fba10109a4
The policy tick() method is normally called from interrupt context. Both the mq and smq policies do some bottom half work for the tick method in their map functions. However if no IO is going through the cache, then that bottom half work doesn't occur. With these policies this means recently hit entries do not age and do not get written back as early as we'd like. Fix this by introducing a new 'can_block' parameter to the tick() method. When this is set the bottom half work occurs immediately. 'can_block' is set when the tick method is called every second by the core target (not in interrupt context). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
164 lines
4.4 KiB
C
164 lines
4.4 KiB
C
/*
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* Copyright (C) 2012 Red Hat. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#ifndef DM_CACHE_POLICY_INTERNAL_H
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#define DM_CACHE_POLICY_INTERNAL_H
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#include <linux/vmalloc.h>
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#include "dm-cache-policy.h"
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/*----------------------------------------------------------------*/
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/*
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* Little inline functions that simplify calling the policy methods.
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*/
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static inline int policy_map(struct dm_cache_policy *p, dm_oblock_t oblock,
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bool can_block, bool can_migrate, bool discarded_oblock,
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struct bio *bio, struct policy_locker *locker,
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struct policy_result *result)
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{
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return p->map(p, oblock, can_block, can_migrate, discarded_oblock, bio, locker, result);
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}
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static inline int policy_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
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{
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BUG_ON(!p->lookup);
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return p->lookup(p, oblock, cblock);
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}
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static inline void policy_set_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
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{
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if (p->set_dirty)
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p->set_dirty(p, oblock);
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}
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static inline void policy_clear_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
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{
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if (p->clear_dirty)
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p->clear_dirty(p, oblock);
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}
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static inline int policy_load_mapping(struct dm_cache_policy *p,
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dm_oblock_t oblock, dm_cblock_t cblock,
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uint32_t hint, bool hint_valid)
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{
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return p->load_mapping(p, oblock, cblock, hint, hint_valid);
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}
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static inline int policy_walk_mappings(struct dm_cache_policy *p,
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policy_walk_fn fn, void *context)
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{
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return p->walk_mappings ? p->walk_mappings(p, fn, context) : 0;
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}
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static inline int policy_writeback_work(struct dm_cache_policy *p,
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dm_oblock_t *oblock,
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dm_cblock_t *cblock,
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bool critical_only)
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{
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return p->writeback_work ? p->writeback_work(p, oblock, cblock, critical_only) : -ENOENT;
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}
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static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
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{
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p->remove_mapping(p, oblock);
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}
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static inline int policy_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock)
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{
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return p->remove_cblock(p, cblock);
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}
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static inline void policy_force_mapping(struct dm_cache_policy *p,
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dm_oblock_t current_oblock, dm_oblock_t new_oblock)
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{
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return p->force_mapping(p, current_oblock, new_oblock);
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}
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static inline dm_cblock_t policy_residency(struct dm_cache_policy *p)
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{
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return p->residency(p);
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}
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static inline void policy_tick(struct dm_cache_policy *p, bool can_block)
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{
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if (p->tick)
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return p->tick(p, can_block);
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}
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static inline int policy_emit_config_values(struct dm_cache_policy *p, char *result,
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unsigned maxlen, ssize_t *sz_ptr)
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{
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ssize_t sz = *sz_ptr;
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if (p->emit_config_values)
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return p->emit_config_values(p, result, maxlen, sz_ptr);
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DMEMIT("0 ");
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*sz_ptr = sz;
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return 0;
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}
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static inline int policy_set_config_value(struct dm_cache_policy *p,
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const char *key, const char *value)
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{
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return p->set_config_value ? p->set_config_value(p, key, value) : -EINVAL;
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}
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/*----------------------------------------------------------------*/
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/*
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* Some utility functions commonly used by policies and the core target.
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*/
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static inline size_t bitset_size_in_bytes(unsigned nr_entries)
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{
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return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
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}
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static inline unsigned long *alloc_bitset(unsigned nr_entries)
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{
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size_t s = bitset_size_in_bytes(nr_entries);
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return vzalloc(s);
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}
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static inline void clear_bitset(void *bitset, unsigned nr_entries)
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{
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size_t s = bitset_size_in_bytes(nr_entries);
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memset(bitset, 0, s);
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}
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static inline void free_bitset(unsigned long *bits)
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{
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vfree(bits);
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}
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/*----------------------------------------------------------------*/
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/*
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* Creates a new cache policy given a policy name, a cache size, an origin size and the block size.
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*/
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struct dm_cache_policy *dm_cache_policy_create(const char *name, dm_cblock_t cache_size,
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sector_t origin_size, sector_t block_size);
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/*
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* Destroys the policy. This drops references to the policy module as well
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* as calling it's destroy method. So always use this rather than calling
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* the policy->destroy method directly.
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*/
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void dm_cache_policy_destroy(struct dm_cache_policy *p);
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/*
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* In case we've forgotten.
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*/
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const char *dm_cache_policy_get_name(struct dm_cache_policy *p);
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const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p);
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size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p);
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/*----------------------------------------------------------------*/
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#endif /* DM_CACHE_POLICY_INTERNAL_H */
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