From owner-dev-commits-src-main@freebsd.org Fri May 14 18:04:10 2021 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 9E84D64F1C9; Fri, 14 May 2021 18:04:10 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (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 mx1.freebsd.org (Postfix) with ESMTPS id 4Fhby21x9fz4mqQ; Fri, 14 May 2021 18:04:09 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.16.1/8.16.1) with ESMTPS id 14EI41V2074110 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Fri, 14 May 2021 21:04:04 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 14EI41V2074110 Received: (from kostik@localhost) by tom.home (8.16.1/8.16.1/Submit) id 14EI41oN074109; Fri, 14 May 2021 21:04:01 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Fri, 14 May 2021 21:04:01 +0300 From: Konstantin Belousov To: Mateusz Guzik Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: b5fb9ae6872c - main - vfs: lockless writecount adjustment in set/unset text Message-ID: References: <202105141423.14EENtDX058648@gitrepo.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202105141423.14EENtDX058648@gitrepo.freebsd.org> X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on tom.home X-Rspamd-Queue-Id: 4Fhby21x9fz4mqQ X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] 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: Fri, 14 May 2021 18:04:10 -0000 On Fri, May 14, 2021 at 02:23:55PM +0000, Mateusz Guzik wrote: > The branch main has been updated by mjg: > > URL: https://cgit.FreeBSD.org/src/commit/?id=b5fb9ae6872c499f1a02bec41f48b163a73a2aaa > > commit b5fb9ae6872c499f1a02bec41f48b163a73a2aaa > Author: Mateusz Guzik > AuthorDate: 2021-05-07 14:04:27 +0000 > Commit: Mateusz Guzik > CommitDate: 2021-05-14 14:22:21 +0000 > > vfs: lockless writecount adjustment in set/unset text > > ... for cases where this is not the first/last exec. > --- > sys/kern/vfs_default.c | 32 ++++++++++++++++++++++++++++++-- > 1 file changed, 30 insertions(+), 2 deletions(-) > > diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c > index cf224981cbe7..3518bbeaa279 100644 > --- a/sys/kern/vfs_default.c > +++ b/sys/kern/vfs_default.c > @@ -1177,9 +1177,23 @@ vop_stdset_text(struct vop_set_text_args *ap) > { > struct vnode *vp; > struct mount *mp; > - int error; > + int error, n; > > vp = ap->a_vp; > + > + /* > + * Avoid the interlock if execs are already present. > + */ > + n = atomic_load_int(&vp->v_writecount); > + for (;;) { > + if (n > -1) { > + break; If you split the VOP for tmpfs/non-tmpfs implementations, then non-tmpfs can go with the atomics only.