HWPOISON: add memory cgroup filter

[safe/jmp/linux-2.6] / mm / memory-failure.c

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 22d2b20..117ef15 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -100,6 +100,49 @@ static int hwpoison_filter_flags(struct page *p)
                return -EINVAL;
 }
 
+/*
+ * This allows stress tests to limit test scope to a collection of tasks
+ * by putting them under some memcg. This prevents killing unrelated/important
+ * processes such as /sbin/init. Note that the target task may share clean
+ * pages with init (eg. libc text), which is harmless. If the target task
+ * share _dirty_ pages with another task B, the test scheme must make sure B
+ * is also included in the memcg. At last, due to race conditions this filter
+ * can only guarantee that the page either belongs to the memcg tasks, or is
+ * a freed page.
+ */
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+u64 hwpoison_filter_memcg;
+EXPORT_SYMBOL_GPL(hwpoison_filter_memcg);
+static int hwpoison_filter_task(struct page *p)
+{
+       struct mem_cgroup *mem;
+       struct cgroup_subsys_state *css;
+       unsigned long ino;
+
+       if (!hwpoison_filter_memcg)
+               return 0;
+
+       mem = try_get_mem_cgroup_from_page(p);
+       if (!mem)
+               return -EINVAL;
+
+       css = mem_cgroup_css(mem);
+       /* root_mem_cgroup has NULL dentries */
+       if (!css->cgroup->dentry)
+               return -EINVAL;
+
+       ino = css->cgroup->dentry->d_inode->i_ino;
+       css_put(css);
+
+       if (ino != hwpoison_filter_memcg)
+               return -EINVAL;
+
+       return 0;
+}
+#else
+static int hwpoison_filter_task(struct page *p) { return 0; }
+#endif
+
 int hwpoison_filter(struct page *p)
 {
        if (hwpoison_filter_dev(p))
@@ -108,6 +151,9 @@ int hwpoison_filter(struct page *p)
        if (hwpoison_filter_flags(p))
                return -EINVAL;
 
+       if (hwpoison_filter_task(p))
+               return -EINVAL;
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(hwpoison_filter);