![Tejun Heo](/assets/img/avatar_default.png)
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
|
|
#define IOCONTEXT_H
|
|
|
|
#include <linux/radix-tree.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/workqueue.h>
|
|
|
|
enum {
|
|
ICQ_IOPRIO_CHANGED,
|
|
ICQ_CGROUP_CHANGED,
|
|
};
|
|
|
|
struct io_cq {
|
|
struct request_queue *q;
|
|
struct io_context *ioc;
|
|
|
|
/*
|
|
* q_node and ioc_node link io_cq through icq_list of q and ioc
|
|
* respectively. Both fields are unused once ioc_exit_icq() is
|
|
* called and shared with __rcu_icq_cache and __rcu_head which are
|
|
* used for RCU free of io_cq.
|
|
*/
|
|
union {
|
|
struct list_head q_node;
|
|
struct kmem_cache *__rcu_icq_cache;
|
|
};
|
|
union {
|
|
struct hlist_node ioc_node;
|
|
struct rcu_head __rcu_head;
|
|
};
|
|
|
|
unsigned long changed;
|
|
};
|
|
|
|
/*
|
|
* I/O subsystem state of the associated processes. It is refcounted
|
|
* and kmalloc'ed. These could be shared between processes.
|
|
*/
|
|
struct io_context {
|
|
atomic_long_t refcount;
|
|
atomic_t nr_tasks;
|
|
|
|
/* all the fields below are protected by this lock */
|
|
spinlock_t lock;
|
|
|
|
unsigned short ioprio;
|
|
|
|
/*
|
|
* For request batching
|
|
*/
|
|
int nr_batch_requests; /* Number of requests left in the batch */
|
|
unsigned long last_waited; /* Time last woken after wait for request */
|
|
|
|
struct radix_tree_root icq_tree;
|
|
struct io_cq __rcu *icq_hint;
|
|
struct hlist_head icq_list;
|
|
|
|
struct work_struct release_work;
|
|
};
|
|
|
|
static inline struct io_context *ioc_task_link(struct io_context *ioc)
|
|
{
|
|
/*
|
|
* if ref count is zero, don't allow sharing (ioc is going away, it's
|
|
* a race).
|
|
*/
|
|
if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
|
|
atomic_inc(&ioc->nr_tasks);
|
|
return ioc;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
struct task_struct;
|
|
#ifdef CONFIG_BLOCK
|
|
void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
|
|
void exit_io_context(struct task_struct *task);
|
|
struct io_context *get_task_io_context(struct task_struct *task,
|
|
gfp_t gfp_flags, int node);
|
|
void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
|
|
void ioc_cgroup_changed(struct io_context *ioc);
|
|
#else
|
|
struct io_context;
|
|
static inline void put_io_context(struct io_context *ioc,
|
|
struct request_queue *locked_q) { }
|
|
static inline void exit_io_context(struct task_struct *task) { }
|
|
#endif
|
|
|
|
#endif
|