2 * Copyright (C) 2017 Red Hat. All rights reserved.
4 * This file is released under the GPL.
7 #include "dm-cache-background-tracker.h"
9 /*----------------------------------------------------------------*/
11 #define DM_MSG_PREFIX "dm-background-tracker"
14 struct list_head list
;
16 struct policy_work work
;
19 struct background_tracker
{
21 atomic_t pending_promotes
;
22 atomic_t pending_writebacks
;
23 atomic_t pending_demotes
;
25 struct list_head issued
;
26 struct list_head queued
;
27 struct rb_root pending
;
29 struct kmem_cache
*work_cache
;
32 struct background_tracker
*btracker_create(unsigned max_work
)
34 struct background_tracker
*b
= kmalloc(sizeof(*b
), GFP_KERNEL
);
36 b
->max_work
= max_work
;
37 atomic_set(&b
->pending_promotes
, 0);
38 atomic_set(&b
->pending_writebacks
, 0);
39 atomic_set(&b
->pending_demotes
, 0);
41 INIT_LIST_HEAD(&b
->issued
);
42 INIT_LIST_HEAD(&b
->queued
);
45 b
->work_cache
= KMEM_CACHE(bt_work
, 0);
47 DMERR("couldn't create mempool for background work items");
54 EXPORT_SYMBOL_GPL(btracker_create
);
56 void btracker_destroy(struct background_tracker
*b
)
58 kmem_cache_destroy(b
->work_cache
);
61 EXPORT_SYMBOL_GPL(btracker_destroy
);
63 static int cmp_oblock(dm_oblock_t lhs
, dm_oblock_t rhs
)
65 if (from_oblock(lhs
) < from_oblock(rhs
))
68 if (from_oblock(rhs
) < from_oblock(lhs
))
74 static bool __insert_pending(struct background_tracker
*b
,
79 struct rb_node
**new = &b
->pending
.rb_node
, *parent
= NULL
;
82 w
= container_of(*new, struct bt_work
, node
);
85 cmp
= cmp_oblock(w
->work
.oblock
, nw
->work
.oblock
);
87 new = &((*new)->rb_left
);
90 new = &((*new)->rb_right
);
97 rb_link_node(&nw
->node
, parent
, new);
98 rb_insert_color(&nw
->node
, &b
->pending
);
103 static struct bt_work
*__find_pending(struct background_tracker
*b
,
108 struct rb_node
**new = &b
->pending
.rb_node
;
111 w
= container_of(*new, struct bt_work
, node
);
113 cmp
= cmp_oblock(w
->work
.oblock
, oblock
);
115 new = &((*new)->rb_left
);
118 new = &((*new)->rb_right
);
124 return *new ? w
: NULL
;
128 static void update_stats(struct background_tracker
*b
, struct policy_work
*w
, int delta
)
132 atomic_add(delta
, &b
->pending_promotes
);
136 atomic_add(delta
, &b
->pending_demotes
);
139 case POLICY_WRITEBACK
:
140 atomic_add(delta
, &b
->pending_writebacks
);
145 unsigned btracker_nr_writebacks_queued(struct background_tracker
*b
)
147 return atomic_read(&b
->pending_writebacks
);
149 EXPORT_SYMBOL_GPL(btracker_nr_writebacks_queued
);
151 unsigned btracker_nr_demotions_queued(struct background_tracker
*b
)
153 return atomic_read(&b
->pending_demotes
);
155 EXPORT_SYMBOL_GPL(btracker_nr_demotions_queued
);
157 static bool max_work_reached(struct background_tracker
*b
)
163 int btracker_queue(struct background_tracker
*b
,
164 struct policy_work
*work
,
165 struct policy_work
**pwork
)
172 if (max_work_reached(b
))
175 w
= kmem_cache_alloc(b
->work_cache
, GFP_NOWAIT
);
179 memcpy(&w
->work
, work
, sizeof(*work
));
181 if (!__insert_pending(b
, w
)) {
183 * There was a race, we'll just ignore this second
184 * bit of work for the same oblock.
186 kmem_cache_free(b
->work_cache
, w
);
192 list_add(&w
->list
, &b
->issued
);
194 list_add(&w
->list
, &b
->queued
);
195 update_stats(b
, &w
->work
, 1);
199 EXPORT_SYMBOL_GPL(btracker_queue
);
202 * Returns -ENODATA if there's no work.
204 int btracker_issue(struct background_tracker
*b
, struct policy_work
**work
)
208 if (list_empty(&b
->queued
))
211 w
= list_first_entry(&b
->queued
, struct bt_work
, list
);
212 list_move(&w
->list
, &b
->issued
);
217 EXPORT_SYMBOL_GPL(btracker_issue
);
219 void btracker_complete(struct background_tracker
*b
,
220 struct policy_work
*op
)
222 struct bt_work
*w
= container_of(op
, struct bt_work
, work
);
224 update_stats(b
, &w
->work
, -1);
225 rb_erase(&w
->node
, &b
->pending
);
227 kmem_cache_free(b
->work_cache
, w
);
229 EXPORT_SYMBOL_GPL(btracker_complete
);
231 bool btracker_promotion_already_present(struct background_tracker
*b
,
234 return __find_pending(b
, oblock
) != NULL
;
236 EXPORT_SYMBOL_GPL(btracker_promotion_already_present
);
238 /*----------------------------------------------------------------*/