Merge commit 'v2.6.32-rc6' into perf/core

Conflicts:
	tools/perf/Makefile

Merge reason: Resolve the conflict, merge to upstream and merge in
              perf fixes so we can add a dependent patch.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

12 files changed, 430 insertions, 52 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-usb_host b/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc
index 46b66ad1f1b4..4e8106f7cfd9 100644
--- a/Documentation/ABI/testing/sysfs-class-usb_host
+++ b/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc
@@ -1,4 +1,4 @@
-What:           /sys/class/usb_host/usb_hostN/wusb_chid
+What:           /sys/class/uwb_rc/uwbN/wusbhc/wusb_chid
 Date:           July 2008
 KernelVersion:  2.6.27
 Contact:        David Vrabel <david.vrabel@csr.com>
@@ -9,7 +9,7 @@ Description:
 
                 Set an all zero CHID to stop the host controller.
 
-What:           /sys/class/usb_host/usb_hostN/wusb_trust_timeout
+What:           /sys/class/uwb_rc/uwbN/wusbhc/wusb_trust_timeout
 Date:           July 2008
 KernelVersion:  2.6.27
 Contact:        David Vrabel <david.vrabel@csr.com>
diff --git a/Documentation/ABI/testing/sysfs-devices-cache_disable b/Documentation/ABI/testing/sysfs-devices-cache_disable
deleted file mode 100644
index 175bb4f70512..000000000000
--- a/Documentation/ABI/testing/sysfs-devices-cache_disable
+++ /dev/null
@@ -1,18 +0,0 @@
-What:      /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X
-Date:      August 2008
-KernelVersion:  2.6.27
-Contact:        mark.langsdorf@amd.com
-Description:    These files exist in every cpu's cache index directories.
-                There are currently 2 cache_disable_# files in each
-                directory.  Reading from these files on a supported
-                processor will return that cache disable index value
-                for that processor and node.  Writing to one of these
-                files will cause the specificed cache index to be disabled.
-
-                Currently, only AMD Family 10h Processors support cache index
-                disable, and only for their L3 caches.  See the BIOS and
-                Kernel Developer's Guide at
-                http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf
-                for formatting information and other details on the
-                cache index disable.
-Users:    joachim.deguara@amd.com
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
new file mode 100644
index 000000000000..a703b9e9aeb9
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -0,0 +1,156 @@
+What:           /sys/devices/system/cpu/
+Date:           pre-git history
+Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description:
+                A collection of both global and individual CPU attributes
+
+                Individual CPU attributes are contained in subdirectories
+                named by the kernel's logical CPU number, e.g.:
+
+                /sys/devices/system/cpu/cpu#/
+
+What:           /sys/devices/system/cpu/sched_mc_power_savings
+                /sys/devices/system/cpu/sched_smt_power_savings
+Date:           June 2006
+Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description:    Discover and adjust the kernel's multi-core scheduler support.
+
+                Possible values are:
+
+                0 - No power saving load balance (default value)
+                1 - Fill one thread/core/package first for long running threads
+                2 - Also bias task wakeups to semi-idle cpu package for power
+                    savings
+
+                sched_mc_power_savings is dependent upon SCHED_MC, which is
+                itself architecture dependent.
+
+                sched_smt_power_savings is dependent upon SCHED_SMT, which
+                is itself architecture dependent.
+
+                The two files are independent of each other. It is possible
+                that one file may be present without the other.
+
+                Introduced by git commit 5c45bf27.
+
+
+What:           /sys/devices/system/cpu/kernel_max
+                /sys/devices/system/cpu/offline
+                /sys/devices/system/cpu/online
+                /sys/devices/system/cpu/possible
+                /sys/devices/system/cpu/present
+Date:           December 2008
+Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description:    CPU topology files that describe kernel limits related to
+                hotplug. Briefly:
+
+                kernel_max: the maximum cpu index allowed by the kernel
+                configuration.
+
+                offline: cpus that are not online because they have been
+                HOTPLUGGED off or exceed the limit of cpus allowed by the
+                kernel configuration (kernel_max above).
+
+                online: cpus that are online and being scheduled.
+
+                possible: cpus that have been allocated resources and can be
+                brought online if they are present.
+
+                present: cpus that have been identified as being present in
+                the system.
+
+                See Documentation/cputopology.txt for more information.
+
+
+
+What:           /sys/devices/system/cpu/cpu#/node
+Date:           October 2009
+Contact:        Linux memory management mailing list <linux-mm@kvack.org>
+Description:    Discover NUMA node a CPU belongs to
+
+                When CONFIG_NUMA is enabled, a symbolic link that points
+                to the corresponding NUMA node directory.
+
+                For example, the following symlink is created for cpu42
+                in NUMA node 2:
+
+                /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
+
+
+What:           /sys/devices/system/cpu/cpu#/topology/core_id
+                /sys/devices/system/cpu/cpu#/topology/core_siblings
+                /sys/devices/system/cpu/cpu#/topology/core_siblings_list
+                /sys/devices/system/cpu/cpu#/topology/physical_package_id
+                /sys/devices/system/cpu/cpu#/topology/thread_siblings
+                /sys/devices/system/cpu/cpu#/topology/thread_siblings_list
+Date:           December 2008
+Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description:    CPU topology files that describe a logical CPU's relationship
+                to other cores and threads in the same physical package.
+
+                One cpu# directory is created per logical CPU in the system,
+                e.g. /sys/devices/system/cpu/cpu42/.
+
+                Briefly, the files above are:
+
+                core_id: the CPU core ID of cpu#. Typically it is the
+                hardware platform's identifier (rather than the kernel's).
+                The actual value is architecture and platform dependent.
+
+                core_siblings: internal kernel map of cpu#'s hardware threads
+                within the same physical_package_id.
+
+                core_siblings_list: human-readable list of the logical CPU
+                numbers within the same physical_package_id as cpu#.
+
+                physical_package_id: physical package id of cpu#. Typically
+                corresponds to a physical socket number, but the actual value
+                is architecture and platform dependent.
+
+                thread_siblings: internel kernel map of cpu#'s hardware
+                threads within the same core as cpu#
+
+                thread_siblings_list: human-readable list of cpu#'s hardware
+                threads within the same core as cpu#
+
+                See Documentation/cputopology.txt for more information.
+
+
+What:           /sys/devices/system/cpu/cpuidle/current_driver
+                /sys/devices/system/cpu/cpuidle/current_governer_ro
+Date:           September 2007
+Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description:    Discover cpuidle policy and mechanism
+
+                Various CPUs today support multiple idle levels that are
+                differentiated by varying exit latencies and power
+                consumption during idle.
+
+                Idle policy (governor) is differentiated from idle mechanism
+                (driver)
+
+                current_driver: displays current idle mechanism
+
+                current_governor_ro: displays current idle policy
+
+                See files in Documentation/cpuidle/ for more information.
+
+
+What:      /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X
+Date:      August 2008
+KernelVersion:  2.6.27
+Contact:        mark.langsdorf@amd.com
+Description:    These files exist in every cpu's cache index directories.
+                There are currently 2 cache_disable_# files in each
+                directory.  Reading from these files on a supported
+                processor will return that cache disable index value
+                for that processor and node.  Writing to one of these
+                files will cause the specificed cache index to be disabled.
+
+                Currently, only AMD Family 10h Processors support cache index
+                disable, and only for their L3 caches.  See the BIOS and
+                Kernel Developer's Guide at
+                http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf
+                for formatting information and other details on the
+                cache index disable.
+Users:    joachim.deguara@amd.com
diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index b41f3e58aefa..f1c5c4bccd3e 100644
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -1,15 +1,28 @@
 
-Export cpu topology info via sysfs. Items (attributes) are similar
+Export CPU topology info via sysfs. Items (attributes) are similar
 to /proc/cpuinfo.
 
 1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
-represent the physical package id of  cpu X;
+
+        physical package id of cpuX. Typically corresponds to a physical
+        socket number, but the actual value is architecture and platform
+        dependent.
+
 2) /sys/devices/system/cpu/cpuX/topology/core_id:
-represent the cpu core id to cpu X;
+
+        the CPU core ID of cpuX. Typically it is the hardware platform's
+        identifier (rather than the kernel's).  The actual value is
+        architecture and platform dependent.
+
 3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
-represent the thread siblings to cpu X in the same core;
+
+        internel kernel map of cpuX's hardware threads within the same
+        core as cpuX
+
 4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
-represent the thread siblings to cpu X in the same physical package;
+
+        internal kernel map of cpuX's hardware threads within the same
+        physical_package_id.
 
 To implement it in an architecture-neutral way, a new source file,
 drivers/base/topology.c, is to export the 4 attributes.
@@ -32,32 +45,32 @@ not defined by include/asm-XXX/topology.h:
 3) thread_siblings: just the given CPU
 4) core_siblings: just the given CPU
 
-Additionally, cpu topology information is provided under
+Additionally, CPU topology information is provided under
 /sys/devices/system/cpu and includes these files.  The internal
 source for the output is in brackets ("[]").
 
-    kernel_max: the maximum cpu index allowed by the kernel configuration.
+    kernel_max: the maximum CPU index allowed by the kernel configuration.
                 [NR_CPUS-1]
 
-    offline:    cpus that are not online because they have been
+    offline:    CPUs that are not online because they have been
                 HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit
-                of cpus allowed by the kernel configuration (kernel_max
+                of CPUs allowed by the kernel configuration (kernel_max
                 above). [~cpu_online_mask + cpus >= NR_CPUS]
 
-    online:     cpus that are online and being scheduled [cpu_online_mask]
+    online:     CPUs that are online and being scheduled [cpu_online_mask]
 
-    possible:   cpus that have been allocated resources and can be
+    possible:   CPUs that have been allocated resources and can be
                 brought online if they are present. [cpu_possible_mask]
 
-    present:    cpus that have been identified as being present in the
+    present:    CPUs that have been identified as being present in the
                 system. [cpu_present_mask]
 
 The format for the above output is compatible with cpulist_parse()
 [see <linux/cpumask.h>].  Some examples follow.
 
-In this example, there are 64 cpus in the system but cpus 32-63 exceed
+In this example, there are 64 CPUs in the system but cpus 32-63 exceed
 the kernel max which is limited to 0..31 by the NR_CPUS config option
-being 32.  Note also that cpus 2 and 4-31 are not online but could be
+being 32.  Note also that CPUs 2 and 4-31 are not online but could be
 brought online as they are both present and possible.
 
      kernel_max: 31
@@ -67,8 +80,8 @@ brought online as they are both present and possible.
         present: 0-31
 
 In this example, the NR_CPUS config option is 128, but the kernel was
-started with possible_cpus=144.  There are 4 cpus in the system and cpu2
-was manually taken offline (and is the only cpu that can be brought
+started with possible_cpus=144.  There are 4 CPUs in the system and cpu2
+was manually taken offline (and is the only CPU that can be brought
 online.)
 
      kernel_max: 127
@@ -78,4 +91,4 @@ online.)
         present: 0-3
 
 See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter
-as well as more information on the various cpumask's.
+as well as more information on the various cpumasks.
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 04e6c819b28a..bc693fffabe0 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -418,6 +418,14 @@ When:	2.6.33
 Why:    Should be implemented in userspace, policy daemon.
 Who:    Johannes Berg <johannes@sipsolutions.net>
 
+---------------------------
+
+What:   CONFIG_INOTIFY
+When:   2.6.33
+Why:    last user (audit) will be converted to the newer more generic
+        and more easily maintained fsnotify subsystem
+Who:    Eric Paris <eparis@redhat.com>
+
 ----------------------------
 
 What:   lock_policy_rwsem_* and unlock_policy_rwsem_* will not be
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index bf4f4b7e11b3..6d94e0696f8c 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -134,9 +134,15 @@ ro                   	Mount filesystem read only. Note that ext4 will
                         mount options "ro,noload" can be used to prevent
                         writes to the filesystem.
 
+journal_checksum        Enable checksumming of the journal transactions.
+                        This will allow the recovery code in e2fsck and the
+                        kernel to detect corruption in the kernel.  It is a
+                        compatible change and will be ignored by older kernels.
+
 journal_async_commit    Commit block can be written to disk without waiting
                         for descriptor blocks. If enabled older kernels cannot
-                        mount the device.
+                        mount the device. This will enable 'journal_checksum'
+                        internally.
 
 journal=update          Update the ext4 file system's journal to the current
                         format.
diff --git a/Documentation/flexible-arrays.txt b/Documentation/flexible-arrays.txt
index 84eb26808dee..cb8a3a00cc92 100644
--- a/Documentation/flexible-arrays.txt
+++ b/Documentation/flexible-arrays.txt
@@ -1,5 +1,5 @@
 Using flexible arrays in the kernel
-Last updated for 2.6.31
+Last updated for 2.6.32
 Jonathan Corbet <corbet@lwn.net>
 
 Large contiguous memory allocations can be unreliable in the Linux kernel.
@@ -40,6 +40,13 @@ argument is passed directly to the internal memory allocation calls.  With
 the current code, using flags to ask for high memory is likely to lead to
 notably unpleasant side effects.
 
+It is also possible to define flexible arrays at compile time with:
+
+    DEFINE_FLEX_ARRAY(name, element_size, total);
+
+This macro will result in a definition of an array with the given name; the
+element size and total will be checked for validity at compile time.
+
 Storing data into a flexible array is accomplished with a call to:
 
     int flex_array_put(struct flex_array *array, unsigned int element_nr,
@@ -76,16 +83,30 @@ particular element has never been allocated.
 Note that it is possible to get back a valid pointer for an element which
 has never been stored in the array.  Memory for array elements is allocated
 one page at a time; a single allocation could provide memory for several
-adjacent elements.  The flexible array code does not know if a specific
-element has been written; it only knows if the associated memory is
-present.  So a flex_array_get() call on an element which was never stored
-in the array has the potential to return a pointer to random data.  If the
-caller does not have a separate way to know which elements were actually
-stored, it might be wise, at least, to add GFP_ZERO to the flags argument
-to ensure that all elements are zeroed.
-
-There is no way to remove a single element from the array.  It is possible,
-though, to remove all elements with a call to:
+adjacent elements.  Flexible array elements are normally initialized to the
+value FLEX_ARRAY_FREE (defined as 0x6c in <linux/poison.h>), so errors
+involving that number probably result from use of unstored array entries.
+Note that, if array elements are allocated with __GFP_ZERO, they will be
+initialized to zero and this poisoning will not happen.
+
+Individual elements in the array can be cleared with:
+
+    int flex_array_clear(struct flex_array *array, unsigned int element_nr);
+
+This function will set the given element to FLEX_ARRAY_FREE and return
+zero.  If storage for the indicated element is not allocated for the array,
+flex_array_clear() will return -EINVAL instead.  Note that clearing an
+element does not release the storage associated with it; to reduce the
+allocated size of an array, call:
+
+    int flex_array_shrink(struct flex_array *array);
+
+The return value will be the number of pages of memory actually freed.
+This function works by scanning the array for pages containing nothing but
+FLEX_ARRAY_FREE bytes, so (1) it can be expensive, and (2) it will not work
+if the array's pages are allocated with __GFP_ZERO.
+
+It is possible to remove all elements of an array with a call to:
 
     void flex_array_free_parts(struct flex_array *array);
 
diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
index dcbd502c8792..82def883361b 100644
--- a/Documentation/hwmon/sysfs-interface
+++ b/Documentation/hwmon/sysfs-interface
@@ -353,10 +353,20 @@ power[1-*]_average		Average power use
                                 Unit: microWatt
                                 RO
 
-power[1-*]_average_interval     Power use averaging interval
+power[1-*]_average_interval     Power use averaging interval.  A poll
+                                notification is sent to this file if the
+                                hardware changes the averaging interval.
                                 Unit: milliseconds
                                 RW
 
+power[1-*]_average_interval_max Maximum power use averaging interval
+                                Unit: milliseconds
+                                RO
+
+power[1-*]_average_interval_min Minimum power use averaging interval
+                                Unit: milliseconds
+                                RO
+
 power[1-*]_average_highest      Historical average maximum power use
                                 Unit: microWatt
                                 RO
@@ -365,6 +375,18 @@ power[1-*]_average_lowest	Historical average minimum power use
                                 Unit: microWatt
                                 RO
 
+power[1-*]_average_max          A poll notification is sent to
+                                power[1-*]_average when power use
+                                rises above this value.
+                                Unit: microWatt
+                                RW
+
+power[1-*]_average_min          A poll notification is sent to
+                                power[1-*]_average when power use
+                                sinks below this value.
+                                Unit: microWatt
+                                RW
+
 power[1-*]_input                Instantaneous power use
                                 Unit: microWatt
                                 RO
@@ -381,6 +403,39 @@ power[1-*]_reset_history	Reset input_highest, input_lowest,
                                 average_highest and average_lowest.
                                 WO
 
+power[1-*]_accuracy             Accuracy of the power meter.
+                                Unit: Percent
+                                RO
+
+power[1-*]_alarm                1 if the system is drawing more power than the
+                                cap allows; 0 otherwise.  A poll notification is
+                                sent to this file when the power use exceeds the
+                                cap.  This file only appears if the cap is known
+                                to be enforced by hardware.
+                                RO
+
+power[1-*]_cap                  If power use rises above this limit, the
+                                system should take action to reduce power use.
+                                A poll notification is sent to this file if the
+                                cap is changed by the hardware.  The *_cap
+                                files only appear if the cap is known to be
+                                enforced by hardware.
+                                Unit: microWatt
+                                RW
+
+power[1-*]_cap_hyst             Margin of hysteresis built around capping and
+                                notification.
+                                Unit: microWatt
+                                RW
+
+power[1-*]_cap_max              Maximum cap that can be set.
+                                Unit: microWatt
+                                RO
+
+power[1-*]_cap_min              Minimum cap that can be set.
+                                Unit: microWatt
+                                RO
+
 **********
 * Energy *
 **********
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index ba9373f82ab5..098de5bce00a 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -42,7 +42,6 @@
 #include <signal.h>
 #include "linux/lguest_launcher.h"
 #include "linux/virtio_config.h"
-#include <linux/virtio_ids.h>
 #include "linux/virtio_net.h"
 #include "linux/virtio_blk.h"
 #include "linux/virtio_console.h"
diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 1c8eb4518ce0..fd9a2f67edf2 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -522,7 +522,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
     pcm_devs       - Number of PCM devices assigned to each card
                      (default = 1, up to 4)
     pcm_substreams - Number of PCM substreams assigned to each PCM
-                     (default = 8, up to 16)
+                     (default = 8, up to 128)
     hrtimer        - Use hrtimer (=1, default) or system timer (=0)
     fake_buffer    - Fake buffer allocations (default = 1)
 
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 957b22fde2df..8179692fbb90 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -1231,6 +1231,7 @@ something like this simple program:
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <string.h>
 
 #define _STR(x) #x
 #define STR(x) _STR(x)
@@ -1265,6 +1266,7 @@ const char *find_debugfs(void)
                return NULL;
        }
 
+       strcat(debugfs, "/tracing/");
        debugfs_found = 1;
 
        return debugfs;
diff --git a/Documentation/vm/hwpoison.txt b/Documentation/vm/hwpoison.txt
new file mode 100644
index 000000000000..3ffadf8da61f
--- /dev/null
+++ b/Documentation/vm/hwpoison.txt
@@ -0,0 +1,136 @@
+What is hwpoison?
+
+Upcoming Intel CPUs have support for recovering from some memory errors
+(``MCA recovery''). This requires the OS to declare a page "poisoned",
+kill the processes associated with it and avoid using it in the future.
+
+This patchkit implements the necessary infrastructure in the VM.
+
+To quote the overview comment:
+
+ * High level machine check handler. Handles pages reported by the
+ * hardware as being corrupted usually due to a 2bit ECC memory or cache
+ * failure.
+ *
+ * This focusses on pages detected as corrupted in the background.
+ * When the current CPU tries to consume corruption the currently
+ * running process can just be killed directly instead. This implies
+ * that if the error cannot be handled for some reason it's safe to
+ * just ignore it because no corruption has been consumed yet. Instead
+ * when that happens another machine check will happen.
+ *
+ * Handles page cache pages in various states. The tricky part
+ * here is that we can access any page asynchronous to other VM
+ * users, because memory failures could happen anytime and anywhere,
+ * possibly violating some of their assumptions. This is why this code
+ * has to be extremely careful. Generally it tries to use normal locking
+ * rules, as in get the standard locks, even if that means the
+ * error handling takes potentially a long time.
+ *
+ * Some of the operations here are somewhat inefficient and have non
+ * linear algorithmic complexity, because the data structures have not
+ * been optimized for this case. This is in particular the case
+ * for the mapping from a vma to a process. Since this case is expected
+ * to be rare we hope we can get away with this.
+
+The code consists of a the high level handler in mm/memory-failure.c,
+a new page poison bit and various checks in the VM to handle poisoned
+pages.
+
+The main target right now is KVM guests, but it works for all kinds
+of applications. KVM support requires a recent qemu-kvm release.
+
+For the KVM use there was need for a new signal type so that
+KVM can inject the machine check into the guest with the proper
+address. This in theory allows other applications to handle
+memory failures too. The expection is that near all applications
+won't do that, but some very specialized ones might.
+
+---
+
+There are two (actually three) modi memory failure recovery can be in:
+
+vm.memory_failure_recovery sysctl set to zero:
+        All memory failures cause a panic. Do not attempt recovery.
+        (on x86 this can be also affected by the tolerant level of the
+        MCE subsystem)
+
+early kill
+        (can be controlled globally and per process)
+        Send SIGBUS to the application as soon as the error is detected
+        This allows applications who can process memory errors in a gentle
+        way (e.g. drop affected object)
+        This is the mode used by KVM qemu.
+
+late kill
+        Send SIGBUS when the application runs into the corrupted page.
+        This is best for memory error unaware applications and default
+        Note some pages are always handled as late kill.
+
+---
+
+User control:
+
+vm.memory_failure_recovery
+        See sysctl.txt
+
+vm.memory_failure_early_kill
+        Enable early kill mode globally
+
+PR_MCE_KILL
+        Set early/late kill mode/revert to system default
+        arg1: PR_MCE_KILL_CLEAR: Revert to system default
+        arg1: PR_MCE_KILL_SET: arg2 defines thread specific mode
+                PR_MCE_KILL_EARLY: Early kill
+                PR_MCE_KILL_LATE:  Late kill
+                PR_MCE_KILL_DEFAULT: Use system global default
+PR_MCE_KILL_GET
+        return current mode
+
+
+---
+
+Testing:
+
+madvise(MADV_POISON, ....)
+        (as root)
+        Poison a page in the process for testing
+
+
+hwpoison-inject module through debugfs
+        /sys/debug/hwpoison/corrupt-pfn
+
+Inject hwpoison fault at PFN echoed into this file
+
+
+Architecture specific MCE injector
+
+x86 has mce-inject, mce-test
+
+Some portable hwpoison test programs in mce-test, see blow.
+
+---
+
+References:
+
+http://halobates.de/mce-lc09-2.pdf
+        Overview presentation from LinuxCon 09
+
+git://git.kernel.org/pub/scm/utils/cpu/mce/mce-test.git
+        Test suite (hwpoison specific portable tests in tsrc)
+
+git://git.kernel.org/pub/scm/utils/cpu/mce/mce-inject.git
+        x86 specific injector
+
+
+---
+
+Limitations:
+
+- Not all page types are supported and never will. Most kernel internal
+objects cannot be recovered, only LRU pages for now.
+- Right now hugepage support is missing.
+
+---
+Andi Kleen, Oct 2009
+