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authorOmar Sandoval <osandov@fb.com>2016-09-17 08:38:44 -0600
committerJens Axboe <axboe@fb.com>2016-09-17 08:38:44 -0600
commit88459642cba452630326b9cab1c651e09577d4e4 (patch)
treecd7ecd917b294a92ff827b0e7dab526f0069547f /block/blk-mq.c
parent703fd1c0f177219e3a84e6c095c31dc566514d81 (diff)
blk-mq: abstract tag allocation out into sbitmap library
This is a generally useful data structure, so make it available to anyone else who might want to use it. It's also a nice cleanup separating the allocation logic from the rest of the tag handling logic. The code is behind a new Kconfig option, CONFIG_SBITMAP, which is only selected by CONFIG_BLOCK for now. This should be a complete noop functionality-wise. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r--block/blk-mq.c112
1 files changed, 32 insertions, 80 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0cb93625d812..6603be18064e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -41,42 +41,23 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx);
*/
static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
{
- unsigned int i;
-
- for (i = 0; i < hctx->ctx_map.size; i++)
- if (hctx->ctx_map.map[i].word)
- return true;
-
- return false;
-}
-
-static inline struct blk_align_bitmap *get_bm(struct blk_mq_hw_ctx *hctx,
- struct blk_mq_ctx *ctx)
-{
- return &hctx->ctx_map.map[ctx->index_hw / hctx->ctx_map.bits_per_word];
+ return sbitmap_any_bit_set(&hctx->ctx_map);
}
-#define CTX_TO_BIT(hctx, ctx) \
- ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
-
/*
* Mark this ctx as having pending work in this hardware queue
*/
static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
- struct blk_align_bitmap *bm = get_bm(hctx, ctx);
-
- if (!test_bit(CTX_TO_BIT(hctx, ctx), &bm->word))
- set_bit(CTX_TO_BIT(hctx, ctx), &bm->word);
+ if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw))
+ sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw);
}
static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
- struct blk_align_bitmap *bm = get_bm(hctx, ctx);
-
- clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word);
+ sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
}
void blk_mq_freeze_queue_start(struct request_queue *q)
@@ -755,38 +736,36 @@ static bool blk_mq_attempt_merge(struct request_queue *q,
return false;
}
+struct flush_busy_ctx_data {
+ struct blk_mq_hw_ctx *hctx;
+ struct list_head *list;
+};
+
+static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
+{
+ struct flush_busy_ctx_data *flush_data = data;
+ struct blk_mq_hw_ctx *hctx = flush_data->hctx;
+ struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
+
+ sbitmap_clear_bit(sb, bitnr);
+ spin_lock(&ctx->lock);
+ list_splice_tail_init(&ctx->rq_list, flush_data->list);
+ spin_unlock(&ctx->lock);
+ return true;
+}
+
/*
* Process software queues that have been marked busy, splicing them
* to the for-dispatch
*/
static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
{
- struct blk_mq_ctx *ctx;
- int i;
-
- for (i = 0; i < hctx->ctx_map.size; i++) {
- struct blk_align_bitmap *bm = &hctx->ctx_map.map[i];
- unsigned int off, bit;
-
- if (!bm->word)
- continue;
-
- bit = 0;
- off = i * hctx->ctx_map.bits_per_word;
- do {
- bit = find_next_bit(&bm->word, bm->depth, bit);
- if (bit >= bm->depth)
- break;
-
- ctx = hctx->ctxs[bit + off];
- clear_bit(bit, &bm->word);
- spin_lock(&ctx->lock);
- list_splice_tail_init(&ctx->rq_list, list);
- spin_unlock(&ctx->lock);
+ struct flush_busy_ctx_data data = {
+ .hctx = hctx,
+ .list = list,
+ };
- bit++;
- } while (1);
- }
+ sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
}
static inline unsigned int queued_to_index(unsigned int queued)
@@ -1609,32 +1588,6 @@ fail:
return NULL;
}
-static void blk_mq_free_bitmap(struct blk_mq_ctxmap *bitmap)
-{
- kfree(bitmap->map);
-}
-
-static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap *bitmap, int node)
-{
- unsigned int bpw = 8, total, num_maps, i;
-
- bitmap->bits_per_word = bpw;
-
- num_maps = ALIGN(nr_cpu_ids, bpw) / bpw;
- bitmap->map = kzalloc_node(num_maps * sizeof(struct blk_align_bitmap),
- GFP_KERNEL, node);
- if (!bitmap->map)
- return -ENOMEM;
-
- total = nr_cpu_ids;
- for (i = 0; i < num_maps; i++) {
- bitmap->map[i].depth = min(total, bitmap->bits_per_word);
- total -= bitmap->map[i].depth;
- }
-
- return 0;
-}
-
/*
* 'cpu' is going away. splice any existing rq_list entries from this
* software queue to the hw queue dispatch list, and ensure that it
@@ -1700,7 +1653,7 @@ static void blk_mq_exit_hctx(struct request_queue *q,
blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
blk_free_flush_queue(hctx->fq);
- blk_mq_free_bitmap(&hctx->ctx_map);
+ sbitmap_free(&hctx->ctx_map);
}
static void blk_mq_exit_hw_queues(struct request_queue *q,
@@ -1760,7 +1713,8 @@ static int blk_mq_init_hctx(struct request_queue *q,
if (!hctx->ctxs)
goto unregister_cpu_notifier;
- if (blk_mq_alloc_bitmap(&hctx->ctx_map, node))
+ if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL,
+ node))
goto free_ctxs;
hctx->nr_ctx = 0;
@@ -1787,7 +1741,7 @@ static int blk_mq_init_hctx(struct request_queue *q,
if (set->ops->exit_hctx)
set->ops->exit_hctx(hctx, hctx_idx);
free_bitmap:
- blk_mq_free_bitmap(&hctx->ctx_map);
+ sbitmap_free(&hctx->ctx_map);
free_ctxs:
kfree(hctx->ctxs);
unregister_cpu_notifier:
@@ -1863,8 +1817,6 @@ static void blk_mq_map_swqueue(struct request_queue *q,
mutex_unlock(&q->sysfs_lock);
queue_for_each_hw_ctx(q, hctx, i) {
- struct blk_mq_ctxmap *map = &hctx->ctx_map;
-
/*
* If no software queues are mapped to this hardware queue,
* disable it and free the request entries.
@@ -1890,7 +1842,7 @@ static void blk_mq_map_swqueue(struct request_queue *q,
* This is more accurate and more efficient than looping
* over all possibly mapped software queues.
*/
- map->size = DIV_ROUND_UP(hctx->nr_ctx, map->bits_per_word);
+ sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
/*
* Initialize batch roundrobin counts