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* hwpoison, memcg: forcibly uncharge LRU pagesMichal Hocko2017-05-121-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Laurent Dufour has noticed that hwpoinsoned pages are kept charged. In his particular case he has hit a bad_page("page still charged to cgroup") when onlining a hwpoison page. While this looks like something that shouldn't happen in the first place because onlining hwpages and returning them to the page allocator makes only little sense it shows a real problem. hwpoison pages do not get freed usually so we do not uncharge them (at least not since commit 0a31bc97c80c ("mm: memcontrol: rewrite uncharge API")). Each charge pins memcg (since e8ea14cc6ead ("mm: memcontrol: take a css reference for each charged page")) as well and so the mem_cgroup and the associated state will never go away. Fix this leak by forcibly uncharging a LRU hwpoisoned page in delete_from_lru_cache(). We also have to tweak uncharge_list because it cannot rely on zero ref count for these pages. [akpm@linux-foundation.org: coding-style fixes] Fixes: 0a31bc97c80c ("mm: memcontrol: rewrite uncharge API") Link: http://lkml.kernel.org/r/20170502185507.GB19165@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Reviewed-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hwpoison: call shake_page() after try_to_unmap() for mlocked pageNaoya Horiguchi2017-05-031-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | Memory error handler calls try_to_unmap() for error pages in various states. If the error page is a mlocked page, error handling could fail with "still referenced by 1 users" message. This is because the page is linked to and stays in lru cache after the following call chain. try_to_unmap_one page_remove_rmap clear_page_mlock putback_lru_page lru_cache_add memory_failure() calls shake_page() to hanlde the similar issue, but current code doesn't cover because shake_page() is called only before try_to_unmap(). So this patches adds shake_page(). Fixes: 23a003bfd23ea9ea0b7756b920e51f64b284b468 ("mm/madvise: pass return code of memory_failure() to userspace") Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop Link: http://lkml.kernel.org/r/1493197841-23986-3-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: kernel test robot <lkp@intel.com> Cc: Xiaolong Ye <xiaolong.ye@intel.com> Cc: Chen Gong <gong.chen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hwpoison: call shake_page() unconditionallyNaoya Horiguchi2017-05-031-16/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | shake_page() is called before going into core error handling code in order to ensure that the error page is flushed from lru_cache lists where pages stay during transferring among LRU lists. But currently it's not fully functional because when the page is linked to lru_cache by calling activate_page(), its PageLRU flag is set and shake_page() is skipped. The result is to fail error handling with "still referenced by 1 users" message. When the page is linked to lru_cache by isolate_lru_page(), its PageLRU is clear, so that's fine. This patch makes shake_page() unconditionally called to avoild the failure. Fixes: 23a003bfd23ea9ea0b7756b920e51f64b284b468 ("mm/madvise: pass return code of memory_failure() to userspace") Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop Link: http://lkml.kernel.org/r/1493197841-23986-2-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: kernel test robot <lkp@intel.com> Cc: Xiaolong Ye <xiaolong.ye@intel.com> Cc: Chen Gong <gong.chen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure.c: add page flag description in error pathsAnshuman Khandual2017-05-031-8/+8
| | | | | | | | | | | | | | | | | | | | | It helps to provide page flag description along with the raw value in error paths during soft offline process. From sample experiments Before the patch: soft offline: 0x6100: migration failed 1, type 3ffff800008018 soft offline: 0x7400: migration failed 1, type 3ffff800008018 After the patch: soft offline: 0x5900: migration failed 1, type 3ffff800008018 (uptodate|dirty|head) soft offline: 0x6c00: migration failed 1, type 3ffff800008018 (uptodate|dirty|head) Link: http://lkml.kernel.org/r/20170409023829.10788-1-khandual@linux.vnet.ibm.com Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: make ttu's return booleanMinchan Kim2017-05-031-14/+12
| | | | | | | | | | | | | | | | | try_to_unmap() returns SWAP_SUCCESS or SWAP_FAIL so it's suitable for boolean return. This patch changes it. Link: http://lkml.kernel.org/r/1489555493-14659-8-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: delete unnecessary TTU_* flagsShaohua Li2017-05-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm: fix some MADV_FREE issues", v5. We are trying to use MADV_FREE in jemalloc. Several issues are found. Without solving the issues, jemalloc can't use the MADV_FREE feature. - Doesn't support system without swap enabled. Because if swap is off, we can't or can't efficiently age anonymous pages. And since MADV_FREE pages are mixed with other anonymous pages, we can't reclaim MADV_FREE pages. In current implementation, MADV_FREE will fallback to MADV_DONTNEED without swap enabled. But in our environment, a lot of machines don't enable swap. This will prevent our setup using MADV_FREE. - Increases memory pressure. page reclaim bias file pages reclaim against anonymous pages. This doesn't make sense for MADV_FREE pages, because those pages could be freed easily and refilled with very slight penality. Even page reclaim doesn't bias file pages, there is still an issue, because MADV_FREE pages and other anonymous pages are mixed together. To reclaim a MADV_FREE page, we probably must scan a lot of other anonymous pages, which is inefficient. In our test, we usually see oom with MADV_FREE enabled and nothing without it. - Accounting. There are two accounting problems. We don't have a global accounting. If the system is abnormal, we don't know if it's a problem from MADV_FREE side. The other problem is RSS accounting. MADV_FREE pages are accounted as normal anon pages and reclaimed lazily, so application's RSS becomes bigger. This confuses our workloads. We have monitoring daemon running and if it finds applications' RSS becomes abnormal, the daemon will kill the applications even kernel can reclaim the memory easily. To address the first the two issues, we can either put MADV_FREE pages into a separate LRU list (Minchan's previous patches and V1 patches), or put them into LRU_INACTIVE_FILE list (suggested by Johannes). The patchset use the second idea. The reason is LRU_INACTIVE_FILE list is tiny nowadays and should be full of used once file pages. So we can still efficiently reclaim MADV_FREE pages there without interference with other anon and active file pages. Putting the pages into inactive file list also has an advantage which allows page reclaim to prioritize MADV_FREE pages and used once file pages. MADV_FREE pages are put into the lru list and clear SwapBacked flag, so PageAnon(page) && !PageSwapBacked(page) will indicate a MADV_FREE pages. These pages will directly freed without pageout if they are clean, otherwise normal swap will reclaim them. For the third issue, the previous post adds global accounting and a separate RSS count for MADV_FREE pages. The problem is we never get accurate accounting for MADV_FREE pages. The pages are mapped to userspace, can be dirtied without notice from kernel side. To get accurate accounting, we could write protect the page, but then there is extra page fault overhead, which people don't want to pay. Jemalloc guys have concerns about the inaccurate accounting, so this post drops the accounting patches temporarily. The info exported to /proc/pid/smaps for MADV_FREE pages are kept, which is the only place we can get accurate accounting right now. This patch (of 6): Johannes pointed out TTU_LZFREE is unnecessary. It's true because we always have the flag set if we want to do an unmap. For cases we don't do an unmap, the TTU_LZFREE part of code should never run. Also the TTU_UNMAP is unnecessary. If no other flags set (for example, TTU_MIGRATION), an unmap is implied. The patch includes Johannes's cleanup and dead TTU_ACTION macro removal code Link: http://lkml.kernel.org/r/4be3ea1bc56b26fd98a54d0a6f70bec63f6d8980.1487965799.git.shli@fb.com Signed-off-by: Shaohua Li <shli@fb.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/task.h> We are going to split <linux/sched/task.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* HWPOISON: soft offlining for non-lru movable pageYisheng Xie2017-02-241-10/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend soft offlining framework to support non-lru page, which already support migration after commit bda807d44454 ("mm: migrate: support non-lru movable page migration") When memory corrected errors occur on a non-lru movable page, we can choose to stop using it by migrating data onto another page and disable the original (maybe half-broken) one. Link: http://lkml.kernel.org/r/1485867981-16037-4-git-send-email-ysxie@foxmail.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Suggested-by: Michal Hocko <mhocko@kernel.org> Suggested-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Taku Izumi <izumi.taku@jp.fujitsu.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Use owner_priv bit for PageSwapCache, valid when PageSwapBackedNicholas Piggin2016-12-251-3/+1
| | | | | | | | | | | | | | | | A page is not added to the swap cache without being swap backed, so PageSwapBacked mappings can use PG_owner_priv_1 for PageSwapCache. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Bob Peterson <rpeterso@redhat.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hwpoison: fix thp split handling in memory_failure()Naoya Horiguchi2016-11-111-7/+5
| | | | | | | | | | | | | | | | | | | | | | When memory_failure() runs on a thp tail page after pmd is split, we trigger the following VM_BUG_ON_PAGE(): page:ffffd7cd819b0040 count:0 mapcount:0 mapping: (null) index:0x1 flags: 0x1fffc000400000(hwpoison) page dumped because: VM_BUG_ON_PAGE(!page_count(p)) ------------[ cut here ]------------ kernel BUG at /src/linux-dev/mm/memory-failure.c:1132! memory_failure() passed refcount and page lock from tail page to head page, which is not needed because we can pass any subpage to split_huge_page(). Fixes: 61f5d698cc97 ("mm: re-enable THP") Link: http://lkml.kernel.org/r/1477961577-7183-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> [4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hwpoison: remove incorrect commentsNaoya Horiguchi2016-07-281-2/+0
| | | | | | | | | | | | | | | | | | dequeue_hwpoisoned_huge_page() can be called without page lock hold, so let's remove incorrect comment. The reason why the page lock is not really needed is that dequeue_hwpoisoned_huge_page() checks page_huge_active() inside hugetlb_lock, which allows us to avoid trying to dequeue a hugepage that are just allocated but not linked to active list yet, even without taking page lock. Link: http://lkml.kernel.org/r/20160720092901.GA15995@www9186uo.sakura.ne.jp Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Zhan Chen <zhanc1@andrew.cmu.edu> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, vmscan: move LRU lists to nodeMel Gorman2016-07-281-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This moves the LRU lists from the zone to the node and related data such as counters, tracing, congestion tracking and writeback tracking. Unfortunately, due to reclaim and compaction retry logic, it is necessary to account for the number of LRU pages on both zone and node logic. Most reclaim logic is based on the node counters but the retry logic uses the zone counters which do not distinguish inactive and active sizes. It would be possible to leave the LRU counters on a per-zone basis but it's a heavier calculation across multiple cache lines that is much more frequent than the retry checks. Other than the LRU counters, this is mostly a mechanical patch but note that it introduces a number of anomalies. For example, the scans are per-zone but using per-node counters. We also mark a node as congested when a zone is congested. This causes weird problems that are fixed later but is easier to review. In the event that there is excessive overhead on 32-bit systems due to the nodes being on LRU then there are two potential solutions 1. Long-term isolation of highmem pages when reclaim is lowmem When pages are skipped, they are immediately added back onto the LRU list. If lowmem reclaim persisted for long periods of time, the same highmem pages get continually scanned. The idea would be that lowmem keeps those pages on a separate list until a reclaim for highmem pages arrives that splices the highmem pages back onto the LRU. It potentially could be implemented similar to the UNEVICTABLE list. That would reduce the skip rate with the potential corner case is that highmem pages have to be scanned and reclaimed to free lowmem slab pages. 2. Linear scan lowmem pages if the initial LRU shrink fails This will break LRU ordering but may be preferable and faster during memory pressure than skipping LRU pages. Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure.c: replace "MCE" with "Memory failure"Chen Yucong2016-05-201-32/+40
| | | | | | | | | | | | | | | | | | | | | | | HWPoison was specific to some particular x86 platforms. And it is often seen as high level machine check handler. And therefore, 'MCE' is used for the format prefix of printk(). However, 'PowerNV' has also used HWPoison for handling memory errors[1], so 'MCE' is no longer suitable to memory_failure.c. Additionally, 'MCE' and 'Memory failure' have different context. The former belongs to exception context and the latter belongs to process context. Furthermore, HWPoison can also be used for off-lining those sub-health pages that do not trigger any machine check exception. This patch aims to replace 'MCE' with a more appropriate prefix. [1] commit 75eb3d9b60c2 ("powerpc/powernv: Get FSP memory errors and plumb into memory poison infrastructure.") Signed-off-by: Chen Yucong <slaoub@gmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure: fix race with compound page split/mergeKonstantin Khlebnikov2016-04-281-1/+9
| | | | | | | | | | | | get_hwpoison_page() must recheck relation between head and tail pages. n-horiguchi said: without this recheck, the race causes kernel to pin an irrelevant page, and finally makes kernel crash for refcount mismatch. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov2016-04-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: convert printk(KERN_<LEVEL> to pr_<level>Joe Perches2016-03-171-31/+21
| | | | | | | | | | | | | | | | Most of the mm subsystem uses pr_<level> so make it consistent. Miscellanea: - Realign arguments - Add missing newline to format - kmemleak-test.c has a "kmemleak: " prefix added to the "Kmemleak testing" logging message via pr_fmt Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Tejun Heo <tj@kernel.org> [percpu] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure.c: remove useless "undef"sWang Xiaoqiang2016-03-151-2/+0
| | | | | | | | | Remove the useless #undef, since the corresponding #define has already been removed. Signed-off-by: Wang Xiaoqiang <wangxq10@lzu.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: soft-offline: exit with failure for non anonymous thpNaoya Horiguchi2016-01-151-8/+8
| | | | | | | | | | | | | | | | | | | | Currently memory_failure() doesn't handle non anonymous thp case, because we can hardly expect the error handling to be successful, and it can just hit some corner case which results in BUG_ON or something severe like that. This is also the case for soft offline code, so let's make it in the same way. Orignal code has a MF_COUNT_INCREASED check before put_hwpoison_page(), but it's unnecessary because get_any_page() is already called when running on this code, which takes a refcount of the target page regardress of the flag. So this patch also removes it. [akpm@linux-foundation.org: fix build] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: soft-offline: clean up soft_offline_page()Naoya Horiguchi2016-01-151-31/+47
| | | | | | | | | | | soft_offline_page() has some deeply indented code, that's the sign of demand for cleanup. So let's do this. No functionality change. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hwpoison: adjust for new thp refcountingNaoya Horiguchi2016-01-151-52/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | Some mm-related BUG_ON()s could trigger from hwpoison code due to recent changes in thp refcounting rule. This patch fixes them up. In the new refcounting, we no longer use tail->_mapcount to keep tail's refcount, and thereby we can simplify get/put_hwpoison_page(). And another change is that tail's refcount is not transferred to the raw page during thp split (more precisely, in new rule we don't take refcount on tail page any more.) So when we need thp split, we have to transfer the refcount properly to the 4kB soft-offlined page before migration. thp split code goes into core code only when precheck (total_mapcount(head) == page_count(head) - 1) passes to avoid useless split, where we assume that one refcount is held by the caller of thp split and the others are taken via mapping. To meet this assumption, this patch moves thp split part in soft_offline_page() after get_any_page(). [akpm@linux-foundation.org: remove unneeded #define, per Kirill] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: soft-offline: check return value in second __get_any_page() callNaoya Horiguchi2016-01-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I saw the following BUG_ON triggered in a testcase where a process calls madvise(MADV_SOFT_OFFLINE) on thps, along with a background process that calls migratepages command repeatedly (doing ping-pong among different NUMA nodes) for the first process: Soft offlining page 0x60000 at 0x700000600000 __get_any_page: 0x60000 free buddy page page:ffffea0001800000 count:0 mapcount:-127 mapping: (null) index:0x1 flags: 0x1fffc0000000000() page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0) ------------[ cut here ]------------ kernel BUG at /src/linux-dev/include/linux/mm.h:342! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: cfg80211 rfkill crc32c_intel serio_raw virtio_balloon i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi CPU: 3 PID: 3035 Comm: test_alloc_gene Tainted: G O 4.4.0-rc8-v4.4-rc8-160107-1501-00000-rc8+ #74 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff88007c63d5c0 ti: ffff88007c210000 task.ti: ffff88007c210000 RIP: 0010:[<ffffffff8118998c>] [<ffffffff8118998c>] put_page+0x5c/0x60 RSP: 0018:ffff88007c213e00 EFLAGS: 00010246 Call Trace: put_hwpoison_page+0x4e/0x80 soft_offline_page+0x501/0x520 SyS_madvise+0x6bc/0x6f0 entry_SYSCALL_64_fastpath+0x12/0x6a Code: 8b fc ff ff 5b 5d c3 48 89 df e8 b0 fa ff ff 48 89 df 31 f6 e8 c6 7d ff ff 5b 5d c3 48 c7 c6 08 54 a2 81 48 89 df e8 a4 c5 01 00 <0f> 0b 66 90 66 66 66 66 90 55 48 89 e5 41 55 41 54 53 48 8b 47 RIP [<ffffffff8118998c>] put_page+0x5c/0x60 RSP <ffff88007c213e00> The root cause resides in get_any_page() which retries to get a refcount of the page to be soft-offlined. This function calls put_hwpoison_page(), expecting that the target page is putback to LRU list. But it can be also freed to buddy. So the second check need to care about such case. Fixes: af8fae7c0886 ("mm/memory-failure.c: clean up soft_offline_page()") Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* thp, mm: split_huge_page(): caller need to lock pageKirill A. Shutemov2016-01-151-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We're going to use migration entries instead of compound_lock() to stabilize page refcounts. Setup and remove migration entries require page to be locked. Some of split_huge_page() callers already have the page locked. Let's require everybody to lock the page before calling split_huge_page(). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.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>
* page-flags: define PG_locked behavior on compound pagesKirill A. Shutemov2016-01-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lock_page() must operate on the whole compound page. It doesn't make much sense to lock part of compound page. Change code to use head page's PG_locked, if tail page is passed. This patch also gets rid of custom helper functions -- __set_page_locked() and __clear_page_locked(). They are replaced with helpers generated by __SETPAGEFLAG/__CLEARPAGEFLAG. Tail pages to these helper would trigger VM_BUG_ON(). SLUB uses PG_locked as a bit spin locked. IIUC, tail pages should never appear there. VM_BUG_ON() is added to make sure that this assumption is correct. [akpm@linux-foundation.org: fix fs/cifs/file.c] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: make compound_head() robustKirill A. Shutemov2015-11-061-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hugh has pointed that compound_head() call can be unsafe in some context. There's one example: CPU0 CPU1 isolate_migratepages_block() page_count() compound_head() !!PageTail() == true put_page() tail->first_page = NULL head = tail->first_page alloc_pages(__GFP_COMP) prep_compound_page() tail->first_page = head __SetPageTail(p); !!PageTail() == true <head == NULL dereferencing> The race is pure theoretical. I don't it's possible to trigger it in practice. But who knows. We can fix the race by changing how encode PageTail() and compound_head() within struct page to be able to update them in one shot. The patch introduces page->compound_head into third double word block in front of compound_dtor and compound_order. Bit 0 encodes PageTail() and the rest bits are pointer to head page if bit zero is set. The patch moves page->pmd_huge_pte out of word, just in case if an architecture defines pgtable_t into something what can have the bit 0 set. hugetlb_cgroup uses page->lru.next in the second tail page to store pointer struct hugetlb_cgroup. The patch switch it to use page->private in the second tail page instead. The space is free since ->first_page is removed from the union. The patch also opens possibility to remove HUGETLB_CGROUP_MIN_ORDER limitation, since there's now space in first tail page to store struct hugetlb_cgroup pointer. But that's out of scope of the patch. That means page->compound_head shares storage space with: - page->lru.next; - page->next; - page->rcu_head.next; That's too long list to be absolutely sure, but looks like nobody uses bit 0 of the word. page->rcu_head.next guaranteed[1] to have bit 0 clean as long as we use call_rcu(), call_rcu_bh(), call_rcu_sched(), or call_srcu(). But future call_rcu_lazy() is not allowed as it makes use of the bit and we can get false positive PageTail(). [1] http://lkml.kernel.org/g/20150827163634.GD4029@linux.vnet.ibm.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hwpoison: ratelimit messages from unpoison_memory()Naoya Horiguchi2015-11-051-9/+25
| | | | | | | | | | | | | | | | | Currently kernel prints out results of every single unpoison event, which i= s not necessary because unpoison is purely a testing feature and testers can = get little or no information from lots of lines of unpoison log storm. So this patch ratelimits printk in unpoison_memory(). This patch introduces a file local ratelimit_state, which adds 64 bytes to memory-failure.o. If we apply pr_info_ratelimited() for 8 callsite below, 2= 56 bytes is added, so it's a win. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hwpoison: use page_cgroup_ino for filtering by memcgVladimir Davydov2015-09-101-14/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | Hwpoison allows to filter pages by memory cgroup ino. Currently, it calls try_get_mem_cgroup_from_page to obtain the cgroup from a page and then its ino using cgroup_ino, but now we have a helper method for that, page_cgroup_ino, so use it instead. This patch also loosens the hwpoison memcg filter dependency rules - it makes it depend on CONFIG_MEMCG instead of CONFIG_MEMCG_SWAP, because hwpoison memcg filter does not require anything (nor it used to) from CONFIG_MEMCG_SWAP side. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: rename alloc_pages_exact_node() to __alloc_pages_node()Vlastimil Babka2015-09-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | alloc_pages_exact_node() was introduced in commit 6484eb3e2a81 ("page allocator: do not check NUMA node ID when the caller knows the node is valid") as an optimized variant of alloc_pages_node(), that doesn't fallback to current node for nid == NUMA_NO_NODE. Unfortunately the name of the function can easily suggest that the allocation is restricted to the given node and fails otherwise. In truth, the node is only preferred, unless __GFP_THISNODE is passed among the gfp flags. The misleading name has lead to mistakes in the past, see for example commits 5265047ac301 ("mm, thp: really limit transparent hugepage allocation to local node") and b360edb43f8e ("mm, mempolicy: migrate_to_node should only migrate to node"). Another issue with the name is that there's a family of alloc_pages_exact*() functions where 'exact' means exact size (instead of page order), which leads to more confusion. To prevent further mistakes, this patch effectively renames alloc_pages_exact_node() to __alloc_pages_node() to better convey that it's an optimized variant of alloc_pages_node() not intended for general usage. Both functions get described in comments. It has been also considered to really provide a convenience function for allocations restricted to a node, but the major opinion seems to be that __GFP_THISNODE already provides that functionality and we shouldn't duplicate the API needlessly. The number of users would be small anyway. Existing callers of alloc_pages_exact_node() are simply converted to call __alloc_pages_node(), with the exception of sba_alloc_coherent() which open-codes the check for NUMA_NO_NODE, so it is converted to use alloc_pages_node() instead. This means it no longer performs some VM_BUG_ON checks, and since the current check for nid in alloc_pages_node() uses a 'nid < 0' comparison (which includes NUMA_NO_NODE), it may hide wrong values which would be previously exposed. Both differences will be rectified by the next patch. To sum up, this patch makes no functional changes, except temporarily hiding potentially buggy callers. Restricting the checks in alloc_pages_node() is left for the next patch which can in turn expose more existing buggy callers. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Robin Holt <robinmholt@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Cliff Whickman <cpw@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: don't try to unpoison containment-failed pagesNaoya Horiguchi2015-09-081-0/+16
| | | | | | | | | | | | | | | | | | | | | memory_failure() can be called at any page at any time, which means that we can't eliminate the possibility of containment failure. In such case the best option is to leak the page intentionally (and never touch it later.) We have an unpoison function for testing, and it cannot handle such containment-failed pages, which results in kernel panic (visible with various calltraces.) So this patch suggests that we limit the unpoisonable pages to properly contained pages and ignore any other ones. Testers are recommended to keep in mind that there're un-unpoisonable pages when writing test programs. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: fix race between soft_offline_page and unpoison_memoryWanpeng Li2015-09-081-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wanpeng Li reported a race between soft_offline_page() and unpoison_memory(), which causes the following kernel panic: BUG: Bad page state in process bash pfn:97000 page:ffffea00025c0000 count:0 mapcount:1 mapping: (null) index:0x7f4fdbe00 flags: 0x1fffff80080048(uptodate|active|swapbacked) page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set bad because of flags: flags: 0x40(active) Modules linked in: snd_hda_codec_hdmi i915 rpcsec_gss_krb5 nfsv4 dns_resolver bnep rfcomm nfsd bluetooth auth_rpcgss nfs_acl nfs rfkill lockd grace sunrpc i2c_algo_bit drm_kms_helper snd_hda_codec_realtek snd_hda_codec_generic drm snd_hda_intel fscache snd_hda_codec x86_pkg_temp_thermal coretemp kvm_intel snd_hda_core snd_hwdep kvm snd_pcm snd_seq_dummy snd_seq_oss crct10dif_pclmul snd_seq_midi crc32_pclmul snd_seq_midi_event ghash_clmulni_intel snd_rawmidi aesni_intel lrw gf128mul snd_seq glue_helper ablk_helper snd_seq_device cryptd fuse snd_timer dcdbas serio_raw mei_me parport_pc snd mei ppdev i2c_core video lp soundcore parport lpc_ich shpchp mfd_core ext4 mbcache jbd2 sd_mod e1000e ahci ptp libahci crc32c_intel libata pps_core CPU: 3 PID: 2211 Comm: bash Not tainted 4.2.0-rc5-mm1+ #45 Hardware name: Dell Inc. OptiPlex 7020/0F5C5X, BIOS A03 01/08/2015 Call Trace: dump_stack+0x48/0x5c bad_page+0xe6/0x140 free_pages_prepare+0x2f9/0x320 ? uncharge_list+0xdd/0x100 free_hot_cold_page+0x40/0x170 __put_single_page+0x20/0x30 put_page+0x25/0x40 unmap_and_move+0x1a6/0x1f0 migrate_pages+0x100/0x1d0 ? kill_procs+0x100/0x100 ? unlock_page+0x6f/0x90 __soft_offline_page+0x127/0x2a0 soft_offline_page+0xa6/0x200 This race is explained like below: CPU0 CPU1 soft_offline_page __soft_offline_page TestSetPageHWPoison unpoison_memory PageHWPoison check (true) TestClearPageHWPoison put_page -> release refcount held by get_hwpoison_page in unpoison_memory put_page -> release refcount held by isolate_lru_page in __soft_offline_page migrate_pages The second put_page() releases refcount held by isolate_lru_page() which will lead to unmap_and_move() releases the last refcount of page and w/ mapcount still 1 since try_to_unmap() is not called if there is only one user map the page. Anyway, the page refcount and mapcount will still mess if the page is mapped by multiple users. This race was introduced by commit 4491f71260 ("mm/memory-failure: set PageHWPoison before migrate_pages()"), which focuses on preventing the reuse of successfully migrated page. Before this commit we prevent the reuse by changing the migratetype to MIGRATE_ISOLATE during soft offlining, which has the following problems, so simply reverting the commit is not a best option: 1) it doesn't eliminate the reuse completely, because set_migratetype_isolate() can fail to set MIGRATE_ISOLATE to the target page if the pageblock of the page contains one or more unmovable pages (i.e. has_unmovable_pages() returns true). 2) the original code changes migratetype to MIGRATE_ISOLATE forcibly, and sets it to MIGRATE_MOVABLE forcibly after soft offline, regardless of the original migratetype state, which could impact other subsystems like memory hotplug or compaction. This patch moves PageSetHWPoison just after put_page() in unmap_and_move(), which closes up the reported race window and minimizes another race window b/w SetPageHWPoison and reallocation (which causes the reuse of soft-offlined page.) The latter race window still exists but it's acceptable, because it's rare and effectively the same as ordinary "containment failure" case even if it happens, so keep the window open is acceptable. Fixes: 4491f71260 ("mm/memory-failure: set PageHWPoison before migrate_pages()") Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Wanpeng Li <wanpeng.li@hotmail.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: introduce num_poisoned_pages wrappersNaoya Horiguchi2015-09-081-16/+14
| | | | | | | | | | num_poisoned_pages counter will be changed outside mm/memory-failure.c by a subsequent patch, so this patch prepares wrappers to manipulate it. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: replace most of put_page in memory error handling by ↵Wanpeng Li2015-09-081-17/+15
| | | | | | | | | | | | put_hwpoison_page Replace most instances of put_page() in memory error handling with put_hwpoison_page(). Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: introduce put_hwpoison_page to put refcount for memory error ↵Wanpeng Li2015-09-081-0/+21
| | | | | | | | | | | | handling Introduce put_hwpoison_page to put refcount for memory error handling. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: fix PageHWPoison test/set raceWanpeng Li2015-09-081-0/+2
| | | | | | | | | | | | | | | | | | | | There is a race between madvise_hwpoison path and memory_failure: CPU0 CPU1 madvise_hwpoison get_user_pages_fast PageHWPoison check (false) memory_failure TestSetPageHWPoison soft_offline_page PageHWPoison check (true) return -EBUSY (without put_page) Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: fix failure to split thp w/ refcount heldWanpeng Li2015-09-081-0/+2
| | | | | | | | | | | | | THP pages will get a refcount in madvise_hwpoison() w/ MF_COUNT_INCREASED flag, however, the refcount is still held when fail to split THP pages. Fix it by reducing the refcount of THP pages when fail to split THP. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: export struct mem_cgroupMichal Hocko2015-09-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mem_cgroup structure is defined in mm/memcontrol.c currently which means that the code outside of this file has to use external API even for trivial access stuff. This patch exports mm_struct with its dependencies and makes some of the exported functions inlines. This even helps to reduce the code size a bit (make defconfig + CONFIG_MEMCG=y) text data bss dec hex filename 12355346 1823792 1089536 15268674 e8fb42 vmlinux.before 12354970 1823792 1089536 15268298 e8f9ca vmlinux.after This is not much (370B) but better than nothing. We also save a function call in some hot paths like callers of mem_cgroup_count_vm_event which is used for accounting. The patch doesn't introduce any functional changes. [vdavykov@parallels.com: inline memcg_kmem_is_active] [vdavykov@parallels.com: do not expose type outside of CONFIG_MEMCG] [akpm@linux-foundation.org: memcontrol.h needs eventfd.h for eventfd_ctx] [akpm@linux-foundation.org: export mem_cgroup_from_task() to modules] Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Vladimir Davydov <vdavydov@parallels.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: fix panic due to split huge zero pageWanpeng Li2015-08-141-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Bug: ------------[ cut here ]------------ kernel BUG at mm/huge_memory.c:1957! invalid opcode: 0000 [#1] SMP Modules linked in: snd_hda_codec_hdmi i915 rpcsec_gss_krb5 snd_hda_codec_realtek snd_hda_codec_generic nfsv4 dns_re CPU: 2 PID: 2576 Comm: test_huge Not tainted 4.2.0-rc5-mm1+ #27 Hardware name: Dell Inc. OptiPlex 7020/0F5C5X, BIOS A03 01/08/2015 task: ffff880204e3d600 ti: ffff8800db16c000 task.ti: ffff8800db16c000 RIP: split_huge_page_to_list+0xdb/0x120 Call Trace: memory_failure+0x32e/0x7c0 madvise_hwpoison+0x8b/0x160 SyS_madvise+0x40/0x240 ? do_page_fault+0x37/0x90 entry_SYSCALL_64_fastpath+0x12/0x71 Code: ff f0 41 ff 4c 24 30 74 0d 31 c0 48 83 c4 08 5b 41 5c 41 5d c9 c3 4c 89 e7 e8 e2 58 fd ff 48 83 c4 08 31 c0 RIP split_huge_page_to_list+0xdb/0x120 RSP <ffff8800db16fde8> ---[ end trace aee7ce0df8e44076 ]--- Testcase: #define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <errno.h> #include <string.h> #define MB 1024*1024 int main(void) { char *mem; posix_memalign((void **)&mem, 2 * MB, 200 * MB); madvise(mem, 200 * MB, MADV_HWPOISON); free(mem); return 0; } Huge zero page is allocated if page fault w/o FAULT_FLAG_WRITE flag. The get_user_pages_fast() which called in madvise_hwpoison() will get huge zero page if the page is not allocated before. Huge zero page is a tranparent huge page, however, it is not an anonymous page. memory_failure will split the huge zero page and trigger BUG_ON(is_huge_zero_page(page)); After commit 98ed2b0052e6 ("mm/memory-failure: give up error handling for non-tail-refcounted thp"), memory_failure will not catch non anon thp from madvise_hwpoison path and this bug occur. Fix it by catching non anon thp in memory_failure in order to not split huge zero page in madvise_hwpoison path. After this patch: Injecting memory failure for page 0x202800 at 0x7fd8ae800000 MCE: 0x202800: non anonymous thp [...] [akpm@linux-foundation.org: remove second split, per Wanpeng] Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount heldWanpeng Li2015-08-141-7/+6
| | | | | | | | | | | | | | | Hugetlbfs pages will get a refcount in get_any_page() or madvise_hwpoison() if soft offlining through madvise. The refcount which is held by the soft offline path should be released if we fail to isolate hugetlbfs pages. Fix it by reducing the refcount for both isolation success and failure. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hwpoison: fix page refcount of unknown non LRU pageWanpeng Li2015-08-141-0/+2
| | | | | | | | | | | | | | | After trying to drain pages from pagevec/pageset, we try to get reference count of the page again, however, the reference count of the page is not reduced if the page is still not on LRU list. Fix it by adding the put_page() to drop the page reference which is from __get_any_page(). Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> [3.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure: set PageHWPoison before migrate_pages()Naoya Horiguchi2015-08-071-3/+4
| | | | | | | | | | | | | | | | | | | | Now page freeing code doesn't consider PageHWPoison as a bad page, so by setting it before completing the page containment, we can prevent the error page from being reused just after successful page migration. I added TTU_IGNORE_HWPOISON for try_to_unmap() to make sure that the page table entry is transformed into migration entry, not to hwpoison entry. 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>
* mm/memory-failure: give up error handling for non-tail-refcounted thpNaoya Horiguchi2015-08-071-9/+12
| | | | | | | | | | | | | | | | | "non anonymous thp" case is still racy with freeing thp, which causes panic due to put_page() for refcount-0 page. It seems that closing up this race might be hard (and/or not worth doing,) so let's give up the error handling for this case. 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>
* mm/memory-failure: fix race in counting num_poisoned_pagesNaoya Horiguchi2015-08-071-2/+2
| | | | | | | | | | | | | | | | When memory_failure() is called on a page which are just freed after page migration from soft offlining, the counter num_poisoned_pages is raised twi= ce. So let's fix it with using TestSetPageHWPoison. 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>
* mm/memory-failure: unlock_page before put_pageNaoya Horiguchi2015-08-071-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently I addressed a few of hwpoison race problems and the patches are merged on v4.2-rc1. It made progress, but unfortunately some problems still remain due to less coverage of my testing. So I'm trying to fix or avoid them in this series. One point I'm expecting to discuss is that patch 4/5 changes the page flag set to be checked on free time. In current behavior, __PG_HWPOISON is not supposed to be set when the page is freed. I think that there is no strong reason for this behavior, and it causes a problem hard to fix only in error handler side (because __PG_HWPOISON could be set at arbitrary timing.) So I suggest to change it. With this patchset, hwpoison stress testing in official mce-test testsuite (which previously failed) passes. This patch (of 5): In "just unpoisoned" path, we do put_page and then unlock_page, which is a wrong order and causes "freeing locked page" bug. So let's fix it. 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> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tracing: add trace event for memory-failureXie XiuQi2015-06-241-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RAS user space tools like rasdaemon which base on trace event, could receive mce error event, but no memory recovery result event. So, I want to add this event to make this scenario complete. This patch add a event at ras group for memory-failure. The output like below: # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:24 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | mce-inject-13150 [001] .... 277.019359: memory_failure_event: pfn 0x19869: recovery action for free buddy page: Delayed [xiexiuqi@huawei.com: fix build error] Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: Jim Davis <jim.epost@gmail.com> Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory-failure: change type of action_result's param 3 to enumXie XiuQi2015-06-241-1/+2
| | | | | | | | | | | | | | Change type of action_result's param 3 to enum for type consistency, and rename mf_outcome to mf_result for clearly. Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: Jim Davis <jim.epost@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory-failure: export page_type and action resultXie XiuQi2015-06-241-101/+67
| | | | | | | | | | | | | | | | | Export 'outcome' and 'action_page_type' to mm.h, so we could use this emnus outside. This patch is preparation for adding trace events for memory-failure recovery action. Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Chen Gong <gong.chen@linux.intel.com> Cc: Jim Davis <jim.epost@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure: me_huge_page() does nothing for thpNaoya Horiguchi2015-06-241-0/+4
| | | | | | | | | | | | | | | | | | | memory_failure() is supposed not to handle thp itself, but to split it. But if something were wrong and page_action() were called on thp, me_huge_page() (action routine for hugepages) should be better to take no action, rather than to take wrong action prepared for hugetlb (which triggers BUG_ON().) This change is for potential problems, but makes sense to me because thp is an actively developing feature and this code path can be open in the future. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: soft-offline: don't free target page in successful page migrationNaoya Horiguchi2015-06-241-22/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stress testing showed that soft offline events for a process iterating "mmap-pagefault-munmap" loop can trigger VM_BUG_ON(PAGE_FLAGS_CHECK_AT_PREP) in __free_one_page(): Soft offlining page 0x70fe1 at 0x70100008d000 Soft offlining page 0x705fb at 0x70300008d000 page:ffffea0001c3f840 count:0 mapcount:0 mapping: (null) index:0x2 flags: 0x1fffff80800000(hwpoison) page dumped because: VM_BUG_ON_PAGE(page->flags & ((1 << 25) - 1)) ------------[ cut here ]------------ kernel BUG at /src/linux-dev/mm/page_alloc.c:585! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: cfg80211 rfkill crc32c_intel microcode ppdev parport_pc pcspkr serio_raw virtio_balloon parport i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi floppy CPU: 3 PID: 1779 Comm: test_base_madv_ Not tainted 4.0.0-v4.0-150511-1451-00009-g82360a3730e6 #139 RIP: free_pcppages_bulk+0x52a/0x6f0 Call Trace: drain_pages_zone+0x3d/0x50 drain_local_pages+0x1d/0x30 on_each_cpu_mask+0x46/0x80 drain_all_pages+0x14b/0x1e0 soft_offline_page+0x432/0x6e0 SyS_madvise+0x73c/0x780 system_call_fastpath+0x12/0x17 Code: ff 89 45 b4 48 8b 45 c0 48 83 b8 a8 00 00 00 00 0f 85 e3 fb ff ff 0f 1f 00 0f 0b 48 8b 7d 90 48 c7 c6 e8 95 a6 81 e8 e6 32 02 00 <0f> 0b 8b 45 cc 49 89 47 30 41 8b 47 18 83 f8 ff 0f 85 10 ff ff RIP [<ffffffff811a806a>] free_pcppages_bulk+0x52a/0x6f0 RSP <ffff88007a117d28> ---[ end trace 53926436e76d1f35 ]--- When soft offline successfully migrates page, the source page is supposed to be freed. But there is a race condition where a source page looks isolated (i.e. the refcount is 0 and the PageHWPoison is set) but somewhat linked to pcplist. Then another soft offline event calls drain_all_pages() and tries to free such hwpoisoned page, which is forbidden. This odd page state seems to happen due to the race between put_page() in putback_lru_page() and __pagevec_lru_add_fn(). But I don't want to play with tweaking drain code as done in commit 9ab3b598d2df "mm: hwpoison: drop lru_add_drain_all() in __soft_offline_page()", or to change page freeing code for this soft offline's purpose. Instead, let's think about the difference between hard offline and soft offline. There is an interesting difference in how to isolate the in-use page between these, that is, hard offline marks PageHWPoison of the target page at first, and doesn't free it by keeping its refcount 1. OTOH, soft offline tries to free the target page then marks PageHWPoison. This difference might be the source of complexity and result in bugs like the above. So making soft offline isolate with keeping refcount can be a solution for this problem. We can pass to page migration code the "reason" which shows the caller, so let's use this more to avoid calling putback_lru_page() when called from soft offline, which effectively does the isolation for soft offline. With this change, target pages of soft offline never be reused without changing migratetype, so this patch also removes the related code. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure: introduce get_hwpoison_page() for consistent refcount ↵Naoya Horiguchi2015-06-241-5/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | handling memory_failure() can run in 2 different mode (specified by MF_COUNT_INCREASED) in page refcount perspective. When MF_COUNT_INCREASED is set, memory_failure() assumes that the caller takes a refcount of the target page. And if cleared, memory_failure() takes it in it's own. In current code, however, refcounting is done differently in each caller. For example, madvise_hwpoison() uses get_user_pages_fast() and hwpoison_inject() uses get_page_unless_zero(). So this inconsistent refcounting causes refcount failure especially for thp tail pages. Typical user visible effects are like memory leak or VM_BUG_ON_PAGE(!page_count(page)) in isolate_lru_page(). To fix this refcounting issue, this patch introduces get_hwpoison_page() to handle thp tail pages in the same manner for each caller of hwpoison code. memory_failure() might fail to split thp and in such case it returns without completing page isolation. This is not good because PageHWPoison on the thp is still set and there's no easy way to unpoison such thps. So this patch try to roll back any action to the thp in "non anonymous thp" case and "thp split failed" case, expecting an MCE(SRAR) generated by later access afterward will properly free such thps. [akpm@linux-foundation.org: fix CONFIG_HWPOISON_INJECT=m] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory-failure: split thp earlier in memory error handlingNaoya Horiguchi2015-06-241-63/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | memory_failure() doesn't handle thp itself at this time and need to split it before doing isolation. Currently thp is split in the middle of hwpoison_user_mappings(), but there're corner cases where memory_failure() wrongly tries to handle thp without splitting. 1) "non anonymous" thp, which is not a normal operating mode of thp, but a memory error could hit a thp before anon_vma is initialized. In such case, split_huge_page() fails and me_huge_page() (intended for hugetlb) is called for thp, which triggers BUG_ON in page_hstate(). 2) !PageLRU case, where hwpoison_user_mappings() returns with SWAP_SUCCESS and the result is the same as case 1. memory_failure() can't avoid splitting, so let's split it more earlier, which also reduces code which are prepared for both of normal page and thp. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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