Commit 02107148 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

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: default avatarChuck Lever <cel@netapp.com>
 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 03c21733

include/linux/sunrpc/sched.h

+1 −2
Original line number Diff line number Diff line
@@ -52,8 +52,6 @@ struct rpc_task { 
	 * RPC call state

	 */

	struct rpc_message	tk_msg;		/* RPC call info */

	__u32 *			tk_buffer;	/* XDR buffer */

	size_t			tk_bufsize;

	__u8			tk_garb_retry;

	__u8			tk_cred_retry;
@@ -268,6 +266,7 @@ struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *); 
void		rpc_wake_up_status(struct rpc_wait_queue *, int);

void		rpc_delay(struct rpc_task *, unsigned long);

void *		rpc_malloc(struct rpc_task *, size_t);

void		rpc_free(struct rpc_task *);

int		rpciod_up(void);

void		rpciod_down(void);

void		rpciod_wake_up(void);

include/linux/sunrpc/xprt.h

+5 −5
Original line number Diff line number Diff line
@@ -79,21 +79,19 @@ struct rpc_rqst { 
	void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */

	struct list_head	rq_list;



	__u32 *			rq_buffer;	/* XDR encode buffer */

	size_t			rq_bufsize;



	struct xdr_buf		rq_private_buf;		/* The receive buffer

							 * used in the softirq.

							 */

	unsigned long		rq_majortimeo;	/* major timeout alarm */

	unsigned long		rq_timeout;	/* Current timeout value */

	unsigned int		rq_retries;	/* # of retries */

	/*

	 * For authentication (e.g. auth_des)

	 */

	u32			rq_creddata[2];

	

	/*

	 * Partial send handling

	 */

	

	u32			rq_bytes_sent;	/* Bytes we have sent */



	unsigned long		rq_xtime;	/* when transmitted */
@@ -107,6 +105,8 @@ struct rpc_xprt_ops { 
	int		(*reserve_xprt)(struct rpc_task *task);

	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);

	void		(*connect)(struct rpc_task *task);

	void *		(*buf_alloc)(struct rpc_task *task, size_t size);

	void		(*buf_free)(struct rpc_task *task);

	int		(*send_request)(struct rpc_task *task);

	void		(*set_retrans_timeout)(struct rpc_task *task);

	void		(*timer)(struct rpc_task *task);

net/sunrpc/clnt.c

+8 −6
Original line number Diff line number Diff line
@@ -644,24 +644,26 @@ call_reserveresult(struct rpc_task *task) 


/*

 * 2.	Allocate the buffer. For details, see sched.c:rpc_malloc.

 *	(Note: buffer memory is freed in rpc_task_release).

 *	(Note: buffer memory is freed in xprt_release).

 */

static void

call_allocate(struct rpc_task *task)

{

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_xprt *xprt = task->tk_xprt;

	unsigned int	bufsiz;



	dprintk("RPC: %4d call_allocate (status %d)\n", 

				task->tk_pid, task->tk_status);

	task->tk_action = call_bind;

	if (task->tk_buffer)

	if (req->rq_buffer)

		return;



	/* FIXME: compute buffer requirements more exactly using

	 * auth->au_wslack */

	bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;



	if (rpc_malloc(task, bufsiz << 1) != NULL)

	if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)

		return;

	printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
@@ -704,14 +706,14 @@ call_encode(struct rpc_task *task) 
				task->tk_pid, task->tk_status);



	/* Default buffer setup */

	bufsiz = task->tk_bufsize >> 1;

	sndbuf->head[0].iov_base = (void *)task->tk_buffer;

	bufsiz = req->rq_bufsize >> 1;

	sndbuf->head[0].iov_base = (void *)req->rq_buffer;

	sndbuf->head[0].iov_len  = bufsiz;

	sndbuf->tail[0].iov_len  = 0;

	sndbuf->page_len	 = 0;

	sndbuf->len		 = 0;

	sndbuf->buflen		 = bufsiz;

	rcvbuf->head[0].iov_base = (void *)((char *)task->tk_buffer + bufsiz);

	rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);

	rcvbuf->head[0].iov_len  = bufsiz;

	rcvbuf->tail[0].iov_len  = 0;

	rcvbuf->page_len	 = 0;

net/sunrpc/sched.c

+27 −23
Original line number Diff line number Diff line
@@ -41,8 +41,6 @@ static mempool_t *rpc_buffer_mempool __read_mostly; 


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 @@ void rpc_exit_task(struct rpc_task *task) 
			WARN_ON(RPC_ASSASSINATED(task));

			/* Always release the RPC slot and buffer memory */

			xprt_release(task);

			rpc_free(task);

		}

	}

}
@@ -724,17 +721,19 @@ static void rpc_async_schedule(void *arg) 
	__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 @@ rpc_malloc(struct rpc_task *task, size_t size) 
		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 @@ void rpc_release_task(struct rpc_task *task) 
		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;

net/sunrpc/xprt.c

+3 −0
Original line number Diff line number Diff line
@@ -838,6 +838,8 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) 
	req->rq_timeout = xprt->timeout.to_initval;

	req->rq_task	= task;

	req->rq_xprt    = xprt;

	req->rq_buffer  = NULL;

	req->rq_bufsize = 0;

	req->rq_xid     = xprt_alloc_xid(xprt);

	req->rq_release_snd_buf = NULL;

	dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
@@ -867,6 +869,7 @@ void xprt_release(struct rpc_task *task) 
		mod_timer(&xprt->timer,

				xprt->last_used + xprt->idle_timeout);

	spin_unlock_bh(&xprt->transport_lock);

	xprt->ops->buf_free(task);

	task->tk_rqstp = NULL;

	if (req->rq_release_snd_buf)

		req->rq_release_snd_buf(req);

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