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Message-ID: <52D47999.5080905@redhat.com>
Date: Mon, 13 Jan 2014 18:41:13 -0500
From: Prarit Bhargava <prarit@...hat.com>
To: KOSAKI Motohiro <kosaki.motohiro@...il.com>
CC: LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
the arch/x86 maintainers <x86@...nel.org>,
Len Brown <lenb@...nel.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Linn Crosetto <linn@...com>, Pekka Enberg <penberg@...nel.org>,
Yinghai Lu <yinghai@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Toshi Kani <toshi.kani@...com>,
Tang Chen <tangchen@...fujitsu.com>,
Wen Congyang <wency@...fujitsu.com>,
Vivek Goyal <vgoyal@...hat.com>,
Dave Young <dyoung@...hat.com>, linux-acpi@...r.kernel.org,
"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH] x86, acpi memory hotplug, add parameter to disable memory
hotplug
On 01/13/2014 05:17 PM, KOSAKI Motohiro wrote:
> On Mon, Jan 13, 2014 at 4:56 PM, Prarit Bhargava <prarit@...hat.com> wrote:
>> When booting a kexec/kdump kernel on a system that has specific memory hotplug
>> regions the boot will fail with warnings like:
>>
>> [ 2.939467] swapper/0: page allocation failure: order:9, mode:0x84d0
>> [ 2.946564] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>> 3.10.0-65.el7.x86_64 #1
>> [ 2.954532] Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS
>> QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011
>> [ 2.964926] 0000000000000000 ffff8800341bd8c8 ffffffff815bcc67
>> ffff8800341bd950
>> [ 2.973224] ffffffff8113b1a0 ffff880036339b00 0000000000000009
>> 00000000000084d0
>> [ 2.981523] ffff8800341bd950 ffffffff815b87ee 0000000000000000
>> 0000000000000200
>> [ 2.989821] Call Trace:
>> [ 2.992560] [<ffffffff815bcc67>] dump_stack+0x19/0x1b
>> [ 2.998300] [<ffffffff8113b1a0>] warn_alloc_failed+0xf0/0x160
>> [ 3.004817] [<ffffffff815b87ee>] ?
>> __alloc_pages_direct_compact+0xac/0x196
>> [ 3.012594] [<ffffffff8113f14f>] __alloc_pages_nodemask+0x7ff/0xa00
>> [ 3.019692] [<ffffffff815b417c>] vmemmap_alloc_block+0x62/0xba
>> [ 3.026303] [<ffffffff815b41e9>] vmemmap_alloc_block_buf+0x15/0x3b
>> [ 3.033302] [<ffffffff815b1ff6>] vmemmap_populate+0xb4/0x21b
>> [ 3.039718] [<ffffffff815b461d>] sparse_mem_map_populate+0x27/0x35
>> [ 3.046717] [<ffffffff815b400f>] sparse_add_one_section+0x7a/0x185
>> [ 3.053720] [<ffffffff815a1e9f>] __add_pages+0xaf/0x240
>> [ 3.059656] [<ffffffff81047359>] arch_add_memory+0x59/0xd0
>> [ 3.065877] [<ffffffff815a21d9>] add_memory+0xb9/0x1b0
>> [ 3.071713] [<ffffffff81333b9c>] acpi_memory_device_add+0x18d/0x26d
>> [ 3.078813] [<ffffffff81309a01>] acpi_bus_device_attach+0x7d/0xcd
>> [ 3.085719] [<ffffffff8132379d>] acpi_ns_walk_namespace+0xc8/0x17f
>> [ 3.092716] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
>> [ 3.100004] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
>> [ 3.107293] [<ffffffff81323c8c>] acpi_walk_namespace+0x95/0xc5
>> [ 3.113904] [<ffffffff8130a6d6>] acpi_bus_scan+0x8b/0x9d
>> [ 3.119933] [<ffffffff81a2019a>] acpi_scan_init+0x63/0x160
>> [ 3.126153] [<ffffffff81a1ffb5>] acpi_init+0x25d/0x2a6
>> [ 3.131987] [<ffffffff81a1fd58>] ? acpi_sleep_proc_init+0x2a/0x2a
>> [ 3.138889] [<ffffffff810020e2>] do_one_initcall+0xe2/0x190
>> [ 3.145210] [<ffffffff819e20c4>] kernel_init_freeable+0x17c/0x207
>> [ 3.152111] [<ffffffff819e18d0>] ? do_early_param+0x88/0x88
>> [ 3.158430] [<ffffffff8159fea0>] ? rest_init+0x80/0x80
>> [ 3.164264] [<ffffffff8159feae>] kernel_init+0xe/0x180
>> [ 3.170097] [<ffffffff815cca2c>] ret_from_fork+0x7c/0xb0
>> [ 3.176123] [<ffffffff8159fea0>] ? rest_init+0x80/0x80
>> [ 3.181956] Mem-Info:
>> [ 3.184490] Node 0 DMA per-cpu:
>> [ 3.188007] CPU 0: hi: 0, btch: 1 usd: 0
>> [ 3.193353] Node 0 DMA32 per-cpu:
>> [ 3.197060] CPU 0: hi: 42, btch: 7 usd: 0
>> [ 3.202410] active_anon:0 inactive_anon:0 isolated_anon:0
>> [ 3.202410] active_file:0 inactive_file:0 isolated_file:0
>> [ 3.202410] unevictable:0 dirty:0 writeback:0 unstable:0
>> [ 3.202410] free:872 slab_reclaimable:13 slab_unreclaimable:1880
>> [ 3.202410] mapped:0 shmem:0 pagetables:0 bounce:0
>> [ 3.202410] free_cma:0
>>
>> because the system has run out of memory at boot time. This occurs
>> because of the following sequence in the boot:
>>
>> Main kernel boots and sets E820 map. The second kernel is booted with a
>> map generated by the kdump service using memmap= and memmap=exactmap.
>> These parameters are added to the kernel parameters of the kexec/kdump
>> kernel. The kexec/kdump kernel has limited memory resources so as not
>> to severely impact the main kernel.
>>
>> The system then panics and the kdump/kexec kernel boots (which is a
>> completely new kernel boot). During this boot ACPI is initialized and the
>> kernel (as can be seen above) traverses the ACPI namespace and finds an
>> entry for a memory device to be hotadded.
>>
>> ie)
>>
>> [ 3.053720] [<ffffffff815a1e9f>] __add_pages+0xaf/0x240
>> [ 3.059656] [<ffffffff81047359>] arch_add_memory+0x59/0xd0
>> [ 3.065877] [<ffffffff815a21d9>] add_memory+0xb9/0x1b0
>> [ 3.071713] [<ffffffff81333b9c>] acpi_memory_device_add+0x18d/0x26d
>> [ 3.078813] [<ffffffff81309a01>] acpi_bus_device_attach+0x7d/0xcd
>> [ 3.085719] [<ffffffff8132379d>] acpi_ns_walk_namespace+0xc8/0x17f
>> [ 3.092716] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
>> [ 3.100004] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90
>> [ 3.107293] [<ffffffff81323c8c>] acpi_walk_namespace+0x95/0xc5
>> [ 3.113904] [<ffffffff8130a6d6>] acpi_bus_scan+0x8b/0x9d
>> [ 3.119933] [<ffffffff81a2019a>] acpi_scan_init+0x63/0x160
>> [ 3.126153] [<ffffffff81a1ffb5>] acpi_init+0x25d/0x2a6
>>
>> At this point the kernel adds page table information and the the kexec/kdump
>> kernel runs out of memory.
>>
>> This can also be reproduced with a "regular" kernel by using the
>> memmap=exactmap and mem=X parameters on the main kernel and booting.
>>
>> This patchset resolves the problem by adding a kernel parameter,
>> acpi_no_memhotplug, to disable ACPI memory hotplug. ACPI memory hotplug
>> should also be disabled by default when a user specified a memory mapping with
>> "memmap=exactmap" or "mem=X".
>>
>> Signed-off-by: Prarit Bhargava <prarit@...hat.com>
>> Cc: Thomas Gleixner <tglx@...utronix.de>
>> Cc: Ingo Molnar <mingo@...hat.com>
>> Cc: "H. Peter Anvin" <hpa@...or.com>
>> Cc: x86@...nel.org
>> Cc: Len Brown <lenb@...nel.org>
>> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
>> Cc: Linn Crosetto <linn@...com>
>> Cc: Pekka Enberg <penberg@...nel.org>
>> Cc: Yinghai Lu <yinghai@...nel.org>
>> Cc: Andrew Morton <akpm@...ux-foundation.org>
>> Cc: Toshi Kani <toshi.kani@...com>
>> Cc: Tang Chen <tangchen@...fujitsu.com>
>> Cc: Wen Congyang <wency@...fujitsu.com>
>> Cc: Vivek Goyal <vgoyal@...hat.com>
>> Cc: kosaki.motohiro@...il.com
>> Cc: dyoung@...hat.com
>> Cc: Toshi Kani <toshi.kani@...com>
>> Cc: linux-acpi@...r.kernel.org
>> Cc: linux-mm@...ck.org
>
> I think we need a knob manually enable mem-hotplug when specify memmap. But
> it is another story.
>
> Acked-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
As mentioned, self-NAK. I have seen a system that I needed to specify
memmap=exactmap & had hotplug memory. I will only keep the acpi_no_memhotplug
option in the next version of the patch.
P.
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