13bd94003SHeinz Mauelshagen /* SPDX-License-Identifier: GPL-2.0-only */ 2b29d4986SJoe Thornber /* 3b29d4986SJoe Thornber * Copyright (C) 2017 Red Hat. All rights reserved. 4b29d4986SJoe Thornber * 5b29d4986SJoe Thornber * This file is released under the GPL. 6b29d4986SJoe Thornber */ 7b29d4986SJoe Thornber 8b29d4986SJoe Thornber #ifndef DM_CACHE_BACKGROUND_WORK_H 9b29d4986SJoe Thornber #define DM_CACHE_BACKGROUND_WORK_H 10b29d4986SJoe Thornber 11b29d4986SJoe Thornber #include <linux/vmalloc.h> 12b29d4986SJoe Thornber #include "dm-cache-policy.h" 13b29d4986SJoe Thornber 14b29d4986SJoe Thornber /*----------------------------------------------------------------*/ 15b29d4986SJoe Thornber 1622c40e13SJoe Thornber /* 1722c40e13SJoe Thornber * The cache policy decides what background work should be performed, 1822c40e13SJoe Thornber * such as promotions, demotions and writebacks. The core cache target 1922c40e13SJoe Thornber * is in charge of performing the work, and does so when it sees fit. 2022c40e13SJoe Thornber * 2122c40e13SJoe Thornber * The background_tracker acts as a go between. Keeping track of future 2222c40e13SJoe Thornber * work that the policy has decided upon, and handing (issuing) it to 2322c40e13SJoe Thornber * the core target when requested. 2422c40e13SJoe Thornber * 2522c40e13SJoe Thornber * There is no locking in this, so calls will probably need to be 2622c40e13SJoe Thornber * protected with a spinlock. 2722c40e13SJoe Thornber */ 2822c40e13SJoe Thornber 29b29d4986SJoe Thornber struct background_work; 30b29d4986SJoe Thornber struct background_tracker; 31b29d4986SJoe Thornber 32b29d4986SJoe Thornber /* 3322c40e13SJoe Thornber * Create a new tracker, it will not be able to queue more than 3422c40e13SJoe Thornber * 'max_work' entries. 35b29d4986SJoe Thornber */ 36*86a3238cSHeinz Mauelshagen struct background_tracker *btracker_create(unsigned int max_work); 3722c40e13SJoe Thornber 3822c40e13SJoe Thornber /* 3922c40e13SJoe Thornber * Destroy the tracker. No issued, but not complete, work should 4022c40e13SJoe Thornber * exist when this is called. It is fine to have queued but unissued 4122c40e13SJoe Thornber * work. 4222c40e13SJoe Thornber */ 43b29d4986SJoe Thornber void btracker_destroy(struct background_tracker *b); 44b29d4986SJoe Thornber 45*86a3238cSHeinz Mauelshagen unsigned int btracker_nr_writebacks_queued(struct background_tracker *b); 46*86a3238cSHeinz Mauelshagen unsigned int btracker_nr_demotions_queued(struct background_tracker *b); 47b29d4986SJoe Thornber 48b29d4986SJoe Thornber /* 4922c40e13SJoe Thornber * Queue some work within the tracker. 'work' should point to the work 5022c40e13SJoe Thornber * to queue, this will be copied (ownership doesn't pass). If pwork 5122c40e13SJoe Thornber * is not NULL then it will be set to point to the tracker's internal 5222c40e13SJoe Thornber * copy of the work. 5322c40e13SJoe Thornber * 54b29d4986SJoe Thornber * returns -EINVAL iff the work is already queued. -ENOMEM if the work 55b29d4986SJoe Thornber * couldn't be queued for another reason. 56b29d4986SJoe Thornber */ 57b29d4986SJoe Thornber int btracker_queue(struct background_tracker *b, 58b29d4986SJoe Thornber struct policy_work *work, 59b29d4986SJoe Thornber struct policy_work **pwork); 60b29d4986SJoe Thornber 61b29d4986SJoe Thornber /* 6222c40e13SJoe Thornber * Hands out the next piece of work to be performed. 63b29d4986SJoe Thornber * Returns -ENODATA if there's no work. 64b29d4986SJoe Thornber */ 65b29d4986SJoe Thornber int btracker_issue(struct background_tracker *b, struct policy_work **work); 6622c40e13SJoe Thornber 6722c40e13SJoe Thornber /* 6822c40e13SJoe Thornber * Informs the tracker that the work has been completed and it may forget 6922c40e13SJoe Thornber * about it. 7022c40e13SJoe Thornber */ 7122c40e13SJoe Thornber void btracker_complete(struct background_tracker *b, struct policy_work *op); 7222c40e13SJoe Thornber 7322c40e13SJoe Thornber /* 7422c40e13SJoe Thornber * Predicate to see if an origin block is already scheduled for promotion. 7522c40e13SJoe Thornber */ 76b29d4986SJoe Thornber bool btracker_promotion_already_present(struct background_tracker *b, 77b29d4986SJoe Thornber dm_oblock_t oblock); 78b29d4986SJoe Thornber 79b29d4986SJoe Thornber /*----------------------------------------------------------------*/ 80b29d4986SJoe Thornber 81b29d4986SJoe Thornber #endif 82