le64(cap->cap_id);
+ item->migrate_seq = cpu_to_le32(cap->mseq);
+ item->seq = cpu_to_le32(cap->issue_seq);
+ msg->front.iov_len += sizeof(*item);
+
+ ceph_put_cap(mdsc, cap);
+
+ if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
+ msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+ dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
+ ceph_con_send(&session->s_con, msg);
+ msg = NULL;
+ }
+ }
+
+ BUG_ON(num_cap_releases != 0);
+
+ spin_lock(&session->s_cap_lock);
+ if (!list_empty(&session->s_cap_releases))
+ goto again;
+ spin_unlock(&session->s_cap_lock);
+
+ if (msg) {
msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
ceph_con_send(&session->s_con, msg);
- spin_lock(&session->s_cap_lock);
}
+ return;
+out_err:
+ pr_err("send_cap_releases mds%d, failed to allocate message\n",
+ session->s_mds);
+ spin_lock(&session->s_cap_lock);
+ list_splice(&tmp_list, &session->s_cap_releases);
+ session->s_num_cap_releases += num_cap_releases;
spin_unlock(&session->s_cap_lock);
}
-static void discard_cap_releases(struct ceph_mds_client *mdsc,
- struct ceph_mds_session *session)
-{
- struct ceph_msg *msg;
- struct ceph_mds_cap_release *head;
- unsigned num;
-
- dout("discard_cap_releases mds%d\n", session->s_mds);
-
- if (!list_empty(&session->s_cap_releases)) {
- /* zero out the in-progress message */
- msg = list_first_entry(&session->s_cap_releases,
- struct ceph_msg, list_head);
- head = msg->front.iov_base;
- num = le32_to_cpu(head->num);
- dout("discard_cap_releases mds%d %p %u\n",
- session->s_mds, msg, num);
- head->num = cpu_to_le32(0);
- msg->front.iov_len = sizeof(*head);
- session->s_num_cap_releases += num;
- }
-
- /* requeue completed messages */
- while (!list_empty(&session->s_cap_releases_done)) {
- msg = list_first_entry(&session->s_cap_releases_done,
- struct ceph_msg, list_head);
- list_del_init(&msg->list_head);
-
- head = msg->front.iov_base;
- num = le32_to_cpu(head->num);
- dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg,
- num);
- session->s_num_cap_releases += num;
- head->num = cpu_to_le32(0);
- msg->front.iov_len = sizeof(*head);
- list_add(&msg->list_head, &session->s_cap_releases);
- }
-}
-
/*
* requests
*/
@@ -2529,7 +2481,6 @@
}
mutex_unlock(&mdsc->mutex);
- ceph_add_cap_releases(mdsc, req->r_session);
mutex_unlock(&session->s_mutex);
/* kick calling process */
@@ -2921,8 +2872,7 @@
*/
session->s_cap_reconnect = 1;
/* drop old cap expires; we're about to reestablish that state */
- discard_cap_releases(mdsc, session);
- spin_unlock(&session->s_cap_lock);
+ cleanup_cap_releases(mdsc, session);
/* trim unused caps to reduce MDS's cache rejoin time */
if (mdsc->fsc->sb->s_root)
@@ -3385,7 +3335,6 @@
send_renew_caps(mdsc, s);
else
ceph_con_keepalive(&s->s_con);
- ceph_add_cap_releases(mdsc, s);
if (s->s_state == CEPH_MDS_SESSION_OPEN ||
s->s_state == CEPH_MDS_SESSION_HUNG)
ceph_send_cap_releases(mdsc, s);