From owner-svn-src-head@freebsd.org Fri Oct 20 18:40:30 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D1906E3D03E; Fri, 20 Oct 2017 18:40:30 +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 mx1.freebsd.org (Postfix) with ESMTPS id 9F43E2288; Fri, 20 Oct 2017 18:40:30 +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 v9KIeTod093718; Fri, 20 Oct 2017 18:40:29 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v9KIeT9F093717; Fri, 20 Oct 2017 18:40:29 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201710201840.v9KIeT9F093717@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Fri, 20 Oct 2017 18:40:29 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r324807 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 324807 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: 2.1.23 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: Fri, 20 Oct 2017 18:40:30 -0000 Author: kib Date: Fri Oct 20 18:40:29 2017 New Revision: 324807 URL: https://svnweb.freebsd.org/changeset/base/324807 Log: Take the vm object lock in read mode in vnode_generic_putpages(). Only upgrade it to write mode if we need to clear dirty bits of the partially valid page after EOF. Suggested and reviewed by: alc Sponsored by: The FreeBSD Foundation MFC after: 3 weeks Modified: head/sys/vm/vnode_pager.c Modified: head/sys/vm/vnode_pager.c ============================================================================== --- head/sys/vm/vnode_pager.c Fri Oct 20 15:29:28 2017 (r324806) +++ head/sys/vm/vnode_pager.c Fri Oct 20 18:40:29 2017 (r324807) @@ -1252,8 +1252,14 @@ vnode_pager_generic_putpages(struct vnode *vp, vm_page * We do not under any circumstances truncate the valid bits, as * this will screw up bogus page replacement. */ - VM_OBJECT_WLOCK(object); + VM_OBJECT_RLOCK(object); if (maxsize + poffset > object->un_pager.vnp.vnp_size) { + if (!VM_OBJECT_TRYUPGRADE(object)) { + VM_OBJECT_RUNLOCK(object); + VM_OBJECT_WLOCK(object); + if (maxsize + poffset <= object->un_pager.vnp.vnp_size) + goto downgrade; + } if (object->un_pager.vnp.vnp_size > poffset) { maxsize = object->un_pager.vnp.vnp_size - poffset; ncount = btoc(maxsize); @@ -1278,6 +1284,8 @@ vnode_pager_generic_putpages(struct vnode *vp, vm_page } for (i = ncount; i < count; i++) rtvals[i] = VM_PAGER_BAD; +downgrade: + VM_OBJECT_LOCK_DOWNGRADE(object); } auio.uio_iov = &aiov; @@ -1324,7 +1332,7 @@ start_write: */ MPASS(prev_offset < next_offset); - VM_OBJECT_WUNLOCK(object); + VM_OBJECT_RUNLOCK(object); aiov.iov_base = NULL; auio.uio_iovcnt = 1; auio.uio_offset = prev_offset; @@ -1340,7 +1348,7 @@ start_write: "zero-length write at %ju resid %zd\n", auio.uio_offset, auio.uio_resid); } - VM_OBJECT_WLOCK(object); + VM_OBJECT_RLOCK(object); break; } @@ -1358,7 +1366,7 @@ start_write: vn_printf(vp, "vnode_pager_putpages: residual I/O %zd " "at %ju\n", auio.uio_resid, (uintmax_t)ma[0]->pindex); - VM_OBJECT_WLOCK(object); + VM_OBJECT_RLOCK(object); if (error != 0 || auio.uio_resid != 0) break; } @@ -1372,7 +1380,7 @@ write_done: /* Unwritten pages in range, free bonus if the page is clean. */ for (; i < ncount; i++) rtvals[i] = ma[i]->dirty == 0 ? VM_PAGER_OK : VM_PAGER_ERROR; - VM_OBJECT_WUNLOCK(object); + VM_OBJECT_RUNLOCK(object); VM_CNT_ADD(v_vnodepgsout, i); VM_CNT_INC(v_vnodeout); return (rtvals[0]);