2008-05-06 21:32:35

by [email protected]

[permalink] [raw]
Subject: Re: [PATCH 11/17] svcrdma: Use standard Linux lists for context cache

On Fri, May 02, 2008 at 11:28:26AM -0500, Tom Tucker wrote:
> Replace the one-off linked list implementation used to implement the
> context cache with the standard Linux list_head lists. Add a cpmtext

cmptext == context?

Some spell checking might help those of us who are already a little lost
in the alphabet soup here.

Also, I assume that's referring to sc_ctxt_used. It's initialized,
incremented, and decremented, but doesn't actually seem to be used
anywhere yet?

--b.

> counter to catch resource leaks.
>
> Signed-off-by: Tom Tucker <[email protected]>
>
> ---
> include/linux/sunrpc/svc_rdma.h | 5 ++-
> net/sunrpc/xprtrdma/svc_rdma_transport.c | 47 ++++++++++++++++-------------
> 2 files changed, 29 insertions(+), 23 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
> index c447c41..7014390 100644
> --- a/include/linux/sunrpc/svc_rdma.h
> +++ b/include/linux/sunrpc/svc_rdma.h
> @@ -72,7 +72,7 @@ extern atomic_t rdma_stat_sq_prod;
> */
> struct svc_rdma_op_ctxt {
> struct svc_rdma_op_ctxt *read_hdr;
> - struct svc_rdma_op_ctxt *next;
> + struct list_head free_list;
> struct xdr_buf arg;
> struct list_head dto_q;
> enum ib_wr_opcode wr_op;
> @@ -104,7 +104,8 @@ struct svcxprt_rdma {
>
> struct ib_pd *sc_pd;
>
> - struct svc_rdma_op_ctxt *sc_ctxt_head;
> + atomic_t sc_ctxt_used;
> + struct list_head sc_ctxt_free;
> int sc_ctxt_cnt;
> int sc_ctxt_bump;
> int sc_ctxt_max;
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> index c852fd9..c842cc2 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> @@ -103,8 +103,8 @@ static int rdma_bump_context_cache(struct svcxprt_rdma *xprt)
> spin_lock_bh(&xprt->sc_ctxt_lock);
> if (ctxt) {
> at_least_one = 1;
> - ctxt->next = xprt->sc_ctxt_head;
> - xprt->sc_ctxt_head = ctxt;
> + 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--;
> @@ -123,7 +123,7 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
>
> while (1) {
> spin_lock_bh(&xprt->sc_ctxt_lock);
> - if (unlikely(xprt->sc_ctxt_head == NULL)) {
> + if (unlikely(list_empty(&xprt->sc_ctxt_free))) {
> /* Try to bump my cache. */
> spin_unlock_bh(&xprt->sc_ctxt_lock);
>
> @@ -136,12 +136,15 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
> schedule_timeout_uninterruptible(msecs_to_jiffies(500));
> continue;
> }
> - ctxt = xprt->sc_ctxt_head;
> - xprt->sc_ctxt_head = ctxt->next;
> + 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;
> }
> return ctxt;
> @@ -163,10 +166,11 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
> ctxt->sge[i].addr,
> ctxt->sge[i].length,
> ctxt->direction);
> +
> spin_lock_bh(&xprt->sc_ctxt_lock);
> - ctxt->next = xprt->sc_ctxt_head;
> - xprt->sc_ctxt_head = ctxt;
> + list_add(&ctxt->free_list, &xprt->sc_ctxt_free);
> spin_unlock_bh(&xprt->sc_ctxt_lock);
> + atomic_dec(&xprt->sc_ctxt_used);
> }
>
> /* ib_cq event handler */
> @@ -409,28 +413,29 @@ static void create_context_cache(struct svcxprt_rdma *xprt,
> xprt->sc_ctxt_max = ctxt_max;
> xprt->sc_ctxt_bump = ctxt_bump;
> xprt->sc_ctxt_cnt = 0;
> - xprt->sc_ctxt_head = NULL;
> + 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) {
> - ctxt->next = xprt->sc_ctxt_head;
> - xprt->sc_ctxt_head = 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 svc_rdma_op_ctxt *ctxt)
> +static void destroy_context_cache(struct svcxprt_rdma *xprt)
> {
> - struct svc_rdma_op_ctxt *next;
> - if (!ctxt)
> - return;
> -
> - do {
> - next = ctxt->next;
> + 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);
> - ctxt = next;
> - } while (next);
> + }
> }
>
> static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
> @@ -467,7 +472,7 @@ static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
> reqs +
> cma_xprt->sc_sq_depth +
> RPCRDMA_MAX_THREADS + 1); /* max */
> - if (!cma_xprt->sc_ctxt_head) {
> + if (list_empty(&cma_xprt->sc_ctxt_free)) {
> kfree(cma_xprt);
> return NULL;
> }
> @@ -971,7 +976,7 @@ static void svc_rdma_free(struct svc_xprt *xprt)
> if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
> ib_dealloc_pd(rdma->sc_pd);
>
> - destroy_context_cache(rdma->sc_ctxt_head);
> + destroy_context_cache(rdma);
> kfree(rdma);
> }
>


2008-05-07 00:49:28

by Tom Tucker

[permalink] [raw]
Subject: Re: [PATCH 11/17] svcrdma: Use standard Linux lists for context cache




On 5/6/08 4:32 PM, "J. Bruce Fields" <[email protected]> wrote:

> On Fri, May 02, 2008 at 11:28:26AM -0500, Tom Tucker wrote:
>> Replace the one-off linked list implementation used to implement the
>> context cache with the standard Linux list_head lists. Add a cpmtext
>
> cmptext == context?
>
> Some spell checking might help those of us who are already a little lost
> in the alphabet soup here.
>
> Also, I assume that's referring to sc_ctxt_used. It's initialized,
> incremented, and decremented, but doesn't actually seem to be used
> anywhere yet?

There's a patch at the end that added a WARN_ON if it's not zero when the
transport is getting destroyed.

>
> --b.
>
>> counter to catch resource leaks.
>>
>> Signed-off-by: Tom Tucker <[email protected]>
>>
>> ---
>> include/linux/sunrpc/svc_rdma.h | 5 ++-
>> net/sunrpc/xprtrdma/svc_rdma_transport.c | 47
>> ++++++++++++++++-------------
>> 2 files changed, 29 insertions(+), 23 deletions(-)
>>
>> diff --git a/include/linux/sunrpc/svc_rdma.h
>> b/include/linux/sunrpc/svc_rdma.h
>> index c447c41..7014390 100644
>> --- a/include/linux/sunrpc/svc_rdma.h
>> +++ b/include/linux/sunrpc/svc_rdma.h
>> @@ -72,7 +72,7 @@ extern atomic_t rdma_stat_sq_prod;
>> */
>> struct svc_rdma_op_ctxt {
>> struct svc_rdma_op_ctxt *read_hdr;
>> - struct svc_rdma_op_ctxt *next;
>> + struct list_head free_list;
>> struct xdr_buf arg;
>> struct list_head dto_q;
>> enum ib_wr_opcode wr_op;
>> @@ -104,7 +104,8 @@ struct svcxprt_rdma {
>>
>> struct ib_pd *sc_pd;
>>
>> - struct svc_rdma_op_ctxt *sc_ctxt_head;
>> + atomic_t sc_ctxt_used;
>> + struct list_head sc_ctxt_free;
>> int sc_ctxt_cnt;
>> int sc_ctxt_bump;
>> int sc_ctxt_max;
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> index c852fd9..c842cc2 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
>> @@ -103,8 +103,8 @@ static int rdma_bump_context_cache(struct svcxprt_rdma
>> *xprt)
>> spin_lock_bh(&xprt->sc_ctxt_lock);
>> if (ctxt) {
>> at_least_one = 1;
>> - ctxt->next = xprt->sc_ctxt_head;
>> - xprt->sc_ctxt_head = ctxt;
>> + 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--;
>> @@ -123,7 +123,7 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct
>> svcxprt_rdma *xprt)
>>
>> while (1) {
>> spin_lock_bh(&xprt->sc_ctxt_lock);
>> - if (unlikely(xprt->sc_ctxt_head == NULL)) {
>> + if (unlikely(list_empty(&xprt->sc_ctxt_free))) {
>> /* Try to bump my cache. */
>> spin_unlock_bh(&xprt->sc_ctxt_lock);
>>
>> @@ -136,12 +136,15 @@ struct svc_rdma_op_ctxt *svc_rdma_get_context(struct
>> svcxprt_rdma *xprt)
>> schedule_timeout_uninterruptible(msecs_to_jiffies(500));
>> continue;
>> }
>> - ctxt = xprt->sc_ctxt_head;
>> - xprt->sc_ctxt_head = ctxt->next;
>> + 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;
>> }
>> return ctxt;
>> @@ -163,10 +166,11 @@ void svc_rdma_put_context(struct svc_rdma_op_ctxt
>> *ctxt, int free_pages)
>> ctxt->sge[i].addr,
>> ctxt->sge[i].length,
>> ctxt->direction);
>> +
>> spin_lock_bh(&xprt->sc_ctxt_lock);
>> - ctxt->next = xprt->sc_ctxt_head;
>> - xprt->sc_ctxt_head = ctxt;
>> + list_add(&ctxt->free_list, &xprt->sc_ctxt_free);
>> spin_unlock_bh(&xprt->sc_ctxt_lock);
>> + atomic_dec(&xprt->sc_ctxt_used);
>> }
>>
>> /* ib_cq event handler */
>> @@ -409,28 +413,29 @@ static void create_context_cache(struct svcxprt_rdma
>> *xprt,
>> xprt->sc_ctxt_max = ctxt_max;
>> xprt->sc_ctxt_bump = ctxt_bump;
>> xprt->sc_ctxt_cnt = 0;
>> - xprt->sc_ctxt_head = NULL;
>> + 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) {
>> - ctxt->next = xprt->sc_ctxt_head;
>> - xprt->sc_ctxt_head = 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 svc_rdma_op_ctxt *ctxt)
>> +static void destroy_context_cache(struct svcxprt_rdma *xprt)
>> {
>> - struct svc_rdma_op_ctxt *next;
>> - if (!ctxt)
>> - return;
>> -
>> - do {
>> - next = ctxt->next;
>> + 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);
>> - ctxt = next;
>> - } while (next);
>> + }
>> }
>>
>> static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
>> @@ -467,7 +472,7 @@ static struct svcxprt_rdma *rdma_create_xprt(struct
>> svc_serv *serv,
>> reqs +
>> cma_xprt->sc_sq_depth +
>> RPCRDMA_MAX_THREADS + 1); /* max */
>> - if (!cma_xprt->sc_ctxt_head) {
>> + if (list_empty(&cma_xprt->sc_ctxt_free)) {
>> kfree(cma_xprt);
>> return NULL;
>> }
>> @@ -971,7 +976,7 @@ static void svc_rdma_free(struct svc_xprt *xprt)
>> if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
>> ib_dealloc_pd(rdma->sc_pd);
>>
>> - destroy_context_cache(rdma->sc_ctxt_head);
>> + destroy_context_cache(rdma);
>> kfree(rdma);
>> }
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html