From: Andy Adamson <andros@xxxxxxxxxx>
When a slotid is to freed, check to see if a task is waiting for a slot.
If so, then the slot to be freed is the lowest (the only) slot, and can
therefore be assigned to a waiting task.
This saves a bit lookup in nfs4_free_slot and nfs4_find_slot, and an hist
lookup in nfs4_lookup_slot_locked.
Add a new tk_private field to the rpc_task structure to hold the assigned slot.
Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 61 +++++++++++++++++++++++++++++++-----------
include/linux/sunrpc/sched.h | 1 +
2 files changed, 46 insertions(+), 16 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 11f4e96..17b3d0b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -485,15 +485,33 @@ static void nfs4_free_all_slots(struct nfs4_slot_table *tbl)
*
* Must be called while holding tbl->slot_tbl_lock
*/
-static void
-nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
+static bool
+nfs4_free_slot(struct nfs4_session *ses, struct nfs4_slot *slot)
{
- int slotid = free_slotid;
+ struct nfs4_slot_table *tbl = &ses->fc_slot_table;
+ struct rpc_task *task = NULL;
+ int slotid = slot->slot_id;
+ bool clear_it = true;
BUG_ON(slotid < 0 || slotid >= NFS4_MAX_SLOT_TABLE);
+
+ if (!rpc_queue_empty(&tbl->slot_tbl_waitq) &&
+ !test_bit(NFS4_SESSION_DRAINING, &ses->session_state)) {
+ /* The slot is the lowest (the only) free slotid.
+ * Try to give it to the next task. */
+ task = rpc_wake_up_next(&tbl->slot_tbl_waitq);
+ if (task) {
+ rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
+ task->tk_private = slot;
+ clear_it = false;
+ goto highslot;
+ }
+ }
+
/* clear used bit in bitmap */
__clear_bit(slotid, tbl->used_slots);
+highslot:
/* update highest_used_slotid when it is freed */
if (slotid == tbl->highest_used_slotid) {
slotid = find_last_bit(tbl->used_slots, tbl->max_slots);
@@ -503,17 +521,19 @@ nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
tbl->highest_used_slotid = -1;
}
dprintk("%s: free_slotid %u highest_used_slotid %d\n", __func__,
- free_slotid, tbl->highest_used_slotid);
+ slot->slot_id, tbl->highest_used_slotid);
+
+ return clear_it;
}
/*
* Signal state manager thread if session fore channel is drained
*/
-static void nfs4_check_drain_fc_complete(struct nfs4_session *ses)
+static void nfs4_check_drain_fc_complete(struct nfs4_session *ses, bool wakeup)
{
struct rpc_task *task;
- if (!test_bit(NFS4_SESSION_DRAINING, &ses->session_state)) {
+ if (wakeup && !test_bit(NFS4_SESSION_DRAINING, &ses->session_state)) {
task = rpc_wake_up_next(&ses->fc_slot_table.slot_tbl_waitq);
if (task)
rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
@@ -542,6 +562,7 @@ void nfs4_check_drain_bc_complete(struct nfs4_session *ses)
static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
{
struct nfs4_slot_table *tbl;
+ bool wakeup;
tbl = &res->sr_session->fc_slot_table;
if (!res->sr_slot) {
@@ -552,8 +573,8 @@ static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
}
spin_lock(&tbl->slot_tbl_lock);
- nfs4_free_slot(tbl, res->sr_slot->slot_id);
- nfs4_check_drain_fc_complete(res->sr_session);
+ wakeup = nfs4_free_slot(res->sr_session, res->sr_slot);
+ nfs4_check_drain_fc_complete(res->sr_session, wakeup);
spin_unlock(&tbl->slot_tbl_lock);
res->sr_slot = NULL;
}
@@ -688,14 +709,21 @@ int nfs41_setup_sequence(struct nfs4_session *session,
return -EAGAIN;
}
- slotid = nfs4_find_slot(tbl);
- if (slotid == NFS4_MAX_SLOT_TABLE) {
- rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
- spin_unlock(&tbl->slot_tbl_lock);
- dprintk("<-- %s: no free slots\n", __func__);
- return -EAGAIN;
+ if (task->tk_private) {
+ /* use slot assigned in nfs4_free_slot */
+ slot = (struct nfs4_slot *)task->tk_private;
+ task->tk_private = NULL;
+ dprintk("%s Using tk_private slot\n", __func__);
+ } else {
+ slotid = nfs4_find_slot(tbl);
+ if (slotid == NFS4_MAX_SLOT_TABLE) {
+ rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
+ spin_unlock(&tbl->slot_tbl_lock);
+ dprintk("<-- %s: no free slots\n", __func__);
+ return -EAGAIN;
+ }
+ slot = nfs4_lookup_slot_locked(tbl, slotid);
}
- slot = nfs4_lookup_slot_locked(tbl, slotid);
spin_unlock(&tbl->slot_tbl_lock);
rpc_task_set_priority(task, RPC_PRIORITY_NORMAL);
@@ -703,7 +731,8 @@ int nfs41_setup_sequence(struct nfs4_session *session,
args->sa_slot = slot;
args->sa_cache_this = cache_reply;
- dprintk("<-- %s slotid=%d seqid=%d\n", __func__, slotid, slot->seq_nr);
+ dprintk("<-- %s slotid=%d seqid=%d\n", __func__, slot->slot_id,
+ slot->seq_nr);
res->sr_session = session;
res->sr_slot = slot;
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index e775689..b4429bcf 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -60,6 +60,7 @@ struct rpc_task {
void (*tk_action)(struct rpc_task *);
const struct rpc_call_ops *tk_ops;
void * tk_calldata;
+ void * tk_private;
unsigned long tk_timeout; /* timeout for rpc_sleep() */
unsigned long tk_runstate; /* Task run status */
--
1.7.6.4
--
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