@@ -4235,11 +4235,6 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
slot = xa_load(&session->se_slots, seq->slotid);
dprintk("%s: slotid %d\n", __func__, seq->slotid);
- /* We do not negotiate the number of slots yet, so set the
- * maxslots to the session maxreqs which is used to encode
- * sr_highest_slotid and the sr_target_slot id to maxslots */
- seq->maxslots = session->se_fchannel.maxreqs;
-
trace_nfsd_slot_seqid_sequence(clp, seq, slot);
status = check_slot_seqid(seq->seqid, slot->sl_seqid,
slot->sl_flags & NFSD4_SLOT_INUSE);
@@ -4289,6 +4284,38 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
cstate->session = session;
cstate->clp = clp;
+ /*
+ * If the client ever uses the highest available slot,
+ * gently try to allocate another 20%. This allows
+ * fairly quick growth without grossly over-shooting what
+ * the client might use.
+ */
+ if (seq->slotid == session->se_fchannel.maxreqs - 1 &&
+ session->se_fchannel.maxreqs < NFSD_MAX_SLOTS_PER_SESSION) {
+ int s = session->se_fchannel.maxreqs;
+ int cnt = DIV_ROUND_UP(s, 5);
+
+ do {
+ /*
+ * GFP_NOWAIT both allows allocation under a
+ * spinlock, and only succeeds if there is
+ * plenty of memory.
+ */
+ slot = kzalloc(slot_bytes(&session->se_fchannel),
+ GFP_NOWAIT);
+ if (slot &&
+ !xa_is_err(xa_store(&session->se_slots, s, slot,
+ GFP_NOWAIT))) {
+ s += 1;
+ session->se_fchannel.maxreqs = s;
+ } else {
+ kfree(slot);
+ slot = NULL;
+ }
+ } while (slot && --cnt > 0);
+ }
+ seq->maxslots = session->se_fchannel.maxreqs;
+
out:
switch (clp->cl_cb_state) {
case NFSD4_CB_DOWN:
If a client ever uses the highest available slot for a given session, attempt to allocate more slots so there is room for the client to use them if wanted. GFP_NOWAIT is used so if there is not plenty of free memory, failure is expected - which is what we want. It also allows the allocation while holding a spinlock. Each time we increase the number of slots by 20% (rounded up). This allows fairly quick growth while avoiding excessive over-shoot. We would expect to stablise with around 10% more slots available than the client actually uses. Signed-off-by: NeilBrown <neilb@suse.de> --- fs/nfsd/nfs4state.c | 37 ++++++++++++++++++++++++++++++++----- 1 file changed, 32 insertions(+), 5 deletions(-)