From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266161AbUGTTyC (ORCPT ); Tue, 20 Jul 2004 15:54:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266147AbUGTTxo (ORCPT ); Tue, 20 Jul 2004 15:53:44 -0400 Received: from hermes.fachschaften.tu-muenchen.de ([129.187.202.12]:35576 "HELO hermes.fachschaften.tu-muenchen.de") by vger.kernel.org with SMTP id S266161AbUGTTuX (ORCPT ); Tue, 20 Jul 2004 15:50:23 -0400 Date: Tue, 20 Jul 2004 21:50:12 +0200 From: Adrian Bunk To: "Jeffrey E. Hundstad" , Linus Torvalds , Andrew Morton , Steve Lord Cc: linux-xfs@oss.sgi.com, xfs-masters@oss.sgi.com, nathans@sgi.com, Cahya Wirawan , linux-kernel@vger.kernel.org Subject: [2.6 patch] let 4KSTACKS depend on EXPERIMENTAL and XFS on 4KSTACKS=n Message-ID: <20040720195012.GN14733@fs.tum.de> References: <20040720114418.GH21918@email.archlab.tuwien.ac.at> <40FD0A61.1040503@xfs.org> <40FD2E99.20707@mnsu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <40FD2E99.20707@mnsu.edu> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 20, 2004 at 09:39:21AM -0500, Jeffrey E. Hundstad wrote: > Steve Lord wrote: > > >Don't use 4K stacks and XFS. What you hit here is a path where the > >filesystem is getting full and it needs to free some reserved space > >by flushing cached data which is using reserved extents. Reserved > >extents do not yet have an on disk address and they include a > >reservation for the worst case metadata usage. Flushing them will > >get you room back. > > > >As you can see, it is a pretty deep call stack, most of XFS is going > >to work just fine with a 4K stack, but there are end cases like > >this one which will just not fit. > > > If this is a known truth with XFS maybe it would be a good idea to have > 4K stacks and XFS be an impossible combination using the config tool. The patch below does: 1. let 4KSTACKS depend on EXPERIMENTAL Rationale: 4Kb stacks on i386 are the future. But currently this option might still cause problems in some areas of the kernel. OTOH, 4Kb stacks isn't a big gain for most people. 2.6 is a stable kernel series, and 4KSTACKS=n is the safe choice. Once all issues with 4KSTACKS=y are resolved this can be reverted. 2. let XFS depend on (4KSTACKS=n || BROKEN) Rationale: Mark Loy said: Don't use 4K stacks and XFS. Mark this combination as BROKEN until XFS is fixed. This might result in XFS support disappearing for some people, but if they use EXPERIMENTAL=y they should know what they are doing. The 4KSTACKS option has to be moved for that it's asked before XFS in "make config". diffstat output: arch/i386/Kconfig | 19 ++++++++++--------- fs/Kconfig | 1 + 2 files changed, 11 insertions(+), 9 deletions(-) Signed-off-by: Adrian Bunk --- linux-2.6.8-rc2-full/arch/i386/Kconfig.old 2004-07-20 21:00:32.000000000 +0200 +++ linux-2.6.8-rc2-full/arch/i386/Kconfig 2004-07-20 21:03:30.000000000 +0200 @@ -865,6 +865,16 @@ generate incorrect output with certain kernel constructs when -mregparm=3 is used. +config 4KSTACKS + bool "Use 4Kb for kernel stacks instead of 8Kb" + depends on EXPERIMENTAL + help + If you say Y here the kernel will use a 4Kb stacksize for the + kernel stack attached to each process/thread. This facilitates + running more threads on a system and also reduces the pressure + on the VM subsystem for higher order allocations. This option + will also use IRQ stacks to compensate for the reduced stackspace. + endmenu @@ -1289,15 +1299,6 @@ If you don't debug the kernel, you can say N, but we may not be able to solve problems without frame pointers. -config 4KSTACKS - bool "Use 4Kb for kernel stacks instead of 8Kb" - help - If you say Y here the kernel will use a 4Kb stacksize for the - kernel stack attached to each process/thread. This facilitates - running more threads on a system and also reduces the pressure - on the VM subsystem for higher order allocations. This option - will also use IRQ stacks to compensate for the reduced stackspace. - config X86_FIND_SMP_CONFIG bool depends on X86_LOCAL_APIC || X86_VOYAGER --- linux-2.6.8-rc2-full/fs/Kconfig.old 2004-07-20 21:04:02.000000000 +0200 +++ linux-2.6.8-rc2-full/fs/Kconfig 2004-07-20 21:04:25.000000000 +0200 @@ -294,6 +294,7 @@ config XFS_FS tristate "XFS filesystem support" + depends on (4KSTACKS=n || BROKEN) help XFS is a high performance journaling filesystem which originated on the SGI IRIX platform. It is completely multi-threaded, can