litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'drivers/message/i2o/exec-osm.c')

-rw-r--r--

1 files changed, 1 insertions, 1 deletions


diff --git a/drivers/message/i2o/exec-osm.c b/drivers/message/i2o/exec-osm.c index a539d3b61e76..5278aad92bc4 100644 --- a/drivers/message/i2o/exec-osm.c +++ b/drivers/message/i2o/exec-osm.c
@@ -367,7 +367,7 @@ static int i2o_exec_remove(struct device *dev)
367		367
368	/**	368	/**
369	* i2o_exec_lct_modified - Called on LCT NOTIFY reply	369	* i2o_exec_lct_modified - Called on LCT NOTIFY reply
370	* @work: work struct for a specific controller	370	* @_work: work struct for a specific controller
371	*	371	*
372	* This function handles asynchronus LCT NOTIFY replies. It parses the	372	* This function handles asynchronus LCT NOTIFY replies. It parses the
373	* new LCT and if the buffer for the LCT was to small sends a LCT NOTIFY	373	* new LCT and if the buffer for the LCT was to small sends a LCT NOTIFY

/* * Deadline i/o scheduler. * * Copyright (C) 2002 Jens Axboe <axboe@kernel.dk> */ #include <linux/kernel.h> #include <linux/fs.h> #include <linux/blkdev.h> #include <linux/elevator.h> #include <linux/bio.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/compiler.h> #include <linux/rbtree.h> /* * See Documentation/block/deadline-iosched.txt */ static const int read_expire = HZ / 2; /* max time before a read is submitted. */ static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */ static const int writes_starved = 2; /* max times reads can starve a write */ static const int fifo_batch = 16; /* # of sequential requests treated as one by the above parameters. For throughput. */ struct deadline_data { /* * run time data */ /* * requests (deadline_rq s) are present on both sort_list and fifo_list */ struct rb_root sort_list[2]; struct list_head fifo_list[2]; /* * next in sort order. read, write or both are NULL */ struct request *next_rq[2]; unsigned int batching; /* number of sequential requests made */ sector_t last_sector; /* head position */ unsigned int starved; /* times reads have starved writes */ /* * settings that change how the i/o scheduler behaves */ int fifo_expire[2]; int fifo_batch; int writes_starved; int front_merges; }; static void deadline_move_request(struct deadline_data *, struct request *); static inline struct rb_root * deadline_rb_root(struct deadline_data *dd, struct request *rq) { return &dd->sort_list[rq_data_dir(rq)]; } /* * get the request after `rq' in sector-sorted order */ static inline struct request * deadline_latter_request(struct request *rq) { struct rb_node *node = rb_next(&rq->rb_node); if (node) return rb_entry_rq(node); return NULL; } static void deadline_add_rq_rb(struct deadline_data *dd, struct request *rq) { struct rb_root *root = deadline_rb_root(dd, rq); elv_rb_add(root, rq); } static inline void deadline_del_rq_rb(struct deadline_data *dd, struct request *rq) { const int data_dir = rq_data_dir(rq); if (dd->next_rq[data_dir] == rq) dd->next_rq[data_dir] = deadline_latter_request(rq); elv_rb_del(deadline_rb_root(dd, rq), rq); } /* * add rq to rbtree and fifo */ static void deadline_add_request(struct request_queue *q, struct request *rq) { struct deadline_data *dd = q->elevator->elevator_data; const int data_dir = rq_data_dir(rq); deadline_add_rq_rb(dd, rq); /* * set expire time and add to fifo list */ rq->fifo_time = jiffies + dd->fifo_expire[data_dir]; list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]); } /* * remove rq from rbtree and fifo. */ static void deadline_remove_request(struct request_queue *q, struct request *rq) { struct deadline_data *dd = q->elevator->elevator_data; rq_fifo_clear(rq); deadline_del_rq_rb(dd, rq); } static int deadline_merge(struct request_queue *q, struct request **req, struct bio *bio) { struct deadline_data *dd = q->elevator->elevator_data; struct request *__rq; int ret; /* * check for front merge */ if (dd->front_merges) { sector_t sector = bio_end_sector(bio); __rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector); if (__rq) { BUG_ON(sector != blk_rq_pos(__rq)); if (elv_rq_merge_ok(__rq, bio)) { ret = ELEVATOR_FRONT_MERGE; goto out; } } } return ELEVATOR_NO_MERGE; out: *req = __rq; return ret; } static void deadline_merged_request(struct request_queue *q, struct request *req, int type) { struct deadline_data *dd = q->elevator->elevator_data; /* * if the merge was a front merge, we need to reposition request */ if (type == ELEVATOR_FRONT_MERGE) { elv_rb_del(deadline_rb_root(dd, req), req); deadline_add_rq_rb(dd, req); } } static void deadline_merged_requests(struct request_queue *q, struct request *req, struct request *next) { /* * if next expires before rq, assign its expire time to rq * and move into next position (next will be deleted) in fifo */ if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) { if (time_before(next->fifo_time, req->fifo_time)) { list_move(&req->queuelist, &next->queuelist); req->fifo_time = next->fifo_time; } } /* * kill knowledge of next, this one is a goner */ deadline_remove_request(q, next); } /* * move request from sort list to dispatch queue. */ static inline void deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq) { struct request_queue *q = rq->q; deadline_remove_request(q, rq); elv_dispatch_add_tail(q, rq); } /* * move an entry to dispatch queue */ static void deadline_move_request(struct deadline_data *dd, struct request *rq) { const int data_dir = rq_data_dir(rq); dd->next_rq[READ] = NULL; dd->next_rq[WRITE] = NULL; dd->next_rq[data_dir] = deadline_latter_request(rq); dd->last_sector = rq_end_sector(rq); /* * take it off the sort and fifo list, move * to dispatch queue */ deadline_move_to_dispatch(dd, rq); } /* * deadline_check_fifo returns 0 if there are no expired requests on the fifo, * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) */ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) { struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next); /* * rq is expired! */ if (time_after_eq(jiffies, rq->fifo_time)) return 1; return 0; } /* * deadline_dispatch_requests selects the best request according to * read/write expire, fifo_batch, etc */ static int deadline_dispatch_requests(struct request_queue *q, int force) { struct deadline_data *dd = q->elevator->elevator_data; const int reads = !list_empty(&dd->fifo_list[READ]); const int writes = !list_empty(&dd->fifo_list[WRITE]); struct request *rq; int data_dir; /* * batches are currently reads XOR writes */ if (dd->next_rq[WRITE]) rq = dd->next_rq[WRITE]; else rq = dd->next_rq[READ]; if (rq && dd->batching < dd->fifo_batch) /* we have a next request are still entitled to batch */ goto dispatch_request; /* * at this point we are not running a batch. select the appropriate * data direction (read / write) */ if (reads) { BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ])); if (writes && (dd->starved++ >= dd->writes_starved)) goto dispatch_writes; data_dir = READ; goto dispatch_find_request; } /* * there are either no reads or writes have been starved */ if (writes) { dispatch_writes: BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE])); dd->starved = 0; data_dir = WRITE; goto dispatch_find_request; } return 0; dispatch_find_request: /* * we are not running a batch, find best request for selected data_dir */ if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) { /* * A deadline has expired, the last request was in the other * direction, or we have run out of higher-sectored requests. * Start again from the request with the earliest expiry time. */ rq = rq_entry_fifo(dd->fifo_list[data_dir].next); } else { /* * The last req was the same dir and we have a next request in * sort order. No expired requests so continue on from here. */ rq = dd->next_rq[data_dir]; } dd->batching = 0; dispatch_request: /* * rq is the selected appropriate request. */ dd->batching++; deadline_move_request(dd, rq); return 1; } static void deadline_exit_queue(struct elevator_queue *e) { struct deadline_data *dd = e->elevator_data; BUG_ON(!list_empty(&dd->fifo_list[READ])); BUG_ON(!list_empty(&dd->fifo_list[WRITE])); kfree(dd); } /* * initialize elevator private data (deadline_data). */ static int deadline_init_queue(struct request_queue *q, struct elevator_type *e) { struct deadline_data *dd; struct elevator_queue *eq; eq = elevator_alloc(q, e); if (!eq) return -ENOMEM; dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node); if (!dd) { kobject_put(&eq->kobj); return -ENOMEM; } eq->elevator_data = dd; INIT_LIST_HEAD(&dd->fifo_list[READ]); INIT_LIST_HEAD(&dd->fifo_list[WRITE]); dd->sort_list[READ] = RB_ROOT; dd->sort_list[WRITE] = RB_ROOT; dd->fifo_expire[READ] = read_expire; dd->fifo_expire[WRITE] = write_expire; dd->writes_starved = writes_starved; dd->front_merges = 1; dd->fifo_batch = fifo_batch; spin_lock_irq(q->queue_lock); q->elevator = eq; spin_unlock_irq(q->queue_lock); return 0; } /* * sysfs parts below */ static ssize_t deadline_var_show(int var, char *page) { return sprintf(page, "%d\n", var); } static ssize_t deadline_var_store(int *var, const char *page, size_t count) { char *p = (char *) page; *var = simple_strtol(p, &p, 10); return count; } #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ static ssize_t __FUNC(struct elevator_queue *e, char *page) \ { \ struct deadline_data *dd = e->elevator_data; \ int __data = __VAR; \ if (__CONV) \ __data = jiffies_to_msecs(__data); \ return deadline_var_show(__data, (page)); \ } SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1); SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1); SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0); SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0); SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0); #undef SHOW_FUNCTION #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \ { \ struct deadline_data *dd = e->elevator_data; \ int __data; \ int ret = deadline_var_store(&__data, (page), count); \ if (__data < (MIN)) \ __data = (MIN); \ else if (__data > (MAX)) \ __data = (MAX); \ if (__CONV) \ *(__PTR) = msecs_to_jiffies(__data); \ else \ *(__PTR) = __data; \ return ret; \ } STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1); STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1); STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0); STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0); STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0); #undef STORE_FUNCTION #define DD_ATTR(name) \ __ATTR(name, S_IRUGO|S_IWUSR, deadline_##name##_show, \ deadline_##name##_store) static struct elv_fs_entry deadline_attrs[] = { DD_ATTR(read_expire), DD_ATTR(write_expire), DD_ATTR(writes_starved), DD_ATTR(front_merges), DD_ATTR(fifo_batch), __ATTR_NULL }; static struct elevator_type iosched_deadline = { .ops = { .elevator_merge_fn = deadline_merge, .elevator_merged_fn = deadline_merged_request, .elevator_merge_req_fn = deadline_merged_requests, .elevator_dispatch_fn = deadline_dispatch_requests, .elevator_add_req_fn = deadline_add_request, .elevator_former_req_fn = elv_rb_former_request, .elevator_latter_req_fn = elv_rb_latter_request, .elevator_init_fn = deadline_init_queue, .elevator_exit_fn = deadline_exit_queue, }, .elevator_attrs = deadline_attrs, .elevator_name = "deadline", .elevator_owner = THIS_MODULE, }; static int __init deadline_init(void) { return elv_register(&iosched_deadline); } static void __exit deadline_exit(void) { elv_unregister(&iosched_deadline); } module_init(deadline_init); module_exit(deadline_exit); MODULE_AUTHOR("Jens Axboe"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("deadline IO scheduler");


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