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authorJoe Thornber <ejt@redhat.com>2013-05-10 14:37:20 +0100
committerAlasdair G Kergon <agk@redhat.com>2013-05-10 14:37:20 +0100
commit2fc48021f4afdd109b9e52b6eef5db89ca80bac7 (patch)
tree38ee98f1a8fb8ca377822c01e34554fe0befd30a /drivers
parent7c3d3f2a87b01ff167a5f048285d5e3dee920235 (diff)
downloadlinux-linaro-stable-2fc48021f4afdd109b9e52b6eef5db89ca80bac7.tar.gz
dm persistent metadata: add space map threshold callback
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/persistent-data/dm-space-map-metadata.c77
1 files changed, 76 insertions, 1 deletions
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 883b465794d4..1c959684caef 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -17,6 +17,55 @@
/*----------------------------------------------------------------*/
/*
+ * 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.
*
* The low level disk format is written using the standard btree and
@@ -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;