SUNRPC: switchable buffer allocation
Add RPC client transport switch support for replacing buffer management
on a per-transport basis.
In the current IPv4 socket transport implementation, RPC buffers are
allocated as needed for each RPC message that is sent. Some transport
implementations may choose to use pre-allocated buffers for encoding,
sending, receiving, and unmarshalling RPC messages, however. For
transports capable of direct data placement, the buffers can be carved
out of a pre-registered area of memory rather than from a slab cache.
Test-plan:
Millions of fsx operations. Performance characterization with "sio" and
"iozone". Use oprofile and other tools to look for significant regression
in CPU utilization.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 48510e3..7415406 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -41,8 +41,6 @@
static void __rpc_default_timer(struct rpc_task *task);
static void rpciod_killall(void);
-static void rpc_free(struct rpc_task *task);
-
static void rpc_async_schedule(void *);
/*
@@ -599,7 +597,6 @@
WARN_ON(RPC_ASSASSINATED(task));
/* Always release the RPC slot and buffer memory */
xprt_release(task);
- rpc_free(task);
}
}
}
@@ -724,17 +721,19 @@
__rpc_execute((struct rpc_task *)arg);
}
-/*
- * Allocate memory for RPC purposes.
+/**
+ * rpc_malloc - allocate an RPC buffer
+ * @task: RPC task that will use this buffer
+ * @size: requested byte size
*
* We try to ensure that some NFS reads and writes can always proceed
* by using a mempool when allocating 'small' buffers.
* In order to avoid memory starvation triggering more writebacks of
* NFS requests, we use GFP_NOFS rather than GFP_KERNEL.
*/
-void *
-rpc_malloc(struct rpc_task *task, size_t size)
+void * rpc_malloc(struct rpc_task *task, size_t size)
{
+ struct rpc_rqst *req = task->tk_rqstp;
gfp_t gfp;
if (task->tk_flags & RPC_TASK_SWAPPER)
@@ -743,27 +742,33 @@
gfp = GFP_NOFS;
if (size > RPC_BUFFER_MAXSIZE) {
- task->tk_buffer = kmalloc(size, gfp);
- if (task->tk_buffer)
- task->tk_bufsize = size;
+ req->rq_buffer = kmalloc(size, gfp);
+ if (req->rq_buffer)
+ req->rq_bufsize = size;
} else {
- task->tk_buffer = mempool_alloc(rpc_buffer_mempool, gfp);
- if (task->tk_buffer)
- task->tk_bufsize = RPC_BUFFER_MAXSIZE;
+ req->rq_buffer = mempool_alloc(rpc_buffer_mempool, gfp);
+ if (req->rq_buffer)
+ req->rq_bufsize = RPC_BUFFER_MAXSIZE;
}
- return task->tk_buffer;
+ return req->rq_buffer;
}
-static void
-rpc_free(struct rpc_task *task)
+/**
+ * rpc_free - free buffer allocated via rpc_malloc
+ * @task: RPC task with a buffer to be freed
+ *
+ */
+void rpc_free(struct rpc_task *task)
{
- if (task->tk_buffer) {
- if (task->tk_bufsize == RPC_BUFFER_MAXSIZE)
- mempool_free(task->tk_buffer, rpc_buffer_mempool);
+ struct rpc_rqst *req = task->tk_rqstp;
+
+ if (req->rq_buffer) {
+ if (req->rq_bufsize == RPC_BUFFER_MAXSIZE)
+ mempool_free(req->rq_buffer, rpc_buffer_mempool);
else
- kfree(task->tk_buffer);
- task->tk_buffer = NULL;
- task->tk_bufsize = 0;
+ kfree(req->rq_buffer);
+ req->rq_buffer = NULL;
+ req->rq_bufsize = 0;
}
}
@@ -887,7 +892,6 @@
xprt_release(task);
if (task->tk_msg.rpc_cred)
rpcauth_unbindcred(task);
- rpc_free(task);
if (task->tk_client) {
rpc_release_client(task->tk_client);
task->tk_client = NULL;