From patchwork Mon Jul 12 18:57:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever III X-Patchwork-Id: 12371865 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B6F3C07E9C for ; Mon, 12 Jul 2021 18:57:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72C346120A for ; Mon, 12 Jul 2021 18:57:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235009AbhGLTAm (ORCPT ); Mon, 12 Jul 2021 15:00:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:54348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234296AbhGLTAl (ORCPT ); Mon, 12 Jul 2021 15:00:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0C5E561221; Mon, 12 Jul 2021 18:57:52 +0000 (UTC) Subject: [PATCH v4 1/3] NFSD: Clean up splice actor From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-mm@kvack.org Cc: neilb@suse.de Date: Mon, 12 Jul 2021 14:57:52 -0400 Message-ID: <162611627232.1416.3505133517679486921.stgit@klimt.1015granger.net> In-Reply-To: <162611520339.1416.14646909890289253420.stgit@klimt.1015granger.net> References: <162611520339.1416.14646909890289253420.stgit@klimt.1015granger.net> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org A few useful observations: - The value in @size is never modified. - splice_desc.len is an unsigned int, and so is xdr_buf.page_len. An implicit cast to size_t is unnecessary. - The computation of .page_len is the same in all three arms of the "if" statement, so hoist it out to make it clear that the operation is an unconditional invariant. The resulting function is 18 bytes shorter on my system (-Os). Signed-off-by: Chuck Lever Reviewed-by: NeilBrown --- fs/nfsd/vfs.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index a224a5e23cc1..46a6d9fce3d2 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -847,26 +847,21 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct svc_rqst *rqstp = sd->u.data; struct page **pp = rqstp->rq_next_page; struct page *page = buf->page; - size_t size; - - size = sd->len; if (rqstp->rq_res.page_len == 0) { get_page(page); put_page(*rqstp->rq_next_page); *(rqstp->rq_next_page++) = page; rqstp->rq_res.page_base = buf->offset; - rqstp->rq_res.page_len = size; } else if (page != pp[-1]) { get_page(page); if (*rqstp->rq_next_page) put_page(*rqstp->rq_next_page); *(rqstp->rq_next_page++) = page; - rqstp->rq_res.page_len += size; - } else - rqstp->rq_res.page_len += size; + } + rqstp->rq_res.page_len += sd->len; - return size; + return sd->len; } static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, From patchwork Mon Jul 12 18:57:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever III X-Patchwork-Id: 12371867 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B37A1C07E99 for ; Mon, 12 Jul 2021 18:58:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 943D7611AD for ; Mon, 12 Jul 2021 18:58:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235253AbhGLTAs (ORCPT ); Mon, 12 Jul 2021 15:00:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:54486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230409AbhGLTAs (ORCPT ); Mon, 12 Jul 2021 15:00:48 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2CAA16120A; Mon, 12 Jul 2021 18:57:59 +0000 (UTC) Subject: [PATCH v4 2/3] SUNRPC: Add svc_rqst_replace_page() API From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-mm@kvack.org Cc: neilb@suse.de Date: Mon, 12 Jul 2021 14:57:58 -0400 Message-ID: <162611627845.1416.14661720296610549505.stgit@klimt.1015granger.net> In-Reply-To: <162611520339.1416.14646909890289253420.stgit@klimt.1015granger.net> References: <162611520339.1416.14646909890289253420.stgit@klimt.1015granger.net> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Replacing a page in rq_pages[] requires a get_page(), which is a bus-locked operation, and a put_page(), which can be even more costly. To reduce the cost of replacing a page in rq_pages[], batch the put_page() operations by collecting "freed" pages in a pagevec, and then release those pages when the pagevec is full. This pagevec is also emptied when each RPC completes. Signed-off-by: Chuck Lever --- include/linux/sunrpc/svc.h | 4 ++++ net/sunrpc/svc.c | 21 +++++++++++++++++++++ net/sunrpc/svc_xprt.c | 3 +++ 3 files changed, 28 insertions(+) diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index e91d51ea028b..ab9afbf0a0d8 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -19,6 +19,7 @@ #include #include #include +#include /* statistics for svc_pool structures */ struct svc_pool_stats { @@ -256,6 +257,7 @@ struct svc_rqst { struct page * *rq_next_page; /* next reply page to use */ struct page * *rq_page_end; /* one past the last page */ + struct pagevec rq_pvec; struct kvec rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */ struct bio_vec rq_bvec[RPCSVC_MAXPAGES]; @@ -502,6 +504,8 @@ struct svc_rqst *svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node); struct svc_rqst *svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node); +void svc_rqst_replace_page(struct svc_rqst *rqstp, + struct page *page); void svc_rqst_free(struct svc_rqst *); void svc_exit_thread(struct svc_rqst *); unsigned int svc_pool_map_get(void); diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 0de918cb3d90..d2d412d43827 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -838,6 +838,27 @@ svc_set_num_threads_sync(struct svc_serv *serv, struct svc_pool *pool, int nrser } EXPORT_SYMBOL_GPL(svc_set_num_threads_sync); +/** + * svc_rqst_replace_page - Replace one page in rq_pages[] + * @rqstp: svc_rqst with pages to replace + * @page: replacement page + * + * When replacing a page in rq_pages, batch the release of the + * replaced pages to avoid hammering the page allocator. + */ +void svc_rqst_replace_page(struct svc_rqst *rqstp, struct page *page) +{ + if (*rqstp->rq_next_page) { + if (!pagevec_space(&rqstp->rq_pvec)) + __pagevec_release(&rqstp->rq_pvec); + pagevec_add(&rqstp->rq_pvec, *rqstp->rq_next_page); + } + + get_page(page); + *(rqstp->rq_next_page++) = page; +} +EXPORT_SYMBOL_GPL(svc_rqst_replace_page); + /* * Called from a server thread as it's exiting. Caller must hold the "service * mutex" for the service. diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index d66a8e44a1ae..682058a5ec13 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -539,6 +539,7 @@ static void svc_xprt_release(struct svc_rqst *rqstp) kfree(rqstp->rq_deferred); rqstp->rq_deferred = NULL; + pagevec_release(&rqstp->rq_pvec); svc_free_res_pages(rqstp); rqstp->rq_res.page_len = 0; rqstp->rq_res.page_base = 0; @@ -664,6 +665,8 @@ static int svc_alloc_arg(struct svc_rqst *rqstp) struct xdr_buf *arg = &rqstp->rq_arg; unsigned long pages, filled; + pagevec_init(&rqstp->rq_pvec); + pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT; if (pages > RPCSVC_MAXPAGES) { pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n", From patchwork Mon Jul 12 18:58:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever III X-Patchwork-Id: 12371869 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73709C07E9C for ; Mon, 12 Jul 2021 18:58:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6124461222 for ; Mon, 12 Jul 2021 18:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235539AbhGLTAy (ORCPT ); Mon, 12 Jul 2021 15:00:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:54562 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230409AbhGLTAy (ORCPT ); Mon, 12 Jul 2021 15:00:54 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 49844611AD; Mon, 12 Jul 2021 18:58:05 +0000 (UTC) Subject: [PATCH v4 3/3] NFSD: Batch release pages during splice read From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-mm@kvack.org Cc: neilb@suse.de Date: Mon, 12 Jul 2021 14:58:04 -0400 Message-ID: <162611628458.1416.5951210328076512466.stgit@klimt.1015granger.net> In-Reply-To: <162611520339.1416.14646909890289253420.stgit@klimt.1015granger.net> References: <162611520339.1416.14646909890289253420.stgit@klimt.1015granger.net> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Large splice reads call put_page() repeatedly. put_page() is relatively expensive to call, so replace it with the new svc_rqst_replace_page() helper to help amortize that cost. Signed-off-by: Chuck Lever Reviewed-by: NeilBrown --- fs/nfsd/vfs.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 46a6d9fce3d2..7732a384f949 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -849,15 +849,10 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct page *page = buf->page; if (rqstp->rq_res.page_len == 0) { - get_page(page); - put_page(*rqstp->rq_next_page); - *(rqstp->rq_next_page++) = page; + svc_rqst_replace_page(rqstp, page); rqstp->rq_res.page_base = buf->offset; } else if (page != pp[-1]) { - get_page(page); - if (*rqstp->rq_next_page) - put_page(*rqstp->rq_next_page); - *(rqstp->rq_next_page++) = page; + svc_rqst_replace_page(rqstp, page); } rqstp->rq_res.page_len += sd->len;