projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 3bd94003 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
| b29d4986 JT |
2 | /* |
| 3 | * Copyright (C) 2017 Red Hat. All rights reserved. | |
| 4 | * | |
| 5 | * This file is released under the GPL. | |
| 6 | */ | |
| 7 | ||
| 8 | #ifndef DM_CACHE_BACKGROUND_WORK_H | |
| 9 | #define DM_CACHE_BACKGROUND_WORK_H | |
| 10 | ||
| 11 | #include <linux/vmalloc.h> | |
| 12 | #include "dm-cache-policy.h" | |
| 13 | ||
| 14 | /*----------------------------------------------------------------*/ | |
| 15 | ||
| 22c40e13 JT |
16 | /* |
| 17 | * The cache policy decides what background work should be performed, | |
| 18 | * such as promotions, demotions and writebacks. The core cache target | |
| 19 | * is in charge of performing the work, and does so when it sees fit. | |
| 20 | * | |
| 21 | * The background_tracker acts as a go between. Keeping track of future | |
| 22 | * work that the policy has decided upon, and handing (issuing) it to | |
| 23 | * the core target when requested. | |
| 24 | * | |
| 25 | * There is no locking in this, so calls will probably need to be | |
| 26 | * protected with a spinlock. | |
| 27 | */ | |
| 28 | ||
| b29d4986 JT |
29 | struct background_work; |
| 30 | struct background_tracker; | |
| 31 | ||
| 32 | /* | |
| 22c40e13 JT |
33 | * Create a new tracker, it will not be able to queue more than |
| 34 | * 'max_work' entries. | |
| b29d4986 | 35 | */ |
| 86a3238c | 36 | struct background_tracker *btracker_create(unsigned int max_work); |
| 22c40e13 JT |
37 | |
| 38 | /* | |
| 39 | * Destroy the tracker. No issued, but not complete, work should | |
| 40 | * exist when this is called. It is fine to have queued but unissued | |
| 41 | * work. | |
| 42 | */ | |
| b29d4986 JT |
43 | void btracker_destroy(struct background_tracker *b); |
| 44 | ||
| 86a3238c HM |
45 | unsigned int btracker_nr_writebacks_queued(struct background_tracker *b); |
| 46 | unsigned int btracker_nr_demotions_queued(struct background_tracker *b); | |
| b29d4986 JT |
47 | |
| 48 | /* | |
| 22c40e13 JT |
49 | * Queue some work within the tracker. 'work' should point to the work |
| 50 | * to queue, this will be copied (ownership doesn't pass). If pwork | |
| 51 | * is not NULL then it will be set to point to the tracker's internal | |
| 52 | * copy of the work. | |
| 53 | * | |
| b29d4986 JT |
54 | * returns -EINVAL iff the work is already queued. -ENOMEM if the work |
| 55 | * couldn't be queued for another reason. | |
| 56 | */ | |
| 57 | int btracker_queue(struct background_tracker *b, | |
| 58 | struct policy_work *work, | |
| 59 | struct policy_work **pwork); | |
| 60 | ||
| 61 | /* | |
| 22c40e13 | 62 | * Hands out the next piece of work to be performed. |
| b29d4986 JT |
63 | * Returns -ENODATA if there's no work. |
| 64 | */ | |
| 65 | int btracker_issue(struct background_tracker *b, struct policy_work **work); | |
| 22c40e13 JT |
66 | |
| 67 | /* | |
| 68 | * Informs the tracker that the work has been completed and it may forget | |
| 69 | * about it. | |
| 70 | */ | |
| 71 | void btracker_complete(struct background_tracker *b, struct policy_work *op); | |
| 72 | ||
| 73 | /* | |
| 74 | * Predicate to see if an origin block is already scheduled for promotion. | |
| 75 | */ | |
| b29d4986 JT |
76 | bool btracker_promotion_already_present(struct background_tracker *b, |
| 77 | dm_oblock_t oblock); | |
| 78 | ||
| 79 | /*----------------------------------------------------------------*/ | |
| 80 | ||
| 81 | #endif |