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IB/hfi1: Implement SDMA-side buffer caching 

Add support for caching of user buffers used for SDMA
transfers. This change improves performance by
avoiding repeatedly pinning the pages of buffers, which
are being re-used by the application.

While the cost of the pinning operation has been made
heavier by adding the extra code to search the cache tree,
re-allocate pages arrays, and future cache evictions,
that cost will be amortized against the savings when the
same buffer is re-used. It is also worth noting that in
most cases, the cost of pinning should be much lower due
to the buffer already being in the cache.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
hifive-unleashed-5.1
Mitko Haralanov 2016-03-08 11:15:22 -08:00 committed by Doug Ledford
parent a489876010
commit 5cd3a88d7f
2 changed files with 155 additions and 101 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

255
drivers/staging/rdma/hfi1/user_sdma.c
View File

@ -68,6 +68,7 @@
#include "verbs.h" /* for the headers */
#include "common.h" /* for struct hfi1_tid_info */
#include "trace.h"
#include "mmu_rb.h"
static uint hfi1_sdma_comp_ring_size = 128;
module_param_named(sdma_comp_size, hfi1_sdma_comp_ring_size, uint, S_IRUGO);
@ -145,9 +146,6 @@ MODULE_PARM_DESC(sdma_comp_size, "Size of User SDMA completion ring. Default: 12
/* Last packet in the request */
#define TXREQ_FLAGS_REQ_LAST_PKT BIT(0)
/* Last packet that uses a particular io vector */
#define TXREQ_FLAGS_IOVEC_LAST_PKT BIT(0)
#define SDMA_REQ_IN_USE 0
#define SDMA_REQ_FOR_THREAD 1
#define SDMA_REQ_SEND_DONE 2
@ -183,6 +181,13 @@ struct user_sdma_iovec {
u64 offset;
};
struct sdma_mmu_node {
struct mmu_rb_node rb;
atomic_t refcount;
struct page **pages;
unsigned npages;
};
struct user_sdma_request {
struct sdma_req_info info;
struct hfi1_user_sdma_pkt_q *pq;
@ -252,11 +257,6 @@ struct user_sdma_txreq {
struct sdma_txreq txreq;
struct list_head list;
struct user_sdma_request *req;
struct {
struct user_sdma_iovec *vec;
u8 flags;
} iovecs[3];
int idx;
u16 flags;
unsigned busycount;
u64 seqnum;
@ -277,7 +277,7 @@ static inline void pq_update(struct hfi1_user_sdma_pkt_q *);
static void user_sdma_free_request(struct user_sdma_request *, bool);
static int pin_vector_pages(struct user_sdma_request *,
struct user_sdma_iovec *);
static void unpin_vector_pages(struct user_sdma_iovec *);
static void unpin_vector_pages(struct page **, unsigned);
static int check_header_template(struct user_sdma_request *,
struct hfi1_pkt_header *, u32, u32);
static int set_txreq_header(struct user_sdma_request *,
@ -296,6 +296,17 @@ static int defer_packet_queue(
struct sdma_txreq *,
unsigned seq);
static void activate_packet_queue(struct iowait *, int);
static bool sdma_rb_filter(struct mmu_rb_node *, unsigned long, unsigned long);
static int sdma_rb_insert(struct rb_root *, struct mmu_rb_node *);
static void sdma_rb_remove(struct rb_root *, struct mmu_rb_node *, bool);
static int sdma_rb_invalidate(struct rb_root *, struct mmu_rb_node *);
static struct mmu_rb_ops sdma_rb_ops = {
.filter = sdma_rb_filter,
.insert = sdma_rb_insert,
.remove = sdma_rb_remove,
.invalidate = sdma_rb_invalidate
};
static int defer_packet_queue(
struct sdma_engine *sde,
@ -385,6 +396,7 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt, struct file *fp)
pq->state = SDMA_PKT_Q_INACTIVE;
atomic_set(&pq->n_reqs, 0);
init_waitqueue_head(&pq->wait);
pq->sdma_rb_root = RB_ROOT;
iowait_init(&pq->busy, 0, NULL, defer_packet_queue,
activate_packet_queue, NULL);
@ -415,6 +427,12 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt, struct file *fp)
cq->nentries = hfi1_sdma_comp_ring_size;
fd->cq = cq;
ret = hfi1_mmu_rb_register(&pq->sdma_rb_root, &sdma_rb_ops);
if (ret) {
dd_dev_err(dd, "Failed to register with MMU %d", ret);
goto done;
}
spin_lock_irqsave(&uctxt->sdma_qlock, flags);
list_add(&pq->list, &uctxt->sdma_queues);
spin_unlock_irqrestore(&uctxt->sdma_qlock, flags);
@ -444,6 +462,7 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd)
hfi1_cdbg(SDMA, "[%u:%u:%u] Freeing user SDMA queues", uctxt->dd->unit,
uctxt->ctxt, fd->subctxt);
pq = fd->pq;
hfi1_mmu_rb_unregister(&pq->sdma_rb_root);
if (pq) {
spin_lock_irqsave(&uctxt->sdma_qlock, flags);
if (!list_empty(&pq->list))
@ -477,7 +496,7 @@ int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec,
struct hfi1_user_sdma_pkt_q *pq = fd->pq;
struct hfi1_user_sdma_comp_q *cq = fd->cq;
struct hfi1_devdata *dd = pq->dd;
unsigned long idx = 0, unpinned;
unsigned long idx = 0;
u8 pcount = initial_pkt_count;
struct sdma_req_info info;
struct user_sdma_request *req;
@ -498,14 +517,6 @@ int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec,
return -EFAULT;
}
/* Process any completed vectors */
unpinned = xchg(&pq->unpinned, 0);
if (unpinned) {
down_write(&current->mm->mmap_sem);
current->mm->pinned_vm -= unpinned;
up_write(&current->mm->mmap_sem);
}
trace_hfi1_sdma_user_reqinfo(dd, uctxt->ctxt, fd->subctxt,
(u16 *)&info);
if (cq->comps[info.comp_idx].status == QUEUED ||
@ -609,7 +620,11 @@ int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec,
while (i < req->data_iovs) {
INIT_LIST_HEAD(&req->iovs[i].list);
memcpy(&req->iovs[i].iov, iovec + idx++, sizeof(struct iovec));
req->iovs[i].offset = 0;
ret = pin_vector_pages(req, &req->iovs[i]);
if (ret) {
req->status = ret;
goto free_req;
}
req->data_len += req->iovs[i++].iov.iov_len;
}
SDMA_DBG(req, "total data length %u", req->data_len);
@ -827,9 +842,7 @@ static int user_sdma_send_pkts(struct user_sdma_request *req, unsigned maxpkts)
tx->flags = 0;
tx->req = req;
tx->busycount = 0;
tx->idx = -1;
INIT_LIST_HEAD(&tx->list);
memset(tx->iovecs, 0, sizeof(tx->iovecs));
if (req->seqnum == req->info.npkts - 1)
tx->flags |= TXREQ_FLAGS_REQ_LAST_PKT;
@ -850,18 +863,6 @@ static int user_sdma_send_pkts(struct user_sdma_request *req, unsigned maxpkts)
WARN_ON(iovec->offset);
}
/*
* This request might include only a header and no user
* data, so pin pages only if there is data and it the
* pages have not been pinned already.
*/
if (unlikely(!iovec->pages && iovec->iov.iov_len)) {
ret = pin_vector_pages(req, iovec);
if (ret)
goto free_tx;
}
tx->iovecs[++tx->idx].vec = iovec;
datalen = compute_data_length(req, tx);
if (!datalen) {
SDMA_DBG(req,
@ -960,19 +961,10 @@ static int user_sdma_send_pkts(struct user_sdma_request *req, unsigned maxpkts)
data_sent += len;
if (unlikely(queued < datalen &&
pageidx == iovec->npages &&
req->iov_idx < req->data_iovs - 1 &&
tx->idx < ARRAY_SIZE(tx->iovecs))) {
req->iov_idx < req->data_iovs - 1)) {
iovec->offset += iov_offset;
tx->iovecs[tx->idx].flags |=
TXREQ_FLAGS_IOVEC_LAST_PKT;
iovec = &req->iovs[++req->iov_idx];
if (!iovec->pages) {
ret = pin_vector_pages(req, iovec);
if (ret)
goto free_txreq;
}
iov_offset = 0;
tx->iovecs[++tx->idx].vec = iovec;
}
}
/*
@ -983,18 +975,8 @@ static int user_sdma_send_pkts(struct user_sdma_request *req, unsigned maxpkts)
if (req_opcode(req->info.ctrl) == EXPECTED)
req->tidoffset += datalen;
req->sent += data_sent;
if (req->data_len) {
tx->iovecs[tx->idx].vec->offset += iov_offset;
/*
* If we've reached the end of the io vector, mark it
* so the callback can unpin the pages and free it.
*/
if (tx->iovecs[tx->idx].vec->offset ==
tx->iovecs[tx->idx].vec->iov.iov_len)
tx->iovecs[tx->idx].flags |=
TXREQ_FLAGS_IOVEC_LAST_PKT;
}
if (req->data_len)
iovec->offset += iov_offset;
list_add_tail(&tx->txreq.list, &req->txps);
/*
* It is important to increment this here as it is used to
@ -1047,38 +1029,78 @@ static inline int num_user_pages(const struct iovec *iov)
static int pin_vector_pages(struct user_sdma_request *req,
struct user_sdma_iovec *iovec) {
int pinned, npages;
int ret = 0, pinned, npages;
struct page **pages;
struct hfi1_user_sdma_pkt_q *pq = req->pq;
struct sdma_mmu_node *node = NULL;
struct mmu_rb_node *rb_node;
rb_node = hfi1_mmu_rb_search(&pq->sdma_rb_root,
(unsigned long)iovec->iov.iov_base,
iovec->iov.iov_len);
if (rb_node)
node = container_of(rb_node, struct sdma_mmu_node, rb);
if (!node) {
node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return -ENOMEM;
node->rb.addr = (unsigned long)iovec->iov.iov_base;
node->rb.len = iovec->iov.iov_len;
atomic_set(&node->refcount, 0);
}
npages = num_user_pages(&iovec->iov);
iovec->pages = kcalloc(npages, sizeof(*iovec->pages), GFP_KERNEL);
if (!iovec->pages) {
SDMA_DBG(req, "Failed page array alloc");
return -ENOMEM;
if (node->npages < npages) {
pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL);
if (!pages) {
SDMA_DBG(req, "Failed page array alloc");
ret = -ENOMEM;
goto bail;
}
memcpy(pages, node->pages, node->npages * sizeof(*pages));
npages -= node->npages;
pinned = hfi1_acquire_user_pages(
((unsigned long)iovec->iov.iov_base +
(node->npages * PAGE_SIZE)), npages, 0,
pages + node->npages);
if (pinned < 0) {
kfree(pages);
ret = pinned;
goto bail;
}
if (pinned != npages) {
unpin_vector_pages(pages, pinned);
ret = -EFAULT;
goto bail;
}
kfree(node->pages);
node->pages = pages;
node->npages += pinned;
npages = node->npages;
}
iovec->pages = node->pages;
iovec->npages = npages;
pinned = hfi1_acquire_user_pages((unsigned long)iovec->iov.iov_base,
npages, 0, iovec->pages);
if (pinned < 0)
return pinned;
iovec->npages = pinned;
if (pinned != npages) {
SDMA_DBG(req, "Failed to pin pages (%d/%u)", pinned, npages);
unpin_vector_pages(iovec);
return -EFAULT;
if (!rb_node) {
if (hfi1_mmu_rb_insert(&req->pq->sdma_rb_root, &node->rb))
goto bail;
} else {
atomic_inc(&node->refcount);
}
return 0;
bail:
if (!rb_node)
kfree(node);
return ret;
}
static void unpin_vector_pages(struct user_sdma_iovec *iovec)
static void unpin_vector_pages(struct page **pages, unsigned npages)
{
hfi1_release_user_pages(iovec->pages, iovec->npages, 0);
kfree(iovec->pages);
iovec->pages = NULL;
iovec->npages = 0;
iovec->offset = 0;
hfi1_release_user_pages(pages, npages, 0);
kfree(pages);
}
static int check_header_template(struct user_sdma_request *req,
@ -1360,7 +1382,6 @@ static void user_sdma_txreq_cb(struct sdma_txreq *txreq, int status)
struct hfi1_user_sdma_pkt_q *pq;
struct hfi1_user_sdma_comp_q *cq;
u16 idx;
int i, j;
if (!tx->req)
return;
@ -1369,24 +1390,6 @@ static void user_sdma_txreq_cb(struct sdma_txreq *txreq, int status)
pq = req->pq;
cq = req->cq;
/*
* If we have any io vectors associated with this txreq,
* check whether they need to be 'freed'.
*/
for (i = tx->idx; i >= 0; i--) {
if (tx->iovecs[i].flags & TXREQ_FLAGS_IOVEC_LAST_PKT) {
struct user_sdma_iovec *vec =
tx->iovecs[i].vec;
for (j = 0; j < vec->npages; j++)
put_page(vec->pages[j]);
xadd(&pq->unpinned, vec->npages);
kfree(vec->pages);
vec->pages = NULL;
vec->npages = 0;
}
}
if (status != SDMA_TXREQ_S_OK) {
SDMA_DBG(req, "SDMA completion with error %d",
status);
@ -1439,12 +1442,26 @@ static void user_sdma_free_request(struct user_sdma_request *req, bool unpin)
kmem_cache_free(req->pq->txreq_cache, tx);
}
}
if (req->data_iovs && unpin) {
if (req->data_iovs) {
struct sdma_mmu_node *node;
struct mmu_rb_node *mnode;
int i;
for (i = 0; i < req->data_iovs; i++)
if (req->iovs[i].npages && req->iovs[i].pages)
unpin_vector_pages(&req->iovs[i]);
for (i = 0; i < req->data_iovs; i++) {
mnode = hfi1_mmu_rb_search(
&req->pq->sdma_rb_root,
(unsigned long)req->iovs[i].iov.iov_base,
req->iovs[i].iov.iov_len);
if (!mnode)
continue;
node = container_of(mnode, struct sdma_mmu_node, rb);
if (unpin)
hfi1_mmu_rb_remove(&req->pq->sdma_rb_root,
&node->rb);
else
atomic_dec(&node->refcount);
}
}
kfree(req->tids);
clear_bit(SDMA_REQ_IN_USE, &req->flags);
@ -1463,3 +1480,39 @@ static inline void set_comp_state(struct hfi1_user_sdma_pkt_q *pq,
trace_hfi1_sdma_user_completion(pq->dd, pq->ctxt, pq->subctxt,
idx, state, ret);
}
static bool sdma_rb_filter(struct mmu_rb_node *node, unsigned long addr,
unsigned long len)
{
return (bool)(node->addr == addr);
}
static int sdma_rb_insert(struct rb_root *root, struct mmu_rb_node *mnode)
{
struct sdma_mmu_node *node =
container_of(mnode, struct sdma_mmu_node, rb);
atomic_inc(&node->refcount);
return 0;
}
static void sdma_rb_remove(struct rb_root *root, struct mmu_rb_node *mnode,
bool notifier)
{
struct sdma_mmu_node *node =
container_of(mnode, struct sdma_mmu_node, rb);
if (!notifier)
unpin_vector_pages(node->pages, node->npages);
kfree(node);
}
static int sdma_rb_invalidate(struct rb_root *root, struct mmu_rb_node *mnode)
{
struct sdma_mmu_node *node =
container_of(mnode, struct sdma_mmu_node, rb);
if (!atomic_read(&node->refcount))
return 1;
return 0;
}

1
drivers/staging/rdma/hfi1/user_sdma.h
View File

@ -67,6 +67,7 @@ struct hfi1_user_sdma_pkt_q {
unsigned state;
wait_queue_head_t wait;
unsigned long unpinned;
struct rb_root sdma_rb_root;
};
struct hfi1_user_sdma_comp_q {