Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

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

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 729d4b1..dacc641 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -35,6 +35,7 @@
 #include <linux/mm.h>
 #include <linux/page-flags.h>
 #include <linux/sched.h>
+#include <linux/ksm.h>
 #include <linux/rmap.h>
 #include <linux/pagemap.h>
 #include <linux/swap.h>
@@ -370,9 +371,6 @@ static int me_pagecache_clean(struct page *p, unsigned long pfn)
        int ret = FAILED;
        struct address_space *mapping;
 
-       if (!isolate_lru_page(p))
-               page_cache_release(p);
-
        /*
         * For anonymous pages we're done the only reference left
         * should be the one m_f() holds.
@@ -498,30 +496,18 @@ static int me_pagecache_dirty(struct page *p, unsigned long pfn)
  */
 static int me_swapcache_dirty(struct page *p, unsigned long pfn)
 {
-       int ret = FAILED;
-
        ClearPageDirty(p);
        /* Trigger EIO in shmem: */
        ClearPageUptodate(p);
 
-       if (!isolate_lru_page(p)) {
-               page_cache_release(p);
-               ret = DELAYED;
-       }
-
-       return ret;
+       return DELAYED;
 }
 
 static int me_swapcache_clean(struct page *p, unsigned long pfn)
 {
-       int ret = FAILED;
-
-       if (!isolate_lru_page(p)) {
-               page_cache_release(p);
-               ret = RECOVERED;
-       }
        delete_from_swap_cache(p);
-       return ret;
+
+       return RECOVERED;
 }
 
 /*
@@ -611,8 +597,6 @@ static struct page_state {
        { 0,            0,              "unknown page state",   me_unknown },
 };
 
-#undef lru
-
 static void action_result(unsigned long pfn, char *msg, int result)
 {
        struct page *page = NULL;
@@ -629,13 +613,16 @@ static int page_action(struct page_state *ps, struct page *p,
                        unsigned long pfn, int ref)
 {
        int result;
+       int count;
 
        result = ps->action(p, pfn);
        action_result(pfn, ps->msg, result);
-       if (page_count(p) != 1 + ref)
+
+       count = page_count(p) - 1 - ref;
+       if (count != 0)
                printk(KERN_ERR
                       "MCE %#lx: %s page still referenced by %d users\n",
-                      pfn, ps->msg, page_count(p) - 1);
+                      pfn, ps->msg, count);
 
        /* Could do more checks here if page looks ok */
        /*
@@ -661,12 +648,9 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
        int i;
        int kill = 1;
 
-       if (PageReserved(p) || PageCompound(p) || PageSlab(p))
+       if (PageReserved(p) || PageCompound(p) || PageSlab(p) || PageKsm(p))
                return;
 
-       if (!PageLRU(p))
-               lru_add_drain_all();
-
        /*
         * This check implies we don't kill processes if their pages
         * are in the swap cache early. Those are always late kills.
@@ -738,6 +722,7 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
 
 int __memory_failure(unsigned long pfn, int trapno, int ref)
 {
+       unsigned long lru_flag;
        struct page_state *ps;
        struct page *p;
        int res;
@@ -775,6 +760,24 @@ int __memory_failure(unsigned long pfn, int trapno, int ref)
        }
 
        /*
+        * We ignore non-LRU pages for good reasons.
+        * - PG_locked is only well defined for LRU pages and a few others
+        * - to avoid races with __set_page_locked()
+        * - to avoid races with __SetPageSlab*() (and more non-atomic ops)
+        * The check (unnecessarily) ignores LRU pages being isolated and
+        * walked by the page reclaim code, however that's not a big loss.
+        */
+       if (!PageLRU(p))
+               lru_add_drain_all();
+       lru_flag = p->flags & lru;
+       if (isolate_lru_page(p)) {
+               action_result(pfn, "non LRU", IGNORED);
+               put_page(p);
+               return -EBUSY;
+       }
+       page_cache_release(p);
+
+       /*
         * Lock the page and wait for writeback to finish.
         * It's very difficult to mess with pages currently under IO
         * and in many cases impossible, so we just avoid it here.
@@ -790,7 +793,7 @@ int __memory_failure(unsigned long pfn, int trapno, int ref)
        /*
         * Torn down by someone else?
         */
-       if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
+       if ((lru_flag & lru) && !PageSwapCache(p) && p->mapping == NULL) {
                action_result(pfn, "already truncated LRU", IGNORED);
                res = 0;
                goto out;
@@ -798,7 +801,7 @@ int __memory_failure(unsigned long pfn, int trapno, int ref)
 
        res = -EBUSY;
        for (ps = error_states;; ps++) {
-               if ((p->flags & ps->mask) == ps->res) {
+               if (((p->flags | lru_flag)& ps->mask) == ps->res) {
                        res = page_action(ps, p, pfn, ref);
                        break;
                }