mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-13 19:36:40 +07:00
2b566fa55b
After the previous patch to cfq, there's no ioc_get_changed() user left. This patch yanks out ioc_{ioprio|cgroup|get}_changed() and all related stuff. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
158 lines
4.7 KiB
C
158 lines
4.7 KiB
C
#ifndef IOCONTEXT_H
|
|
#define IOCONTEXT_H
|
|
|
|
#include <linux/radix-tree.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/workqueue.h>
|
|
|
|
enum {
|
|
ICQ_EXITED = 1 << 2,
|
|
};
|
|
|
|
/*
|
|
* An io_cq (icq) is association between an io_context (ioc) and a
|
|
* request_queue (q). This is used by elevators which need to track
|
|
* information per ioc - q pair.
|
|
*
|
|
* Elevator can request use of icq by setting elevator_type->icq_size and
|
|
* ->icq_align. Both size and align must be larger than that of struct
|
|
* io_cq and elevator can use the tail area for private information. The
|
|
* recommended way to do this is defining a struct which contains io_cq as
|
|
* the first member followed by private members and using its size and
|
|
* align. For example,
|
|
*
|
|
* struct snail_io_cq {
|
|
* struct io_cq icq;
|
|
* int poke_snail;
|
|
* int feed_snail;
|
|
* };
|
|
*
|
|
* struct elevator_type snail_elv_type {
|
|
* .ops = { ... },
|
|
* .icq_size = sizeof(struct snail_io_cq),
|
|
* .icq_align = __alignof__(struct snail_io_cq),
|
|
* ...
|
|
* };
|
|
*
|
|
* If icq_size is set, block core will manage icq's. All requests will
|
|
* have its ->elv.icq field set before elevator_ops->elevator_set_req_fn()
|
|
* is called and be holding a reference to the associated io_context.
|
|
*
|
|
* Whenever a new icq is created, elevator_ops->elevator_init_icq_fn() is
|
|
* called and, on destruction, ->elevator_exit_icq_fn(). Both functions
|
|
* are called with both the associated io_context and queue locks held.
|
|
*
|
|
* Elevator is allowed to lookup icq using ioc_lookup_icq() while holding
|
|
* queue lock but the returned icq is valid only until the queue lock is
|
|
* released. Elevators can not and should not try to create or destroy
|
|
* icq's.
|
|
*
|
|
* As icq's are linked from both ioc and q, the locking rules are a bit
|
|
* complex.
|
|
*
|
|
* - ioc lock nests inside q lock.
|
|
*
|
|
* - ioc->icq_list and icq->ioc_node are protected by ioc lock.
|
|
* q->icq_list and icq->q_node by q lock.
|
|
*
|
|
* - ioc->icq_tree and ioc->icq_hint are protected by ioc lock, while icq
|
|
* itself is protected by q lock. However, both the indexes and icq
|
|
* itself are also RCU managed and lookup can be performed holding only
|
|
* the q lock.
|
|
*
|
|
* - icq's are not reference counted. They are destroyed when either the
|
|
* ioc or q goes away. Each request with icq set holds an extra
|
|
* reference to ioc to ensure it stays until the request is completed.
|
|
*
|
|
* - Linking and unlinking icq's are performed while holding both ioc and q
|
|
* locks. Due to the lock ordering, q exit is simple but ioc exit
|
|
* requires reverse-order double lock dance.
|
|
*/
|
|
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 int flags;
|
|
};
|
|
|
|
/*
|
|
* 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 active_ref;
|
|
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;
|
|
};
|
|
|
|
/**
|
|
* get_io_context_active - get active reference on ioc
|
|
* @ioc: ioc of interest
|
|
*
|
|
* Only iocs with active reference can issue new IOs. This function
|
|
* acquires an active reference on @ioc. The caller must already have an
|
|
* active reference on @ioc.
|
|
*/
|
|
static inline void get_io_context_active(struct io_context *ioc)
|
|
{
|
|
WARN_ON_ONCE(atomic_long_read(&ioc->refcount) <= 0);
|
|
WARN_ON_ONCE(atomic_read(&ioc->active_ref) <= 0);
|
|
atomic_long_inc(&ioc->refcount);
|
|
atomic_inc(&ioc->active_ref);
|
|
}
|
|
|
|
static inline void ioc_task_link(struct io_context *ioc)
|
|
{
|
|
get_io_context_active(ioc);
|
|
|
|
WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0);
|
|
atomic_inc(&ioc->nr_tasks);
|
|
}
|
|
|
|
struct task_struct;
|
|
#ifdef CONFIG_BLOCK
|
|
void put_io_context(struct io_context *ioc);
|
|
void put_io_context_active(struct io_context *ioc);
|
|
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);
|
|
#else
|
|
struct io_context;
|
|
static inline void put_io_context(struct io_context *ioc) { }
|
|
static inline void exit_io_context(struct task_struct *task) { }
|
|
#endif
|
|
|
|
#endif
|