dm bitset: only flush the current word if it has been dirtied
This change offers a big performance boost for dm-era.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/persistent-data/dm-bitset.c b/drivers/md/persistent-data/dm-bitset.c
index cd9a86d..36f7cc2 100644
--- a/drivers/md/persistent-data/dm-bitset.c
+++ b/drivers/md/persistent-data/dm-bitset.c
@@ -65,7 +65,7 @@
int r;
__le64 value;
- if (!info->current_index_set)
+ if (!info->current_index_set || !info->dirty)
return 0;
value = cpu_to_le64(info->current_bits);
@@ -77,6 +77,8 @@
return r;
info->current_index_set = false;
+ info->dirty = false;
+
return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_flush);
@@ -94,6 +96,8 @@
info->current_bits = le64_to_cpu(value);
info->current_index_set = true;
info->current_index = array_index;
+ info->dirty = false;
+
return 0;
}
@@ -126,6 +130,8 @@
return r;
set_bit(b, (unsigned long *) &info->current_bits);
+ info->dirty = true;
+
return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
@@ -141,6 +147,8 @@
return r;
clear_bit(b, (unsigned long *) &info->current_bits);
+ info->dirty = true;
+
return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
diff --git a/drivers/md/persistent-data/dm-bitset.h b/drivers/md/persistent-data/dm-bitset.h
index e1b9bea..c2287d6 100644
--- a/drivers/md/persistent-data/dm-bitset.h
+++ b/drivers/md/persistent-data/dm-bitset.h
@@ -71,6 +71,7 @@
uint64_t current_bits;
bool current_index_set:1;
+ bool dirty:1;
};
/*