From owner-dev-commits-src-main@freebsd.org Mon Dec 28 02:03:18 2020 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4E30A4CE037; Mon, 28 Dec 2020 02:03:18 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4D416Z1nBMz4XLJ; Mon, 28 Dec 2020 02:03:18 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3005411C36; Mon, 28 Dec 2020 02:03:18 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 0BS23IoH005370; Mon, 28 Dec 2020 02:03:18 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 0BS23I5T005369; Mon, 28 Dec 2020 02:03:18 GMT (envelope-from git) Date: Mon, 28 Dec 2020 02:03:18 GMT Message-Id: <202012280203.0BS23I5T005369@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mateusz Guzik Subject: git: ff97bc034fcd - main - cache: simplify lockless dot lookups MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mjg X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: ff97bc034fcdf16207ed75e43622e9f0d91fa553 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: "Commit messages for the main branch of the src repository." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 Dec 2020 02:03:18 -0000 The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=ff97bc034fcdf16207ed75e43622e9f0d91fa553 commit ff97bc034fcdf16207ed75e43622e9f0d91fa553 Author: Mateusz Guzik AuthorDate: 2020-12-28 00:12:28 +0000 Commit: Mateusz Guzik CommitDate: 2020-12-28 01:53:27 +0000 cache: simplify lockless dot lookups --- sys/kern/vfs_cache.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c index 75c362534c91..22dfe01ac624 100644 --- a/sys/kern/vfs_cache.c +++ b/sys/kern/vfs_cache.c @@ -4317,19 +4317,18 @@ cache_fplookup_noentry(struct cache_fpl *fpl) static int __noinline cache_fplookup_dot(struct cache_fpl *fpl) { - struct vnode *dvp; - - dvp = fpl->dvp; - fpl->tvp = dvp; - fpl->tvp_seqc = vn_seqc_read_any(dvp); - if (seqc_in_modify(fpl->tvp_seqc)) { - return (cache_fpl_aborted(fpl)); - } + MPASS(!seqc_in_modify(fpl->dvp_seqc)); + /* + * Just re-assign the value. seqc will be checked later for the first + * non-dot path component in line and/or before deciding to return the + * vnode. + */ + fpl->tvp = fpl->dvp; + fpl->tvp_seqc = fpl->dvp_seqc; counter_u64_add(dothits, 1); - SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ".", dvp); - + SDT_PROBE3(vfs, namecache, lookup, hit, fpl->dvp, ".", fpl->dvp); return (0); }