From owner-freebsd-current@FreeBSD.ORG Fri Jun 24 16:20:06 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (unknown [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 753E7106564A for ; Fri, 24 Jun 2011 16:20:06 +0000 (UTC) (envelope-from pho@holm.cc) Received: from relay01.pair.com (relay01.pair.com [209.68.5.15]) by mx1.freebsd.org (Postfix) with SMTP id 350178FC0A for ; Fri, 24 Jun 2011 16:20:05 +0000 (UTC) Received: (qmail 95570 invoked from network); 24 Jun 2011 16:20:04 -0000 Received: from 87.58.145.224 (HELO x2.osted.lan) (87.58.145.224) by relay01.pair.com with SMTP; 24 Jun 2011 16:20:04 -0000 X-pair-Authenticated: 87.58.145.224 Received: from x2.osted.lan (localhost [127.0.0.1]) by x2.osted.lan (8.14.4/8.14.4) with ESMTP id p5OGK3Ta079214; Fri, 24 Jun 2011 18:20:03 +0200 (CEST) (envelope-from pho@x2.osted.lan) Received: (from pho@localhost) by x2.osted.lan (8.14.4/8.14.4/Submit) id p5OGK3Sd079213; Fri, 24 Jun 2011 18:20:03 +0200 (CEST) (envelope-from pho) Date: Fri, 24 Jun 2011 18:20:03 +0200 From: Peter Holm To: Kostik Belousov Message-ID: <20110624162003.GA79067@x2.osted.lan> References: <20110623163109.GA508@dragon.NUXI.org> <20110623202153.GS48734@deviant.kiev.zoral.com.ua> <20110624103016.GA71991@x2.osted.lan> <20110624110627.GW48734@deviant.kiev.zoral.com.ua> <20110624132105.GA75382@x2.osted.lan> <20110624145043.GY48734@deviant.kiev.zoral.com.ua> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110624145043.GY48734@deviant.kiev.zoral.com.ua> User-Agent: Mutt/1.4.2.3i Cc: freebsd-current@freebsd.org Subject: Re: Thoughts on TMPFS no longer being considered "highly experimental" X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jun 2011 16:20:06 -0000 On Fri, Jun 24, 2011 at 05:50:43PM +0300, Kostik Belousov wrote: > On Fri, Jun 24, 2011 at 03:21:05PM +0200, Peter Holm wrote: > > On Fri, Jun 24, 2011 at 02:06:27PM +0300, Kostik Belousov wrote: > > > On Fri, Jun 24, 2011 at 12:30:16PM +0200, Peter Holm wrote: > > > > On Thu, Jun 23, 2011 at 11:21:53PM +0300, Kostik Belousov wrote: > > > > > On Thu, Jun 23, 2011 at 09:31:09AM -0700, David O'Brien wrote: > > > > > > Does anyone object to this patch? > > > > > > > > > > > > David Wolfskill and I have run TMPFS on a number of machines for two > > > > > > years with no problems. > > > > > > > > > > > > I may have missed something, but I'm not aware of any serious PRs on > > > > > > TMPFS either. > > > > > > > > > > > > > > > > > > Index: tmpfs_vfsops.c > > > > > > =================================================================== > > > > > > --- tmpfs_vfsops.c (revision 221113) > > > > > > +++ tmpfs_vfsops.c (working copy) > > > > > > @@ -155,9 +155,6 @@ tmpfs_mount(struct mount *mp) > > > > > > return EOPNOTSUPP; > > > > > > } > > > > > > > > > > > > - printf("WARNING: TMPFS is considered to be a highly experimental " > > > > > > - "feature in FreeBSD.\n"); > > > > > > - > > > > > > vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); > > > > > > error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred); > > > > > > VOP_UNLOCK(mp->mnt_vnodecovered, 0); > > > > > > > > > > The things I am aware of: > > > > > - there is a races on the lookup. They were papered over in r212305, > > > > > but the bug was not really fixed, AFAIR. > > > > > > > > > > - the tmpfs does double-buffering for the mapped vnodes. This is quite > > > > > insulting for the memory-backed fs, isn't it ? I have a patch, but it is > > > > > still under review. > > > > > > > > > > - I believe Peter Holm has more test cases that fails with tmpfs. He > > > > > would have more details. I somewhat remember some panic on execve(2) the > > > > > binary located on tmpfs. > > > > > > > > > > > > > I ran the TMPFS tests I have and so far I only spotted the mmap(2) > > > > problem: > > > > > > > > http://people.freebsd.org/~pho/stress/log/tmpfs/ > > > It would be indeed good if the issue was the only remaining problem. > > > > Well, more testing is needed for sure. > > > > > The deadlock in tmpfs6.txt is caused by doing copyin() while having > > > a page busied. This should be fixed indirectly by the patch to > > > avoid double-buffering, I uploaded the latest version at > > > http://people.freebsd.org/~kib/misc/tmpfs.5.patch > > > > > > > > > > > > Removing the warning will not make the issues coming away. > > > > > > > > This doesn't compile: > > > > ===> tmpfs (all) > > cc -O2 -pipe -fno-strict-aliasing -Werror -D_KERNEL -DKLD_MODULE -nostdinc -DHAVE_KERNEL_OPTION_HEADERS -include /usr/src/sys/i386/compile/PHO/opt_global.h -I. -I@ -I@/contrib/altq > > -finline-limit=8000 --param inline-unit-growth=100 --param large-function-growth=1000 -fno-common -g -I/usr/src/sys/i386/compile/PHO -mno-align-long-strings -mpreferred-stack-boundary=2 -mno-sse > > -mno-mmx -msoft-float -ffreestanding -fstack-protector -std=iso9899:1999 -fstack-protector -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Winline > > -Wcast-qual -Wundef -Wno-pointer-sign -fformat-extensions -Wmissing-include-dirs -fdiagnostics-show-option -c /usr/src/sys/modules/tmpfs/../../fs/tmpfs/tmpfs_subr.c > > cc1: warnings being treated as errors > > /usr/src/sys/modules/tmpfs/../../fs/tmpfs/tmpfs_subr.c: In function 'tmpfs_reg_resize': > > /usr/src/sys/modules/tmpfs/../../fs/tmpfs/tmpfs_subr.c:911: warning: 'uobj' is used uninitialized in this function > > *** Error code 1 > > Yes, the patch has rotten. Please try > http://people.freebsd.org/~kib/misc/tmpfs.6.patch Got a "panic: Not a vnode object" quite fast: http://people.freebsd.org/~pho/stress/log/kostik441.txt - Peter