From patchwork Sun Jun 5 19:58:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 12869855 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1960C43334 for ; Sun, 5 Jun 2022 19:58:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344478AbiFET6k (ORCPT ); Sun, 5 Jun 2022 15:58:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347132AbiFET6g (ORCPT ); Sun, 5 Jun 2022 15:58:36 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEAD04D9C6 for ; Sun, 5 Jun 2022 12:58:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 50798B80DCA for ; Sun, 5 Jun 2022 19:58:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E759FC385A5 for ; Sun, 5 Jun 2022 19:58:32 +0000 (UTC) Subject: [PATCH v1 2/5] SUNRPC: Optimize xdr_reserve_space() From: Chuck Lever To: linux-nfs@vger.kernel.org Date: Sun, 05 Jun 2022 15:58:31 -0400 Message-ID: <165445911199.1664.12318094116152634589.stgit@bazille.1015granger.net> In-Reply-To: <165445865736.1664.4497130284832282034.stgit@bazille.1015granger.net> References: <165445865736.1664.4497130284832282034.stgit@bazille.1015granger.net> User-Agent: StGit/1.5 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org The xdr_get_next_encode_buffer() function is called infrequently. On a typical build/test workload, it's called about 1 time in 400 calls to xdr_reserve_space() (measured on NFSD). Force the compiler to remove it from xdr_reserve_space(), which is a hot path. This change reduces the size of xdr_reserve_space() from 10 cache lines to 4 on my test system. Signed-off-by: Chuck Lever --- net/sunrpc/xdr.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index b57cf9df4de8..08a85375b311 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -945,8 +945,13 @@ inline void xdr_commit_encode(struct xdr_stream *xdr) } EXPORT_SYMBOL_GPL(xdr_commit_encode); -static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, - size_t nbytes) +/* + * The buffer space to be reserved crosses the boundary between + * xdr->buf->head and xdr->buf->pages, or between two pages + * in xdr->buf->pages. + */ +static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, + size_t nbytes) { __be32 *p; int space_left;