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svcrdma: Change WR context get/put to use the kmem cache
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Change the WR context pool to be shared across mount points. This
reduces the RDMA transport memory footprint significantly since
idle mounts don't consume WR context memory.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
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Tom Tucker committed Jul 2, 2008
1 parent bf5927d commit 8948896
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Showing 2 changed files with 12 additions and 115 deletions.
6 changes: 0 additions & 6 deletions include/linux/sunrpc/svc_rdma.h
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Original file line number Diff line number Diff line change
Expand Up @@ -73,7 +73,6 @@ extern atomic_t rdma_stat_sq_prod;
struct svc_rdma_op_ctxt {
struct svc_rdma_op_ctxt *read_hdr;
int hdr_count;
struct list_head free_list;
struct xdr_buf arg;
struct list_head dto_q;
enum ib_wr_opcode wr_op;
Expand Down Expand Up @@ -131,11 +130,6 @@ struct svcxprt_rdma {

atomic_t sc_dma_used;
atomic_t sc_ctxt_used;
struct list_head sc_ctxt_free;
int sc_ctxt_cnt;
int sc_ctxt_bump;
int sc_ctxt_max;
spinlock_t sc_ctxt_lock;
struct list_head sc_rq_dto_q;
spinlock_t sc_rq_dto_lock;
struct ib_qp *sc_qp;
Expand Down
121 changes: 12 additions & 109 deletions net/sunrpc/xprtrdma/svc_rdma_transport.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -84,69 +84,23 @@ struct svc_xprt_class svc_rdma_class = {
.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
};

static int rdma_bump_context_cache(struct svcxprt_rdma *xprt)
{
int target;
int at_least_one = 0;
struct svc_rdma_op_ctxt *ctxt;

target = min(xprt->sc_ctxt_cnt + xprt->sc_ctxt_bump,
xprt->sc_ctxt_max);

spin_lock_bh(&xprt->sc_ctxt_lock);
while (xprt->sc_ctxt_cnt < target) {
xprt->sc_ctxt_cnt++;
spin_unlock_bh(&xprt->sc_ctxt_lock);

ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);

spin_lock_bh(&xprt->sc_ctxt_lock);
if (ctxt) {
at_least_one = 1;
INIT_LIST_HEAD(&ctxt->free_list);
list_add(&ctxt->free_list, &xprt->sc_ctxt_free);
} else {
/* kmalloc failed...give up for now */
xprt->sc_ctxt_cnt--;
break;
}
}
spin_unlock_bh(&xprt->sc_ctxt_lock);
dprintk("svcrdma: sc_ctxt_max=%d, sc_ctxt_cnt=%d\n",
xprt->sc_ctxt_max, xprt->sc_ctxt_cnt);
return at_least_one;
}
/* WR context cache. Created in svc_rdma.c */
extern struct kmem_cache *svc_rdma_ctxt_cachep;

struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
{
struct svc_rdma_op_ctxt *ctxt;

while (1) {
spin_lock_bh(&xprt->sc_ctxt_lock);
if (unlikely(list_empty(&xprt->sc_ctxt_free))) {
/* Try to bump my cache. */
spin_unlock_bh(&xprt->sc_ctxt_lock);

if (rdma_bump_context_cache(xprt))
continue;

printk(KERN_INFO "svcrdma: sleeping waiting for "
"context memory on xprt=%p\n",
xprt);
schedule_timeout_uninterruptible(msecs_to_jiffies(500));
continue;
}
ctxt = list_entry(xprt->sc_ctxt_free.next,
struct svc_rdma_op_ctxt,
free_list);
list_del_init(&ctxt->free_list);
spin_unlock_bh(&xprt->sc_ctxt_lock);
ctxt->xprt = xprt;
INIT_LIST_HEAD(&ctxt->dto_q);
ctxt->count = 0;
atomic_inc(&xprt->sc_ctxt_used);
break;
ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep, GFP_KERNEL);
if (ctxt)
break;
schedule_timeout_uninterruptible(msecs_to_jiffies(500));
}
ctxt->xprt = xprt;
INIT_LIST_HEAD(&ctxt->dto_q);
ctxt->count = 0;
atomic_inc(&xprt->sc_ctxt_used);
return ctxt;
}

Expand Down Expand Up @@ -174,9 +128,7 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
for (i = 0; i < ctxt->count; i++)
put_page(ctxt->pages[i]);

spin_lock_bh(&xprt->sc_ctxt_lock);
list_add(&ctxt->free_list, &xprt->sc_ctxt_free);
spin_unlock_bh(&xprt->sc_ctxt_lock);
kmem_cache_free(svc_rdma_ctxt_cachep, ctxt);
atomic_dec(&xprt->sc_ctxt_used);
}

Expand Down Expand Up @@ -461,40 +413,6 @@ static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
tasklet_schedule(&dto_tasklet);
}

static void create_context_cache(struct svcxprt_rdma *xprt,
int ctxt_count, int ctxt_bump, int ctxt_max)
{
struct svc_rdma_op_ctxt *ctxt;
int i;

xprt->sc_ctxt_max = ctxt_max;
xprt->sc_ctxt_bump = ctxt_bump;
xprt->sc_ctxt_cnt = 0;
atomic_set(&xprt->sc_ctxt_used, 0);

INIT_LIST_HEAD(&xprt->sc_ctxt_free);
for (i = 0; i < ctxt_count; i++) {
ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);
if (ctxt) {
INIT_LIST_HEAD(&ctxt->free_list);
list_add(&ctxt->free_list, &xprt->sc_ctxt_free);
xprt->sc_ctxt_cnt++;
}
}
}

static void destroy_context_cache(struct svcxprt_rdma *xprt)
{
while (!list_empty(&xprt->sc_ctxt_free)) {
struct svc_rdma_op_ctxt *ctxt;
ctxt = list_entry(xprt->sc_ctxt_free.next,
struct svc_rdma_op_ctxt,
free_list);
list_del_init(&ctxt->free_list);
kfree(ctxt);
}
}

static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
int listener)
{
Expand All @@ -511,7 +429,6 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,

spin_lock_init(&cma_xprt->sc_lock);
spin_lock_init(&cma_xprt->sc_read_complete_lock);
spin_lock_init(&cma_xprt->sc_ctxt_lock);
spin_lock_init(&cma_xprt->sc_rq_dto_lock);

cma_xprt->sc_ord = svcrdma_ord;
Expand All @@ -522,20 +439,7 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
atomic_set(&cma_xprt->sc_sq_count, 0);
atomic_set(&cma_xprt->sc_ctxt_used, 0);

if (!listener) {
int reqs = cma_xprt->sc_max_requests;
create_context_cache(cma_xprt,
reqs << 1, /* starting size */
reqs, /* bump amount */
reqs +
cma_xprt->sc_sq_depth +
RPCRDMA_MAX_THREADS + 1); /* max */
if (list_empty(&cma_xprt->sc_ctxt_free)) {
kfree(cma_xprt);
return NULL;
}
clear_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
} else
if (listener)
set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);

return cma_xprt;
Expand Down Expand Up @@ -1077,7 +981,6 @@ static void __svc_rdma_free(struct work_struct *work)
/* Destroy the CM ID */
rdma_destroy_id(rdma->sc_cm_id);

destroy_context_cache(rdma);
kfree(rdma);
}

Expand Down

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