bca4b914b5
Remove ->dead_key field from cfq_io_context to shrink its size to 128 bytes. (64 bytes for 32-bit hosts) Use lower bit in ->key as dead-mark, instead of moving key to separate field. After this for dead cfq_io_context we got cic->key != cfqd automatically. Thus, io_context's last-hit cache should work without changing. Now to check ->key for non-dead state compare it with cfqd, instead of checking ->key for non-null value as it was before. Plus remove obsolete race protection in cfq_cic_lookup. This race gone after v2.6.24-1728-g4ac845a Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
93 lines
2 KiB
C
93 lines
2 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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struct cfq_queue;
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struct cfq_io_context {
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void *key;
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struct cfq_queue *cfqq[2];
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struct io_context *ioc;
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unsigned long last_end_request;
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unsigned long ttime_total;
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unsigned long ttime_samples;
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unsigned long ttime_mean;
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struct list_head queue_list;
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struct hlist_node cic_list;
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void (*dtor)(struct io_context *); /* destructor */
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void (*exit)(struct io_context *); /* called on task exit */
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struct rcu_head rcu_head;
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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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unsigned short ioprio_changed;
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#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
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unsigned short cgroup_changed;
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#endif
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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 radix_root;
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struct hlist_head cic_list;
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void *ioc_data;
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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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int put_io_context(struct io_context *ioc);
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void exit_io_context(struct task_struct *task);
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struct io_context *get_io_context(gfp_t gfp_flags, int node);
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struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
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void copy_io_context(struct io_context **pdst, struct io_context **psrc);
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#else
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static inline void exit_io_context(struct task_struct *task)
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{
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}
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struct io_context;
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static inline int put_io_context(struct io_context *ioc)
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{
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return 1;
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}
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#endif
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#endif
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