From owner-svn-src-all@freebsd.org Mon Apr 2 05:12:00 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 6C565F7342B; Mon, 2 Apr 2018 05:12:00 +0000 (UTC) (envelope-from glebius@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 1AA796DCD0; Mon, 2 Apr 2018 05:12:00 +0000 (UTC) (envelope-from glebius@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 1594111526; Mon, 2 Apr 2018 05:12:00 +0000 (UTC) (envelope-from glebius@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w325BxPx014265; Mon, 2 Apr 2018 05:11:59 GMT (envelope-from glebius@FreeBSD.org) Received: (from glebius@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w325Bx89014264; Mon, 2 Apr 2018 05:11:59 GMT (envelope-from glebius@FreeBSD.org) Message-Id: <201804020511.w325Bx89014264@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: glebius set sender to glebius@FreeBSD.org using -f From: Gleb Smirnoff Date: Mon, 2 Apr 2018 05:11:59 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r331871 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: glebius X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 331871 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: 2.1.25 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: Mon, 02 Apr 2018 05:12:00 -0000 Author: glebius Date: Mon Apr 2 05:11:59 2018 New Revision: 331871 URL: https://svnweb.freebsd.org/changeset/base/331871 Log: Handle a special case when a slab can fit only one allocation, and zone has a large alignment. With alignment taken into account uk_rsize will be greater than space in a slab. However, since we have only one item per slab, it is always naturally aligned. Code that will panic before this change with 4k page: z = uma_zcreate("test", 3984, NULL, NULL, NULL, NULL, 31, 0); uma_zalloc(z, M_WAITOK); A practical scenario to hit the panic is a machine with 56 CPUs and 2 NUMA domains, which yields in zone size of 3984. PR: 227116 MFC after: 2 weeks Modified: head/sys/vm/uma_core.c Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Sun Apr 1 22:59:53 2018 (r331870) +++ head/sys/vm/uma_core.c Mon Apr 2 05:11:59 2018 (r331871) @@ -1290,7 +1290,15 @@ keg_small_init(uma_keg_t keg) else shsize = sizeof(struct uma_slab); - keg->uk_ipers = (slabsize - shsize) / rsize; + if (rsize <= slabsize - shsize) + keg->uk_ipers = (slabsize - shsize) / rsize; + else { + /* Handle special case when we have 1 item per slab, so + * alignment requirement can be relaxed. */ + KASSERT(keg->uk_size <= slabsize - shsize, + ("%s: size %u greater than slab", __func__, keg->uk_size)); + keg->uk_ipers = 1; + } KASSERT(keg->uk_ipers > 0 && keg->uk_ipers <= SLAB_SETSIZE, ("%s: keg->uk_ipers %u", __func__, keg->uk_ipers));