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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>