diff mbox series

[3/5] SUNRPC: Refresh rq_pages using a bulk page allocator

Message ID 20210311114935.11379-4-mgorman@techsingularity.net (mailing list archive)
State New, archived
Headers show
Series Introduce a bulk order-0 page allocator with two in-tree users | expand

Commit Message

Mel Gorman March 11, 2021, 11:49 a.m. UTC 
From: Chuck Lever <chuck.lever@oracle.com>

Reduce the rate at which nfsd threads hammer on the page allocator.
This improve throughput scalability by enabling the threads to run
more independently of each other.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
 net/sunrpc/svc_xprt.c | 43 +++++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 12 deletions(-)

Comments

Chuck Lever March 11, 2021, 2:23 p.m. UTC | #1 
> On Mar 11, 2021, at 6:49 AM, Mel Gorman <mgorman@techsingularity.net> wrote:
> 
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> Reduce the rate at which nfsd threads hammer on the page allocator.
> This improve throughput scalability by enabling the threads to run
> more independently of each other.

Mel, if you should repost this series: ^improve^improves


> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
> ---
> net/sunrpc/svc_xprt.c | 43 +++++++++++++++++++++++++++++++------------
> 1 file changed, 31 insertions(+), 12 deletions(-)
> 
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index cfa7e4776d0e..38a8d6283801 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -642,11 +642,12 @@ static void svc_check_conn_limits(struct svc_serv *serv)
> static int svc_alloc_arg(struct svc_rqst *rqstp)
> {
> 	struct svc_serv *serv = rqstp->rq_server;
> +	unsigned long needed;
> 	struct xdr_buf *arg;
> +	struct page *page;
> 	int pages;
> 	int i;
> 
> -	/* now allocate needed pages.  If we get a failure, sleep briefly */
> 	pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
> 	if (pages > RPCSVC_MAXPAGES) {
> 		pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
> @@ -654,19 +655,28 @@ static int svc_alloc_arg(struct svc_rqst *rqstp)
> 		/* use as many pages as possible */
> 		pages = RPCSVC_MAXPAGES;
> 	}
> -	for (i = 0; i < pages ; i++)
> -		while (rqstp->rq_pages[i] == NULL) {
> -			struct page *p = alloc_page(GFP_KERNEL);
> -			if (!p) {
> -				set_current_state(TASK_INTERRUPTIBLE);
> -				if (signalled() || kthread_should_stop()) {
> -					set_current_state(TASK_RUNNING);
> -					return -EINTR;
> -				}
> -				schedule_timeout(msecs_to_jiffies(500));
> +
> +	for (needed = 0, i = 0; i < pages ; i++)
> +		if (!rqstp->rq_pages[i])
> +			needed++;
> +	if (needed) {
> +		LIST_HEAD(list);
> +
> +retry:
> +		alloc_pages_bulk(GFP_KERNEL, needed, &list);
> +		for (i = 0; i < pages; i++) {
> +			if (!rqstp->rq_pages[i]) {
> +				page = list_first_entry_or_null(&list,
> +								struct page,
> +								lru);
> +				if (unlikely(!page))
> +					goto empty_list;
> +				list_del(&page->lru);
> +				rqstp->rq_pages[i] = page;
> +				needed--;
> 			}
> -			rqstp->rq_pages[i] = p;
> 		}
> +	}
> 	rqstp->rq_page_end = &rqstp->rq_pages[pages];
> 	rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
> 
> @@ -681,6 +691,15 @@ static int svc_alloc_arg(struct svc_rqst *rqstp)
> 	arg->len = (pages-1)*PAGE_SIZE;
> 	arg->tail[0].iov_len = 0;
> 	return 0;
> +
> +empty_list:
> +	set_current_state(TASK_INTERRUPTIBLE);
> +	if (signalled() || kthread_should_stop()) {
> +		set_current_state(TASK_RUNNING);
> +		return -EINTR;
> +	}
> +	schedule_timeout(msecs_to_jiffies(500));
> +	goto retry;
> }
> 
> static bool
> -- 
> 2.26.2
> 

--
Chuck Lever
diff mbox series

Patch

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index cfa7e4776d0e..38a8d6283801 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -642,11 +642,12 @@  static void svc_check_conn_limits(struct svc_serv *serv)
 static int svc_alloc_arg(struct svc_rqst *rqstp)
 {
 	struct svc_serv *serv = rqstp->rq_server;
+	unsigned long needed;
 	struct xdr_buf *arg;
+	struct page *page;
 	int pages;
 	int i;
 
-	/* now allocate needed pages.  If we get a failure, sleep briefly */
 	pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
 	if (pages > RPCSVC_MAXPAGES) {
 		pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
@@ -654,19 +655,28 @@  static int svc_alloc_arg(struct svc_rqst *rqstp)
 		/* use as many pages as possible */
 		pages = RPCSVC_MAXPAGES;
 	}
-	for (i = 0; i < pages ; i++)
-		while (rqstp->rq_pages[i] == NULL) {
-			struct page *p = alloc_page(GFP_KERNEL);
-			if (!p) {
-				set_current_state(TASK_INTERRUPTIBLE);
-				if (signalled() || kthread_should_stop()) {
-					set_current_state(TASK_RUNNING);
-					return -EINTR;
-				}
-				schedule_timeout(msecs_to_jiffies(500));
+
+	for (needed = 0, i = 0; i < pages ; i++)
+		if (!rqstp->rq_pages[i])
+			needed++;
+	if (needed) {
+		LIST_HEAD(list);
+
+retry:
+		alloc_pages_bulk(GFP_KERNEL, needed, &list);
+		for (i = 0; i < pages; i++) {
+			if (!rqstp->rq_pages[i]) {
+				page = list_first_entry_or_null(&list,
+								struct page,
+								lru);
+				if (unlikely(!page))
+					goto empty_list;
+				list_del(&page->lru);
+				rqstp->rq_pages[i] = page;
+				needed--;
 			}
-			rqstp->rq_pages[i] = p;
 		}
+	}
 	rqstp->rq_page_end = &rqstp->rq_pages[pages];
 	rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
 
@@ -681,6 +691,15 @@  static int svc_alloc_arg(struct svc_rqst *rqstp)
 	arg->len = (pages-1)*PAGE_SIZE;
 	arg->tail[0].iov_len = 0;
 	return 0;
+
+empty_list:
+	set_current_state(TASK_INTERRUPTIBLE);
+	if (signalled() || kthread_should_stop()) {
+		set_current_state(TASK_RUNNING);
+		return -EINTR;
+	}
+	schedule_timeout(msecs_to_jiffies(500));
+	goto retry;
 }
 
 static bool