linux/drivers/md/dm-cache-background-tracker.h
Mikulas Patocka 346dbf1b13 dm-cache: fix warnings about duplicate slab caches
The commit 4c39529663 adds a warning about duplicate cache names if
CONFIG_DEBUG_VM is selected. These warnings are triggered by the dm-cache
code.

The dm-cache code allocates a slab cache for each device. This commit
changes it to allocate just one slab cache in the module init function.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 4c39529663 ("slab: Warn on duplicate cache names when DEBUG_VM=y")
2024-11-11 17:04:39 +01:00

90 lines
2.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2017 Red Hat. All rights reserved.
*
* This file is released under the GPL.
*/
#ifndef DM_CACHE_BACKGROUND_WORK_H
#define DM_CACHE_BACKGROUND_WORK_H
#include <linux/vmalloc.h>
#include "dm-cache-policy.h"
/*----------------------------------------------------------------*/
/*
* The cache policy decides what background work should be performed,
* such as promotions, demotions and writebacks. The core cache target
* is in charge of performing the work, and does so when it sees fit.
*
* The background_tracker acts as a go between. Keeping track of future
* work that the policy has decided upon, and handing (issuing) it to
* the core target when requested.
*
* There is no locking in this, so calls will probably need to be
* protected with a spinlock.
*/
struct bt_work {
struct list_head list;
struct rb_node node;
struct policy_work work;
};
extern struct kmem_cache *btracker_work_cache;
struct background_work;
struct background_tracker;
/*
* Create a new tracker, it will not be able to queue more than
* 'max_work' entries.
*/
struct background_tracker *btracker_create(unsigned int max_work);
/*
* Destroy the tracker. No issued, but not complete, work should
* exist when this is called. It is fine to have queued but unissued
* work.
*/
void btracker_destroy(struct background_tracker *b);
unsigned int btracker_nr_writebacks_queued(struct background_tracker *b);
unsigned int btracker_nr_demotions_queued(struct background_tracker *b);
/*
* Queue some work within the tracker. 'work' should point to the work
* to queue, this will be copied (ownership doesn't pass). If pwork
* is not NULL then it will be set to point to the tracker's internal
* copy of the work.
*
* returns -EINVAL iff the work is already queued. -ENOMEM if the work
* couldn't be queued for another reason.
*/
int btracker_queue(struct background_tracker *b,
struct policy_work *work,
struct policy_work **pwork);
/*
* Hands out the next piece of work to be performed.
* Returns -ENODATA if there's no work.
*/
int btracker_issue(struct background_tracker *b, struct policy_work **work);
/*
* Informs the tracker that the work has been completed and it may forget
* about it.
*/
void btracker_complete(struct background_tracker *b, struct policy_work *op);
/*
* Predicate to see if an origin block is already scheduled for promotion.
*/
bool btracker_promotion_already_present(struct background_tracker *b,
dm_oblock_t oblock);
/*----------------------------------------------------------------*/
#endif