1b29d4986SJoe Thornber /* 2b29d4986SJoe Thornber * Copyright (C) 2017 Red Hat. All rights reserved. 3b29d4986SJoe Thornber * 4b29d4986SJoe Thornber * This file is released under the GPL. 5b29d4986SJoe Thornber */ 6b29d4986SJoe Thornber 7b29d4986SJoe Thornber #ifndef DM_CACHE_BACKGROUND_WORK_H 8b29d4986SJoe Thornber #define DM_CACHE_BACKGROUND_WORK_H 9b29d4986SJoe Thornber 10b29d4986SJoe Thornber #include <linux/vmalloc.h> 11b29d4986SJoe Thornber #include "dm-cache-policy.h" 12b29d4986SJoe Thornber 13b29d4986SJoe Thornber /*----------------------------------------------------------------*/ 14b29d4986SJoe Thornber 15*22c40e13SJoe Thornber /* 16*22c40e13SJoe Thornber * The cache policy decides what background work should be performed, 17*22c40e13SJoe Thornber * such as promotions, demotions and writebacks. The core cache target 18*22c40e13SJoe Thornber * is in charge of performing the work, and does so when it sees fit. 19*22c40e13SJoe Thornber * 20*22c40e13SJoe Thornber * The background_tracker acts as a go between. Keeping track of future 21*22c40e13SJoe Thornber * work that the policy has decided upon, and handing (issuing) it to 22*22c40e13SJoe Thornber * the core target when requested. 23*22c40e13SJoe Thornber * 24*22c40e13SJoe Thornber * There is no locking in this, so calls will probably need to be 25*22c40e13SJoe Thornber * protected with a spinlock. 26*22c40e13SJoe Thornber */ 27*22c40e13SJoe Thornber 28b29d4986SJoe Thornber struct background_work; 29b29d4986SJoe Thornber struct background_tracker; 30b29d4986SJoe Thornber 31b29d4986SJoe Thornber /* 32*22c40e13SJoe Thornber * Create a new tracker, it will not be able to queue more than 33*22c40e13SJoe Thornber * 'max_work' entries. 34b29d4986SJoe Thornber */ 35b29d4986SJoe Thornber struct background_tracker *btracker_create(unsigned max_work); 36*22c40e13SJoe Thornber 37*22c40e13SJoe Thornber /* 38*22c40e13SJoe Thornber * Destroy the tracker. No issued, but not complete, work should 39*22c40e13SJoe Thornber * exist when this is called. It is fine to have queued but unissued 40*22c40e13SJoe Thornber * work. 41*22c40e13SJoe Thornber */ 42b29d4986SJoe Thornber void btracker_destroy(struct background_tracker *b); 43b29d4986SJoe Thornber 44b29d4986SJoe Thornber unsigned btracker_nr_writebacks_queued(struct background_tracker *b); 45b29d4986SJoe Thornber unsigned btracker_nr_demotions_queued(struct background_tracker *b); 46b29d4986SJoe Thornber 47b29d4986SJoe Thornber /* 48*22c40e13SJoe Thornber * Queue some work within the tracker. 'work' should point to the work 49*22c40e13SJoe Thornber * to queue, this will be copied (ownership doesn't pass). If pwork 50*22c40e13SJoe Thornber * is not NULL then it will be set to point to the tracker's internal 51*22c40e13SJoe Thornber * copy of the work. 52*22c40e13SJoe Thornber * 53b29d4986SJoe Thornber * returns -EINVAL iff the work is already queued. -ENOMEM if the work 54b29d4986SJoe Thornber * couldn't be queued for another reason. 55b29d4986SJoe Thornber */ 56b29d4986SJoe Thornber int btracker_queue(struct background_tracker *b, 57b29d4986SJoe Thornber struct policy_work *work, 58b29d4986SJoe Thornber struct policy_work **pwork); 59b29d4986SJoe Thornber 60b29d4986SJoe Thornber /* 61*22c40e13SJoe Thornber * Hands out the next piece of work to be performed. 62b29d4986SJoe Thornber * Returns -ENODATA if there's no work. 63b29d4986SJoe Thornber */ 64b29d4986SJoe Thornber int btracker_issue(struct background_tracker *b, struct policy_work **work); 65*22c40e13SJoe Thornber 66*22c40e13SJoe Thornber /* 67*22c40e13SJoe Thornber * Informs the tracker that the work has been completed and it may forget 68*22c40e13SJoe Thornber * about it. 69*22c40e13SJoe Thornber */ 70*22c40e13SJoe Thornber void btracker_complete(struct background_tracker *b, struct policy_work *op); 71*22c40e13SJoe Thornber 72*22c40e13SJoe Thornber /* 73*22c40e13SJoe Thornber * Predicate to see if an origin block is already scheduled for promotion. 74*22c40e13SJoe Thornber */ 75b29d4986SJoe Thornber bool btracker_promotion_already_present(struct background_tracker *b, 76b29d4986SJoe Thornber dm_oblock_t oblock); 77b29d4986SJoe Thornber 78b29d4986SJoe Thornber /*----------------------------------------------------------------*/ 79b29d4986SJoe Thornber 80b29d4986SJoe Thornber #endif 81