Naoya Horiguchi f4c18e6f7b mm: check __PG_HWPOISON separately from PAGE_FLAGS_CHECK_AT_* ... The race condition addressed in commit add05cecef ("mm: soft-offline: don't free target page in successful page migration") was not closed completely, because that can happen not only for soft-offline, but also for hard-offline. Consider that a slab page is about to be freed into buddy pool, and then an uncorrected memory error hits the page just after entering __free_one_page(), then VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP) is triggered, despite the fact that it's not necessary because the data on the affected page is not consumed. To solve it, this patch drops __PG_HWPOISON from page flag checks at allocation/free time. I think it's justified because __PG_HWPOISON flags is defined to prevent the page from being reused, and setting it outside the page's alloc-free cycle is a designed behavior (not a bug.) For recent months, I was annoyed about BUG_ON when soft-offlined page remains on lru cache list for a while, which is avoided by calling put_page() instead of putback_lru_page() in page migration's success path. This means that this patch reverts a major change from commit add05cecef about the new refcounting rule of soft-offlined pages, so "reuse window" revives. This will be closed by a subsequent patch. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Dean Nelson <dnelson@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2015-08-07 04:39:42 +03:00
..
acpi	Additional ACPICA material for v4.2-rc1	2015-07-02 17:11:28 -07:00
asm-generic	mm: clean up per architecture MM hook header files	2015-07-17 16:39:53 -07:00
clocksource
crypto
drm	drm/atomic-helper: Add an atomice best_encoder callback	2015-08-04 11:09:25 +02:00
dt-bindings	The changes to the common clock framework for 4.2 are dominated by new	2015-07-01 19:22:00 -07:00
keys
kvm
linux	mm: check __PG_HWPOISON separately from PAGE_FLAGS_CHECK_AT_*	2015-08-07 04:39:42 +03:00
math-emu
media	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds	2015-07-01 19:09:11 -07:00
memory
misc
net	net: sched: fix refcount imbalance in actions	2015-07-30 14:20:39 -07:00
pcmcia
ras
rdma	IB: Add rdma_cap_ib_switch helper and use where appropriate	2015-07-14 13:20:08 -04:00
rxrpc
scsi	IB/srp: Avoid using uninitialized variable	2015-07-14 13:20:09 -04:00
soc	Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm	2015-06-26 12:20:00 -07:00
sound
target	iscsi-target: Fix iscsit_start_kthreads failure OOPs	2015-07-24 14:19:43 -07:00
trace	Merge branch 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2015-06-30 20:07:45 -07:00
uapi	PCI update for v4.2:	2015-08-04 09:27:19 -07:00
video	Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux	2015-06-26 13:18:51 -07:00
xen
Kbuild