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authorJohn Garry <john.garry@huawei.com>2020-08-19 23:20:25 +0800
committerJens Axboe <axboe@kernel.dk>2020-09-03 15:20:47 -0600
commita0235d230f3245aa4bd70b514d5effb24be61acd (patch)
tree6a1bec801b10efc12e6a3dcec35df21731a47ff7 /block/blk-mq.h
parent32bc15afed04bd73e29d713d8db47818d6aa89af (diff)
blk-mq: Relocate hctx_may_queue()
blk-mq.h and blk-mq-tag.h include on each other, which is less than ideal. Locate hctx_may_queue() to blk-mq.h, as it is not really tag specific code. In this way, we can drop the blk-mq-tag.h include of blk-mq.h Signed-off-by: John Garry <john.garry@huawei.com> Tested-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.h')
-rw-r--r--block/blk-mq.h32
1 files changed, 32 insertions, 0 deletions
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 3acdb56065e1..56dc37c21908 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -259,4 +259,36 @@ static inline struct blk_plug *blk_mq_plug(struct request_queue *q,
return NULL;
}
+/*
+ * For shared tag users, we track the number of currently active users
+ * and attempt to provide a fair share of the tag depth for each of them.
+ */
+static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
+ struct sbitmap_queue *bt)
+{
+ unsigned int depth, users;
+
+ if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
+ return true;
+ if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+ return true;
+
+ /*
+ * Don't try dividing an ant
+ */
+ if (bt->sb.depth == 1)
+ return true;
+
+ users = atomic_read(&hctx->tags->active_queues);
+ if (!users)
+ return true;
+
+ /*
+ * Allow at least some tags
+ */
+ depth = max((bt->sb.depth + users - 1) / users, 4U);
+ return atomic_read(&hctx->nr_active) < depth;
+}
+
+
#endif