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authorKeith Busch <keith.busch@intel.com>2015-12-18 01:08:14 +0100
committerJens Axboe <axboe@fb.com>2016-02-09 20:42:17 +0100
commit868f2f0b72068a097508b6e8870a8950fd8eb7ef (patch)
treef88aed0e80d7b08c7a7907d8bcf4ff6df0150b66 /block/blk-mq.h
parentcfq-iosched: Allow parent cgroup to preempt its child (diff)
downloadlinux-868f2f0b72068a097508b6e8870a8950fd8eb7ef.tar.xz
linux-868f2f0b72068a097508b6e8870a8950fd8eb7ef.zip
blk-mq: dynamic h/w context count
The hardware's provided queue count may change at runtime with resource provisioning. This patch allows a block driver to alter the number of h/w queues available when its resource count changes. The main part is a new blk-mq API to request a new number of h/w queues for a given live tag set. The new API freezes all queues using that set, then adjusts the allocated count prior to remapping these to CPUs. The bulk of the rest just shifts where h/w contexts and all their artifacts are allocated and freed. The number of max h/w contexts is capped to the number of possible cpus since there is no use for more than that. As such, all pre-allocated memory for pointers need to account for the max possible rather than the initial number of queues. A side effect of this is that the blk-mq will proceed successfully as long as it can allocate at least one h/w context. Previously it would fail request queue initialization if less than the requested number was allocated. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq.h')
-rw-r--r--block/blk-mq.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/block/blk-mq.h b/block/blk-mq.h
index eaede8e45c9c..9087b11037b7 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -57,6 +57,7 @@ extern int blk_mq_hw_queue_to_node(unsigned int *map, unsigned int);
*/
extern int blk_mq_sysfs_register(struct request_queue *q);
extern void blk_mq_sysfs_unregister(struct request_queue *q);
+extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
extern void blk_mq_rq_timed_out(struct request *req, bool reserved);