From owner-svn-src-head@freebsd.org Wed Sep 2 19:59:26 2020 Return-Path: Delivered-To: svn-src-head@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 5E6793C8201; Wed, 2 Sep 2020 19:59:26 +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 TLSv1.3 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 4BhZXG1rK1z4BsB; Wed, 2 Sep 2020 19:59:26 +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 1DA21FBA1; Wed, 2 Sep 2020 19:59:26 +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 082JxPDd068125; Wed, 2 Sep 2020 19:59:25 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 082JxP5X068124; Wed, 2 Sep 2020 19:59:25 GMT (envelope-from markj@FreeBSD.org) Message-Id: <202009021959.082JxP5X068124@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Wed, 2 Sep 2020 19:59:25 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r365275 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: markj X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 365275 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Sep 2020 19:59:26 -0000 Author: markj Date: Wed Sep 2 19:59:25 2020 New Revision: 365275 URL: https://svnweb.freebsd.org/changeset/base/365275 Log: Avoid unnecessary object locking in vm_page_grab_pages_unlocked(). We were needlessly acquiring the object lock to call vm_page_grab_pages() even when all of the requested pages were looked up locklessly. Fix that, stop testing for count == 0 in vm_page_grab_pages(), and add assertions to help catch this kind of mistake. Reported by: cem Reviewed by: alc, cem, dougm, jeff Differential Revision: https://reviews.freebsd.org/D26304 Modified: head/sys/vm/vm_page.c Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Wed Sep 2 19:37:47 2020 (r365274) +++ head/sys/vm/vm_page.c Wed Sep 2 19:59:25 2020 (r365275) @@ -4724,12 +4724,11 @@ vm_page_grab_pages(vm_object_t object, vm_pindex_t pin VM_OBJECT_ASSERT_WLOCKED(object); KASSERT(((u_int)allocflags >> VM_ALLOC_COUNT_SHIFT) == 0, ("vm_page_grap_pages: VM_ALLOC_COUNT() is not allowed")); + KASSERT(count > 0, + ("vm_page_grab_pages: invalid page count %d", count)); vm_page_grab_check(allocflags); pflags = vm_page_grab_pflags(allocflags); - if (count == 0) - return (0); - i = 0; retrylookup: m = vm_radix_lookup_le(&object->rtree, pindex + i); @@ -4783,6 +4782,8 @@ vm_page_grab_pages_unlocked(vm_object_t object, vm_pin int flags; int i; + KASSERT(count > 0, + ("vm_page_grab_pages_unlocked: invalid page count %d", count)); vm_page_grab_check(allocflags); /* @@ -4805,7 +4806,7 @@ vm_page_grab_pages_unlocked(vm_object_t object, vm_pin vm_page_grab_release(m, allocflags); pred = ma[i] = m; } - if ((allocflags & VM_ALLOC_NOCREAT) != 0) + if (i == count || (allocflags & VM_ALLOC_NOCREAT) != 0) return (i); count -= i; VM_OBJECT_WLOCK(object);