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authorJens Axboe <jaxboe@fusionio.com>2010-10-19 09:13:04 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-10-19 09:13:04 +0200
commitfa251f89903d73989e2f63e13d0eaed1e07ce0da (patch)
tree3f7fe779941e3b6d67754dd7c44a32f48ea47c74 /mm/swapfile.c
parentdd3932eddf428571762596e17b65f5dc92ca361b (diff)
parentcd07202cc8262e1669edff0d97715f3dd9260917 (diff)
Merge branch 'v2.6.36-rc8' into for-2.6.37/barrier
Conflicts: block/blk-core.c drivers/block/loop.c mm/swapfile.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c120
1 files changed, 43 insertions, 77 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index e132e1708ac..9fc7bac7db0 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -47,8 +47,6 @@ long nr_swap_pages;
long total_swap_pages;
static int least_priority;
-static bool swap_for_hibernation;
-
static const char Bad_file[] = "Bad swap file entry ";
static const char Unused_file[] = "Unused swap file entry ";
static const char Bad_offset[] = "Bad swap offset entry ";
@@ -317,10 +315,8 @@ checks:
if (offset > si->highest_bit)
scan_base = offset = si->lowest_bit;
- /* reuse swap entry of cache-only swap if not hibernation. */
- if (vm_swap_full()
- && usage == SWAP_HAS_CACHE
- && si->swap_map[offset] == SWAP_HAS_CACHE) {
+ /* reuse swap entry of cache-only swap if not busy. */
+ if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
int swap_was_freed;
spin_unlock(&swap_lock);
swap_was_freed = __try_to_reclaim_swap(si, offset);
@@ -450,8 +446,6 @@ swp_entry_t get_swap_page(void)
spin_lock(&swap_lock);
if (nr_swap_pages <= 0)
goto noswap;
- if (swap_for_hibernation)
- goto noswap;
nr_swap_pages--;
for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) {
@@ -484,6 +478,28 @@ noswap:
return (swp_entry_t) {0};
}
+/* The only caller of this function is now susupend routine */
+swp_entry_t get_swap_page_of_type(int type)
+{
+ struct swap_info_struct *si;
+ pgoff_t offset;
+
+ spin_lock(&swap_lock);
+ si = swap_info[type];
+ if (si && (si->flags & SWP_WRITEOK)) {
+ nr_swap_pages--;
+ /* This is called for allocating swap entry, not cache */
+ offset = scan_swap_map(si, 1);
+ if (offset) {
+ spin_unlock(&swap_lock);
+ return swp_entry(type, offset);
+ }
+ nr_swap_pages++;
+ }
+ spin_unlock(&swap_lock);
+ return (swp_entry_t) {0};
+}
+
static struct swap_info_struct *swap_info_get(swp_entry_t entry)
{
struct swap_info_struct *p;
@@ -667,6 +683,24 @@ int try_to_free_swap(struct page *page)
if (page_swapcount(page))
return 0;
+ /*
+ * Once hibernation has begun to create its image of memory,
+ * there's a danger that one of the calls to try_to_free_swap()
+ * - most probably a call from __try_to_reclaim_swap() while
+ * hibernation is allocating its own swap pages for the image,
+ * but conceivably even a call from memory reclaim - will free
+ * the swap from a page which has already been recorded in the
+ * image as a clean swapcache page, and then reuse its swap for
+ * another page of the image. On waking from hibernation, the
+ * original page might be freed under memory pressure, then
+ * later read back in from swap, now with the wrong data.
+ *
+ * Hibernation clears bits from gfp_allowed_mask to prevent
+ * memory reclaim from writing to disk, so check that here.
+ */
+ if (!(gfp_allowed_mask & __GFP_IO))
+ return 0;
+
delete_from_swap_cache(page);
SetPageDirty(page);
return 1;
@@ -743,74 +777,6 @@ int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
#endif
#ifdef CONFIG_HIBERNATION
-
-static pgoff_t hibernation_offset[MAX_SWAPFILES];
-/*
- * Once hibernation starts to use swap, we freeze swap_map[]. Otherwise,
- * saved swap_map[] image to the disk will be an incomplete because it's
- * changing without synchronization with hibernation snap shot.
- * At resume, we just make swap_for_hibernation=false. We can forget
- * used maps easily.
- */
-void hibernation_freeze_swap(void)
-{
- int i;
-
- spin_lock(&swap_lock);
-
- printk(KERN_INFO "PM: Freeze Swap\n");
- swap_for_hibernation = true;
- for (i = 0; i < MAX_SWAPFILES; i++)
- hibernation_offset[i] = 1;
- spin_unlock(&swap_lock);
-}
-
-void hibernation_thaw_swap(void)
-{
- spin_lock(&swap_lock);
- if (swap_for_hibernation) {
- printk(KERN_INFO "PM: Thaw Swap\n");
- swap_for_hibernation = false;
- }
- spin_unlock(&swap_lock);
-}
-
-/*
- * Because updateing swap_map[] can make not-saved-status-change,
- * we use our own easy allocator.
- * Please see kernel/power/swap.c, Used swaps are recorded into
- * RB-tree.
- */
-swp_entry_t get_swap_for_hibernation(int type)
-{
- pgoff_t off;
- swp_entry_t val = {0};
- struct swap_info_struct *si;
-
- spin_lock(&swap_lock);
-
- si = swap_info[type];
- if (!si || !(si->flags & SWP_WRITEOK))
- goto done;
-
- for (off = hibernation_offset[type]; off < si->max; ++off) {
- if (!si->swap_map[off])
- break;
- }
- if (off < si->max) {
- val = swp_entry(type, off);
- hibernation_offset[type] = off + 1;
- }
-done:
- spin_unlock(&swap_lock);
- return val;
-}
-
-void swap_free_for_hibernation(swp_entry_t ent)
-{
- /* Nothing to do */
-}
-
/*
* Find the swap type that corresponds to given device (if any).
*
@@ -2081,7 +2047,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
p->flags |= SWP_SOLIDSTATE;
p->cluster_next = 1 + (random32() % p->highest_bit);
}
- if (discard_swap(p) == 0)
+ if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD))
p->flags |= SWP_DISCARDABLE;
}