Btrfs: tune the chunk allocation to 5% of the FS as metadata (e5bc2458) · Commits · 戴 / test

fs/btrfs/extent-tree.c

+18 −4

Original line number	Diff line number	Diff line
		@@ -580,6 +580,15 @@ static u64 div_factor(u64 num, int factor)
		return num;
		}

		static u64 div_factor_fine(u64 num, int factor)
		{
		if (factor == 100)
		return num;
		num *= factor;
		do_div(num, 100);
		return num;
		}

		u64 btrfs_find_block_group(struct btrfs_root *root,
		u64 search_start, u64 search_hint, int owner)
		{
		@@ -3218,9 +3227,11 @@ static void force_metadata_allocation(struct btrfs_fs_info *info)
		rcu_read_unlock();
		}

		static int should_alloc_chunk(struct btrfs_space_info *sinfo, u64 alloc_bytes)
		static int should_alloc_chunk(struct btrfs_root *root,
		struct btrfs_space_info *sinfo, u64 alloc_bytes)
		{
		u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
		u64 thresh;

		if (sinfo->bytes_used + sinfo->bytes_reserved +
		alloc_bytes + 256 * 1024 * 1024 < num_bytes)
		@@ -3230,8 +3241,10 @@ static int should_alloc_chunk(struct btrfs_space_info *sinfo, u64 alloc_bytes)
		alloc_bytes < div_factor(num_bytes, 8))
		return 0;

		if (num_bytes > 256 * 1024 * 1024 &&
		sinfo->bytes_used < div_factor(num_bytes, 3))
		thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
		thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));

		if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
		return 0;

		return 1;
		@@ -3265,7 +3278,8 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
		goto out;
		}

		if (!force && !should_alloc_chunk(space_info, alloc_bytes)) {
		if (!force && !should_alloc_chunk(extent_root, space_info,
		alloc_bytes)) {
		spin_unlock(&space_info->lock);
		goto out;
		}