The patch titled
Subject: mm: fix mapcount mismatch in hugepage migration
has been added to the -mm tree. Its filename is
rmap-add-argument-to-charge-compound-page-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/rmap-add-argument-to-charge-compound-page-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/rmap-add-argument-to-charge-compound-page-fix.patch
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------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: mm: fix mapcount mismatch in hugepage migration
try_to_unmap_one() should be able to handle hugetlb, but page_remove_rmap()
in that function takes false as a compound flag, which breaks hugepage migration
with the following message.
Soft offlining page 0x1d4a00 at 0x7ff634a00000
soft offline: 0x1d4a00: migration failed 1, type 60000000000401c
BUG: Bad page state in process sysctl pfn:1d4a00
page:ffffea0007528000 count:0 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 10
flags: 0x600000000004008(uptodate|head)
page dumped because: nonzero mapcount
Modules linked in: cfg80211 rfkill crc32c_intel virtio_balloon serio_raw i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi
CPU: 3 PID: 11882 Comm: sysctl Tainted: G W 4.3.0-mmotm-2015-11-10-15-53-151112-1812-00015-53+ #240
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
ffffffff81a1a124 ffff8800da047bd0 ffffffff81340adf ffffea0007528000
ffff8800da047bf8 ffffffff8116e206 0000000000000009 ffffffff81f72538
ffffea0007528000 ffff8800da047c48 ffffffff8116e6d6 0000020000000000
Call Trace:
[<ffffffff81340adf>] dump_stack+0x44/0x55
[<ffffffff8116e206>] bad_page+0xc6/0x110
[<ffffffff8116e6d6>] free_pages_prepare+0x486/0x500
[<ffffffff81170f9a>] __free_pages_ok+0x1a/0xb0
[<ffffffff81171af1>] __free_pages+0x21/0x40
[<ffffffff811b5d79>] update_and_free_page+0xa9/0x230
[<ffffffff811b6641>] free_pool_huge_page+0xc1/0xe0
[<ffffffff811b6d02>] set_max_huge_pages+0x382/0x4d0
[<ffffffff811b7002>] hugetlb_sysctl_handler_common+0xa2/0xd0
[<ffffffff811b823e>] hugetlb_sysctl_handler+0x1e/0x20
[<ffffffff812535fe>] proc_sys_call_handler+0xae/0xc0
[<ffffffff81253624>] proc_sys_write+0x14/0x20
[<ffffffff811e8758>] __vfs_write+0x28/0xe0
[<ffffffff810d1864>] ? percpu_down_read+0x14/0x60
[<ffffffff811e8d29>] vfs_write+0xa9/0x190
[<ffffffff811e9646>] SyS_write+0x46/0xb0
[<ffffffff8163d797>] entry_SYSCALL_64_fastpath+0x12/0x6a
This patch simply fixes this by giving the compound flag via PageHuge.
Fixes: "rmap: add argument to charge compound page".
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/rmap.c~rmap-add-argument-to-charge-compound-page-fix mm/rmap.c
--- a/mm/rmap.c~rmap-add-argument-to-charge-compound-page-fix
+++ a/mm/rmap.c
@@ -1436,7 +1436,7 @@ static int try_to_unmap_one(struct page
} else
dec_mm_counter(mm, MM_FILEPAGES);
- page_remove_rmap(page, false);
+ page_remove_rmap(page, PageHuge(page));
page_cache_release(page);
out_unmap:
_
Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are
tools-vm-page-typesc-support-kpf_idle.patch
rmap-add-argument-to-charge-compound-page-fix.patch
mm-hwpoison-adjust-for-new-thp-refcounting.patch
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