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SubjectRe: [PATCH v5 07/14] memory-hotplug: move pgdat_resize_lock into sparse_remove_one_section()
On 12/26/2012 11:47 AM, Kamezawa Hiroyuki wrote:
> (2012/12/24 21:09), Tang Chen wrote:
>> In __remove_section(), we locked pgdat_resize_lock when calling
>> sparse_remove_one_section(). This lock will disable irq. But we don't need
>> to lock the whole function. If we do some work to free pagetables in
>> free_section_usemap(), we need to call flush_tlb_all(), which need
>> irq enabled. Otherwise the WARN_ON_ONCE() in smp_call_function_many()
>> will be triggered.
>>
>> Signed-off-by: Tang Chen<tangchen@cn.fujitsu.com>
>> Signed-off-by: Lai Jiangshan<laijs@cn.fujitsu.com>
>> Signed-off-by: Wen Congyang<wency@cn.fujitsu.com>
>
> If this is a bug fix, call-trace in your log and BUGFIX or -fix- in patch title
> will be appreciated, I think.
>
> Acked-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com>
>
Hi Kamezawa-san,

Thanks for the reviewing.

I don't think this would be a bug. It is OK to lock the whole
sparse_remove_one_section() if no tlb flushing in free_section_usemap().

But we need to flush tlb in free_section_usemap(), so we need to take
free_section_usemap() out of the lock. :)

I add the call trace to the patch so that people could review it more
easily.

And here is the call trace for this version:

[ 454.796248] ------------[ cut here ]------------
[ 454.851408] WARNING: at kernel/smp.c:461
smp_call_function_many+0xbd/0x260()
[ 454.935620] Hardware name: PRIMEQUEST 1800E
......
[ 455.652201] Call Trace:
[ 455.681391] [<ffffffff8106e73f>] warn_slowpath_common+0x7f/0xc0
[ 455.753151] [<ffffffff810560a0>] ? leave_mm+0x50/0x50
[ 455.814527] [<ffffffff8106e79a>] warn_slowpath_null+0x1a/0x20
[ 455.884208] [<ffffffff810e7a9d>] smp_call_function_many+0xbd/0x260
[ 455.959082] [<ffffffff810e7ecb>] smp_call_function+0x3b/0x50
[ 456.027722] [<ffffffff810560a0>] ? leave_mm+0x50/0x50
[ 456.089098] [<ffffffff810e7f4b>] on_each_cpu+0x3b/0xc0
[ 456.151512] [<ffffffff81055f0c>] flush_tlb_all+0x1c/0x20
[ 456.216004] [<ffffffff8104f8de>] remove_pagetable+0x14e/0x1d0
[ 456.285683] [<ffffffff8104f978>] vmemmap_free+0x18/0x20
[ 456.349139] [<ffffffff811b8797>] sparse_remove_one_section+0xf7/0x100
[ 456.427126] [<ffffffff811c5fc2>] __remove_section+0xa2/0xb0
[ 456.494726] [<ffffffff811c6070>] __remove_pages+0xa0/0xd0
[ 456.560258] [<ffffffff81669c7b>] arch_remove_memory+0x6b/0xc0
[ 456.629937] [<ffffffff8166ad28>] remove_memory+0xb8/0xf0
[ 456.694431] [<ffffffff813e686f>] acpi_memory_device_remove+0x53/0x96
[ 456.771379] [<ffffffff813b33c4>] acpi_device_remove+0x90/0xb2
[ 456.841059] [<ffffffff8144b02c>] __device_release_driver+0x7c/0xf0
[ 456.915928] [<ffffffff8144b1af>] device_release_driver+0x2f/0x50
[ 456.988719] [<ffffffff813b4476>] acpi_bus_remove+0x32/0x6d
[ 457.055285] [<ffffffff813b4542>] acpi_bus_trim+0x91/0x102
[ 457.120814] [<ffffffff813b463b>] acpi_bus_hot_remove_device+0x88/0x16b
[ 457.199840] [<ffffffff813afda7>] acpi_os_execute_deferred+0x27/0x34
[ 457.275756] [<ffffffff81091ece>] process_one_work+0x20e/0x5c0
[ 457.345434] [<ffffffff81091e5f>] ? process_one_work+0x19f/0x5c0
[ 457.417190] [<ffffffff813afd80>] ?
acpi_os_wait_events_complete+0x23/0x23
[ 457.499332] [<ffffffff81093f6e>] worker_thread+0x12e/0x370
[ 457.565896] [<ffffffff81093e40>] ? manage_workers+0x180/0x180
[ 457.635574] [<ffffffff8109a09e>] kthread+0xee/0x100
[ 457.694871] [<ffffffff810dfaf9>] ? __lock_release+0x129/0x190
[ 457.764552] [<ffffffff81099fb0>] ? __init_kthread_worker+0x70/0x70
[ 457.839427] [<ffffffff81690aac>] ret_from_fork+0x7c/0xb0
[ 457.903914] [<ffffffff81099fb0>] ? __init_kthread_worker+0x70/0x70
[ 457.978784] ---[ end trace 25e85300f542aa01 ]---

Thanks. :)





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