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2021-09-03mm: hwpoison: don't drop slab caches for offlining non-LRU pageYang Shi
In the current implementation of soft offline, if non-LRU page is met, all the slab caches will be dropped to free the page then offline. But if the page is not slab page all the effort is wasted in vain. Even though it is a slab page, it is not guaranteed the page could be freed at all. However the side effect and cost is quite high. It does not only drop the slab caches, but also may drop a significant amount of page caches which are associated with inode caches. It could make the most workingset gone in order to just offline a page. And the offline is not guaranteed to succeed at all, actually I really doubt the success rate for real life workload. Furthermore the worse consequence is the system may be locked up and unusable since the page cache release may incur huge amount of works queued for memcg release. Actually we ran into such unpleasant case in our production environment. Firstly, the workqueue of memory_failure_work_func is locked up as below: BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 53s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=14/256 refcnt=15 in-flight: 409271:memory_failure_work_func pending: kfree_rcu_work, kfree_rcu_monitor, kfree_rcu_work, rht_deferred_worker, rht_deferred_worker, rht_deferred_worker, rht_deferred_worker, kfree_rcu_work, kfree_rcu_work, kfree_rcu_work, kfree_rcu_work, drain_local_stock, kfree_rcu_work workqueue mm_percpu_wq: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue cgroup_destroy: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/1 refcnt=12072 pending: css_release_work_fn There were over 12K css_release_work_fn queued, and this caused a few lockups due to the contention of worker pool lock with IRQ disabled, for example: NMI watchdog: Watchdog detected hard LOCKUP on cpu 1 Modules linked in: amd64_edac_mod edac_mce_amd crct10dif_pclmul crc32_pclmul ghash_clmulni_intel xt_DSCP iptable_mangle kvm_amd bpfilter vfat fat acpi_ipmi i2c_piix4 usb_storage ipmi_si k10temp i2c_core ipmi_devintf ipmi_msghandler acpi_cpufreq sch_fq_codel xfs libcrc32c crc32c_intel mlx5_core mlxfw nvme xhci_pci ptp nvme_core pps_core xhci_hcd CPU: 1 PID: 205500 Comm: kworker/1:0 Tainted: G L 5.10.32-t1.el7.twitter.x86_64 #1 Hardware name: TYAN F5AMT /z /S8026GM2NRE-CGN, BIOS V8.030 03/30/2021 Workqueue: events memory_failure_work_func RIP: 0010:queued_spin_lock_slowpath+0x41/0x1a0 Code: 41 f0 0f ba 2f 08 0f 92 c0 0f b6 c0 c1 e0 08 89 c2 8b 07 30 e4 09 d0 a9 00 01 ff ff 75 1b 85 c0 74 0e 8b 07 84 c0 74 08 f3 90 <8b> 07 84 c0 75 f8 b8 01 00 00 00 66 89 07 c3 f6 c4 01 75 04 c6 47 RSP: 0018:ffff9b2ac278f900 EFLAGS: 00000002 RAX: 0000000000480101 RBX: ffff8ce98ce71800 RCX: 0000000000000084 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8ce98ce6a140 RBP: 00000000000284c8 R08: ffffd7248dcb6808 R09: 0000000000000000 R10: 0000000000000003 R11: ffff9b2ac278f9b0 R12: 0000000000000001 R13: ffff8cb44dab9c00 R14: ffffffffbd1ce6a0 R15: ffff8cacaa37f068 FS: 0000000000000000(0000) GS:ffff8ce98ce40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcf6e8cb000 CR3: 0000000a0c60a000 CR4: 0000000000350ee0 Call Trace: __queue_work+0xd6/0x3c0 queue_work_on+0x1c/0x30 uncharge_batch+0x10e/0x110 mem_cgroup_uncharge_list+0x6d/0x80 release_pages+0x37f/0x3f0 __pagevec_release+0x1c/0x50 __invalidate_mapping_pages+0x348/0x380 inode_lru_isolate+0x10a/0x160 __list_lru_walk_one+0x7b/0x170 list_lru_walk_one+0x4a/0x60 prune_icache_sb+0x37/0x50 super_cache_scan+0x123/0x1a0 do_shrink_slab+0x10c/0x2c0 shrink_slab+0x1f1/0x290 drop_slab_node+0x4d/0x70 soft_offline_page+0x1ac/0x5b0 memory_failure_work_func+0x6a/0x90 process_one_work+0x19e/0x340 worker_thread+0x30/0x360 kthread+0x116/0x130 The lockup made the machine is quite unusable. And it also made the most workingset gone, the reclaimabled slab caches were reduced from 12G to 300MB, the page caches were decreased from 17G to 4G. But the most disappointing thing is all the effort doesn't make the page offline, it just returns: soft_offline: 0x1469f2: unknown non LRU page type 5ffff0000000000 () It seems the aggressive behavior for non-LRU page didn't pay back, so it doesn't make too much sense to keep it considering the terrible side effect. Link: https://lkml.kernel.org/r/20210819054116.266126-1-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Reported-by: David Mackey <tdmackey@twitter.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.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>
2020-10-16mm,hwpoison-inject: don't pin for hwpoison_filterNaoya Horiguchi
Another memory error injection interface debugfs:hwpoison/corrupt-pfn also takes bogus refcount for hwpoison_filter(). It's justified because this does a coarse filter, expecting that memory_failure() redoes the check for sure. Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Aristeu Rozanski <aris@ruivo.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Dmitry Yakunin <zeil@yandex-team.ru> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/20200922135650.1634-4-osalvador@suse.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fopszhong jiang
It is more clear to use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs file operation rather than DEFINE_SIMPLE_ATTRIBUTE. Link: http://lkml.kernel.org/r/1572403660-44718-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.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>
2019-06-03hwpoison-inject: no need to check return value of debugfs_create functionsGreg Kroah-Hartman
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: linux-mm@kvack.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21treewide: Add SPDX license identifier for more missed filesThomas Gleixner
Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23mm/memory_failure: Remove unused trapno from memory_failureEric W. Biederman
Today 4 architectures set ARCH_SUPPORTS_MEMORY_FAILURE (arm64, parisc, powerpc, and x86), while 4 other architectures set __ARCH_SI_TRAPNO (alpha, metag, sparc, and tile). These two sets of architectures do not interesect so remove the trapno paramater to remove confusion. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-05-03mm: hwpoison: call shake_page() unconditionallyNaoya Horiguchi
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>
2015-09-10hwpoison: use page_cgroup_ino for filtering by memcgVladimir Davydov
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>
2015-09-08mm/hwpoison: fix refcount of THP head page in no-injection caseWanpeng Li
Hwpoison injection takes a refcount of target page and another refcount of head page of THP if the target page is the tail page of a THP. However, current code doesn't release the refcount of head page if the THP is not supported to be injected wrt hwpoison filter. Fix it by reducing the refcount of head page if the target page is the tail page of a THP and it is not supported to be injected. 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>
2015-06-24mm/memory-failure: introduce get_hwpoison_page() for consistent refcount ↵Naoya Horiguchi
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>
2015-05-05mm/hwpoison-inject: check PageLRU of hpageNaoya Horiguchi
Hwpoison injector checks PageLRU of the raw target page to find out whether the page is an appropriate target, but current code now filters out thp tail pages, which prevents us from testing for such cases via this interface. So let's check hpage instead of p. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Dean Nelson <dnelson@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-05-05mm/hwpoison-inject: fix refcounting in no-injection caseNaoya Horiguchi
Hwpoison injection via debugfs:hwpoison/corrupt-pfn takes a refcount of the target page. But current code doesn't release it if the target page is not supposed to be injected, which results in memory leak. This patch simply adds the refcount releasing code. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Dean Nelson <dnelson@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06mm/hwpoison-inject.c: remove unnecessary null test before ↵Fabian Frederick
debugfs_remove_recursive Fix checkpatch warning: "WARNING: debugfs_remove_recursive(NULL) is safe this check is probably not required" Signed-off-by: Fabian Frederick <fabf@skynet.be> 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>
2014-01-21mm/hwpoison: add '#' to hwpoison_injectWanpeng Li
Add '#' to hwpoison_inject just as done in madvise_hwpoison. Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Vladimir Murzin <murzin.v@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-30mm/hwpoison: fix the lack of one reference count against poisoned pageWanpeng Li
The lack of one reference count against poisoned page for hwpoison_inject w/o hwpoison_filter enabled result in hwpoison detect -1 users still referenced the page, however, the number should be 0 except the poison handler held one after successfully unmap. This patch fix it by hold one referenced count against poisoned page for hwpoison_inject w/ and w/o hwpoison_filter enabled. Before patch: [ 71.902112] Injecting memory failure at pfn 224706 [ 71.902137] MCE 0x224706: dirty LRU page recovery: Failed [ 71.902138] MCE 0x224706: dirty LRU page still referenced by -1 users After patch: [ 94.710860] Injecting memory failure at pfn 215b68 [ 94.710885] MCE 0x215b68: dirty LRU page recovery: Recovered Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11mm/hwpoison-inject.c: change permission of corrupt-pfn/unpoison-pfn to 0200Wanpeng Li
Hwpoison injection doesn't implement read method for corrupt-pfn/unpoison-pfn attributes: # cat /sys/kernel/debug/hwpoison/corrupt-pfn cat: /sys/kernel/debug/hwpoison/corrupt-pfn: Permission denied # cat /sys/kernel/debug/hwpoison/unpoison-pfn cat: /sys/kernel/debug/hwpoison/unpoison-pfn: Permission denied This patch changes the permission of corrupt-pfn/unpoison-pfn to 0200. Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31memcg: rename config variablesAndrew Morton
Sanity: CONFIG_CGROUP_MEM_RES_CTLR -> CONFIG_MEMCG CONFIG_CGROUP_MEM_RES_CTLR_SWAP -> CONFIG_MEMCG_SWAP CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED -> CONFIG_MEMCG_SWAP_ENABLED CONFIG_CGROUP_MEM_RES_CTLR_KMEM -> CONFIG_MEMCG_KMEM [mhocko@suse.cz: fix missed bits] Cc: Glauber Costa <glommer@parallels.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-03HWPOISON: Clean up memory_failure() vs. __memory_failure()Tony Luck
There is only one caller of memory_failure(), all other users call __memory_failure() and pass in the flags argument explicitly. The lone user of memory_failure() will soon need to pass flags too. Add flags argument to the callsite in mce.c. Delete the old memory_failure() function, and then rename __memory_failure() without the leading "__". Provide clearer message when action optional memory errors are ignored. Acked-by: Borislav Petkov <bp@amd64.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-03-31Fix common misspellingsLucas De Marchi
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2010-08-11HWPOISON, hugetlb: support hwpoison injection for hugepageNaoya Horiguchi
This patch enables hwpoison injection through debug/hwpoison interfaces, with which we can test memory error handling for free or reserved hugepages (which cannot be tested by madvise() injector). [AK: Export PageHuge too for the injection module] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: Don't do early filtering if filter is disabledAndi Kleen
Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: Add soft page offline supportAndi Kleen
This is a simpler, gentler variant of memory_failure() for soft page offlining controlled from user space. It doesn't kill anything, just tries to invalidate and if that doesn't work migrate the page away. This is useful for predictive failure analysis, where a page has a high rate of corrected errors, but hasn't gone bad yet. Instead it can be offlined early and avoided. The offlining is controlled from sysfs, including a new generic entry point for hard page offlining for symmetry too. We use the page isolate facility to prevent re-allocation race. Normally this is only used by memory hotplug. To avoid races with memory allocation I am using lock_system_sleep(). This avoids the situation where memory hotplug is about to isolate a page range and then hwpoison undoes that work. This is a big hammer currently, but the simplest solution currently. When the page is not free or LRU we try to free pages from slab and other caches. The slab freeing is currently quite dumb and does not try to focus on the specific slab cache which might own the page. This could be potentially improved later. Thanks to Fengguang Wu and Haicheng Li for some fixes. [Added fix from Andrew Morton to adapt to new migrate_pages prototype] Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: add an interface to switch off/on all the page filtersHaicheng Li
In some use cases, user doesn't need extra filtering. E.g. user program can inject errors through madvise syscall to its own pages, however it might not know what the page state exactly is or which inode the page belongs to. So introduce an one-off interface "corrupt-filter-enable". Echo 0 to switch off page filters, and echo 1 to switch on the filters. [AK: changed default to 0] Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: add memory cgroup filterAndi Kleen
The hwpoison test suite need to inject hwpoison to a collection of selected task pages, and must not touch pages not owned by them and thus kill important system processes such as init. (But it's OK to mis-hwpoison free/unowned pages as well as shared clean pages. Mis-hwpoison of shared dirty pages will kill all tasks, so the test suite will target all or non of such tasks in the first place.) The memory cgroup serves this purpose well. We can put the target processes under the control of a memory cgroup, and tell the hwpoison injection code to only kill pages associated with some active memory cgroup. The prerequisite for doing hwpoison stress tests with mem_cgroup is, the mem_cgroup code tracks task pages _accurately_ (unless page is locked). Which we believe is/should be true. The benefits are simplification of hwpoison injector code. Also the mem_cgroup code will automatically be tested by hwpoison test cases. The alternative interfaces pin-pfn/unpin-pfn can also delegate the (process and page flags) filtering functions reliably to user space. However prototype implementation shows that this scheme adds more complexity than we wanted. Example test case: mkdir /cgroup/hwpoison usemem -m 100 -s 1000 & echo `jobs -p` > /cgroup/hwpoison/tasks memcg_ino=$(ls -id /cgroup/hwpoison | cut -f1 -d' ') echo $memcg_ino > /debug/hwpoison/corrupt-filter-memcg page-types -p `pidof init` --hwpoison # shall do nothing page-types -p `pidof usemem` --hwpoison # poison its pages [AK: Fix documentation] [Add fix for problem noticed by Li Zefan <lizf@cn.fujitsu.com>; dentry in the css could be NULL] CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> CC: Hugh Dickins <hugh.dickins@tiscali.co.uk> CC: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> CC: Balbir Singh <balbir@linux.vnet.ibm.com> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: Li Zefan <lizf@cn.fujitsu.com> CC: Paul Menage <menage@google.com> CC: Nick Piggin <npiggin@suse.de> CC: Andi Kleen <andi@firstfloor.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: add page flags filterWu Fengguang
When specified, only poison pages if ((page_flags & mask) == value). - corrupt-filter-flags-mask - corrupt-filter-flags-value This allows stress testing of many kinds of pages. Strictly speaking, the buddy pages requires taking zone lock, to avoid setting PG_hwpoison on a "was buddy but now allocated to someone" page. However we can just do nothing because we set PG_locked in the beginning, this prevents the page allocator from allocating it to someone. (It will BUG() on the unexpected PG_locked, which is fine for hwpoison testing.) [AK: Add select PROC_PAGE_MONITOR to satisfy dependency] CC: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: limit hwpoison injector to known page typesWu Fengguang
__memory_failure()'s workflow is set PG_hwpoison //... unset PG_hwpoison if didn't pass hwpoison filter That could kill unrelated process if it happens to page fault on the page with the (temporary) PG_hwpoison. The race should be big enough to appear in stress tests. Fix it by grabbing the page and checking filter at inject time. This also avoids the very noisy "Injecting memory failure..." messages. - we don't touch madvise() based injection, because the filters are generally not necessary for it. - if we want to apply the filters to h/w aided injection, we'd better to rearrange the logic in __memory_failure() instead of this patch. AK: fix documentation, use drain all, cleanups CC: Haicheng Li <haicheng.li@intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: add fs/device filtersWu Fengguang
Filesystem data/metadata present the most tricky-to-isolate pages. It requires careful code review and stress testing to get them right. The fs/device filter helps to target the stress tests to some specific filesystem pages. The filter condition is block device's major/minor numbers: - corrupt-filter-dev-major - corrupt-filter-dev-minor When specified (non -1), only page cache pages that belong to that device will be poisoned. The filters are checked reliably on the locked and refcounted page. Haicheng: clear PG_hwpoison and drop bad page count if filter not OK AK: Add documentation CC: Haicheng Li <haicheng.li@intel.com> CC: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-12-16HWPOISON: Add unpoisoning supportWu Fengguang
The unpoisoning interface is useful for stress testing tools to reclaim poisoned pages (to prevent OOM) There is no hardware level unpoisioning, so this cannot be used for real memory errors, only for software injected errors. Note that it may leak pages silently - those who have been removed from LRU cache, but not isolated from page cache/swap cache at hwpoison time. Especially the stress test of dirty swap cache pages shall reboot system before exhausting memory. AK: Fix comments, add documentation, add printks, rename symbol Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
2009-09-16HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNsAndi Kleen
Useful for some testing scenarios, although specific testing is often done better through MADV_POISON This can be done with the x86 level MCE injector too, but this interface allows it to do independently from low level x86 changes. v2: Add module license (Haicheng Li) Signed-off-by: Andi Kleen <ak@linux.intel.com>