[PATCH 06/10] nvmet_fc: Reduce work_q count
James Smart
jsmart2021 at gmail.com
Sat May 13 12:03:05 PDT 2017
Instead of a work_q per controller queue, make 1 per cpu and have
controller queues post work elements to the work_q.
Signed-off-by: James Smart <james.smart at broadcom.com>
---
this is version 3 of the patch:
v2:
converted to use DEFINE_PER_CPU()
reworked do {} while into more readable for loop in
nvmet_fc_do_work_on_cpu()
renamed create/delete_threads to create/delete_workqueues
v3:recut on nvme-4.12
drivers/nvme/target/fc.c | 205 +++++++++++++++++++++++++++++++++++------------
1 file changed, 154 insertions(+), 51 deletions(-)
diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 2006fae61980..c6c3c1ffaf2f 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -20,6 +20,7 @@
#include <linux/blk-mq.h>
#include <linux/parser.h>
#include <linux/random.h>
+#include <linux/threads.h>
#include <uapi/scsi/fc/fc_fs.h>
#include <uapi/scsi/fc/fc_els.h>
@@ -81,6 +82,7 @@ struct nvmet_fc_fcp_iod {
u32 offset;
enum nvmet_fcp_datadir io_dir;
bool active;
+ bool started;
bool abort;
bool aborted;
bool writedataactive;
@@ -88,12 +90,12 @@ struct nvmet_fc_fcp_iod {
struct nvmet_req req;
struct work_struct work;
- struct work_struct done_work;
struct nvmet_fc_tgtport *tgtport;
struct nvmet_fc_tgt_queue *queue;
- struct list_head fcp_list; /* tgtport->fcp_list */
+ struct list_head fcp_list; /* queue->fod_list */
+ struct list_head work_list; /* workcpu->work_list */
};
struct nvmet_fc_tgtport {
@@ -132,7 +134,6 @@ struct nvmet_fc_tgt_queue {
struct nvmet_fc_tgt_assoc *assoc;
struct nvmet_fc_fcp_iod *fod; /* array of fcp_iods */
struct list_head fod_list;
- struct workqueue_struct *work_q;
struct kref ref;
} __aligned(sizeof(unsigned long long));
@@ -145,6 +146,20 @@ struct nvmet_fc_tgt_assoc {
struct kref ref;
};
+enum nvmet_fc_workcpu_flags {
+ NVMET_FC_CPU_RUNNING = (1 << 0),
+ NVMET_FC_CPU_TERMINATING = (1 << 1),
+};
+
+struct nvmet_fc_work_by_cpu {
+ struct workqueue_struct *work_q;
+ struct list_head fod_list;
+ spinlock_t clock;
+ int cpu;
+ bool running;
+ struct work_struct cpu_work;
+};
+
static inline int
nvmet_fc_iodnum(struct nvmet_fc_ls_iod *iodptr)
@@ -213,10 +228,11 @@ static DEFINE_SPINLOCK(nvmet_fc_tgtlock);
static LIST_HEAD(nvmet_fc_target_list);
static DEFINE_IDA(nvmet_fc_tgtport_cnt);
+static u32 nvmet_fc_cpu_cnt;
+static DEFINE_PER_CPU(struct nvmet_fc_work_by_cpu, nvmet_fc_cpu_workcpu);
+#define nvmet_fc_workcpu(cpu) (&per_cpu(nvmet_fc_cpu_workcpu, cpu))
static void nvmet_fc_handle_ls_rqst_work(struct work_struct *work);
-static void nvmet_fc_handle_fcp_rqst_work(struct work_struct *work);
-static void nvmet_fc_fcp_rqst_op_done_work(struct work_struct *work);
static void nvmet_fc_tgt_a_put(struct nvmet_fc_tgt_assoc *assoc);
static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
@@ -417,11 +433,10 @@ nvmet_fc_prep_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
int i;
for (i = 0; i < queue->sqsize; fod++, i++) {
- INIT_WORK(&fod->work, nvmet_fc_handle_fcp_rqst_work);
- INIT_WORK(&fod->done_work, nvmet_fc_fcp_rqst_op_done_work);
fod->tgtport = tgtport;
fod->queue = queue;
fod->active = false;
+ fod->started = false;
fod->abort = false;
fod->aborted = false;
fod->fcpreq = NULL;
@@ -498,6 +513,7 @@ nvmet_fc_free_fcp_iod(struct nvmet_fc_tgt_queue *queue,
spin_lock_irqsave(&queue->qlock, flags);
list_add_tail(&fod->fcp_list, &fod->queue->fod_list);
fod->active = false;
+ fod->started = false;
fod->abort = false;
fod->aborted = false;
fod->writedataactive = false;
@@ -556,12 +572,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
if (!nvmet_fc_tgt_a_get(assoc))
goto out_free_queue;
- queue->work_q = alloc_workqueue("ntfc%d.%d.%d", 0, 0,
- assoc->tgtport->fc_target_port.port_num,
- assoc->a_id, qid);
- if (!queue->work_q)
- goto out_a_put;
-
queue->fod = (struct nvmet_fc_fcp_iod *)&queue[1];
queue->qid = qid;
queue->sqsize = sqsize;
@@ -591,8 +601,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc,
out_fail_iodlist:
nvmet_fc_destroy_fcp_iodlist(assoc->tgtport, queue);
- destroy_workqueue(queue->work_q);
-out_a_put:
nvmet_fc_tgt_a_put(assoc);
out_free_queue:
kfree(queue);
@@ -615,8 +623,6 @@ nvmet_fc_tgt_queue_free(struct kref *ref)
nvmet_fc_tgt_a_put(queue->assoc);
- destroy_workqueue(queue->work_q);
-
kfree(queue);
}
@@ -668,8 +674,6 @@ nvmet_fc_delete_target_queue(struct nvmet_fc_tgt_queue *queue)
}
spin_unlock_irqrestore(&queue->qlock, flags);
- flush_workqueue(queue->work_q);
-
if (disconnect)
nvmet_sq_destroy(&queue->nvme_sq);
@@ -1962,24 +1966,28 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
}
static void
-nvmet_fc_fcp_rqst_op_done_work(struct work_struct *work)
-{
- struct nvmet_fc_fcp_iod *fod =
- container_of(work, struct nvmet_fc_fcp_iod, done_work);
-
- nvmet_fc_fod_op_done(fod);
-}
-
-static void
nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq)
{
struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
struct nvmet_fc_tgt_queue *queue = fod->queue;
-
- if (fod->tgtport->ops->target_features & NVMET_FCTGTFEAT_OPDONE_IN_ISR)
- /* context switch so completion is not in ISR context */
- queue_work_on(queue->cpu, queue->work_q, &fod->done_work);
- else
+ struct nvmet_fc_work_by_cpu *workcpu = nvmet_fc_workcpu(queue->cpu);
+ unsigned long flags;
+ bool running;
+
+ if (fod->tgtport->ops->target_features &
+ NVMET_FCTGTFEAT_OPDONE_IN_ISR) {
+ /* context switch for processing */
+
+ spin_lock_irqsave(&workcpu->clock, flags);
+ list_add_tail(&fod->work_list, &workcpu->fod_list);
+ running = workcpu->running;
+ workcpu->running = true;
+ spin_unlock_irqrestore(&workcpu->clock, flags);
+
+ if (!running)
+ queue_work_on(workcpu->cpu, workcpu->work_q,
+ &workcpu->cpu_work);
+ } else
nvmet_fc_fod_op_done(fod);
}
@@ -2069,6 +2077,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
* layer until we have both based on csn.
*/
+ fod->started = true;
fod->fcpreq->done = nvmet_fc_xmt_fcp_op_done;
fod->total_length = be32_to_cpu(cmdiu->data_len);
@@ -2144,19 +2153,6 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
nvmet_fc_abort_op(tgtport, fod);
}
-/*
- * Actual processing routine for received FC-NVME LS Requests from the LLD
- */
-static void
-nvmet_fc_handle_fcp_rqst_work(struct work_struct *work)
-{
- struct nvmet_fc_fcp_iod *fod =
- container_of(work, struct nvmet_fc_fcp_iod, work);
- struct nvmet_fc_tgtport *tgtport = fod->tgtport;
-
- nvmet_fc_handle_fcp_rqst(tgtport, fod);
-}
-
/**
* nvmet_fc_rcv_fcp_req - transport entry point called by an LLDD
* upon the reception of a NVME FCP CMD IU.
@@ -2186,6 +2182,9 @@ nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
struct nvme_fc_cmd_iu *cmdiu = cmdiubuf;
struct nvmet_fc_tgt_queue *queue;
struct nvmet_fc_fcp_iod *fod;
+ struct nvmet_fc_work_by_cpu *workcpu;
+ unsigned long flags;
+ bool running;
/* validate iu, so the connection id can be used to find the queue */
if ((cmdiubuf_len != sizeof(*cmdiu)) ||
@@ -2223,9 +2222,21 @@ nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
((queue->qid - 1) % tgtport->ops->max_hw_queues) : 0;
memcpy(&fod->cmdiubuf, cmdiubuf, cmdiubuf_len);
- if (tgtport->ops->target_features & NVMET_FCTGTFEAT_CMD_IN_ISR)
- queue_work_on(queue->cpu, queue->work_q, &fod->work);
- else
+ if (tgtport->ops->target_features & NVMET_FCTGTFEAT_CMD_IN_ISR) {
+ /* context switch for processing */
+
+ workcpu = nvmet_fc_workcpu(queue->cpu);
+
+ spin_lock_irqsave(&workcpu->clock, flags);
+ list_add_tail(&fod->work_list, &workcpu->fod_list);
+ running = workcpu->running;
+ workcpu->running = true;
+ spin_unlock_irqrestore(&workcpu->clock, flags);
+
+ if (!running)
+ queue_work_on(workcpu->cpu, workcpu->work_q,
+ &workcpu->cpu_work);
+ } else
nvmet_fc_handle_fcp_rqst(tgtport, fod);
return 0;
@@ -2391,13 +2402,17 @@ nvmet_fc_remove_port(struct nvmet_port *port)
{
struct nvmet_fc_tgtport *tgtport = port->priv;
unsigned long flags;
+ bool matched = false;
spin_lock_irqsave(&nvmet_fc_tgtlock, flags);
if (tgtport->port == port) {
- nvmet_fc_tgtport_put(tgtport);
+ matched = true;
tgtport->port = NULL;
}
spin_unlock_irqrestore(&nvmet_fc_tgtlock, flags);
+
+ if (matched)
+ nvmet_fc_tgtport_put(tgtport);
}
static struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
@@ -2410,9 +2425,95 @@ static struct nvmet_fabrics_ops nvmet_fc_tgt_fcp_ops = {
.delete_ctrl = nvmet_fc_delete_ctrl,
};
+static void
+nvmet_fc_do_work_on_cpu(struct work_struct *work)
+{
+ struct nvmet_fc_work_by_cpu *workcpu =
+ container_of(work, struct nvmet_fc_work_by_cpu, cpu_work);
+ struct nvmet_fc_fcp_iod *fod;
+ unsigned long flags;
+
+ spin_lock_irqsave(&workcpu->clock, flags);
+
+ fod = list_first_entry_or_null(&workcpu->fod_list,
+ struct nvmet_fc_fcp_iod, work_list);
+ for ( ; fod; ) {
+ list_del(&fod->work_list);
+
+ spin_unlock_irqrestore(&workcpu->clock, flags);
+
+ if (fod->started)
+ nvmet_fc_fod_op_done(fod);
+ else
+ nvmet_fc_handle_fcp_rqst(fod->tgtport, fod);
+
+ spin_lock_irqsave(&workcpu->clock, flags);
+
+ fod = list_first_entry_or_null(&workcpu->fod_list,
+ struct nvmet_fc_fcp_iod, work_list);
+ }
+
+ workcpu->running = false;
+
+ spin_unlock_irqrestore(&workcpu->clock, flags);
+}
+
+static int
+nvmet_fc_create_workqueues(void)
+{
+ struct nvmet_fc_work_by_cpu *workcpu;
+ int i;
+
+ nvmet_fc_cpu_cnt = num_active_cpus();
+ for (i = 0; i < nvmet_fc_cpu_cnt; i++, workcpu++) {
+ workcpu = nvmet_fc_workcpu(i);
+
+ workcpu->work_q = alloc_workqueue("nvmet-fc-cpu%d", 0, 0, i);
+ if (!workcpu->work_q)
+ return -ENOEXEC;
+ workcpu->cpu = i;
+ workcpu->running = false;
+ spin_lock_init(&workcpu->clock);
+ INIT_LIST_HEAD(&workcpu->fod_list);
+ INIT_WORK(&workcpu->cpu_work, nvmet_fc_do_work_on_cpu);
+ }
+
+ return 0;
+}
+
+static void
+nvmet_fc_delete_workqueues(void)
+{
+ struct nvmet_fc_work_by_cpu *workcpu;
+ int i;
+
+ for (i = 0; i < nvmet_fc_cpu_cnt; i++, workcpu++) {
+ workcpu = nvmet_fc_workcpu(i);
+
+ /* sanity check - all work should be removed */
+ if (!list_empty(&workcpu->fod_list))
+ pr_warn("%s: cpu %d worklist not empty\n", __func__, i);
+
+ if (workcpu->work_q)
+ destroy_workqueue(workcpu->work_q);
+ }
+}
+
static int __init nvmet_fc_init_module(void)
{
- return nvmet_register_transport(&nvmet_fc_tgt_fcp_ops);
+ int ret;
+
+ ret = nvmet_fc_create_workqueues();
+ if (ret)
+ goto fail;
+
+ ret = nvmet_register_transport(&nvmet_fc_tgt_fcp_ops);
+ if (!ret)
+ return 0;
+
+fail:
+ nvmet_fc_delete_workqueues();
+ return -ENXIO;
}
static void __exit nvmet_fc_exit_module(void)
@@ -2423,6 +2524,8 @@ static void __exit nvmet_fc_exit_module(void)
nvmet_unregister_transport(&nvmet_fc_tgt_fcp_ops);
+ nvmet_fc_delete_workqueues();
+
ida_destroy(&nvmet_fc_tgtport_cnt);
}
--
2.11.0
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