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dm space maps: improve performance with inc/dec on ranges of blocks

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When we break sharing on btree nodes we typically need to increment
the reference counts to every value held in the node.  This can
cause a lot of repeated calls to the space maps.  Fix this by changing
the interface to the space map inc/dec methods to take ranges of
adjacent blocks to be operated on.

For installations that are using a lot of snapshots this will reduce
cpu overhead of fundamental operations such as provisioning a new block,
or deleting a snapshot, by as much as 10 times.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Joe Thornber
2021-04-13 11:03:45 +01:00
committed by Mike Snitzer
parent 5faafc77f7
commit be500ed721
15 changed files with 778 additions and 249 deletions
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95
drivers/md/dm-thin-metadata.c
View File

@@ -311,28 +311,53 @@ static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
*t = v & ((1 << 24) - 1);
}
static void data_block_inc(void *context, const void *value_le)
{
struct dm_space_map *sm = context;
__le64 v_le;
uint64_t b;
uint32_t t;
/*
* It's more efficient to call dm_sm_{inc,dec}_blocks as few times as
* possible. 'with_runs' reads contiguous runs of blocks, and calls the
* given sm function.
*/
typedef int (*run_fn)(struct dm_space_map *, dm_block_t, dm_block_t);
memcpy(&v_le, value_le, sizeof(v_le));
unpack_block_time(le64_to_cpu(v_le), &b, &t);
dm_sm_inc_block(sm, b);
static void with_runs(struct dm_space_map *sm, const __le64 *value_le, unsigned count, run_fn fn)
{
uint64_t b, begin, end;
uint32_t t;
bool in_run = false;
unsigned i;
for (i = 0; i < count; i++, value_le++) {
/* We know value_le is 8 byte aligned */
unpack_block_time(le64_to_cpu(*value_le), &b, &t);
if (in_run) {
if (b == end) {
end++;
} else {
fn(sm, begin, end);
begin = b;
end = b + 1;
}
} else {
in_run = true;
begin = b;
end = b + 1;
}
}
if (in_run)
fn(sm, begin, end);
}
static void data_block_dec(void *context, const void *value_le)
static void data_block_inc(void *context, const void *value_le, unsigned count)
{
struct dm_space_map *sm = context;
__le64 v_le;
uint64_t b;
uint32_t t;
with_runs((struct dm_space_map *) context,
(const __le64 *) value_le, count, dm_sm_inc_blocks);
}
memcpy(&v_le, value_le, sizeof(v_le));
unpack_block_time(le64_to_cpu(v_le), &b, &t);
dm_sm_dec_block(sm, b);
static void data_block_dec(void *context, const void *value_le, unsigned count)
{
with_runs((struct dm_space_map *) context,
(const __le64 *) value_le, count, dm_sm_dec_blocks);
}
static int data_block_equal(void *context, const void *value1_le, const void *value2_le)
@@ -349,27 +374,25 @@ static int data_block_equal(void *context, const void *value1_le, const void *va
return b1 == b2;
}
static void subtree_inc(void *context, const void *value)
static void subtree_inc(void *context, const void *value, unsigned count)
{
struct dm_btree_info *info = context;
__le64 root_le;
uint64_t root;
const __le64 *root_le = value;
unsigned i;
memcpy(&root_le, value, sizeof(root_le));
root = le64_to_cpu(root_le);
dm_tm_inc(info->tm, root);
for (i = 0; i < count; i++, root_le++)
dm_tm_inc(info->tm, le64_to_cpu(*root_le));
}
static void subtree_dec(void *context, const void *value)
static void subtree_dec(void *context, const void *value, unsigned count)
{
struct dm_btree_info *info = context;
__le64 root_le;
uint64_t root;
const __le64 *root_le = value;
unsigned i;
memcpy(&root_le, value, sizeof(root_le));
root = le64_to_cpu(root_le);
if (dm_btree_del(info, root))
DMERR("btree delete failed");
for (i = 0; i < count; i++, root_le++)
if (dm_btree_del(info, le64_to_cpu(*root_le)))
DMERR("btree delete failed");
}
static int subtree_equal(void *context, const void *value1_le, const void *value2_le)
@@ -1761,11 +1784,7 @@ int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_
int r = 0;
pmd_write_lock(pmd);
for (; b != e; b++) {
r = dm_sm_inc_block(pmd->data_sm, b);
if (r)
break;
}
r = dm_sm_inc_blocks(pmd->data_sm, b, e);
pmd_write_unlock(pmd);
return r;
@@ -1776,11 +1795,7 @@ int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_
int r = 0;
pmd_write_lock(pmd);
for (; b != e; b++) {
r = dm_sm_dec_block(pmd->data_sm, b);
if (r)
break;
}
r = dm_sm_dec_blocks(pmd->data_sm, b, e);
pmd_write_unlock(pmd);
return r;