[PATCH 3/3] SUNRPC: Refresh rq_pages using a bulk page allocator
From: Mel Gorman <hidden>
Date: 2021-02-24 10:27:29
Also in:
linux-nfs, lkml, netdev
Subsystem:
kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
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 <redacted> --- 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