Cache ddt_get_dedup_dspace() value if there was no ddt changes

Save and reuse ddt dspace calculation when there have been no ddt changes.
This avoids unnecessary traversal of 168KiB of ddt histograms.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Closes #5425
This commit is contained in:
Gvozden Neskovic 2016-12-03 00:59:35 +01:00 committed by Brian Behlendorf
parent baf67d15a5
commit e8a2014436
3 changed files with 15 additions and 2 deletions

View File

@ -239,6 +239,7 @@ struct spa {
uint64_t spa_autoexpand; /* lun expansion on/off */
ddt_t *spa_ddt[ZIO_CHECKSUM_FUNCTIONS]; /* in-core DDTs */
uint64_t spa_ddt_stat_object; /* DDT statistics */
uint64_t spa_dedup_dspace; /* Cache get_dedup_dspace() */
uint64_t spa_dedup_ditto; /* dedup ditto threshold */
uint64_t spa_dedup_checksum; /* default dedup checksum */
uint64_t spa_dspace; /* dspace in normal class */

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@ -529,10 +529,17 @@ ddt_get_dedup_stats(spa_t *spa, ddt_stat_t *dds_total)
uint64_t
ddt_get_dedup_dspace(spa_t *spa)
{
ddt_stat_t dds_total = { 0 };
ddt_stat_t dds_total;
if (spa->spa_dedup_dspace != ~0ULL)
return (spa->spa_dedup_dspace);
bzero(&dds_total, sizeof (ddt_stat_t));
/* Calculate and cache the stats */
ddt_get_dedup_stats(spa, &dds_total);
return (dds_total.dds_ref_dsize - dds_total.dds_dsize);
spa->spa_dedup_dspace = dds_total.dds_ref_dsize - dds_total.dds_dsize;
return (spa->spa_dedup_dspace);
}
uint64_t
@ -915,6 +922,7 @@ ddt_load(spa_t *spa)
*/
bcopy(ddt->ddt_histogram, &ddt->ddt_histogram_cache,
sizeof (ddt->ddt_histogram));
spa->spa_dedup_dspace = ~0ULL;
}
return (0);
@ -1182,6 +1190,7 @@ ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx, uint64_t txg)
bcopy(ddt->ddt_histogram, &ddt->ddt_histogram_cache,
sizeof (ddt->ddt_histogram));
spa->spa_dedup_dspace = ~0ULL;
}
void

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@ -635,6 +635,9 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
spa->spa_min_ashift = INT_MAX;
spa->spa_max_ashift = 0;
/* Reset cached value */
spa->spa_dedup_dspace = ~0ULL;
/*
* As a pool is being created, treat all features as disabled by
* setting SPA_FEATURE_DISABLED for all entries in the feature