In order to save resource allocation and utilize the completion
locality in a better way (compared to SRQ per device that exist today),
allocate Shared Receive Queues (SRQs) per completion vector. Associate
each created QP/CQ with an appropriate SRQ according to the queue index.
This association will reduce the lock contention in the fast path
(compared to SRQ per device solution) and increase the locality in
memory buffers. Add new module parameter for SRQ size to adjust it
according to the expected load. User should make sure the size is >= 256
to avoid lack of resources.
Signed-off-by: Max Gurtovoy <maxg@xxxxxxxxxxxx>
---
drivers/nvme/target/rdma.c | 205 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 154 insertions(+), 51 deletions(-)
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 04062af..e415128 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -18,6 +18,7 @@
#include <asm/unaligned.h>
#include <rdma/ib_verbs.h>
+#include <rdma/srq_pool.h>
#include <rdma/rdma_cm.h>
#include <rdma/rw.h>
@@ -31,6 +32,8 @@
#define NVMET_RDMA_MAX_INLINE_SGE 4
#define NVMET_RDMA_MAX_INLINE_DATA_SIZE max_t(int, SZ_16K, PAGE_SIZE)
+struct nvmet_rdma_srq;
+
struct nvmet_rdma_cmd {
struct ib_sge sge[NVMET_RDMA_MAX_INLINE_SGE + 1];
struct ib_cqe cqe;
@@ -38,7 +41,7 @@ struct nvmet_rdma_cmd {
struct scatterlist inline_sg[NVMET_RDMA_MAX_INLINE_SGE];
struct nvme_command *nvme_cmd;
struct nvmet_rdma_queue *queue;
- struct ib_srq *srq;
+ struct nvmet_rdma_srq *nsrq;
};
enum {
@@ -80,6 +83,7 @@ struct nvmet_rdma_queue {
struct ib_cq *cq;
atomic_t sq_wr_avail;
struct nvmet_rdma_device *dev;
+ struct nvmet_rdma_srq *nsrq;
spinlock_t state_lock;
enum nvmet_rdma_queue_state state;
struct nvmet_cq nvme_cq;
@@ -97,17 +101,24 @@ struct nvmet_rdma_queue {
int idx;
int host_qid;
+ int comp_vector;
int recv_queue_size;
int send_queue_size;
struct list_head queue_list;
};
+struct nvmet_rdma_srq {
+ struct ib_srq *srq;
+ struct nvmet_rdma_cmd *cmds;
+ struct nvmet_rdma_device *ndev;
+};
+
struct nvmet_rdma_device {
struct ib_device *device;
struct ib_pd *pd;
- struct ib_srq *srq;
- struct nvmet_rdma_cmd *srq_cmds;
+ struct nvmet_rdma_srq **srqs;
+ int srq_count;
size_t srq_size;
struct kref ref;
struct list_head entry;
@@ -119,6 +130,16 @@ struct nvmet_rdma_device {
module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
+static int srq_size_set(const char *val, const struct kernel_param *kp);
+static const struct kernel_param_ops srq_size_ops = {
+ .set = srq_size_set,
+ .get = param_get_int,
+};
+
+static int nvmet_rdma_srq_size = 1024;
+module_param_cb(srq_size, &srq_size_ops, &nvmet_rdma_srq_size, 0644);
+MODULE_PARM_DESC(srq_size, "set Shared Receive Queue (SRQ) size, should >= 256 (default: 1024)");
+
static DEFINE_IDA(nvmet_rdma_queue_ida);
static LIST_HEAD(nvmet_rdma_queue_list);
static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
@@ -139,6 +160,17 @@ static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
static const struct nvmet_fabrics_ops nvmet_rdma_ops;
+static int srq_size_set(const char *val, const struct kernel_param *kp)
+{
+ int n = 0, ret;
+
+ ret = kstrtoint(val, 10, &n);
+ if (ret != 0 || n < 256)
+ return -EINVAL;
+
+ return param_set_int(val, kp);
+}
+
static int num_pages(int len)
{
return 1 + (((len - 1) & PAGE_MASK) >> PAGE_SHIFT);
@@ -462,8 +494,8 @@ static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
cmd->sge[0].addr, cmd->sge[0].length,
DMA_FROM_DEVICE);
- if (cmd->srq)
- ret = ib_post_srq_recv(cmd->srq, &cmd->wr, NULL);
+ if (cmd->nsrq)
+ ret = ib_post_srq_recv(cmd->nsrq->srq, &cmd->wr, NULL);
else
ret = ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, NULL);
@@ -841,30 +873,83 @@ static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
nvmet_rdma_handle_command(queue, rsp);
}
-static void nvmet_rdma_destroy_srq(struct nvmet_rdma_device *ndev)
+static void nvmet_rdma_destroy_srq(struct nvmet_rdma_srq *nsrq)
+{
+ nvmet_rdma_free_cmds(nsrq->ndev, nsrq->cmds, nsrq->ndev->srq_size,
+ false);
+ rdma_srq_pool_put(nsrq->ndev->pd, nsrq->srq);
+
+ kfree(nsrq);
+}
+
+static void nvmet_rdma_destroy_srqs(struct nvmet_rdma_device *ndev)
{
- if (!ndev->srq)
+ int i;
+
+ if (!ndev->srqs)
return;
- nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
- ib_destroy_srq(ndev->srq);
+ for (i = 0; i < ndev->srq_count; i++)
+ nvmet_rdma_destroy_srq(ndev->srqs[i]);
+
+ rdma_srq_pool_destroy(ndev->pd);
+ kfree(ndev->srqs);
+ ndev->srqs = NULL;
+ ndev->srq_count = 0;
+ ndev->srq_size = 0;
}
-static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
+static struct nvmet_rdma_srq *
+nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
{
- struct ib_srq_init_attr srq_attr = { NULL, };
+ size_t srq_size = ndev->srq_size;
+ struct nvmet_rdma_srq *nsrq;
struct ib_srq *srq;
- size_t srq_size;
int ret, i;
- srq_size = 4095; /* XXX: tune */
+ nsrq = kzalloc(sizeof(*nsrq), GFP_KERNEL);
+ if (!nsrq)
+ return ERR_PTR(-ENOMEM);
- srq_attr.attr.max_wr = srq_size;
- srq_attr.attr.max_sge = 1 + ndev->inline_page_count;
- srq_attr.attr.srq_limit = 0;
- srq_attr.srq_type = IB_SRQT_BASIC;
- srq = ib_create_srq(ndev->pd, &srq_attr);
- if (IS_ERR(srq)) {
+ srq = rdma_srq_pool_get(ndev->pd);
+ if (!srq) {
+ ret = -EAGAIN;
+ goto out_free_nsrq;
+ }
+
+ nsrq->cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
+ if (IS_ERR(nsrq->cmds)) {
+ ret = PTR_ERR(nsrq->cmds);
+ goto out_put_srq;
+ }
+
+ nsrq->srq = srq;
+ nsrq->ndev = ndev;
+
+ for (i = 0; i < srq_size; i++) {
+ nsrq->cmds[i].nsrq = nsrq;
+ ret = nvmet_rdma_post_recv(ndev, &nsrq->cmds[i]);
+ if (ret)
+ goto out_free_cmds;
+ }
+
+ return nsrq;
+
+out_free_cmds:
+ nvmet_rdma_free_cmds(ndev, nsrq->cmds, srq_size, false);
+out_put_srq:
+ rdma_srq_pool_put(ndev->pd, srq);
+out_free_nsrq:
+ kfree(nsrq);
+ return ERR_PTR(ret);
+}
+
+static int nvmet_rdma_init_srqs(struct nvmet_rdma_device *ndev)
+{
+ struct ib_srq_init_attr srq_attr = { NULL, };
+ int i, ret;
+
+ if (!ndev->device->attrs.max_srq_wr || !ndev->device->attrs.max_srq) {
/*
* If SRQs aren't supported we just go ahead and use normal
* non-shared receive queues.
@@ -873,31 +958,44 @@ static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
return 0;
}
- ndev->srq_cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
- if (IS_ERR(ndev->srq_cmds)) {
- ret = PTR_ERR(ndev->srq_cmds);
- goto out_destroy_srq;
- }
+ ndev->srq_size = min(ndev->device->attrs.max_srq_wr,
+ nvmet_rdma_srq_size);
+ ndev->srq_count = min(ndev->device->num_comp_vectors,
+ ndev->device->attrs.max_srq);
- ndev->srq = srq;
- ndev->srq_size = srq_size;
+ ndev->srqs = kcalloc(ndev->srq_count, sizeof(*ndev->srqs), GFP_KERNEL);
+ if (!ndev->srqs)
+ return -ENOMEM;
- for (i = 0; i < srq_size; i++) {
- ndev->srq_cmds[i].srq = srq;
- ret = nvmet_rdma_post_recv(ndev, &ndev->srq_cmds[i]);
- if (ret)
- goto out_free_cmds;
+ srq_attr.attr.max_wr = ndev->srq_size;
+ srq_attr.attr.max_sge = 2;
+ srq_attr.attr.srq_limit = 0;
+ srq_attr.srq_type = IB_SRQT_BASIC;
+ ret = rdma_srq_pool_init(ndev->pd, ndev->srq_count, &srq_attr);
+ if (ret)
+ goto err_free;
+
+ for (i = 0; i < ndev->srq_count; i++) {
+ ndev->srqs[i] = nvmet_rdma_init_srq(ndev);
+ if (IS_ERR(ndev->srqs[i]))
+ goto err_srq;
}
return 0;
-out_free_cmds:
- nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
-out_destroy_srq:
- ib_destroy_srq(srq);
+err_srq:
+ while (--i >= 0)
+ nvmet_rdma_destroy_srq(ndev->srqs[i]);
+ rdma_srq_pool_destroy(ndev->pd);
+err_free:
+ kfree(ndev->srqs);
+ ndev->srqs = NULL;
+ ndev->srq_count = 0;
+ ndev->srq_size = 0;
return ret;
}
+
static void nvmet_rdma_free_dev(struct kref *ref)
{
struct nvmet_rdma_device *ndev =
@@ -907,7 +1005,7 @@ static void nvmet_rdma_free_dev(struct kref *ref)
list_del(&ndev->entry);
mutex_unlock(&device_list_mutex);
- nvmet_rdma_destroy_srq(ndev);
+ nvmet_rdma_destroy_srqs(ndev);
ib_dealloc_pd(ndev->pd);
kfree(ndev);
@@ -953,7 +1051,7 @@ static void nvmet_rdma_free_dev(struct kref *ref)
goto out_free_dev;
if (nvmet_rdma_use_srq) {
- ret = nvmet_rdma_init_srq(ndev);
+ ret = nvmet_rdma_init_srqs(ndev);
if (ret)
goto out_free_pd;
}
@@ -977,14 +1075,8 @@ static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
{
struct ib_qp_init_attr qp_attr;
struct nvmet_rdma_device *ndev = queue->dev;
- int comp_vector, nr_cqe, ret, i;
+ int nr_cqe, ret, i;
- /*
- * Spread the io queues across completion vectors,
- * but still keep all admin queues on vector 0.
- */
- comp_vector = !queue->host_qid ? 0 :
- queue->idx % ndev->device->num_comp_vectors;
/*
* Reserve CQ slots for RECV + RDMA_READ/RDMA_WRITE + RDMA_SEND.
@@ -992,7 +1084,7 @@ static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
nr_cqe = queue->recv_queue_size + 2 * queue->send_queue_size;
queue->cq = ib_alloc_cq(ndev->device, queue,
- nr_cqe + 1, comp_vector,
+ nr_cqe + 1, queue->comp_vector,
IB_POLL_WORKQUEUE);
if (IS_ERR(queue->cq)) {
ret = PTR_ERR(queue->cq);
@@ -1014,8 +1106,8 @@ static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
qp_attr.cap.max_send_sge = max(ndev->device->attrs.max_sge_rd,
ndev->device->attrs.max_send_sge);
- if (ndev->srq) {
- qp_attr.srq = ndev->srq;
+ if (queue->nsrq) {
+ qp_attr.srq = queue->nsrq->srq;
} else {
/* +1 for drain */
qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
@@ -1034,7 +1126,7 @@ static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
__func__, queue->cq->cqe, qp_attr.cap.max_send_sge,
qp_attr.cap.max_send_wr, queue->cm_id);
- if (!ndev->srq) {
+ if (!queue->nsrq) {
for (i = 0; i < queue->recv_queue_size; i++) {
queue->cmds[i].queue = queue;
ret = nvmet_rdma_post_recv(ndev, &queue->cmds[i]);
@@ -1070,7 +1162,7 @@ static void nvmet_rdma_free_queue(struct nvmet_rdma_queue *queue)
nvmet_sq_destroy(&queue->nvme_sq);
nvmet_rdma_destroy_queue_ib(queue);
- if (!queue->dev->srq) {
+ if (!queue->nsrq) {
nvmet_rdma_free_cmds(queue->dev, queue->cmds,
queue->recv_queue_size,
!queue->host_qid);
@@ -1182,13 +1274,22 @@ static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
goto out_destroy_sq;
}
+ /*
+ * Spread the io queues across completion vectors,
+ * but still keep all admin queues on vector 0.
+ */
+ queue->comp_vector = !queue->host_qid ? 0 :
+ queue->idx % ndev->device->num_comp_vectors;
+
ret = nvmet_rdma_alloc_rsps(queue);
if (ret) {
ret = NVME_RDMA_CM_NO_RSC;
goto out_ida_remove;
}
- if (!ndev->srq) {
+ if (ndev->srqs) {
+ queue->nsrq = ndev->srqs[queue->comp_vector % ndev->srq_count];
+ } else {
queue->cmds = nvmet_rdma_alloc_cmds(ndev,
queue->recv_queue_size,
!queue->host_qid);
@@ -1209,10 +1310,12 @@ static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
return queue;
out_free_cmds:
- if (!ndev->srq) {
+ if (!queue->nsrq) {
nvmet_rdma_free_cmds(queue->dev, queue->cmds,
queue->recv_queue_size,
!queue->host_qid);
+ } else {
+ queue->nsrq = NULL;
}
out_free_responses:
nvmet_rdma_free_rsps(queue);
--
1.8.3.1
