[v4,00/15] Hwpoison soft-offline rework
mbox series

Message ID 20200716123810.25292-1-osalvador@suse.de
Headers show
Series
  • Hwpoison soft-offline rework
Related show

Message

Oscar Salvador July 16, 2020, 12:37 p.m. UTC
Hi all,

this is a follow-up version on [1].
That version had some flaws wrt. handling hugetlb pages, so this version
fixes it.
I checked that the case reported by Qian seems to work fine now.

Cover letter:

This patchset was initially based on Naoya's hwpoison rework [1], so
thanks to him for the initial work.
I would also like to think Naoya for testing the patchset off-line,
and report any issues he found, that was quite helpful.

This patchset aims to fix some issues laying in soft-offline handling,
but it also takes the chance and takes some further steps to perform 
cleanups and some refactoring as well.


 - Motivation:

   A customer and I were facing an issue were processes were killed
   after having soft-offlined some of their pages.
   This should not happen when soft-offlining, as it is meant to be non-disruptive.
   I was able to reproduce the issue when I stressed the memory +
   soft offlining pages in the meantime.

   After debugging the issue, I saw that the problem was that pages were returned
   back to user-space after having offlined them properly.
   So, when those pages were faulted in, the fault handler returned VM_FAULT_POISON
   all the way down to the arch handler, and it simply killed the process.

   After a further anaylsis, it became clear that the problem was that when
   kcompactd kicked in to migrate pages over, compaction_alloc callback
   was handing poisoned pages to the migrate routine.

   All this could happen because isolate_freepages_block and
   fast_isolate_freepages just check for the page to be PageBuddy,
   and since 1) poisoned pages can be part of a higher order page
   and 2) poisoned pages are also Page Buddy, they can sneak in easily.

   I also saw some other problems with sawap pages, but I suspected it
   to be the same sort of problem, so I did not follow that trace.

   The above refers to soft-offline.
   But I also saw problems with hard-offline, specially hugetlb corruption,
   and some other weird stuff. (I could paste the logs)

   The full explanation refering to the soft-offline case can be found at [2].

 - Approach:

   The taken approach is to contain those pages and never let them hit 
   neither pcplists nor buddy freelists.
   Only when they are completely out of reach, we flag them as poisoned.

   A full explanation of this can be found in patch#11 and patch#12

 - Outcome:

   With this patchset, I no longer see the issues with soft-offline.

[1] https://lore.kernel.org/linux-mm/1541746035-13408-1-git-send-email-n-horiguchi@ah.jp.nec.com/
[2] https://lore.kernel.org/linux-mm/20190826104144.GA7849@linux/T/#u

Naoya Horiguchi (6):
  mm,hwpoison: cleanup unused PageHuge() check
  mm, hwpoison: remove recalculating hpage
  mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED
  mm,hwpoison-inject: don't pin for hwpoison_filter
  mm,hwpoison: remove MF_COUNT_INCREASED
  mm,hwpoison: remove flag argument from soft offline functions

Oscar Salvador (9):
  mm,madvise: Refactor madvise_inject_error
  mm,hwpoison: Un-export get_hwpoison_page and make it static
  mm,hwpoison: Kill put_hwpoison_page
  mm,hwpoison: Unify THP handling for hard and soft offline
  mm,hwpoison: Rework soft offline for free pages
  mm,hwpoison: Rework soft offline for in-use pages
  mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page
  mm,hwpoison: Return 0 if the page is already poisoned in soft-offline
  mm,hwpoison: introduce MF_MSG_UNSPLIT_THP

 drivers/base/memory.c      |   2 +-
 include/linux/mm.h         |  12 +-
 include/linux/page-flags.h |   6 +-
 include/ras/ras_event.h    |   3 +
 mm/hugetlb.c               |  60 +++++++-
 mm/hwpoison-inject.c       |  18 +--
 mm/madvise.c               |  37 ++---
 mm/memory-failure.c        | 307 +++++++++++++++----------------------
 mm/migrate.c               |  11 +-
 mm/page_alloc.c            |  70 +++++++--
 10 files changed, 270 insertions(+), 256 deletions(-)

Comments

Qian Cai July 17, 2020, 2:49 p.m. UTC | #1
On Thu, Jul 16, 2020 at 02:37:54PM +0200, Oscar Salvador wrote:
> Hi all,
> 
> this is a follow-up version on [1].
> That version had some flaws wrt. handling hugetlb pages, so this version
> fixes it.
> I checked that the case reported by Qian seems to work fine now.

I am still getting EIO from madvise on some x86 NUMA systems with next-20200717
which includes this patchset.

# git clone https://gitlab.com/cailca/linux-mm
# cd linux-mm; make

# ./random 1
- start: migrate_huge_offline
- use NUMA nodes 0,3.
- mmap and free 8388608 bytes hugepages on node 0
- mmap and free 8388608 bytes hugepages on node 3
madvise: Input/output error

== serial console output ==
[  100.149531][ T1644] Soft offlining pfn 0x3a5000 at process virtual address 0x7f1bf7e00000
[  100.193804][ T1644] Soft offlining pfn 0x3a5200 at process virtual address 0x7f1bf8000000
[  100.263446][ T1644] Soft offlining pfn 0x1fa3e00 at process virtual address 0x7f1bf7e00000
[  100.302745][ T1644] __get_any_page: 0x1fa3e00 free huge page
[  100.330226][ T1644] Soft offlining pfn 0x3bd600 at process virtual address 0x7f1bf8000000
[  100.373717][ T1644] Soft offlining pfn 0x202dc00 at process virtual address 0x7f1bf7e00000
[  100.414605][ T1644] Soft offlining pfn 0x1fa3c00 at process virtual address 0x7f1bf8000000
[  100.457675][ T1644] Soft offlining pfn 0x1fd3a00 at process virtual address 0x7f1bf7e00000
[  100.498519][ T1644] Soft offlining pfn 0x1fd3800 at process virtual address 0x7f1bf8000000
[  100.541750][ T1644] Soft offlining pfn 0x1fa3800 at process virtual address 0x7f1bf7e00000
[  100.582207][ T1644] Soft offlining pfn 0x1ffde00 at process virtual address 0x7f1bf8000000
[  100.625221][ T1644] Soft offlining pfn 0x1f7fe00 at process virtual address 0x7f1bf7e00000
[  100.665768][ T1644] Soft offlining pfn 0x1f7fc00 at process virtual address 0x7f1bf8000000
[  100.712181][ T1644] Soft offlining pfn 0x202d800 at process virtual address 0x7f1bf7e00000
[  100.753815][ T1644] Soft offlining pfn 0x205da00 at process virtual address 0x7f1bf8000000
[  100.796807][ T1644] Soft offlining pfn 0x1f7fa00 at process virtual address 0x7f1bf7e00000
[  100.837403][ T1644] Soft offlining pfn 0x1f7f800 at process virtual address 0x7f1bf8000000
[  100.880442][ T1644] Soft offlining pfn 0x1ffd800 at process virtual address 0x7f1bf7e00000
[  100.921584][ T1644] Soft offlining pfn 0x1fd3600 at process virtual address 0x7f1bf8000000
[  100.964444][ T1644] Soft offlining pfn 0x1fa3600 at process virtual address 0x7f1bf7e00000
[  101.005009][ T1644] Soft offlining pfn 0x1fa3400 at process virtual address 0x7f1bf8000000
[  101.047984][ T1644] Soft offlining pfn 0x1f7f400 at process virtual address 0x7f1bf7e00000
[  101.088665][ T1644] Soft offlining pfn 0x205d600 at process virtual address 0x7f1bf8000000
[  101.131368][ T1644] Soft offlining pfn 0x202d600 at process virtual address 0x7f1bf7e00000
[  101.171717][ T1644] Soft offlining pfn 0x202d400 at process virtual address 0x7f1bf8000000
[  101.216780][ T1644] Soft offlining pfn 0x1fa3000 at process virtual address 0x7f1bf7e00000
[  101.258755][ T1644] Soft offlining pfn 0x1fd3200 at process virtual address 0x7f1bf8000000
[  101.302585][ T1644] Soft offlining pfn 0x1ffd600 at process virtual address 0x7f1bf7e00000
[  101.344729][ T1644] Soft offlining pfn 0x1ffd400 at process virtual address 0x7f1bf8000000
[  101.388958][ T1644] Soft offlining pfn 0x205d000 at process virtual address 0x7f1bf7e00000
[  101.430995][ T1644] Soft offlining pfn 0x1f7f200 at process virtual address 0x7f1bf8000000
[  101.474513][ T1644] Soft offlining pfn 0x1fd2e00 at process virtual address 0x7f1bf7e00000
[  101.515333][ T1644] Soft offlining pfn 0x1fd2c00 at process virtual address 0x7f1bf8000000
[  101.558119][ T1644] Soft offlining pfn 0x1fa2c00 at process virtual address 0x7f1bf7e00000
[  101.600051][ T1644] Soft offlining pfn 0x202d200 at process virtual address 0x7f1bf8000000
[  101.643046][ T1644] Soft offlining pfn 0x1ffd200 at process virtual address 0x7f1bf7e00000
[  101.683842][ T1644] Soft offlining pfn 0x1ffd000 at process virtual address 0x7f1bf8000000
[  101.730551][ T1644] Soft offlining pfn 0x205cc00 at process virtual address 0x7f1bf7e00000
[  101.772575][ T1644] Soft offlining pfn 0x1f7ee00 at process virtual address 0x7f1bf8000000
[  101.818438][ T1644] Soft offlining pfn 0x1fd2a00 at process virtual address 0x7f1bf7e00000
[  101.861488][ T1644] Soft offlining pfn 0x1fd2800 at process virtual address 0x7f1bf8000000
[  101.904410][ T1644] Soft offlining pfn 0x1fa2800 at process virtual address 0x7f1bf7e00000
[  101.946639][ T1644] Soft offlining pfn 0x202ce00 at process virtual address 0x7f1bf8000000
[  101.989523][ T1644] Soft offlining pfn 0x1ffce00 at process virtual address 0x7f1bf7e00000
[  102.030092][ T1644] Soft offlining pfn 0x1ffcc00 at process virtual address 0x7f1bf8000000
[  102.076592][ T1644] Soft offlining pfn 0x437600 at process virtual address 0x7f1bf7e00000
[  102.116941][ T1644] Soft offlining pfn 0x433800 at process virtual address 0x7f1bf8000000
[  102.161314][ T1644] Soft offlining pfn 0x1f7e800 at process virtual address 0x7f1bf7e00000
[  102.200495][ T1644] Soft offlining pfn 0x1fa2a00 at process virtual address 0x7f1bf8000000
[  102.247260][ T1644] Soft offlining pfn 0x1fd2600 at process virtual address 0x7f1bf7e00000
[  102.290189][ T1644] Soft offlining pfn 0x1fd2400 at process virtual address 0x7f1bf8000000
[  102.328558][ T1644] __get_any_page: 0x1fd2400: unknown zero refcount page type 3bfffc000000000

# numactl -H
available: 4 nodes (0-3)
node 0 cpus: 0 1 2 3 4 5 24 25 26 27 28 29
node 0 size: 15646 MB
node 0 free: 14779 MB
node 1 cpus: 6 7 8 9 10 11 30 31 32 33 34 35
node 1 size: 31966 MB
node 1 free: 29825 MB
node 2 cpus: 12 13 14 15 16 17 36 37 38 39 40 41
node 2 size: 32253 MB
node 2 free: 31029 MB
node 3 cpus: 18 19 20 21 22 23 42 43 44 45 46 47
node 3 size: 32252 MB
node 3 free: 31360 MB
node distances:
node   0   1   2   3 
  0:  10  21  21  21 
  1:  21  10  21  21 
  2:  21  21  10  21 
  3:  21  21  21  10

# cat /proc/meminfo 
MemTotal:       114809324 kB
MemFree:        109554164 kB
MemAvailable:   109256800 kB
Buffers:            5376 kB
Cached:           166932 kB
SwapCached:            0 kB
Active:           119804 kB
Inactive:         107788 kB
Active(anon):      56356 kB
Inactive(anon):     9308 kB
Active(file):      63448 kB
Inactive(file):    98480 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       4194300 kB
SwapFree:        4194300 kB
Dirty:               108 kB
Writeback:             0 kB
AnonPages:         55296 kB
Mapped:            82252 kB
Shmem:             10380 kB
KReclaimable:     114784 kB
Slab:            4401424 kB
SReclaimable:     114784 kB
SUnreclaim:      4286640 kB
KernelStack:       18560 kB
PageTables:         5648 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    61547760 kB
Committed_AS:     286384 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      168220 kB
VmallocChunk:          0 kB
Percpu:            39424 kB
HardwareCorrupted:   196 kB
AnonHugePages:     10240 kB
ShmemHugePages:        0 kB
ShmemPmdMapped:        0 kB
FileHugePages:         0 kB
FilePmdMapped:         0 kB
HugePages_Total:      50
HugePages_Free:        2
HugePages_Rsvd:        0
HugePages_Surp:       25
Hugepagesize:       2048 kB
Hugetlb:          102400 kB
DirectMap4k:      578044 kB
DirectMap2M:    22358016 kB
DirectMap1G:    113246208 kB

> 
> Cover letter:
> 
> This patchset was initially based on Naoya's hwpoison rework [1], so
> thanks to him for the initial work.
> I would also like to think Naoya for testing the patchset off-line,
> and report any issues he found, that was quite helpful.
> 
> This patchset aims to fix some issues laying in soft-offline handling,
> but it also takes the chance and takes some further steps to perform 
> cleanups and some refactoring as well.
> 
> 
>  - Motivation:
> 
>    A customer and I were facing an issue were processes were killed
>    after having soft-offlined some of their pages.
>    This should not happen when soft-offlining, as it is meant to be non-disruptive.
>    I was able to reproduce the issue when I stressed the memory +
>    soft offlining pages in the meantime.
> 
>    After debugging the issue, I saw that the problem was that pages were returned
>    back to user-space after having offlined them properly.
>    So, when those pages were faulted in, the fault handler returned VM_FAULT_POISON
>    all the way down to the arch handler, and it simply killed the process.
> 
>    After a further anaylsis, it became clear that the problem was that when
>    kcompactd kicked in to migrate pages over, compaction_alloc callback
>    was handing poisoned pages to the migrate routine.
> 
>    All this could happen because isolate_freepages_block and
>    fast_isolate_freepages just check for the page to be PageBuddy,
>    and since 1) poisoned pages can be part of a higher order page
>    and 2) poisoned pages are also Page Buddy, they can sneak in easily.
> 
>    I also saw some other problems with sawap pages, but I suspected it
>    to be the same sort of problem, so I did not follow that trace.
> 
>    The above refers to soft-offline.
>    But I also saw problems with hard-offline, specially hugetlb corruption,
>    and some other weird stuff. (I could paste the logs)
> 
>    The full explanation refering to the soft-offline case can be found at [2].
> 
>  - Approach:
> 
>    The taken approach is to contain those pages and never let them hit 
>    neither pcplists nor buddy freelists.
>    Only when they are completely out of reach, we flag them as poisoned.
> 
>    A full explanation of this can be found in patch#11 and patch#12
> 
>  - Outcome:
> 
>    With this patchset, I no longer see the issues with soft-offline.
> 
> [1] https://lore.kernel.org/linux-mm/1541746035-13408-1-git-send-email-n-horiguchi@ah.jp.nec.com/
> [2] https://lore.kernel.org/linux-mm/20190826104144.GA7849@linux/T/#u
> 
> Naoya Horiguchi (6):
>   mm,hwpoison: cleanup unused PageHuge() check
>   mm, hwpoison: remove recalculating hpage
>   mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED
>   mm,hwpoison-inject: don't pin for hwpoison_filter
>   mm,hwpoison: remove MF_COUNT_INCREASED
>   mm,hwpoison: remove flag argument from soft offline functions
> 
> Oscar Salvador (9):
>   mm,madvise: Refactor madvise_inject_error
>   mm,hwpoison: Un-export get_hwpoison_page and make it static
>   mm,hwpoison: Kill put_hwpoison_page
>   mm,hwpoison: Unify THP handling for hard and soft offline
>   mm,hwpoison: Rework soft offline for free pages
>   mm,hwpoison: Rework soft offline for in-use pages
>   mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page
>   mm,hwpoison: Return 0 if the page is already poisoned in soft-offline
>   mm,hwpoison: introduce MF_MSG_UNSPLIT_THP
> 
>  drivers/base/memory.c      |   2 +-
>  include/linux/mm.h         |  12 +-
>  include/linux/page-flags.h |   6 +-
>  include/ras/ras_event.h    |   3 +
>  mm/hugetlb.c               |  60 +++++++-
>  mm/hwpoison-inject.c       |  18 +--
>  mm/madvise.c               |  37 ++---
>  mm/memory-failure.c        | 307 +++++++++++++++----------------------
>  mm/migrate.c               |  11 +-
>  mm/page_alloc.c            |  70 +++++++--
>  10 files changed, 270 insertions(+), 256 deletions(-)
> 
> -- 
> 2.26.2
> 
>