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authorMikulas Patocka <mpatocka@redhat.com>2012-12-21 20:23:38 +0000
committerAlasdair G Kergon <agk@redhat.com>2012-12-21 20:23:38 +0000
commitc0820cf5ad09522bdd9ff68e84841a09c9f339d8 (patch)
tree04817d6d9a7d213ac96d1e014a9714f8f29ff07a /drivers/md/dm-table.c
parent70d6c400acc386ea910c77318688541fc32e7ce8 (diff)
dm: introduce per_bio_data
Introduce a field per_bio_data_size in struct dm_target. Targets can set this field in the constructor. If a target sets this field to a non-zero value, "per_bio_data_size" bytes of auxiliary data are allocated for each bio submitted to the target. These data can be used for any purpose by the target and help us improve performance by removing some per-target mempools. Per-bio data is accessed with dm_per_bio_data. The argument data_size must be the same as the value per_bio_data_size in dm_target. If the target has a pointer to per_bio_data, it can get a pointer to the bio with dm_bio_from_per_bio_data() function (data_size must be the same as the value passed to dm_per_bio_data). Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-table.c')
-rw-r--r--drivers/md/dm-table.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 6be58b696377..daf25d0890b3 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -967,13 +967,22 @@ bool dm_table_request_based(struct dm_table *t)
int dm_table_alloc_md_mempools(struct dm_table *t)
{
unsigned type = dm_table_get_type(t);
+ unsigned per_bio_data_size = 0;
+ struct dm_target *tgt;
+ unsigned i;
if (unlikely(type == DM_TYPE_NONE)) {
DMWARN("no table type is set, can't allocate mempools");
return -EINVAL;
}
- t->mempools = dm_alloc_md_mempools(type, t->integrity_supported);
+ if (type == DM_TYPE_BIO_BASED)
+ for (i = 0; i < t->num_targets; i++) {
+ tgt = t->targets + i;
+ per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
+ }
+
+ t->mempools = dm_alloc_md_mempools(type, t->integrity_supported, per_bio_data_size);
if (!t->mempools)
return -ENOMEM;