From owner-svn-src-all@freebsd.org Sun Dec 16 01:51:39 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 71DD51337D7C; Sun, 16 Dec 2018 01:51:39 +0000 (UTC) (envelope-from kib@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) server-signature RSA-PSS (4096 bits) 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 BD09E6ACCB; Sun, 16 Dec 2018 01:51:38 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id AFE512074E; Sun, 16 Dec 2018 01:51:38 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id wBG1pcLH006615; Sun, 16 Dec 2018 01:51:38 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id wBG1pcOV006614; Sun, 16 Dec 2018 01:51:38 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201812160151.wBG1pcOV006614@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Sun, 16 Dec 2018 01:51:38 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r342144 - head/share/man/man9 X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: head/share/man/man9 X-SVN-Commit-Revision: 342144 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: BD09E6ACCB X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-2.83 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_HAM_MEDIUM(-1.00)[-0.997,0]; NEURAL_HAM_SHORT(-0.95)[-0.949,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US]; NEURAL_HAM_LONG(-0.88)[-0.883,0] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 16 Dec 2018 01:51:39 -0000 Author: kib Date: Sun Dec 16 01:51:38 2018 New Revision: 342144 URL: https://svnweb.freebsd.org/changeset/base/342144 Log: Document new required MI behaviour of pmap_enter(9) for CoW. Reviewed by: markj MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential revision: https://reviews.freebsd.org/D18568 Modified: head/share/man/man9/pmap_enter.9 Modified: head/share/man/man9/pmap_enter.9 ============================================================================== --- head/share/man/man9/pmap_enter.9 Sun Dec 16 01:19:10 2018 (r342143) +++ head/share/man/man9/pmap_enter.9 Sun Dec 16 01:51:38 2018 (r342144) @@ -26,7 +26,7 @@ .\" .\" $FreeBSD$ .\" -.Dd February 16, 2018 +.Dd December 16, 2018 .Dt PMAP_ENTER 9 .Os .Sh NAME @@ -119,6 +119,14 @@ It is advised to clear for destroyed mappings if the implementation can ensure that no other writeable managed mappings for the previously mapped pages exist. +.Pp +If the request modifies an existing mapping to use a different physical +page, an implementation of +.Nm +must invalidate the previous mapping before installing the new one. +This ensures that all threads sharing the pmap keep a consistent +view of the mapping, which is necessary for the correct handling +of CoW (copy on write) faults. .Pp If the page .Fa m