lib: Introduce generic list_sort function

[safe/jmp/linux-2.6] / fs / btrfs / free-space-cache.c

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 5edcee3..cb2849f 100644 (file)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -259,7 +259,9 @@ static int link_free_space(struct btrfs_block_group_cache *block_group,
 
 static void recalculate_thresholds(struct btrfs_block_group_cache *block_group)
 {
-       u64 max_bytes, possible_bytes;
+       u64 max_bytes;
+       u64 bitmap_bytes;
+       u64 extent_bytes;
 
        /*
         * The goal is to keep the total amount of memory used per 1gb of space
@@ -269,22 +271,27 @@ static void recalculate_thresholds(struct btrfs_block_group_cache *block_group)
        max_bytes = MAX_CACHE_BYTES_PER_GIG *
                (div64_u64(block_group->key.offset, 1024 * 1024 * 1024));
 
-       possible_bytes = (block_group->total_bitmaps * PAGE_CACHE_SIZE) +
-               (sizeof(struct btrfs_free_space) *
-                block_group->extents_thresh);
+       /*
+        * we want to account for 1 more bitmap than what we have so we can make
+        * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
+        * we add more bitmaps.
+        */
+       bitmap_bytes = (block_group->total_bitmaps + 1) * PAGE_CACHE_SIZE;
 
-       if (possible_bytes > max_bytes) {
-               int extent_bytes = max_bytes -
-                       (block_group->total_bitmaps * PAGE_CACHE_SIZE);
+       if (bitmap_bytes >= max_bytes) {
+               block_group->extents_thresh = 0;
+               return;
+       }
 
-               if (extent_bytes <= 0) {
-                       block_group->extents_thresh = 0;
-                       return;
-               }
+       /*
+        * we want the extent entry threshold to always be at most 1/2 the maxw
+        * bytes we can have, or whatever is less than that.
+        */
+       extent_bytes = max_bytes - bitmap_bytes;
+       extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
 
-               block_group->extents_thresh = extent_bytes /
-                       (sizeof(struct btrfs_free_space));
-       }
+       block_group->extents_thresh =
+               div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
 }
 
 static void bitmap_clear_bits(struct btrfs_block_group_cache *block_group,
@@ -403,6 +410,7 @@ static void add_new_bitmap(struct btrfs_block_group_cache *block_group,
        BUG_ON(block_group->total_bitmaps >= max_bitmaps);
 
        info->offset = offset_to_bitmap(block_group, offset);
+       info->bytes = 0;
        link_free_space(block_group, info);
        block_group->total_bitmaps++;
 
@@ -1288,7 +1296,7 @@ again:
                        window_start = entry->offset;
                        window_free = entry->bytes;
                        last = entry;
-                       max_extent = 0;
+                       max_extent = entry->bytes;
                } else {
                        last = next;
                        window_free += next->bytes;