From owner-svn-src-all@freebsd.org Tue Sep 18 17:51:46 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 9DDBE10A4B47; Tue, 18 Sep 2018 17:51:46 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5121C7B1A2; Tue, 18 Sep 2018 17:51:46 +0000 (UTC) (envelope-from markj@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 4C1502345D; Tue, 18 Sep 2018 17:51:46 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w8IHpks3062429; Tue, 18 Sep 2018 17:51:46 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w8IHpkUV062428; Tue, 18 Sep 2018 17:51:46 GMT (envelope-from markj@FreeBSD.org) Message-Id: <201809181751.w8IHpkUV062428@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Tue, 18 Sep 2018 17:51:46 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r338755 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: markj X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 338755 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.27 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: Tue, 18 Sep 2018 17:51:46 -0000 Author: markj Date: Tue Sep 18 17:51:45 2018 New Revision: 338755 URL: https://svnweb.freebsd.org/changeset/base/338755 Log: Only update the domain cursor once in keg_fetch_slab(). We drop the keg lock when we go to actually allocate the slab, allowing other threads to advance the cursor. This can cause us to exit the round-robin loop before having attempted allocations from all domains, resulting in a hang during a subsequent blocking allocation attempt from a depleted domain. Reported and tested by: Jan Bramkamp Reviewed by: alc, cem Approved by: re (gjb) Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D17209 Modified: head/sys/vm/uma_core.c Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Tue Sep 18 16:57:04 2018 (r338754) +++ head/sys/vm/uma_core.c Tue Sep 18 17:51:45 2018 (r338755) @@ -2698,10 +2698,8 @@ again: LIST_INSERT_HEAD(&dom->ud_part_slab, slab, us_link); return (slab); } - if (rr) { - keg->uk_cursor = (keg->uk_cursor + 1) % vm_ndomains; - domain = keg->uk_cursor; - } + if (rr) + domain = (domain + 1) % vm_ndomains; } while (domain != start); /* Retry domain scan with blocking. */