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path: root/fs/btrfs/free-space-cache.c
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Diffstat (limited to 'fs/btrfs/free-space-cache.c')
-rw-r--r--fs/btrfs/free-space-cache.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 5edcee3a617..5c2caad7621 100644
--- 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++;