CMA, isolate: get warning in page_isolation.c:235 test_pages_isolated

CMA, isolate: get warning in page_isolation.c:235 test_pages_isolated

[朱辉]

Hi guys,

After I back porting your patches:
mm/page_alloc: fix incorrect isolation behavior by rechecking migratetype
mm/page_alloc: add freepage on isolate pageblock to correct buddy list
mm/page_alloc: move freepage counting logic to __free_one_page()
mm/page_alloc: restrict max order of merging on isolated pageblock
mm: page_alloc: store updated page migratetype to avoid misusing stale value
mm: page_isolation: check pfn validity before access
to 3.10 linux kernel.
I also use the CMA_AGGRESSIVE patches in https://lkml.org/lkml/2014/10/15/623.

I got:
[68121.770699@2] ------------[ cut here ]------------
[68121.774592@2] WARNING: at /home/teawater/common/mm/page_isolation.c:235 test_pages_isolated+0x108/0x208()
[68121.793911@2] CPU: 2 PID: 2711 Comm: kthread_xxx Tainted: P           O 3.10.33-250644-gcfd93f8-dirty #184
[68121.803632@2] [<c0016de4>] (unwind_backtrace+0x0/0x128) from [<c0013360>] (show_stack+0x20/0x24)
[68121.812379@2] [<c0013360>] (show_stack+0x20/0x24) from [<c074553c>] (dump_stack+0x20/0x28)
[68121.820612@2] [<c074553c>] (dump_stack+0x20/0x28) from [<c002f2b8>] (warn_slowpath_common+0x5c/0x7c)
[68121.829712@2] [<c002f2b8>] (warn_slowpath_common+0x5c/0x7c) from [<c002f304>] (warn_slowpath_null+0x2c/0x34)
[68121.839508@2] [<c002f304>] (warn_slowpath_null+0x2c/0x34) from [<c011f324>] (test_pages_isolated+0x108/0x208)
[68121.849393@2] [<c011f324>] (test_pages_isolated+0x108/0x208) from [<c00e24d8>] (alloc_contig_range+0x208/0x2b0)
[68121.859447@2] [<c00e24d8>] (alloc_contig_range+0x208/0x2b0) from [<c0320d44>] (dma_alloc_from_contiguous+0x15c/0x24c)

Looks it has some race issue between page isolation and free path after these patches.
And I checked the free path but found nothing.

I worried that it still has some race issue between page isolation and something in upstream.  Or I missed some patches?
If we cannot handle this issue in a short time, I suggest add the "move_freepages" code back to __test_page_isolated_in_pageblock.

Thanks,
Hui

 

RE: CMA, isolate: get warning in page_isolation.c:235 test_pages_isolated

[Weijie Yang]

> -----Original Message-----
> From: 朱辉 [mailto:zhuhui@xiaomi.com]
> Sent: Friday, November 28, 2014 11:15 AM
> To: weijie.yang@samsung.com; iamjoonsoo.kim@lge.com
> Cc: Hui Zhu; linux-mm@kvack.org
> Subject: CMA, isolate: get warning in page_isolation.c:235 test_pages_isolated
> 
> Hi guys,
> 
> After I back porting your patches:
> mm/page_alloc: fix incorrect isolation behavior by rechecking migratetype
> mm/page_alloc: add freepage on isolate pageblock to correct buddy list
> mm/page_alloc: move freepage counting logic to __free_one_page()
> mm/page_alloc: restrict max order of merging on isolated pageblock
> mm: page_alloc: store updated page migratetype to avoid misusing stale value
> mm: page_isolation: check pfn validity before access

My patch is not proper, it doesn't consider the steal freepages in alloc path.
So it should be dropped(I will send a notice email to akpm).

I am now working on its v2 patch and will resend it soon.

Thanks

> to 3.10 linux kernel.
> I also use the CMA_AGGRESSIVE patches in https://lkml.org/lkml/2014/10/15/623.
> 
> I got:
> [68121.770699@2] ------------[ cut here ]------------
> [68121.774592@2] WARNING: at /home/teawater/common/mm/page_isolation.c:235 test_pages_isolated+0x108/0x208()
> [68121.793911@2] CPU: 2 PID: 2711 Comm: kthread_xxx Tainted: P           O 3.10.33-250644-gcfd93f8-dirty #184
> [68121.803632@2] [<c0016de4>] (unwind_backtrace+0x0/0x128) from [<c0013360>] (show_stack+0x20/0x24)
> [68121.812379@2] [<c0013360>] (show_stack+0x20/0x24) from [<c074553c>] (dump_stack+0x20/0x28)
> [68121.820612@2] [<c074553c>] (dump_stack+0x20/0x28) from [<c002f2b8>] (warn_slowpath_common+0x5c/0x7c)
> [68121.829712@2] [<c002f2b8>] (warn_slowpath_common+0x5c/0x7c) from [<c002f304>] (warn_slowpath_null+0x2c/0x34)
> [68121.839508@2] [<c002f304>] (warn_slowpath_null+0x2c/0x34) from [<c011f324>] (test_pages_isolated+0x108/0x208)
> [68121.849393@2] [<c011f324>] (test_pages_isolated+0x108/0x208) from [<c00e24d8>] (alloc_contig_range+0x208/0x2b0)
> [68121.859447@2] [<c00e24d8>] (alloc_contig_range+0x208/0x2b0) from [<c0320d44>] (dma_alloc_from_contiguous+0x15c/0x24c)
> 
> Looks it has some race issue between page isolation and free path after these patches.
> And I checked the free path but found nothing.
> 
> I worried that it still has some race issue between page isolation and something in upstream.  Or I missed some patches?
> If we cannot handle this issue in a short time, I suggest add the "move_freepages" code back to __test_page_isolated_in_pageblock.
> 
> Thanks,
> Hui
> 
> 

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