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dm persistent metadata: add space map threshold callback

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Add a threshold callback to dm persistent data space maps.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Joe Thornber 2013-05-10 14:37:20 +01:00 committed by Alasdair G Kergon
parent 7c3d3f2a87
commit 2fc48021f4
1 changed files with 76 additions and 1 deletions
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77
drivers/md/persistent-data/dm-space-map-metadata.c
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@ -16,6 +16,55 @@
/*----------------------------------------------------------------*/
/*
* An edge triggered threshold.
*/
struct threshold {
bool threshold_set;
bool value_set;
dm_block_t threshold;
dm_block_t current_value;
dm_sm_threshold_fn fn;
void *context;
};
static void threshold_init(struct threshold *t)
{
t->threshold_set = false;
t->value_set = false;
}
static void set_threshold(struct threshold *t, dm_block_t value,
dm_sm_threshold_fn fn, void *context)
{
t->threshold_set = true;
t->threshold = value;
t->fn = fn;
t->context = context;
}
static bool below_threshold(struct threshold *t, dm_block_t value)
{
return t->threshold_set && value <= t->threshold;
}
static bool threshold_already_triggered(struct threshold *t)
{
return t->value_set && below_threshold(t, t->current_value);
}
static void check_threshold(struct threshold *t, dm_block_t value)
{
if (below_threshold(t, value) &&
!threshold_already_triggered(t))
t->fn(t->context);
t->value_set = true;
t->current_value = value;
}
/*----------------------------------------------------------------*/
/*
* Space map interface.
*
@ -54,6 +103,8 @@ struct sm_metadata {
unsigned allocated_this_transaction;
unsigned nr_uncommitted;
struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS];
struct threshold threshold;
};
static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
@ -329,9 +380,19 @@ static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
{
dm_block_t count;
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
int r = sm_metadata_new_block_(sm, b);
if (r)
DMERR("unable to allocate new metadata block");
r = sm_metadata_get_nr_free(sm, &count);
if (r)
DMERR("couldn't get free block count");
check_threshold(&smm->threshold, count);
return r;
}
@ -351,6 +412,18 @@ static int sm_metadata_commit(struct dm_space_map *sm)
return 0;
}
static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
dm_block_t threshold,
dm_sm_threshold_fn fn,
void *context)
{
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
set_threshold(&smm->threshold, threshold, fn, context);
return 0;
}
static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
{
*result = sizeof(struct disk_sm_root);
@ -392,7 +465,7 @@ static struct dm_space_map ops = {
.commit = sm_metadata_commit,
.root_size = sm_metadata_root_size,
.copy_root = sm_metadata_copy_root,
.register_threshold_callback = NULL
.register_threshold_callback = sm_metadata_register_threshold_callback
};
/*----------------------------------------------------------------*/
@ -577,6 +650,7 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
smm->recursion_count = 0;
smm->allocated_this_transaction = 0;
smm->nr_uncommitted = 0;
threshold_init(&smm->threshold);
memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
@ -618,6 +692,7 @@ int dm_sm_metadata_open(struct dm_space_map *sm,
smm->recursion_count = 0;
smm->allocated_this_transaction = 0;
smm->nr_uncommitted = 0;
threshold_init(&smm->threshold);
memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
return 0;