SUNRPC: refresh rq_pages using a bulk page allocator

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

[mgorman: Update interpretation of alloc_pages_bulk return value]

Link: https://lkml.kernel.org/r/20210325114228.27719-8-mgorman@techsingularity.net
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 63eb6b9..d66a8e4 100644 (file)
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -662,30 +662,29 @@ static int svc_alloc_arg(struct svc_rqst *rqstp)
 {
        struct svc_serv *serv = rqstp->rq_server;
        struct xdr_buf *arg = &rqstp->rq_arg;
-       int pages;
-       int i;
+       unsigned long pages, filled;
 
-       /* 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",
+               pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
                             pages, RPCSVC_MAXPAGES);
                /* 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));
-                       }
-                       rqstp->rq_pages[i] = p;
+
+       for (;;) {
+               filled = alloc_pages_bulk_array(GFP_KERNEL, pages,
+                                               rqstp->rq_pages);
+               if (filled == pages)
+                       break;
+
+               set_current_state(TASK_INTERRUPTIBLE);
+               if (signalled() || kthread_should_stop()) {
+                       set_current_state(TASK_RUNNING);
+                       return -EINTR;
                }
+               schedule_timeout(msecs_to_jiffies(500));
+       }
        rqstp->rq_page_end = &rqstp->rq_pages[pages];
        rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */