08.08.2018 15:49, Vladimir Sementsov-Ogievskiy wrote:
The function alters bdrv_dirty_iter_next_area(), which is wrong and
less efficient (see next commit for description).
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
include/block/dirty-bitmap.h | 3 +++
include/qemu/hbitmap.h | 15 +++++++++++++++
block/dirty-bitmap.c | 7 +++++++
util/hbitmap.c | 38 ++++++++++++++++++++++++++++++++++++++
4 files changed, 63 insertions(+)
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 5dc146abf3..c02be67564 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -100,6 +100,9 @@ BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState
*bs,
char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start,
uint64_t bytes);
+bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,
+ uint64_t *offset, uint64_t end,
+ uint64_t *length);
BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap,
Error **errp);
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index cd091f6134..b1e897af28 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -306,6 +306,21 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi);
*/
int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count);
+/* hbitmap_next_dirty_area:
+ * @hb: The HBitmap to operate on
+ * @offset: in-out parameter.
+ * in: the offset to start from
+ * out: (if area found) start of found area
+ * @end: end of requested region. (*@offset + *@length) will be <= @end
+ * @length: length of found area
+ *
+ * If dirty area found within [@offset, @end), returns true and sets @offset
+ * and @length appropriately. Otherwise returns true and leaves @offset and
+ * @length unchanged.
+ */
+bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *offset,
+ uint64_t end, uint64_t *length);
+
/* hbitmap_create_meta:
* Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.
* The caller owns the created bitmap and must call hbitmap_free_meta(hb) to
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index a9ee814da7..c24aa0e229 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -791,6 +791,13 @@ int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap
*bitmap, uint64_t offset,
return hbitmap_next_zero(bitmap->bitmap, offset, bytes);
}
+bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,
+ uint64_t *offset, uint64_t end,
+ uint64_t *length)
+{
+ return hbitmap_next_dirty_area(bitmap->bitmap, offset, end, length);
+}
+
void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap
*src,
Error **errp)
{
diff --git a/util/hbitmap.c b/util/hbitmap.c
index 8dbcd80a3d..9de0d7bf2d 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -244,6 +244,44 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t
start, uint64_t count)
return res;
}
+bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *offset,
+ uint64_t end, uint64_t *length)
+{
+ HBitmapIter hbi;
+ int64_t off1, off0;
+ uint32_t granularity = 1UL << hb->granularity;
+
+ if (end == 0) {
+ end = hb->orig_size;
+ }
+
+ hbitmap_iter_init(&hbi, hb, *offset << hb->granularity);
"<< hb->granularity" should be dropped. Hmm, this patch needs tests.
+ off1 = hbitmap_iter_next(&hbi, true);
+
+ if (off1 < 0 || off1 >= end) {
+ return false;
+ }
+
+ if (off1 + granularity >= end) {
+ if (off1 > *offset) {
+ *offset = off1;
+ }
+ *length = end - *offset;
+ return true;
+ }
+
+ off0 = hbitmap_next_zero(hb, off1 + granularity, end);
+ if (off0 < 0) {
+ off0 = end;
+ }
+
+ if (off1 > *offset) {
+ *offset = off1;
+ }
+ *length = off0 - *offset;
+ return true;
+}
+
bool hbitmap_empty(const HBitmap *hb)
{
return hb->count == 0;
--
Best regards,
Vladimir
