Re: [PATCH v5 00/16] HWPOISON: soft offline rework

[HORIGUCHI NAOYA(堀口 直也)]

Hello,

On Mon, Aug 03, 2020 at 08:39:55AM -0400, Qian Cai wrote:
> On Fri, Jul 31, 2020 at 12:20:56PM +0000, nao.horiguchi@xxxxxxxxx wrote:
> > This patchset is the latest version of soft offline rework patchset
> > targetted for v5.9.
> > 
> > Main focus of this series is to stabilize soft offline.  Historically soft
> > offlined pages have suffered from racy conditions because PageHWPoison is
> > used to a little too aggressively, which (directly or indirectly) invades
> > other mm code which cares little about hwpoison.  This results in unexpected
> > behavior or kernel panic, which is very far from soft offline's "do not
> > disturb userspace or other kernel component" policy.
> > 
> > Main point of this change set is to contain target page "via buddy allocator",
> > where we first free the target page as we do for normal pages, and remove
> > from buddy only when we confirm that it reaches free list. There is surely
> > race window of page allocation, but that's fine because someone really want
> > that page and the page is still working, so soft offline can happily give up.
> > 
> > v4 from Oscar tries to handle the race around reallocation, but that part
> > seems still work in progress, so I decide to separate it for changes into
> > v5.9.  Thank you for your contribution, Oscar.
> > 
> > The issue reported by Qian Cai is fixed by patch 16/16.
> 
> I am still getting EIO everywhere on next-20200803 (which includes this v5).
> 
> # ./random 1
> - start: migrate_huge_offline
> - use NUMA nodes 0,8.
> - mmap and free 8388608 bytes hugepages on node 0
> - mmap and free 8388608 bytes hugepages on node 8
> madvise: Input/output error
> 
> From the serial console,
> 
> [  637.164222][ T8357] soft offline: 0x118ee0: hugepage isolation failed: 0, page count 2, type 7fff800001000e (referenced|uptodate|dirty|head)
> [  637.164890][ T8357] Soft offlining pfn 0x20001380 at process virtual address 0x7fff9f000000
> [  637.165422][ T8357] Soft offlining pfn 0x3ba00 at process virtual address 0x7fff9f200000
> [  637.166409][ T8357] Soft offlining pfn 0x201914a0 at process virtual address 0x7fff9f000000
> [  637.166833][ T8357] Soft offlining pfn 0x12b9a0 at process virtual address 0x7fff9f200000
> [  637.168044][ T8357] Soft offlining pfn 0x1abb60 at process virtual address 0x7fff9f000000
> [  637.168557][ T8357] Soft offlining pfn 0x20014820 at process virtual address 0x7fff9f200000
> [  637.169493][ T8357] Soft offlining pfn 0x119720 at process virtual address 0x7fff9f000000
> [  637.169603][ T8357] soft offline: 0x119720: hugepage isolation failed: 0, page count 2, type 7fff800001000e (referenced|uptodate|dirty|head)
> [  637.169756][ T8357] Soft offlining pfn 0x118ee0 at process virtual address 0x7fff9f200000
> [  637.170653][ T8357] Soft offlining pfn 0x200e81e0 at process virtual address 0x7fff9f000000
> [  637.171067][ T8357] Soft offlining pfn 0x201c5f60 at process virtual address 0x7fff9f200000
> [  637.172101][ T8357] Soft offlining pfn 0x201c8f00 at process virtual address 0x7fff9f000000
> [  637.172241][ T8357] __get_any_page: 0x201c8f00: unknown zero refcount page type 87fff8000000000

I might misjudge to skip the following patch, sorry about that.
Could you try with it?

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