Re: [PATCH 3/5] SUNRPC: Refresh rq_pages using a bulk page allocator
From: Chuck Lever III <hidden>
Date: 2021-03-11 14:25:31
Also in:
linux-mm, linux-nfs, lkml
On Mar 11, 2021, at 6:49 AM, Mel Gorman [off-list ref] wrote: From: Chuck Lever <redacted> 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
quoted hunk ↗ jump to hunk
Signed-off-by: Chuck Lever <redacted> 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
-- Chuck Lever