[PATCH 3/8] bfq: Store full bitmap depth in bfq_data

[Jan Kara <jack@suse.cz>]

Store bitmap depth shift inside bfq_data so that we can use it in
bfq_limit_depth() for proportioning when limiting number of available
request tags for a cgroup.

Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 block/bfq-iosched.c | 10 ++++++----
 block/bfq-iosched.h |  1 +
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index caa7a70d2d5f..1fef82bf4a55 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -6855,7 +6855,9 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd,
 				      struct sbitmap_queue *bt)
 {
 	unsigned int i, j, min_shallow = UINT_MAX;
+	unsigned int depth = 1U << bt->sb.shift;
 
+	bfqd->full_depth_shift = bt->sb.shift;
 	/*
 	 * In-word depths if no bfq_queue is being weight-raised:
 	 * leaving 25% of tags only for sync reads.
@@ -6867,13 +6869,13 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd,
 	 * limit 'something'.
 	 */
 	/* no more than 50% of tags for async I/O */
-	bfqd->word_depths[0][0] = max((1U << bt->sb.shift) >> 1, 1U);
+	bfqd->word_depths[0][0] = max(depth >> 1, 1U);
 	/*
 	 * no more than 75% of tags for sync writes (25% extra tags
 	 * w.r.t. async I/O, to prevent async I/O from starving sync
 	 * writes)
 	 */
-	bfqd->word_depths[0][1] = max(((1U << bt->sb.shift) * 3) >> 2, 1U);
+	bfqd->word_depths[0][1] = max((depth * 3) >> 2, 1U);
 
 	/*
 	 * In-word depths in case some bfq_queue is being weight-
@@ -6883,9 +6885,9 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd,
 	 * shortage.
 	 */
 	/* no more than ~18% of tags for async I/O */
-	bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U);
+	bfqd->word_depths[1][0] = max((depth * 3) >> 4, 1U);
 	/* no more than ~37% of tags for sync writes (~20% extra tags) */
-	bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U);
+	bfqd->word_depths[1][1] = max((depth * 6) >> 4, 1U);
 
 	for (i = 0; i < 2; i++)
 		for (j = 0; j < 2; j++)
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 3787cfb0febb..820cb8c2d1fe 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -769,6 +769,7 @@ struct bfq_data {
 	 * function)
 	 */
 	unsigned int word_depths[2][2];
+	unsigned int full_depth_shift;
 };
 
 enum bfqq_state_flags {
-- 
2.26.2