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Date:   Tue, 14 Jul 2020 22:21:53 -0400
From:   Qian Cai <cai@lca.pw>
To:     Oscar Salvador <osalvador@suse.de>
Cc:     nao.horiguchi@gmail.com, linux-mm@kvack.org, mhocko@kernel.org,
        akpm@linux-foundation.org, mike.kravetz@oracle.com,
        tony.luck@intel.com, david@redhat.com,
        aneesh.kumar@linux.vnet.ibm.com, zeil@yandex-team.ru,
        naoya.horiguchi@nec.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 00/15] HWPOISON: soft offline rework
Message-ID: <20200715022152.GA54790@lca.pw>
References: <20200624150137.7052-1-nao.horiguchi@gmail.com>
 <20200630050803.GA2747@lca.pw>
 <20200714100839.GA1939@linux>
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On Tue, Jul 14, 2020 at 12:08:46PM +0200, Oscar Salvador wrote:
> On Tue, Jun 30, 2020 at 01:08:03AM -0400, Qian Cai wrote:
> > Even after applied the compling fix,
> > 
> > https://lore.kernel.org/linux-mm/20200628065409.GA546944@u2004/
> > 
> > madvise(MADV_SOFT_OFFLINE) will fail with EIO with hugetlb where it
> > would succeed without this series. Steps:
> > 
> > # git clone https://github.com/cailca/linux-mm
> > # cd linux-mm; make
> > # ./random 1 (Need at least two NUMA memory nodes)
> >  start: migrate_huge_offline
> > - use NUMA nodes 0,4.
> > - mmap and free 8388608 bytes hugepages on node 0
> > - mmap and free 8388608 bytes hugepages on node 4
> > madvise: Input/output error
> 
> Ok, sorry for the lateness, but I had to re-fetch the code on my brain again.
> 
> I just finished v4 of this patchset and it seems this problem is gone:
> 
> # ./random 1
> - start: migrate_huge_offline
> - use NUMA nodes 0,1.
> - mmap and free 8388608 bytes hugepages on node 0
> - mmap and free 8388608 bytes hugepages on node 1
> - pass: mmap_offline_node_huge
> - start: hotplug_memory
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Invalid argument
> offline: Device or resource busy
> offline: Invalid argument
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> offline: Device or resource busy
> - pass: hotplug_memory
> 
> The test seems to suceed and no crash on the kernel side.
> 
> I will just run some more tests to make sure the thing is solid enough
> and then I will post v4.

Great, I plan to reproduce a bit more of the crash below which I am not 100%
sure yet which patchset/patch is the culprit where that LTP move_pages12
reproducer does the similar things.

https://lore.kernel.org/lkml/20200708012044.GC992@lca.pw/