Commit 428c8e03 authored by David Sterba's avatar David Sterba
Browse files

btrfs: simplify percent calculation helpers, rename div_factor 



The div_factor* helpers calculate fraction or percentage fraction. The
name is a bit confusing, we use it only for percentage calculations and
there are two helpers.

There's a helper mult_frac that's for general fractions, that tries to
be accurate but we multiply and divide by small numbers so we can use
the div_u64 helper.

Rename the div_factor* helpers and use 1..100 percentage range, also drop
the case checking for percentage == 100, it's never hit.

The conversions:

* div_factor calculates tenths and the numbers need to be adjusted
* div_factor_fine is direct replacement

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 20af93d9

fs/btrfs/block-group.c

+3 −3
Original line number Diff line number Diff line
@@ -1551,7 +1551,7 @@ static bool should_reclaim_block_group(struct btrfs_block_group *bg, u64 bytes_f 
	if (reclaim_thresh == 0)

		return false;



	thresh = div_factor_fine(bg->length, reclaim_thresh);

	thresh = mult_perc(bg->length, reclaim_thresh);



	/*

	 * If we were below the threshold before don't reclaim, we are likely a
@@ -3523,13 +3523,13 @@ static int should_alloc_chunk(struct btrfs_fs_info *fs_info, 
	 */

	if (force == CHUNK_ALLOC_LIMITED) {

		thresh = btrfs_super_total_bytes(fs_info->super_copy);

		thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));

		thresh = max_t(u64, SZ_64M, mult_perc(thresh, 1));



		if (sinfo->total_bytes - bytes_used < thresh)

			return 1;

	}



	if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))

	if (bytes_used + SZ_2M < mult_perc(sinfo->total_bytes, 80))

		return 0;

	return 1;

}

fs/btrfs/block-rsv.c

+2 −2
Original line number Diff line number Diff line
@@ -227,7 +227,7 @@ int btrfs_block_rsv_add(struct btrfs_fs_info *fs_info, 
	return ret;

}



int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)

int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_percent)

{

	u64 num_bytes = 0;

	int ret = -ENOSPC;
@@ -236,7 +236,7 @@ int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor) 
		return 0;



	spin_lock(&block_rsv->lock);

	num_bytes = div_factor(block_rsv->size, min_factor);

	num_bytes = mult_perc(block_rsv->size, min_percent);

	if (block_rsv->reserved >= num_bytes)

		ret = 0;

	spin_unlock(&block_rsv->lock);

fs/btrfs/block-rsv.h

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info, 
int btrfs_block_rsv_add(struct btrfs_fs_info *fs_info,

			struct btrfs_block_rsv *block_rsv, u64 num_bytes,

			enum btrfs_reserve_flush_enum flush);

int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor);

int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_percent);

int btrfs_block_rsv_refill(struct btrfs_fs_info *fs_info,

			   struct btrfs_block_rsv *block_rsv, u64 min_reserved,

			   enum btrfs_reserve_flush_enum flush);

fs/btrfs/free-space-cache.c

+1 −2
Original line number Diff line number Diff line
@@ -2726,8 +2726,7 @@ static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group, 
		btrfs_mark_bg_unused(block_group);

	} else if (bg_reclaim_threshold &&

		   reclaimable_unusable >=

		   div_factor_fine(block_group->zone_capacity,

				   bg_reclaim_threshold)) {

		   mult_perc(block_group->zone_capacity, bg_reclaim_threshold)) {

		btrfs_mark_bg_to_reclaim(block_group);

	}

fs/btrfs/misc.h

+2 −14
Original line number Diff line number Diff line
@@ -40,22 +40,10 @@ static inline void cond_wake_up_nomb(struct wait_queue_head *wq) 
		wake_up(wq);

}



static inline u64 div_factor(u64 num, int factor)

static inline u64 mult_perc(u64 num, u32 percent)

{

	if (factor == 10)

		return num;

	num *= factor;

	return div_u64(num, 10);

	return div_u64(num * percent, 100);

}



static inline u64 div_factor_fine(u64 num, int factor)

{

	if (factor == 100)

		return num;

	num *= factor;

	return div_u64(num, 100);

}



/* Copy of is_power_of_two that is 64bit safe */

static inline bool is_power_of_two_u64(u64 n)

{