NFSv4.1: Ensure smooth handover of slots from one task to the next waiting
Currently, we see a lot of bouncing for the value of highest_used_slotid
due to the fact that slots are getting freed, instead of getting instantly
transmitted to the next waiting task.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
index 7011702..066cfa1 100644
--- a/fs/nfs/nfs4session.c
+++ b/fs/nfs/nfs4session.c
@@ -217,11 +217,65 @@
nfs4_shrink_slot_table(&session->bc_slot_table, 0);
}
+static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
+{
+ struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
+ struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
+ struct nfs4_slot *slot = pslot;
+ struct nfs4_slot_table *tbl = slot->table;
+
+ if (nfs4_session_draining(tbl->session) && !args->sa_privileged)
+ return false;
+ slot->renewal_time = jiffies;
+ slot->generation = tbl->generation;
+ args->sa_slot = slot;
+ res->sr_slot = slot;
+ res->sr_status_flags = 0;
+ res->sr_status = 1;
+ return true;
+}
+
+static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
+ struct nfs4_slot *slot)
+{
+ if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
+ return true;
+ return false;
+}
+
+bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
+ struct nfs4_slot *slot)
+{
+ if (slot->slot_nr > tbl->max_slotid)
+ return false;
+ return __nfs41_wake_and_assign_slot(tbl, slot);
+}
+
+static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
+{
+ struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
+ if (!IS_ERR(slot)) {
+ bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
+ if (ret)
+ return ret;
+ nfs4_free_slot(tbl, slot);
+ }
+ return false;
+}
+
+void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
+{
+ for (;;) {
+ if (!nfs41_try_wake_next_slot_table_entry(tbl))
+ break;
+ }
+}
+
/* Update the client's idea of target_highest_slotid */
static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
u32 target_highest_slotid)
{
- unsigned int max_slotid, i;
+ unsigned int max_slotid;
if (tbl->target_highest_slotid == target_highest_slotid)
return;
@@ -229,9 +283,8 @@
tbl->generation++;
max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, tbl->target_highest_slotid);
- for (i = tbl->max_slotid + 1; i <= max_slotid; i++)
- rpc_wake_up_next(&tbl->slot_tbl_waitq);
tbl->max_slotid = max_slotid;
+ nfs41_wake_slot_table(tbl);
}
void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,