diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 14:13:23 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 14:13:23 -0800 |
commit | 3e12cefbe143b4947171ff92dd50024c4841e291 (patch) | |
tree | f58ec23a4092576ed08843cca5f5443a32106bd1 /block/blk-mq-tag.c | |
parent | Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-block (diff) | |
parent | block: remove unused function blk_bio_map_sg (diff) | |
download | linux-dev-3e12cefbe143b4947171ff92dd50024c4841e291.tar.xz linux-dev-3e12cefbe143b4947171ff92dd50024c4841e291.zip |
Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block
Pull core block IO changes from Jens Axboe:
"This contains:
- A series from Christoph that cleans up and refactors various parts
of the REQ_BLOCK_PC handling. Contributions in that series from
Dongsu Park and Kent Overstreet as well.
- CFQ:
- A bug fix for cfq for realtime IO scheduling from Jeff Moyer.
- A stable patch fixing a potential crash in CFQ in OOM
situations. From Konstantin Khlebnikov.
- blk-mq:
- Add support for tag allocation policies, from Shaohua. This is
a prep patch enabling libata (and other SCSI parts) to use the
blk-mq tagging, instead of rolling their own.
- Various little tweaks from Keith and Mike, in preparation for
DM blk-mq support.
- Minor little fixes or tweaks from me.
- A double free error fix from Tony Battersby.
- The partition 4k issue fixes from Matthew and Boaz.
- Add support for zero+unprovision for blkdev_issue_zeroout() from
Martin"
* 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits)
block: remove unused function blk_bio_map_sg
block: handle the null_mapped flag correctly in blk_rq_map_user_iov
blk-mq: fix double-free in error path
block: prevent request-to-request merging with gaps if not allowed
blk-mq: make blk_mq_run_queues() static
dm: fix multipath regression due to initializing wrong request
cfq-iosched: handle failure of cfq group allocation
block: Quiesce zeroout wrapper
block: rewrite and split __bio_copy_iov()
block: merge __bio_map_user_iov into bio_map_user_iov
block: merge __bio_map_kern into bio_map_kern
block: pass iov_iter to the BLOCK_PC mapping functions
block: add a helper to free bio bounce buffer pages
block: use blk_rq_map_user_iov to implement blk_rq_map_user
block: simplify bio_map_kern
block: mark blk-mq devices as stackable
block: keep established cmd_flags when cloning into a blk-mq request
block: add blk-mq support to blk_insert_cloned_request()
block: require blk_rq_prep_clone() be given an initialized clone request
blk-mq: add tag allocation policy
...
Diffstat (limited to 'block/blk-mq-tag.c')
-rw-r--r-- | block/blk-mq-tag.c | 81 |
1 files changed, 50 insertions, 31 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 60c9d4a93fe4..d53a764b05ea 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -140,35 +140,39 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, return atomic_read(&hctx->nr_active) < depth; } -static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag) +static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag, + bool nowrap) { - int tag, org_last_tag, end; - bool wrap = last_tag != 0; + int tag, org_last_tag = last_tag; - org_last_tag = last_tag; - end = bm->depth; - do { -restart: - tag = find_next_zero_bit(&bm->word, end, last_tag); - if (unlikely(tag >= end)) { + while (1) { + tag = find_next_zero_bit(&bm->word, bm->depth, last_tag); + if (unlikely(tag >= bm->depth)) { /* - * We started with an offset, start from 0 to + * We started with an offset, and we didn't reset the + * offset to 0 in a failure case, so start from 0 to * exhaust the map. */ - if (wrap) { - wrap = false; - end = org_last_tag; - last_tag = 0; - goto restart; + if (org_last_tag && last_tag && !nowrap) { + last_tag = org_last_tag = 0; + continue; } return -1; } + + if (!test_and_set_bit(tag, &bm->word)) + break; + last_tag = tag + 1; - } while (test_and_set_bit(tag, &bm->word)); + if (last_tag >= bm->depth - 1) + last_tag = 0; + } return tag; } +#define BT_ALLOC_RR(tags) (tags->alloc_policy == BLK_TAG_ALLOC_RR) + /* * Straight forward bitmap tag implementation, where each bit is a tag * (cleared == free, and set == busy). The small twist is using per-cpu @@ -181,7 +185,7 @@ restart: * until the map is exhausted. */ static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt, - unsigned int *tag_cache) + unsigned int *tag_cache, struct blk_mq_tags *tags) { unsigned int last_tag, org_last_tag; int index, i, tag; @@ -193,15 +197,24 @@ static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt, index = TAG_TO_INDEX(bt, last_tag); for (i = 0; i < bt->map_nr; i++) { - tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag)); + tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag), + BT_ALLOC_RR(tags)); if (tag != -1) { tag += (index << bt->bits_per_word); goto done; } - last_tag = 0; - if (++index >= bt->map_nr) + /* + * Jump to next index, and reset the last tag to be the + * first tag of that index + */ + index++; + last_tag = (index << bt->bits_per_word); + + if (index >= bt->map_nr) { index = 0; + last_tag = 0; + } } *tag_cache = 0; @@ -212,7 +225,7 @@ static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt, * up using the specific cached tag. */ done: - if (tag == org_last_tag) { + if (tag == org_last_tag || unlikely(BT_ALLOC_RR(tags))) { last_tag = tag + 1; if (last_tag >= bt->depth - 1) last_tag = 0; @@ -241,13 +254,13 @@ static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt, static int bt_get(struct blk_mq_alloc_data *data, struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx, - unsigned int *last_tag) + unsigned int *last_tag, struct blk_mq_tags *tags) { struct bt_wait_state *bs; DEFINE_WAIT(wait); int tag; - tag = __bt_get(hctx, bt, last_tag); + tag = __bt_get(hctx, bt, last_tag, tags); if (tag != -1) return tag; @@ -258,7 +271,7 @@ static int bt_get(struct blk_mq_alloc_data *data, do { prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE); - tag = __bt_get(hctx, bt, last_tag); + tag = __bt_get(hctx, bt, last_tag, tags); if (tag != -1) break; @@ -273,7 +286,7 @@ static int bt_get(struct blk_mq_alloc_data *data, * Retry tag allocation after running the hardware queue, * as running the queue may also have found completions. */ - tag = __bt_get(hctx, bt, last_tag); + tag = __bt_get(hctx, bt, last_tag, tags); if (tag != -1) break; @@ -304,7 +317,7 @@ static unsigned int __blk_mq_get_tag(struct blk_mq_alloc_data *data) int tag; tag = bt_get(data, &data->hctx->tags->bitmap_tags, data->hctx, - &data->ctx->last_tag); + &data->ctx->last_tag, data->hctx->tags); if (tag >= 0) return tag + data->hctx->tags->nr_reserved_tags; @@ -320,7 +333,8 @@ static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_alloc_data *data) return BLK_MQ_TAG_FAIL; } - tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero); + tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero, + data->hctx->tags); if (tag < 0) return BLK_MQ_TAG_FAIL; @@ -392,7 +406,8 @@ void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, BUG_ON(real_tag >= tags->nr_tags); bt_clear_tag(&tags->bitmap_tags, real_tag); - *last_tag = real_tag; + if (likely(tags->alloc_policy == BLK_TAG_ALLOC_FIFO)) + *last_tag = real_tag; } else { BUG_ON(tag >= tags->nr_reserved_tags); bt_clear_tag(&tags->breserved_tags, tag); @@ -509,6 +524,7 @@ static int bt_alloc(struct blk_mq_bitmap_tags *bt, unsigned int depth, bt->bs = kzalloc(BT_WAIT_QUEUES * sizeof(*bt->bs), GFP_KERNEL); if (!bt->bs) { kfree(bt->map); + bt->map = NULL; return -ENOMEM; } @@ -529,10 +545,12 @@ static void bt_free(struct blk_mq_bitmap_tags *bt) } static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags, - int node) + int node, int alloc_policy) { unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; + tags->alloc_policy = alloc_policy; + if (bt_alloc(&tags->bitmap_tags, depth, node, false)) goto enomem; if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, node, true)) @@ -546,7 +564,8 @@ enomem: } struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, - unsigned int reserved_tags, int node) + unsigned int reserved_tags, + int node, int alloc_policy) { struct blk_mq_tags *tags; @@ -562,7 +581,7 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, tags->nr_tags = total_tags; tags->nr_reserved_tags = reserved_tags; - return blk_mq_init_bitmap_tags(tags, node); + return blk_mq_init_bitmap_tags(tags, node, alloc_policy); } void blk_mq_free_tags(struct blk_mq_tags *tags) |