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svcrdma: Improve allocation of struct svc_rdma_req_map 

To ensure this allocation cannot fail and will not sleep,
pre-allocate the req_map structures per-connection.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Chuck Lever 2016-01-07 14:49:20 -05:00 committed by Doug Ledford
parent cc886c9ff1
commit 2fe81b239d
3 changed files with 85 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/sunrpc/svc_rdma.h
View File

@ -113,6 +113,7 @@ struct svc_rdma_fastreg_mr {
struct list_head frmr_list;
};
struct svc_rdma_req_map {
struct list_head free;
unsigned long count;
union {
struct kvec sge[RPCSVC_MAXPAGES];
@ -145,6 +146,8 @@ struct svcxprt_rdma {
spinlock_t sc_ctxt_lock;
struct list_head sc_ctxts;
int sc_ctxt_used;
spinlock_t sc_map_lock;
struct list_head sc_maps;
struct list_head sc_rq_dto_q;
spinlock_t sc_rq_dto_lock;
@ -223,8 +226,9 @@ extern int svc_rdma_create_listen(struct svc_serv *, int, struct sockaddr *);
extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
extern void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt);
extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
extern struct svc_rdma_req_map *svc_rdma_get_req_map(struct svcxprt_rdma *);
extern void svc_rdma_put_req_map(struct svcxprt_rdma *,
struct svc_rdma_req_map *);
extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
struct svc_rdma_fastreg_mr *);

6
net/sunrpc/xprtrdma/svc_rdma_sendto.c
View File

@ -591,7 +591,7 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
/* Build an req vec for the XDR */
ctxt = svc_rdma_get_context(rdma);
ctxt->direction = DMA_TO_DEVICE;
vec = svc_rdma_get_req_map();
vec = svc_rdma_get_req_map(rdma);
ret = map_xdr(rdma, &rqstp->rq_res, vec);
if (ret)
goto err0;
@ -630,14 +630,14 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec,
inline_bytes);
svc_rdma_put_req_map(vec);
svc_rdma_put_req_map(rdma, vec);
dprintk("svcrdma: send_reply returns %d\n", ret);
return ret;
err1:
put_page(res_page);
err0:
svc_rdma_put_req_map(vec);
svc_rdma_put_req_map(rdma, vec);
svc_rdma_put_context(ctxt, 0);
return ret;
}

87
net/sunrpc/xprtrdma/svc_rdma_transport.c
View File

@ -273,23 +273,83 @@ static void svc_rdma_destroy_ctxts(struct svcxprt_rdma *xprt)
}
}
/*
* Temporary NFS req mappings are shared across all transport
* instances. These are short lived and should be bounded by the number
* of concurrent server threads * depth of the SQ.
*/
struct svc_rdma_req_map *svc_rdma_get_req_map(void)
static struct svc_rdma_req_map *alloc_req_map(gfp_t flags)
{
struct svc_rdma_req_map *map;
map = kmem_cache_alloc(svc_rdma_map_cachep,
GFP_KERNEL | __GFP_NOFAIL);
map->count = 0;
map = kmalloc(sizeof(*map), flags);
if (map)
INIT_LIST_HEAD(&map->free);
return map;
}
void svc_rdma_put_req_map(struct svc_rdma_req_map *map)
static bool svc_rdma_prealloc_maps(struct svcxprt_rdma *xprt)
{
kmem_cache_free(svc_rdma_map_cachep, map);
int i;
/* One for each receive buffer on this connection. */
i = xprt->sc_max_requests;
while (i--) {
struct svc_rdma_req_map *map;
map = alloc_req_map(GFP_KERNEL);
if (!map) {
dprintk("svcrdma: No memory for request map\n");
return false;
}
list_add(&map->free, &xprt->sc_maps);
}
return true;
}
struct svc_rdma_req_map *svc_rdma_get_req_map(struct svcxprt_rdma *xprt)
{
struct svc_rdma_req_map *map = NULL;
spin_lock(&xprt->sc_map_lock);
if (list_empty(&xprt->sc_maps))
goto out_empty;
map = list_first_entry(&xprt->sc_maps,
struct svc_rdma_req_map, free);
list_del_init(&map->free);
spin_unlock(&xprt->sc_map_lock);
out:
map->count = 0;
return map;
out_empty:
spin_unlock(&xprt->sc_map_lock);
/* Pre-allocation amount was incorrect */
map = alloc_req_map(GFP_NOIO);
if (map)
goto out;
WARN_ONCE(1, "svcrdma: empty request map list?\n");
return NULL;
}
void svc_rdma_put_req_map(struct svcxprt_rdma *xprt,
struct svc_rdma_req_map *map)
{
spin_lock(&xprt->sc_map_lock);
list_add(&map->free, &xprt->sc_maps);
spin_unlock(&xprt->sc_map_lock);
}
static void svc_rdma_destroy_maps(struct svcxprt_rdma *xprt)
{
while (!list_empty(&xprt->sc_maps)) {
struct svc_rdma_req_map *map;
map = list_first_entry(&xprt->sc_maps,
struct svc_rdma_req_map, free);
list_del(&map->free);
kfree(map);
}
}
/* ib_cq event handler */
@ -593,12 +653,14 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
INIT_LIST_HEAD(&cma_xprt->sc_frmr_q);
INIT_LIST_HEAD(&cma_xprt->sc_ctxts);
INIT_LIST_HEAD(&cma_xprt->sc_maps);
init_waitqueue_head(&cma_xprt->sc_send_wait);
spin_lock_init(&cma_xprt->sc_lock);
spin_lock_init(&cma_xprt->sc_rq_dto_lock);
spin_lock_init(&cma_xprt->sc_frmr_q_lock);
spin_lock_init(&cma_xprt->sc_ctxt_lock);
spin_lock_init(&cma_xprt->sc_map_lock);
if (listener)
set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
@ -988,6 +1050,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
if (!svc_rdma_prealloc_ctxts(newxprt))
goto errout;
if (!svc_rdma_prealloc_maps(newxprt))
goto errout;
/*
* Limit ORD based on client limit, local device limit, and
@ -1259,6 +1323,7 @@ static void __svc_rdma_free(struct work_struct *work)
rdma_dealloc_frmr_q(rdma);
svc_rdma_destroy_ctxts(rdma);
svc_rdma_destroy_maps(rdma);
/* Destroy the QP if present (not a listener) */
if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))