From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 233FB6B0047 for ; Fri, 5 Mar 2010 21:33:08 -0500 (EST) Message-ID: <4B91BE93.8000401@kernel.org> Date: Fri, 05 Mar 2010 18:31:47 -0800 From: Yinghai Lu MIME-Version: 1.0 Subject: Re: mmotm boot panic bootmem-avoid-dma32-zone-by-default.patch References: <49b004811003041321g2567bac8yb73235be32a27e7c@mail.gmail.com> <20100305032106.GA12065@cmpxchg.org> <49b004811003042117n720f356h7e10997a1a783475@mail.gmail.com> <4B915074.4020704@kernel.org> <20100305235812.GA15249@cmpxchg.org> <4B91B4EF.5090502@kernel.org> <20100306022415.GB16967@cmpxchg.org> In-Reply-To: <20100306022415.GB16967@cmpxchg.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Greg Thelen , Andrew Morton , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-mm@kvack.org, "linux-kernel@vger.kernel.org" List-ID: On 03/05/2010 06:24 PM, Johannes Weiner wrote: > On Fri, Mar 05, 2010 at 05:50:39PM -0800, Yinghai Lu wrote: >> On 03/05/2010 03:58 PM, Johannes Weiner wrote: >>> Hello Yinghai, >>> >>> On Fri, Mar 05, 2010 at 10:41:56AM -0800, Yinghai Lu wrote: >>>> On 03/04/2010 09:17 PM, Greg Thelen wrote: >>>>> On Thu, Mar 4, 2010 at 7:21 PM, Johannes Weiner wrote: >>>>>> On Thu, Mar 04, 2010 at 01:21:41PM -0800, Greg Thelen wrote: >>>>>>> On several systems I am seeing a boot panic if I use mmotm >>>>>>> (stamp-2010-03-02-18-38). If I remove >>>>>>> bootmem-avoid-dma32-zone-by-default.patch then no panic is seen. I >>>>>>> find that: >>>>>>> * 2.6.33 boots fine. >>>>>>> * 2.6.33 + mmotm w/o bootmem-avoid-dma32-zone-by-default.patch: boots fine. >>>>>>> * 2.6.33 + mmotm (including >>>>>>> bootmem-avoid-dma32-zone-by-default.patch): panics. >>>> ... >>>>> >>>>> Note: mmotm has been recently updated to stamp-2010-03-04-18-05. I >>>>> re-tested with 'make defconfig' to confirm the panic with this later >>>>> mmotm. >>>> >>>> please check >>>> >>>> [PATCH] early_res: double check with updated goal in alloc_memory_core_early >>>> >>>> Johannes Weiner pointed out that new early_res replacement for alloc_bootmem_node >>>> change the behavoir about goal. >>>> original bootmem one will try go further regardless of goal. >>>> >>>> and it will break his patch about default goal from MAX_DMA to MAX_DMA32... >>>> also broke uncommon machines with <=16M of memory. >>>> (really? our x86 kernel still can run on 16M system?) >>>> >>>> so try again with update goal. >>> >>> Thanks for the patch, it seems to be correct. >>> >>> However, I have a more generic question about it, regarding the future of the >>> early_res allocator. >>> >>> Did you plan on keeping the bootmem API for longer? Because my impression was, >>> emulating it is a temporary measure until all users are gone and bootmem can >>> be finally dropped. >> >> that depends on every arch maintainer. >> >> user can compare them on x86 to check if... > > Humm, now that is a bit disappointing. Because it means we will never get rid > of bootmem as long as it works for the other architectures. And your changeset > just added ~900 lines of code, some of it being a rather ugly compatibility > layer in bootmem that I hoped could go away again sooner than later. > > I do not know what the upsides for x86 are from no longer using bootmem but it > would suck from a code maintainance point of view to get stuck half way through > this transition and have now TWO implementations of the bootmem interface we > would like to get rid of. some data, and others can compare them more on x86 systems... I didn't plan to post this data before you said .... for my 1T system nobootmem: text data bss dec hex filename 19185736 4148404 12170736 35504876 21dc2ec vmlinux.nobootmem Memory: 1058662820k/1075838976k available (11388k kernel code, 2106480k absent, 15069676k reserved, 8589k data, 2744k init [ 220.947157] calling ip_auto_config+0x0/0x24d @ 1 bootmem: text data bss dec hex filename 19188441 4153956 12170736 35513133 21de32d vmlinux.bootmem Memory: 1058662796k/1075838976k available (11388k kernel code, 2106480k absent, 15069700k reserved, 8589k data, 2752k init) [ 236.765364] calling ip_auto_config+0x0/0x24d @ 1 YH -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org