868f2f0b72
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>
123 lines
3.3 KiB
C
123 lines
3.3 KiB
C
#ifndef INT_BLK_MQ_H
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#define INT_BLK_MQ_H
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struct blk_mq_tag_set;
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struct blk_mq_ctx {
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struct {
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spinlock_t lock;
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struct list_head rq_list;
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} ____cacheline_aligned_in_smp;
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unsigned int cpu;
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unsigned int index_hw;
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unsigned int last_tag ____cacheline_aligned_in_smp;
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/* incremented at dispatch time */
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unsigned long rq_dispatched[2];
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unsigned long rq_merged;
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/* incremented at completion time */
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unsigned long ____cacheline_aligned_in_smp rq_completed[2];
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struct request_queue *queue;
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struct kobject kobj;
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} ____cacheline_aligned_in_smp;
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void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
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void blk_mq_freeze_queue(struct request_queue *q);
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void blk_mq_free_queue(struct request_queue *q);
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int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
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void blk_mq_wake_waiters(struct request_queue *q);
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/*
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* CPU hotplug helpers
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*/
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struct blk_mq_cpu_notifier;
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void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,
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int (*fn)(void *, unsigned long, unsigned int),
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void *data);
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void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier);
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void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier);
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void blk_mq_cpu_init(void);
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void blk_mq_enable_hotplug(void);
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void blk_mq_disable_hotplug(void);
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/*
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* CPU -> queue mappings
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*/
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extern unsigned int *blk_mq_make_queue_map(struct blk_mq_tag_set *set);
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extern int blk_mq_update_queue_map(unsigned int *map, unsigned int nr_queues,
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const struct cpumask *online_mask);
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extern int blk_mq_hw_queue_to_node(unsigned int *map, unsigned int);
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/*
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* sysfs helpers
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*/
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extern int blk_mq_sysfs_register(struct request_queue *q);
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extern void blk_mq_sysfs_unregister(struct request_queue *q);
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extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
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extern void blk_mq_rq_timed_out(struct request *req, bool reserved);
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void blk_mq_release(struct request_queue *q);
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/*
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* Basic implementation of sparser bitmap, allowing the user to spread
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* the bits over more cachelines.
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*/
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struct blk_align_bitmap {
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unsigned long word;
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unsigned long depth;
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} ____cacheline_aligned_in_smp;
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static inline struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
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unsigned int cpu)
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{
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return per_cpu_ptr(q->queue_ctx, cpu);
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}
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/*
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* This assumes per-cpu software queueing queues. They could be per-node
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* as well, for instance. For now this is hardcoded as-is. Note that we don't
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* care about preemption, since we know the ctx's are persistent. This does
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* mean that we can't rely on ctx always matching the currently running CPU.
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*/
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static inline struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
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{
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return __blk_mq_get_ctx(q, get_cpu());
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}
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static inline void blk_mq_put_ctx(struct blk_mq_ctx *ctx)
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{
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put_cpu();
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}
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struct blk_mq_alloc_data {
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/* input parameter */
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struct request_queue *q;
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unsigned int flags;
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/* input & output parameter */
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struct blk_mq_ctx *ctx;
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struct blk_mq_hw_ctx *hctx;
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};
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static inline void blk_mq_set_alloc_data(struct blk_mq_alloc_data *data,
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struct request_queue *q, unsigned int flags,
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struct blk_mq_ctx *ctx, struct blk_mq_hw_ctx *hctx)
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{
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data->q = q;
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data->flags = flags;
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data->ctx = ctx;
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data->hctx = hctx;
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}
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static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
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{
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return hctx->nr_ctx && hctx->tags;
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}
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#endif
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