HWPOISON: Add a madvise() injector for soft page offlining

Process based injection is much easier to handle for test programs,
who can first bring a page into a specific state and then test.
So add a new MADV_SOFT_OFFLINE to soft offline a page, similar
to the existing hard offline injector.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

2 files changed, 13 insertions, 3 deletions

diff --git a/include/asm-generic/mman-common.h b/include/asm-generic/mman-common.h
index 20111265afd8..3da9e2742fa0 100644
--- a/include/asm-generic/mman-common.h
+++ b/include/asm-generic/mman-common.h
@@ -40,6 +40,7 @@
 #define MADV_DONTFORK   10              /* don't inherit across fork */
 #define MADV_DOFORK     11              /* do inherit across fork */
 #define MADV_HWPOISON   100             /* poison a page for testing */
+#define MADV_SOFT_OFFLINE 101           /* soft offline page for testing */
 
 #define MADV_MERGEABLE   12             /* KSM may merge identical pages */
 #define MADV_UNMERGEABLE 13             /* KSM may not merge identical pages */
diff --git a/mm/madvise.c b/mm/madvise.c
index 7964e36ba915..319528b8db74 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -9,6 +9,7 @@
 #include <linux/pagemap.h>
 #include <linux/syscalls.h>
 #include <linux/mempolicy.h>
+#include <linux/page-isolation.h>
 #include <linux/hugetlb.h>
 #include <linux/sched.h>
 #include <linux/ksm.h>
@@ -222,7 +223,7 @@ static long madvise_remove(struct vm_area_struct *vma,
 /*
  * Error injection support for memory error handling.
  */
-static int madvise_hwpoison(unsigned long start, unsigned long end)
+static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
 {
         int ret = 0;
 
@@ -233,6 +234,14 @@ static int madvise_hwpoison(unsigned long start, unsigned long end)
                 int ret = get_user_pages_fast(start, 1, 0, &p);
                 if (ret != 1)
                         return ret;
+                if (bhv == MADV_SOFT_OFFLINE) {
+                        printk(KERN_INFO "Soft offlining page %lx at %lx\n",
+                                page_to_pfn(p), start);
+                        ret = soft_offline_page(p, MF_COUNT_INCREASED);
+                        if (ret)
+                                break;
+                        continue;
+                }
                 printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
                        page_to_pfn(p), start);
                 /* Ignore return value for now */
@@ -333,8 +342,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
         size_t len;
 
 #ifdef CONFIG_MEMORY_FAILURE
-        if (behavior == MADV_HWPOISON)
-                return madvise_hwpoison(start, start+len_in);
+        if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
+                return madvise_hwpoison(behavior, start, start+len_in);
 #endif
         if (!madvise_behavior_valid(behavior))
                 return error;