7e5a879449
With kmem_cache managed by blk-ioc, io_cq exit/release can be moved to blk-ioc too. The odd ->io_cq->exit/release() callbacks are replaced with elevator_ops->elevator_exit_icq_fn() with unlinking from both ioc and q, and freeing automatically handled by blk-ioc. The elevator operation only need to perform exit operation specific to the elevator - in cfq's case, exiting the cfqq's. Also, clearing of io_cq's on q detach is moved to block core and automatically performed on elevator switch and q release. Because the q io_cq points to might be freed before RCU callback for the io_cq runs, blk-ioc code should remember to which cache the io_cq needs to be freed when the io_cq is released. New field io_cq->__rcu_icq_cache is added for this purpose. As both the new field and rcu_head are used only after io_cq is released and the q/ioc_node fields aren't, they are put into unions. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
91 lines
2.1 KiB
C
91 lines
2.1 KiB
C
#ifndef IOCONTEXT_H
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#define IOCONTEXT_H
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#include <linux/radix-tree.h>
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#include <linux/rcupdate.h>
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#include <linux/workqueue.h>
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enum {
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ICQ_IOPRIO_CHANGED,
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ICQ_CGROUP_CHANGED,
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};
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struct io_cq {
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struct request_queue *q;
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struct io_context *ioc;
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/*
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* q_node and ioc_node link io_cq through icq_list of q and ioc
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* respectively. Both fields are unused once ioc_exit_icq() is
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* called and shared with __rcu_icq_cache and __rcu_head which are
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* used for RCU free of io_cq.
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*/
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union {
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struct list_head q_node;
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struct kmem_cache *__rcu_icq_cache;
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};
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union {
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struct hlist_node ioc_node;
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struct rcu_head __rcu_head;
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};
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unsigned long changed;
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};
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/*
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* I/O subsystem state of the associated processes. It is refcounted
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* and kmalloc'ed. These could be shared between processes.
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*/
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struct io_context {
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atomic_long_t refcount;
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atomic_t nr_tasks;
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/* all the fields below are protected by this lock */
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spinlock_t lock;
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unsigned short ioprio;
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/*
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* For request batching
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*/
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int nr_batch_requests; /* Number of requests left in the batch */
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unsigned long last_waited; /* Time last woken after wait for request */
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struct radix_tree_root icq_tree;
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struct io_cq __rcu *icq_hint;
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struct hlist_head icq_list;
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struct work_struct release_work;
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};
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static inline struct io_context *ioc_task_link(struct io_context *ioc)
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{
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/*
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* if ref count is zero, don't allow sharing (ioc is going away, it's
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* a race).
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*/
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if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
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atomic_inc(&ioc->nr_tasks);
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return ioc;
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}
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return NULL;
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}
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struct task_struct;
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#ifdef CONFIG_BLOCK
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void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
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void exit_io_context(struct task_struct *task);
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struct io_context *get_task_io_context(struct task_struct *task,
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gfp_t gfp_flags, int node);
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void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
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void ioc_cgroup_changed(struct io_context *ioc);
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#else
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struct io_context;
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static inline void put_io_context(struct io_context *ioc,
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struct request_queue *locked_q) { }
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static inline void exit_io_context(struct task_struct *task) { }
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#endif
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#endif
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