[Qemu-devel] [PATCH v3 0/8] dirty-bitmap: rewrite bdrv_dirty_iter_next_area

[Qemu-devel] [PATCH v3 0/8] dirty-bitmap: rewrite bdrv_dirty_iter_next_area

[Vladimir Sementsov-Ogievskiy]

Hi all.

1. bdrv_dirty_iter_next_area don't use hbitmap_next_zero and uses
inefficient loop instead. Let's improve it.

2. bdrv_dirty_iter_next_area don't handle unaligned offset and
max_offset correctly. I'm not sure that it is a real bug. But if it is,
we need these series in 3.0.

Details are in 05 commit message.

v3:
01: - change interface to start/end, and -1 as special end-marker instead of 0
    - "not found" for invalid regions instead of assert
02: rebase on 01 changes
03: - fix mistake in hbitmap_iter_init arguments (mistake in
      hbitmap_next_zero arguments is fixed automatically due to 01 changes)
04: new


v2:

01: - improve comment
    - s/bytes/count/
    - fix forgotten function call in test
    - introduce orig_size field here for HBitmap,
      make checking in hbitmap_next_zero more effective and safe
02: new
03: - orig_size already introduced in 01
    - fix hbitmap_next_dirty_area to not return value less than
      offset on unaligned requests

Vladimir Sementsov-Ogievskiy (8):
  dirty-bitmap: improve bdrv_dirty_bitmap_next_zero
  tests: add tests for hbitmap_next_zero with specified end parameter
  dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area
  tests: add tests for hbitmap_next_dirty_area
  block/mirror: fix and improve do_sync_target_write
  Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"
  Revert "test-hbitmap: Add non-advancing iter_next tests"
  Revert "hbitmap: Add @advance param to hbitmap_iter_next()"

 include/block/dirty-bitmap.h |   8 +-
 include/qemu/hbitmap.h       |  30 ++++++--
 block/backup.c               |   4 +-
 block/dirty-bitmap.c         |  69 +++--------------
 block/mirror.c               |  16 ++--
 nbd/server.c                 |   2 +-
 tests/test-hbitmap.c         | 176 ++++++++++++++++++++++++++++++++++++-------
 util/hbitmap.c               |  73 +++++++++++++++---
 8 files changed, 258 insertions(+), 120 deletions(-)

-- 
2.11.1

[Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[Vladimir Sementsov-Ogievskiy]

Add bytes parameter to the function, to limit searched range.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/block/dirty-bitmap.h |  3 ++-
 include/qemu/hbitmap.h       | 10 ++++++++--
 block/backup.c               |  2 +-
 block/dirty-bitmap.c         |  5 +++--
 nbd/server.c                 |  2 +-
 tests/test-hbitmap.c         |  2 +-
 util/hbitmap.c               | 25 ++++++++++++++++++++-----
 7 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 259bd27c40..27f5299c4e 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -98,7 +98,8 @@ bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
 BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
                                         BdrvDirtyBitmap *bitmap);
 char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
-int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start);
+int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start,
+                                    int64_t end);
 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 ddca52c48e..fe4dfde27a 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -295,10 +295,16 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi);
 /* hbitmap_next_zero:
  * @hb: The HBitmap to operate on
  * @start: The bit to start from.
+ * @end: End of range to search in. If @end is -1, search up to the bitmap
+ *       end.
  *
- * Find next not dirty bit.
+ * Find next not dirty bit within range [@start, @end), or from
+ * @start to the bitmap end if @end is -1. If not found, return -1.
+ *
+ * @end may be greater than original bitmap size, in this case, search up to
+ * the bitmap end.
  */
-int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
+int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end);
 
 /* hbitmap_create_meta:
  * Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.
diff --git a/block/backup.c b/block/backup.c
index 8630d32926..9bfd3f7189 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -458,7 +458,7 @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
             break;
         }
 
-        offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset);
+        offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset, -1);
         if (offset == -1) {
             hbitmap_set(job->copy_bitmap, cluster, end - cluster);
             break;
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index c9b8a6fd52..037ae62726 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -785,9 +785,10 @@ char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp)
     return hbitmap_sha256(bitmap->bitmap, errp);
 }
 
-int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset)
+int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,
+                                    int64_t end)
 {
-    return hbitmap_next_zero(bitmap->bitmap, offset);
+    return hbitmap_next_zero(bitmap->bitmap, offset, end);
 }
 
 void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
diff --git a/nbd/server.c b/nbd/server.c
index ea5fe0eb33..07920d123b 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1952,7 +1952,7 @@ static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
     assert(begin < overall_end && nb_extents);
     while (begin < overall_end && i < nb_extents) {
         if (dirty) {
-            end = bdrv_dirty_bitmap_next_zero(bitmap, begin);
+            end = bdrv_dirty_bitmap_next_zero(bitmap, begin, -1);
         } else {
             bdrv_set_dirty_iter(it, begin);
             end = bdrv_dirty_iter_next(it);
diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index 5e67ac1d3a..6b6a40bddd 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -939,7 +939,7 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
 
 static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
 {
-    int64_t ret1 = hbitmap_next_zero(data->hb, start);
+    int64_t ret1 = hbitmap_next_zero(data->hb, start, -1);
     int64_t ret2 = start;
     for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
         ;
diff --git a/util/hbitmap.c b/util/hbitmap.c
index bcd304041a..1687372504 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -53,6 +53,9 @@
  */
 
 struct HBitmap {
+    /* Size of the bitmap, as requested in hbitmap_alloc. */
+    uint64_t orig_size;
+
     /* Number of total bits in the bottom level.  */
     uint64_t size;
 
@@ -192,16 +195,26 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first)
     }
 }
 
-int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
+int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end)
 {
     size_t pos = (start >> hb->granularity) >> BITS_PER_LEVEL;
     unsigned long *last_lev = hb->levels[HBITMAP_LEVELS - 1];
-    uint64_t sz = hb->sizes[HBITMAP_LEVELS - 1];
     unsigned long cur = last_lev[pos];
-    unsigned start_bit_offset =
-            (start >> hb->granularity) & (BITS_PER_LONG - 1);
+    unsigned start_bit_offset;
+    uint64_t end_bit, sz;
     int64_t res;
 
+    if (start >= hb->orig_size || (end != -1 && end <= start)) {
+        return -1;
+    }
+
+    end_bit = end == -1 ? hb->size : ((end - 1) >> hb->granularity) + 1;
+    sz = (end_bit + BITS_PER_LONG - 1) >> BITS_PER_LEVEL;
+
+    /* There may be some zero bits in @cur before @start. We are not interested
+     * in them, let's set them.
+     */
+    start_bit_offset = (start >> hb->granularity) & (BITS_PER_LONG - 1);
     cur |= (1UL << start_bit_offset) - 1;
     assert((start >> hb->granularity) < hb->size);
 
@@ -218,7 +231,7 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
     }
 
     res = (pos << BITS_PER_LEVEL) + ctol(cur);
-    if (res >= hb->size) {
+    if (res >= end_bit) {
         return -1;
     }
 
@@ -652,6 +665,8 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
     HBitmap *hb = g_new0(struct HBitmap, 1);
     unsigned i;
 
+    hb->orig_size = size;
+
     assert(granularity >= 0 && granularity < 64);
     size = (size + (1ULL << granularity) - 1) >> granularity;
     assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE));
-- 
2.11.1

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[John Snow]

On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> Add bytes parameter to the function, to limit searched range.
> 

I'm going to assume that Eric Blake has been through here and commented
on the interface itself.

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  include/block/dirty-bitmap.h |  3 ++-
>  include/qemu/hbitmap.h       | 10 ++++++++--
>  block/backup.c               |  2 +-
>  block/dirty-bitmap.c         |  5 +++--
>  nbd/server.c                 |  2 +-
>  tests/test-hbitmap.c         |  2 +-
>  util/hbitmap.c               | 25 ++++++++++++++++++++-----
>  7 files changed, 36 insertions(+), 13 deletions(-)
> 
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 259bd27c40..27f5299c4e 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -98,7 +98,8 @@ bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
>  BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
>                                          BdrvDirtyBitmap *bitmap);
>  char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
> -int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start);
> +int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start,
> +                                    int64_t end);
>  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 ddca52c48e..fe4dfde27a 100644
> --- a/include/qemu/hbitmap.h
> +++ b/include/qemu/hbitmap.h
> @@ -295,10 +295,16 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi);
>  /* hbitmap_next_zero:
>   * @hb: The HBitmap to operate on
>   * @start: The bit to start from.
> + * @end: End of range to search in. If @end is -1, search up to the bitmap
> + *       end.
>   *
> - * Find next not dirty bit.
> + * Find next not dirty bit within range [@start, @end), or from
> + * @start to the bitmap end if @end is -1. If not found, return -1.
> + *
> + * @end may be greater than original bitmap size, in this case, search up to

"original" bitmap size? I think that's just an implementation detail, we
can drop 'original' here, yes?

> + * the bitmap end.
>   */
> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end);
>  

The interface looks weird because we can define a 'start' that's beyond
the 'end'.

I realize that you need a signed integer for 'end' to signify EOF...
should we do a 'bytes' parameter instead? (Did you already do that in an
earlier version and we changed it?)

Well, it's not a big deal to me personally.

>  /* hbitmap_create_meta:
>   * Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.
> diff --git a/block/backup.c b/block/backup.c
> index 8630d32926..9bfd3f7189 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -458,7 +458,7 @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
>              break;
>          }
>  
> -        offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset);
> +        offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset, -1);
>          if (offset == -1) {
>              hbitmap_set(job->copy_bitmap, cluster, end - cluster);
>              break;
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index c9b8a6fd52..037ae62726 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -785,9 +785,10 @@ char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp)
>      return hbitmap_sha256(bitmap->bitmap, errp);
>  }
>  
> -int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset)
> +int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,
> +                                    int64_t end)
>  {
> -    return hbitmap_next_zero(bitmap->bitmap, offset);
> +    return hbitmap_next_zero(bitmap->bitmap, offset, end);
>  }
>  
>  void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
> diff --git a/nbd/server.c b/nbd/server.c
> index ea5fe0eb33..07920d123b 100644
> --- a/nbd/server.c
> +++ b/nbd/server.c
> @@ -1952,7 +1952,7 @@ static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
>      assert(begin < overall_end && nb_extents);
>      while (begin < overall_end && i < nb_extents) {
>          if (dirty) {
> -            end = bdrv_dirty_bitmap_next_zero(bitmap, begin);
> +            end = bdrv_dirty_bitmap_next_zero(bitmap, begin, -1);
>          } else {
>              bdrv_set_dirty_iter(it, begin);
>              end = bdrv_dirty_iter_next(it);
> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
> index 5e67ac1d3a..6b6a40bddd 100644
> --- a/tests/test-hbitmap.c
> +++ b/tests/test-hbitmap.c
> @@ -939,7 +939,7 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
>  
>  static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
>  {
> -    int64_t ret1 = hbitmap_next_zero(data->hb, start);
> +    int64_t ret1 = hbitmap_next_zero(data->hb, start, -1);
>      int64_t ret2 = start;
>      for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
>          ;
> diff --git a/util/hbitmap.c b/util/hbitmap.c
> index bcd304041a..1687372504 100644
> --- a/util/hbitmap.c
> +++ b/util/hbitmap.c
> @@ -53,6 +53,9 @@
>   */
>  
>  struct HBitmap {
> +    /* Size of the bitmap, as requested in hbitmap_alloc. */
> +    uint64_t orig_size;
> +
>      /* Number of total bits in the bottom level.  */
>      uint64_t size;
>  
> @@ -192,16 +195,26 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first)
>      }
>  }
>  
> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end)
>  {
>      size_t pos = (start >> hb->granularity) >> BITS_PER_LEVEL;
>      unsigned long *last_lev = hb->levels[HBITMAP_LEVELS - 1];
> -    uint64_t sz = hb->sizes[HBITMAP_LEVELS - 1];
>      unsigned long cur = last_lev[pos];
> -    unsigned start_bit_offset =
> -            (start >> hb->granularity) & (BITS_PER_LONG - 1);
> +    unsigned start_bit_offset;
> +    uint64_t end_bit, sz;
>      int64_t res;
>  
> +    if (start >= hb->orig_size || (end != -1 && end <= start)) {
> +        return -1;
> +    }
> +
> +    end_bit = end == -1 ? hb->size : ((end - 1) >> hb->granularity) + 1;
> +    sz = (end_bit + BITS_PER_LONG - 1) >> BITS_PER_LEVEL;
> +
> +    /* There may be some zero bits in @cur before @start. We are not interested
> +     * in them, let's set them.
> +     */
> +    start_bit_offset = (start >> hb->granularity) & (BITS_PER_LONG - 1);
>      cur |= (1UL << start_bit_offset) - 1;
>      assert((start >> hb->granularity) < hb->size);
>  
> @@ -218,7 +231,7 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
>      }
>  
>      res = (pos << BITS_PER_LEVEL) + ctol(cur);
> -    if (res >= hb->size) {
> +    if (res >= end_bit) {
>          return -1;
>      }
>  
> @@ -652,6 +665,8 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
>      HBitmap *hb = g_new0(struct HBitmap, 1);
>      unsigned i;
>  
> +    hb->orig_size = size;
> +
>      assert(granularity >= 0 && granularity < 64);
>      size = (size + (1ULL << granularity) - 1) >> granularity;
>      assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE));
> 

Despite my comments, I'm OK with or without changes.

Reviewed-by: John Snow <jsnow@redhat.com>

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[Eric Blake]

On 9/7/18 4:49 PM, John Snow wrote:
> 
> 
> On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
>> Add bytes parameter to the function, to limit searched range.
>>
> 
> I'm going to assume that Eric Blake has been through here and commented
> on the interface itself.

Actually, I haven't had time to look at this series in depth. Do you 
need me to?

> 
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   include/block/dirty-bitmap.h |  3 ++-
>>   include/qemu/hbitmap.h       | 10 ++++++++--
>>   block/backup.c               |  2 +-
>>   block/dirty-bitmap.c         |  5 +++--
>>   nbd/server.c                 |  2 +-
>>   tests/test-hbitmap.c         |  2 +-
>>   util/hbitmap.c               | 25 ++++++++++++++++++++-----
>>   7 files changed, 36 insertions(+), 13 deletions(-)
>>
>> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
>> index 259bd27c40..27f5299c4e 100644
>> --- a/include/block/dirty-bitmap.h
>> +++ b/include/block/dirty-bitmap.h
>> @@ -98,7 +98,8 @@ bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
>>   BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
>>                                           BdrvDirtyBitmap *bitmap);
>>   char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
>> -int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start);
>> +int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start,
>> +                                    int64_t end);

It's already seeming a bit odd to mix uint64_t AND int64_t for the two 
parameters.  Is the intent to allow -1 to mean "end of the bitmap 
instead of a specific end range"? But you can get that with UINT64_MAX 
just as easily, and still get away with spelling it -1 in the source.


>> + * the bitmap end.
>>    */
>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end);
>>   
> 
> The interface looks weird because we can define a 'start' that's beyond
> the 'end'.
> 
> I realize that you need a signed integer for 'end' to signify EOF...
> should we do a 'bytes' parameter instead? (Did you already do that in an
> earlier version and we changed it?)
> 
> Well, it's not a big deal to me personally.

It should always be possible to convert in either direction between 
[start,end) and [start,start+bytes); it boils down to a question of 
convenience (which form is easier for the majority of callers) and 
consistency (which form do we use more frequently in the block layer). I 
haven't checked closely, but I think start+bytes is more common than end 
in our public block layer APIs.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[John Snow]

On 09/10/2018 10:59 AM, Eric Blake wrote:
> On 9/7/18 4:49 PM, John Snow wrote:
>>
>>
>> On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
>>> Add bytes parameter to the function, to limit searched range.
>>>
>>
>> I'm going to assume that Eric Blake has been through here and commented
>> on the interface itself.
> 
> Actually, I haven't had time to look at this series in depth. Do you
> need me to?
> 

Not necessarily, it's just that I didn't read v1 or v2 so I was just
being cautious against recommending changes that maybe we already
recommended against in a different direction.

Historically you've cared the most about start/end/offset/bytes naming
and conventions, so I just made an assumption.

--js

>>
>>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>>> ---
>>>   include/block/dirty-bitmap.h |  3 ++-
>>>   include/qemu/hbitmap.h       | 10 ++++++++--
>>>   block/backup.c               |  2 +-
>>>   block/dirty-bitmap.c         |  5 +++--
>>>   nbd/server.c                 |  2 +-
>>>   tests/test-hbitmap.c         |  2 +-
>>>   util/hbitmap.c               | 25 ++++++++++++++++++++-----
>>>   7 files changed, 36 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
>>> index 259bd27c40..27f5299c4e 100644
>>> --- a/include/block/dirty-bitmap.h
>>> +++ b/include/block/dirty-bitmap.h
>>> @@ -98,7 +98,8 @@ bool
>>> bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
>>>   BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
>>>                                           BdrvDirtyBitmap *bitmap);
>>>   char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error
>>> **errp);
>>> -int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap,
>>> uint64_t start);
>>> +int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap,
>>> uint64_t start,
>>> +                                    int64_t end);
> 
> It's already seeming a bit odd to mix uint64_t AND int64_t for the two
> parameters.  Is the intent to allow -1 to mean "end of the bitmap
> instead of a specific end range"? But you can get that with UINT64_MAX
> just as easily, and still get away with spelling it -1 in the source.
> 
> 
>>> + * the bitmap end.
>>>    */
>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t
>>> end);
>>>   
>>
>> The interface looks weird because we can define a 'start' that's beyond
>> the 'end'.
>>
>> I realize that you need a signed integer for 'end' to signify EOF...
>> should we do a 'bytes' parameter instead? (Did you already do that in an
>> earlier version and we changed it?)
>>
>> Well, it's not a big deal to me personally.
> 
> It should always be possible to convert in either direction between
> [start,end) and [start,start+bytes); it boils down to a question of
> convenience (which form is easier for the majority of callers) and
> consistency (which form do we use more frequently in the block layer). I
> haven't checked closely, but I think start+bytes is more common than end
> in our public block layer APIs.
> 

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[Vladimir Sementsov-Ogievskiy]

08.09.2018 00:49, John Snow wrote:
>
> On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
>> Add bytes parameter to the function, to limit searched range.
>>
> I'm going to assume that Eric Blake has been through here and commented
> on the interface itself.
>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>>   include/block/dirty-bitmap.h |  3 ++-
>>   include/qemu/hbitmap.h       | 10 ++++++++--
>>   block/backup.c               |  2 +-
>>   block/dirty-bitmap.c         |  5 +++--
>>   nbd/server.c                 |  2 +-
>>   tests/test-hbitmap.c         |  2 +-
>>   util/hbitmap.c               | 25 ++++++++++++++++++++-----
>>   7 files changed, 36 insertions(+), 13 deletions(-)
>>
>> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
>> index 259bd27c40..27f5299c4e 100644
>> --- a/include/block/dirty-bitmap.h
>> +++ b/include/block/dirty-bitmap.h
>> @@ -98,7 +98,8 @@ bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
>>   BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
>>                                           BdrvDirtyBitmap *bitmap);
>>   char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
>> -int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start);
>> +int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start,
>> +                                    int64_t end);
>>   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 ddca52c48e..fe4dfde27a 100644
>> --- a/include/qemu/hbitmap.h
>> +++ b/include/qemu/hbitmap.h
>> @@ -295,10 +295,16 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi);
>>   /* hbitmap_next_zero:
>>    * @hb: The HBitmap to operate on
>>    * @start: The bit to start from.
>> + * @end: End of range to search in. If @end is -1, search up to the bitmap
>> + *       end.
>>    *
>> - * Find next not dirty bit.
>> + * Find next not dirty bit within range [@start, @end), or from
>> + * @start to the bitmap end if @end is -1. If not found, return -1.
>> + *
>> + * @end may be greater than original bitmap size, in this case, search up to
> "original" bitmap size? I think that's just an implementation detail, we
> can drop 'original' here, yes?

hm, no. we have field "size", which is not "original". But it all means 
that this place needs a bit more refactoring.

>
>> + * the bitmap end.
>>    */
>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end);
>>   
> The interface looks weird because we can define a 'start' that's beyond
> the 'end'.
>
> I realize that you need a signed integer for 'end' to signify EOF...
> should we do a 'bytes' parameter instead? (Did you already do that in an
> earlier version and we changed it?)
>
> Well, it's not a big deal to me personally.

interface with constant end parameter is more comfortable for loop: we 
don't need to update 'bytes' parameter on each iteration

>
>>   /* hbitmap_create_meta:
>>    * Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.
>> diff --git a/block/backup.c b/block/backup.c
>> index 8630d32926..9bfd3f7189 100644
>> --- a/block/backup.c
>> +++ b/block/backup.c
>> @@ -458,7 +458,7 @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
>>               break;
>>           }
>>   
>> -        offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset);
>> +        offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset, -1);
>>           if (offset == -1) {
>>               hbitmap_set(job->copy_bitmap, cluster, end - cluster);
>>               break;
>> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
>> index c9b8a6fd52..037ae62726 100644
>> --- a/block/dirty-bitmap.c
>> +++ b/block/dirty-bitmap.c
>> @@ -785,9 +785,10 @@ char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp)
>>       return hbitmap_sha256(bitmap->bitmap, errp);
>>   }
>>   
>> -int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset)
>> +int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,
>> +                                    int64_t end)
>>   {
>> -    return hbitmap_next_zero(bitmap->bitmap, offset);
>> +    return hbitmap_next_zero(bitmap->bitmap, offset, end);
>>   }
>>   
>>   void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
>> diff --git a/nbd/server.c b/nbd/server.c
>> index ea5fe0eb33..07920d123b 100644
>> --- a/nbd/server.c
>> +++ b/nbd/server.c
>> @@ -1952,7 +1952,7 @@ static unsigned int bitmap_to_extents(BdrvDirtyBitmap *bitmap, uint64_t offset,
>>       assert(begin < overall_end && nb_extents);
>>       while (begin < overall_end && i < nb_extents) {
>>           if (dirty) {
>> -            end = bdrv_dirty_bitmap_next_zero(bitmap, begin);
>> +            end = bdrv_dirty_bitmap_next_zero(bitmap, begin, -1);
>>           } else {
>>               bdrv_set_dirty_iter(it, begin);
>>               end = bdrv_dirty_iter_next(it);
>> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
>> index 5e67ac1d3a..6b6a40bddd 100644
>> --- a/tests/test-hbitmap.c
>> +++ b/tests/test-hbitmap.c
>> @@ -939,7 +939,7 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
>>   
>>   static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
>>   {
>> -    int64_t ret1 = hbitmap_next_zero(data->hb, start);
>> +    int64_t ret1 = hbitmap_next_zero(data->hb, start, -1);
>>       int64_t ret2 = start;
>>       for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
>>           ;
>> diff --git a/util/hbitmap.c b/util/hbitmap.c
>> index bcd304041a..1687372504 100644
>> --- a/util/hbitmap.c
>> +++ b/util/hbitmap.c
>> @@ -53,6 +53,9 @@
>>    */
>>   
>>   struct HBitmap {
>> +    /* Size of the bitmap, as requested in hbitmap_alloc. */
>> +    uint64_t orig_size;
>> +
>>       /* Number of total bits in the bottom level.  */
>>       uint64_t size;
>>   
>> @@ -192,16 +195,26 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first)
>>       }
>>   }
>>   
>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end)
>>   {
>>       size_t pos = (start >> hb->granularity) >> BITS_PER_LEVEL;
>>       unsigned long *last_lev = hb->levels[HBITMAP_LEVELS - 1];
>> -    uint64_t sz = hb->sizes[HBITMAP_LEVELS - 1];
>>       unsigned long cur = last_lev[pos];
>> -    unsigned start_bit_offset =
>> -            (start >> hb->granularity) & (BITS_PER_LONG - 1);
>> +    unsigned start_bit_offset;
>> +    uint64_t end_bit, sz;
>>       int64_t res;
>>   
>> +    if (start >= hb->orig_size || (end != -1 && end <= start)) {
>> +        return -1;
>> +    }
>> +
>> +    end_bit = end == -1 ? hb->size : ((end - 1) >> hb->granularity) + 1;
>> +    sz = (end_bit + BITS_PER_LONG - 1) >> BITS_PER_LEVEL;
>> +
>> +    /* There may be some zero bits in @cur before @start. We are not interested
>> +     * in them, let's set them.
>> +     */
>> +    start_bit_offset = (start >> hb->granularity) & (BITS_PER_LONG - 1);
>>       cur |= (1UL << start_bit_offset) - 1;
>>       assert((start >> hb->granularity) < hb->size);
>>   
>> @@ -218,7 +231,7 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
>>       }
>>   
>>       res = (pos << BITS_PER_LEVEL) + ctol(cur);
>> -    if (res >= hb->size) {
>> +    if (res >= end_bit) {
>>           return -1;
>>       }
>>   
>> @@ -652,6 +665,8 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
>>       HBitmap *hb = g_new0(struct HBitmap, 1);
>>       unsigned i;
>>   
>> +    hb->orig_size = size;
>> +
>>       assert(granularity >= 0 && granularity < 64);
>>       size = (size + (1ULL << granularity) - 1) >> granularity;
>>       assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE));
>>
> Despite my comments, I'm OK with or without changes.
>
> Reviewed-by: John Snow <jsnow@redhat.com>


-- 
Best regards,
Vladimir

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[Eric Blake]

On 9/10/18 11:49 AM, Vladimir Sementsov-Ogievskiy wrote:

>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t 
>>> end);
>> The interface looks weird because we can define a 'start' that's beyond
>> the 'end'.
>>
>> I realize that you need a signed integer for 'end' to signify EOF...
>> should we do a 'bytes' parameter instead? (Did you already do that in an
>> earlier version and we changed it?)
>>
>> Well, it's not a big deal to me personally.
> 
> interface with constant end parameter is more comfortable for loop: we 
> don't need to update 'bytes' parameter on each iteration

But there's still the question of WHO should be calculating end. Your 
interface argues for the caller:

hbitmap_next_zero(start, start + bytes)

int64_t hbitmap_next_zero(...)
{
     while (offset != end) ...
}

while we're asking about a consistent interface for the caller (if most 
callers already have a 'bytes' rather than an 'end' computed):

hbitmap_next_zero(start, bytes)

int64_t hbitmap_next_zero(...)
{
     int64_t end = start + bytes;
     while (offset != end) ...
}

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[Vladimir Sementsov-Ogievskiy]

10.09.2018 19:55, Eric Blake wrote:
> On 9/10/18 11:49 AM, Vladimir Sementsov-Ogievskiy wrote:
>
>>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, 
>>>> int64_t end);
>>> The interface looks weird because we can define a 'start' that's beyond
>>> the 'end'.
>>>
>>> I realize that you need a signed integer for 'end' to signify EOF...
>>> should we do a 'bytes' parameter instead? (Did you already do that 
>>> in an
>>> earlier version and we changed it?)
>>>
>>> Well, it's not a big deal to me personally.
>>
>> interface with constant end parameter is more comfortable for loop: 
>> we don't need to update 'bytes' parameter on each iteration
>
> But there's still the question of WHO should be calculating end. Your 
> interface argues for the caller:
>
> hbitmap_next_zero(start, start + bytes)
>
> int64_t hbitmap_next_zero(...)
> {
>     while (offset != end) ...
> }
>
> while we're asking about a consistent interface for the caller (if 
> most callers already have a 'bytes' rather than an 'end' computed):
>
> hbitmap_next_zero(start, bytes)
>
> int64_t hbitmap_next_zero(...)
> {
>     int64_t end = start + bytes;
>     while (offset != end) ...
> }
>

Yes, that's an issue. Ok, if you are not comfortable with start,end, I 
can switch to start,bytes.

-- 
Best regards,
Vladimir

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[John Snow]

On 09/10/2018 01:00 PM, Vladimir Sementsov-Ogievskiy wrote:
> 10.09.2018 19:55, Eric Blake wrote:
>> On 9/10/18 11:49 AM, Vladimir Sementsov-Ogievskiy wrote:
>>
>>>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start,
>>>>> int64_t end);
>>>> The interface looks weird because we can define a 'start' that's beyond
>>>> the 'end'.
>>>>
>>>> I realize that you need a signed integer for 'end' to signify EOF...
>>>> should we do a 'bytes' parameter instead? (Did you already do that
>>>> in an
>>>> earlier version and we changed it?)
>>>>
>>>> Well, it's not a big deal to me personally.
>>>
>>> interface with constant end parameter is more comfortable for loop:
>>> we don't need to update 'bytes' parameter on each iteration
>>
>> But there's still the question of WHO should be calculating end. Your
>> interface argues for the caller:
>>
>> hbitmap_next_zero(start, start + bytes)
>>
>> int64_t hbitmap_next_zero(...)
>> {
>>     while (offset != end) ...
>> }
>>
>> while we're asking about a consistent interface for the caller (if
>> most callers already have a 'bytes' rather than an 'end' computed):
>>
>> hbitmap_next_zero(start, bytes)
>>
>> int64_t hbitmap_next_zero(...)
>> {
>>     int64_t end = start + bytes;
>>     while (offset != end) ...
>> }
>>
> 
> Yes, that's an issue. Ok, if you are not comfortable with start,end, I
> can switch to start,bytes.
> 

The series looks pretty close, I can merge the next version if you think
it's worth changing the interface.

--js

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[Vladimir Sementsov-Ogievskiy]

14.09.2018 20:39, John Snow wrote:
>
> On 09/10/2018 01:00 PM, Vladimir Sementsov-Ogievskiy wrote:
>> 10.09.2018 19:55, Eric Blake wrote:
>>> On 9/10/18 11:49 AM, Vladimir Sementsov-Ogievskiy wrote:
>>>
>>>>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>>>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start,
>>>>>> int64_t end);
>>>>> The interface looks weird because we can define a 'start' that's beyond
>>>>> the 'end'.
>>>>>
>>>>> I realize that you need a signed integer for 'end' to signify EOF...
>>>>> should we do a 'bytes' parameter instead? (Did you already do that
>>>>> in an
>>>>> earlier version and we changed it?)
>>>>>
>>>>> Well, it's not a big deal to me personally.
>>>> interface with constant end parameter is more comfortable for loop:
>>>> we don't need to update 'bytes' parameter on each iteration
>>> But there's still the question of WHO should be calculating end. Your
>>> interface argues for the caller:
>>>
>>> hbitmap_next_zero(start, start + bytes)
>>>
>>> int64_t hbitmap_next_zero(...)
>>> {
>>>      while (offset != end) ...
>>> }
>>>
>>> while we're asking about a consistent interface for the caller (if
>>> most callers already have a 'bytes' rather than an 'end' computed):
>>>
>>> hbitmap_next_zero(start, bytes)
>>>
>>> int64_t hbitmap_next_zero(...)
>>> {
>>>      int64_t end = start + bytes;
>>>      while (offset != end) ...
>>> }
>>>
>> Yes, that's an issue. Ok, if you are not comfortable with start,end, I
>> can switch to start,bytes.
>>
> The series looks pretty close, I can merge the next version if you think
> it's worth changing the interface.
>
> --js

I've started to change interface and found a bug in bitmap_to_extents 
(patch sent 
https://lists.gnu.org/archive/html/qemu-devel/2018-09/msg01804.html). 
So, next version will be based on this patch, which will go through 
Eric's tree..

-- 
Best regards,
Vladimir

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[John Snow]

On 09/14/2018 01:51 PM, Vladimir Sementsov-Ogievskiy wrote:
> 14.09.2018 20:39, John Snow wrote:
>>
>> On 09/10/2018 01:00 PM, Vladimir Sementsov-Ogievskiy wrote:
>>> 10.09.2018 19:55, Eric Blake wrote:
>>>> On 9/10/18 11:49 AM, Vladimir Sementsov-Ogievskiy wrote:
>>>>
>>>>>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>>>>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start,
>>>>>>> int64_t end);
>>>>>> The interface looks weird because we can define a 'start' that's
>>>>>> beyond
>>>>>> the 'end'.
>>>>>>
>>>>>> I realize that you need a signed integer for 'end' to signify EOF...
>>>>>> should we do a 'bytes' parameter instead? (Did you already do that
>>>>>> in an
>>>>>> earlier version and we changed it?)
>>>>>>
>>>>>> Well, it's not a big deal to me personally.
>>>>> interface with constant end parameter is more comfortable for loop:
>>>>> we don't need to update 'bytes' parameter on each iteration
>>>> But there's still the question of WHO should be calculating end. Your
>>>> interface argues for the caller:
>>>>
>>>> hbitmap_next_zero(start, start + bytes)
>>>>
>>>> int64_t hbitmap_next_zero(...)
>>>> {
>>>>      while (offset != end) ...
>>>> }
>>>>
>>>> while we're asking about a consistent interface for the caller (if
>>>> most callers already have a 'bytes' rather than an 'end' computed):
>>>>
>>>> hbitmap_next_zero(start, bytes)
>>>>
>>>> int64_t hbitmap_next_zero(...)
>>>> {
>>>>      int64_t end = start + bytes;
>>>>      while (offset != end) ...
>>>> }
>>>>
>>> Yes, that's an issue. Ok, if you are not comfortable with start,end, I
>>> can switch to start,bytes.
>>>
>> The series looks pretty close, I can merge the next version if you think
>> it's worth changing the interface.
>>
>> --js
> 
> I've started to change interface and found a bug in bitmap_to_extents
> (patch sent
> https://lists.gnu.org/archive/html/qemu-devel/2018-09/msg01804.html).
> So, next version will be based on this patch, which will go through
> Eric's tree..
> 

ah, I see. you can send it to the list anyway with the requires: header
and I can have Eric stage it to make the eventual merge easier for Peter.

--js

Re: [Qemu-devel] [PATCH v3 1/8] dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[John Snow]

On 09/14/2018 01:51 PM, Vladimir Sementsov-Ogievskiy wrote:
> 14.09.2018 20:39, John Snow wrote:
>>
>> On 09/10/2018 01:00 PM, Vladimir Sementsov-Ogievskiy wrote:
>>> 10.09.2018 19:55, Eric Blake wrote:
>>>> On 9/10/18 11:49 AM, Vladimir Sementsov-Ogievskiy wrote:
>>>>
>>>>>>> -int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
>>>>>>> +int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start,
>>>>>>> int64_t end);
>>>>>> The interface looks weird because we can define a 'start' that's
>>>>>> beyond
>>>>>> the 'end'.
>>>>>>
>>>>>> I realize that you need a signed integer for 'end' to signify EOF...
>>>>>> should we do a 'bytes' parameter instead? (Did you already do that
>>>>>> in an
>>>>>> earlier version and we changed it?)
>>>>>>
>>>>>> Well, it's not a big deal to me personally.
>>>>> interface with constant end parameter is more comfortable for loop:
>>>>> we don't need to update 'bytes' parameter on each iteration
>>>> But there's still the question of WHO should be calculating end. Your
>>>> interface argues for the caller:
>>>>
>>>> hbitmap_next_zero(start, start + bytes)
>>>>
>>>> int64_t hbitmap_next_zero(...)
>>>> {
>>>>      while (offset != end) ...
>>>> }
>>>>
>>>> while we're asking about a consistent interface for the caller (if
>>>> most callers already have a 'bytes' rather than an 'end' computed):
>>>>
>>>> hbitmap_next_zero(start, bytes)
>>>>
>>>> int64_t hbitmap_next_zero(...)
>>>> {
>>>>      int64_t end = start + bytes;
>>>>      while (offset != end) ...
>>>> }
>>>>
>>> Yes, that's an issue. Ok, if you are not comfortable with start,end, I
>>> can switch to start,bytes.
>>>
>> The series looks pretty close, I can merge the next version if you think
>> it's worth changing the interface.
>>
>> --js
> 
> I've started to change interface and found a bug in bitmap_to_extents
> (patch sent
> https://lists.gnu.org/archive/html/qemu-devel/2018-09/msg01804.html).
> So, next version will be based on this patch, which will go through
> Eric's tree..
> 

OK, I spoke with Eric and if you resend and I R-B & ACK the patches,
he'll stage them through NBD.

Thanks,
--js

[Qemu-devel] [PATCH v3 2/8] tests: add tests for hbitmap_next_zero with specified end parameter

[Vladimir Sementsov-Ogievskiy]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/test-hbitmap.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index 6b6a40bddd..dddb67c3c5 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -937,31 +937,49 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
     check_hbitmap_iter_next(&hbi);
 }
 
-static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
+static void test_hbitmap_next_zero_check_range(TestHBitmapData *data,
+                                               int64_t start,
+                                               int64_t count)
 {
-    int64_t ret1 = hbitmap_next_zero(data->hb, start, -1);
+    int64_t ret1 = hbitmap_next_zero(data->hb, start,
+                                     count == -1 ? -1 : start + count);
     int64_t ret2 = start;
-    for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
+    int64_t end = count == -1 ? data->size : start + count;
+
+    for ( ; ret2 < end && hbitmap_get(data->hb, ret2); ret2++) {
         ;
     }
-    if (ret2 == data->size) {
+    if (ret2 == end) {
         ret2 = -1;
     }
 
     g_assert_cmpint(ret1, ==, ret2);
 }
 
+static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
+{
+    test_hbitmap_next_zero_check_range(data, start, 0);
+}
+
 static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
 {
     hbitmap_test_init(data, L3, granularity);
     test_hbitmap_next_zero_check(data, 0);
     test_hbitmap_next_zero_check(data, L3 - 1);
+    test_hbitmap_next_zero_check_range(data, 0, 1);
+    test_hbitmap_next_zero_check_range(data, L3 - 1, 1);
 
     hbitmap_set(data->hb, L2, 1);
     test_hbitmap_next_zero_check(data, 0);
     test_hbitmap_next_zero_check(data, L2 - 1);
     test_hbitmap_next_zero_check(data, L2);
     test_hbitmap_next_zero_check(data, L2 + 1);
+    test_hbitmap_next_zero_check_range(data, 0, 1);
+    test_hbitmap_next_zero_check_range(data, 0, L2);
+    test_hbitmap_next_zero_check_range(data, L2 - 1, 1);
+    test_hbitmap_next_zero_check_range(data, L2 - 1, 2);
+    test_hbitmap_next_zero_check_range(data, L2, 1);
+    test_hbitmap_next_zero_check_range(data, L2 + 1, 1);
 
     hbitmap_set(data->hb, L2 + 5, L1);
     test_hbitmap_next_zero_check(data, 0);
@@ -970,6 +988,10 @@ static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
     test_hbitmap_next_zero_check(data, L2 + 5);
     test_hbitmap_next_zero_check(data, L2 + L1 - 1);
     test_hbitmap_next_zero_check(data, L2 + L1);
+    test_hbitmap_next_zero_check_range(data, L2, 6);
+    test_hbitmap_next_zero_check_range(data, L2 + 1, 3);
+    test_hbitmap_next_zero_check_range(data, L2 + 4, L1);
+    test_hbitmap_next_zero_check_range(data, L2 + 5, L1);
 
     hbitmap_set(data->hb, L2 * 2, L3 - L2 * 2);
     test_hbitmap_next_zero_check(data, L2 * 2 - L1);
@@ -977,6 +999,8 @@ static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
     test_hbitmap_next_zero_check(data, L2 * 2 - 1);
     test_hbitmap_next_zero_check(data, L2 * 2);
     test_hbitmap_next_zero_check(data, L3 - 1);
+    test_hbitmap_next_zero_check_range(data, L2 * 2 - L1, L1 + 1);
+    test_hbitmap_next_zero_check_range(data, L2 * 2, L2);
 
     hbitmap_set(data->hb, 0, L3);
     test_hbitmap_next_zero_check(data, 0);
-- 
2.11.1

Re: [Qemu-devel] [PATCH v3 2/8] tests: add tests for hbitmap_next_zero with specified end parameter

[John Snow]

On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  tests/test-hbitmap.c | 32 ++++++++++++++++++++++++++++----
>  1 file changed, 28 insertions(+), 4 deletions(-)
> 
> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
> index 6b6a40bddd..dddb67c3c5 100644
> --- a/tests/test-hbitmap.c
> +++ b/tests/test-hbitmap.c
> @@ -937,31 +937,49 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
>      check_hbitmap_iter_next(&hbi);
>  }
>  
> -static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
> +static void test_hbitmap_next_zero_check_range(TestHBitmapData *data,
> +                                               int64_t start,
> +                                               int64_t count)

Should this interface match the implementation? Because ...

>  {
> -    int64_t ret1 = hbitmap_next_zero(data->hb, start, -1);
> +    int64_t ret1 = hbitmap_next_zero(data->hb, start,
> +                                     count == -1 ? -1 : start + count);

I find it confusing that we use 0 as a sentinel value here and have to
swap it out with -1. If the interfaces matched this would read a little
cleaner, wouldn't it?

>      int64_t ret2 = start;
> -    for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
> +    int64_t end = count == -1 ? data->size : start + count;
> +
> +    for ( ; ret2 < end && hbitmap_get(data->hb, ret2); ret2++) {
>          ;
>      }
> -    if (ret2 == data->size) {
> +    if (ret2 == end) {
>          ret2 = -1;
>      }
>  
>      g_assert_cmpint(ret1, ==, ret2);
>  }
>  
> +static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
> +{
> +    test_hbitmap_next_zero_check_range(data, start, 0);
> +}
> +
>  static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
>  {
>      hbitmap_test_init(data, L3, granularity);
>      test_hbitmap_next_zero_check(data, 0);
>      test_hbitmap_next_zero_check(data, L3 - 1);
> +    test_hbitmap_next_zero_check_range(data, 0, 1);
> +    test_hbitmap_next_zero_check_range(data, L3 - 1, 1);
>  
>      hbitmap_set(data->hb, L2, 1);
>      test_hbitmap_next_zero_check(data, 0);
>      test_hbitmap_next_zero_check(data, L2 - 1);
>      test_hbitmap_next_zero_check(data, L2);
>      test_hbitmap_next_zero_check(data, L2 + 1);
> +    test_hbitmap_next_zero_check_range(data, 0, 1);
> +    test_hbitmap_next_zero_check_range(data, 0, L2);
> +    test_hbitmap_next_zero_check_range(data, L2 - 1, 1);
> +    test_hbitmap_next_zero_check_range(data, L2 - 1, 2);
> +    test_hbitmap_next_zero_check_range(data, L2, 1);
> +    test_hbitmap_next_zero_check_range(data, L2 + 1, 1);
>  
>      hbitmap_set(data->hb, L2 + 5, L1);
>      test_hbitmap_next_zero_check(data, 0);
> @@ -970,6 +988,10 @@ static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
>      test_hbitmap_next_zero_check(data, L2 + 5);
>      test_hbitmap_next_zero_check(data, L2 + L1 - 1);
>      test_hbitmap_next_zero_check(data, L2 + L1);
> +    test_hbitmap_next_zero_check_range(data, L2, 6);
> +    test_hbitmap_next_zero_check_range(data, L2 + 1, 3);
> +    test_hbitmap_next_zero_check_range(data, L2 + 4, L1);
> +    test_hbitmap_next_zero_check_range(data, L2 + 5, L1);
>  
>      hbitmap_set(data->hb, L2 * 2, L3 - L2 * 2);
>      test_hbitmap_next_zero_check(data, L2 * 2 - L1);
> @@ -977,6 +999,8 @@ static void test_hbitmap_next_zero_do(TestHBitmapData *data, int granularity)
>      test_hbitmap_next_zero_check(data, L2 * 2 - 1);
>      test_hbitmap_next_zero_check(data, L2 * 2);
>      test_hbitmap_next_zero_check(data, L3 - 1);
> +    test_hbitmap_next_zero_check_range(data, L2 * 2 - L1, L1 + 1);
> +    test_hbitmap_next_zero_check_range(data, L2 * 2, L2);
>  
>      hbitmap_set(data->hb, 0, L3);
>      test_hbitmap_next_zero_check(data, 0);
> 

[Qemu-devel] [PATCH v3 3/8] dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area

[Vladimir Sementsov-Ogievskiy]

The function alters bdrv_dirty_iter_next_area(), which is wrong and
less efficient (see further commit
"block/mirror: fix and improve do_sync_target_write" for description).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@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 27f5299c4e..cb9162fa7e 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,
                                     int64_t end);
+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 fe4dfde27a..7800317bf3 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, int64_t end);
 
+/* 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 037ae62726..4af20a1beb 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, end);
 }
 
+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 1687372504..bf88c1223e 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -244,6 +244,44 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end)
     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);
+    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;
-- 
2.11.1

Re: [Qemu-devel] [PATCH v3 3/8] dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area

[John Snow]

On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> The function alters bdrv_dirty_iter_next_area(), which is wrong and
> less efficient (see further commit
> "block/mirror: fix and improve do_sync_target_write" for description).
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@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 27f5299c4e..cb9162fa7e 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,
>                                      int64_t end);
> +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 fe4dfde27a..7800317bf3 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, int64_t end);
>  
> +/* 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.

It returns true in both cases? I think you mean 'false' the second time.

> + */
> +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 037ae62726..4af20a1beb 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, end);
>  }
>  
> +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 1687372504..bf88c1223e 100644
> --- a/util/hbitmap.c
> +++ b/util/hbitmap.c
> @@ -244,6 +244,44 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, int64_t end)
>      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;

Can we have more descriptive names for these?

> +    uint32_t granularity = 1UL << hb->granularity;
> +
> +    if (end == 0) {
> +        end = hb->orig_size;
> +    }
> +
> +    hbitmap_iter_init(&hbi, hb, *offset);

Even with a new iterator in every call, this is still faster than the
old one? ... I guess the old one uses a new iterator for every call, too.

Well, this does look more straightforward and we don't loop as much, so
it seems right.

> +    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;
> +}
> +

I might have consolidated setting the output parameters to one block
instead of two, but that's only stylistic.

>  bool hbitmap_empty(const HBitmap *hb)
>  {
>      return hb->count == 0;
> 

If you fix your docstring:

Reviewed-by: John Snow <jsnow@redhat.com>

[Qemu-devel] [PATCH v3 4/8] tests: add tests for hbitmap_next_dirty_area

[Vladimir Sementsov-Ogievskiy]

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/test-hbitmap.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)

diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index dddb67c3c5..af5142b481 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -1016,6 +1016,105 @@ static void test_hbitmap_next_zero_4(TestHBitmapData *data, const void *unused)
     test_hbitmap_next_zero_do(data, 4);
 }
 
+static void test_hbitmap_next_dirty_area_check(TestHBitmapData *data,
+                                               uint64_t offset,
+                                               uint64_t count)
+{
+    uint64_t off1, off2;
+    uint64_t len1 = 0, len2 = 0;
+    bool ret1, ret2;
+    int64_t end;
+
+    off1 = offset;
+    end = count ? offset + count : 0;
+    ret1 = hbitmap_next_dirty_area(data->hb, &off1, end, &len1);
+
+    end = count ? offset + count : data->size;
+
+    for (off2 = offset; off2 < end && !hbitmap_get(data->hb, off2); off2++) {
+        ;
+    }
+
+    for (len2 = 1; off2 + len2 < end && hbitmap_get(data->hb, off2 + len2);
+         len2++)
+    {
+    }
+
+    ret2 = off2 < end;
+    if (!ret2) {
+        /* leave unchanged */
+        off2 = offset;
+        len2 = 0;
+    }
+
+    g_assert_cmpint(ret1, ==, ret2);
+    g_assert_cmpint(off1, ==, off2);
+    g_assert_cmpint(len1, ==, len2);
+}
+
+static void test_hbitmap_next_dirty_area_do(TestHBitmapData *data,
+                                            int granularity)
+{
+    hbitmap_test_init(data, L3, granularity);
+    test_hbitmap_next_dirty_area_check(data, 0, 0);
+    test_hbitmap_next_dirty_area_check(data, 0, 1);
+    test_hbitmap_next_dirty_area_check(data, L3 - 1, 1);
+
+    hbitmap_set(data->hb, L2, 1);
+    test_hbitmap_next_dirty_area_check(data, 0, 1);
+    test_hbitmap_next_dirty_area_check(data, 0, L2);
+    test_hbitmap_next_dirty_area_check(data, 0, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 - 1, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 - 1, 1);
+    test_hbitmap_next_dirty_area_check(data, L2 - 1, 2);
+    test_hbitmap_next_dirty_area_check(data, L2 - 1, 3);
+    test_hbitmap_next_dirty_area_check(data, L2, 0);
+    test_hbitmap_next_dirty_area_check(data, L2, 1);
+    test_hbitmap_next_dirty_area_check(data, L2 + 1, 1);
+
+    hbitmap_set(data->hb, L2 + 5, L1);
+    test_hbitmap_next_dirty_area_check(data, 0, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 - 2, 8);
+    test_hbitmap_next_dirty_area_check(data, L2 + 1, 5);
+    test_hbitmap_next_dirty_area_check(data, L2 + 1, 3);
+    test_hbitmap_next_dirty_area_check(data, L2 + 4, L1);
+    test_hbitmap_next_dirty_area_check(data, L2 + 5, L1);
+    test_hbitmap_next_dirty_area_check(data, L2 + 7, L1);
+    test_hbitmap_next_dirty_area_check(data, L2 + L1, L1);
+    test_hbitmap_next_dirty_area_check(data, L2, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 + 1, 0);
+
+    hbitmap_set(data->hb, L2 * 2, L3 - L2 * 2);
+    test_hbitmap_next_dirty_area_check(data, 0, 0);
+    test_hbitmap_next_dirty_area_check(data, L2, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 + 1, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 + 5 + L1 - 1, 0);
+    test_hbitmap_next_dirty_area_check(data, L2 + 5 + L1, 5);
+    test_hbitmap_next_dirty_area_check(data, L2 * 2 - L1, L1 + 1);
+    test_hbitmap_next_dirty_area_check(data, L2 * 2, L2);
+
+    hbitmap_set(data->hb, 0, L3);
+    test_hbitmap_next_dirty_area_check(data, 0, 0);
+}
+
+static void test_hbitmap_next_dirty_area_0(TestHBitmapData *data,
+                                           const void *unused)
+{
+    test_hbitmap_next_dirty_area_do(data, 0);
+}
+
+static void test_hbitmap_next_dirty_area_1(TestHBitmapData *data,
+                                           const void *unused)
+{
+    test_hbitmap_next_dirty_area_do(data, 1);
+}
+
+static void test_hbitmap_next_dirty_area_4(TestHBitmapData *data,
+                                           const void *unused)
+{
+    test_hbitmap_next_dirty_area_do(data, 4);
+}
+
 int main(int argc, char **argv)
 {
     g_test_init(&argc, &argv, NULL);
@@ -1082,6 +1181,13 @@ int main(int argc, char **argv)
     hbitmap_test_add("/hbitmap/next_zero/next_zero_4",
                      test_hbitmap_next_zero_4);
 
+    hbitmap_test_add("/hbitmap/next_dirty_area/next_dirty_area_0",
+                     test_hbitmap_next_dirty_area_0);
+    hbitmap_test_add("/hbitmap/next_dirty_area/next_dirty_area_1",
+                     test_hbitmap_next_dirty_area_1);
+    hbitmap_test_add("/hbitmap/next_dirty_area/next_dirty_area_4",
+                     test_hbitmap_next_dirty_area_4);
+
     g_test_run();
 
     return 0;
-- 
2.11.1

Re: [Qemu-devel] [PATCH v3 4/8] tests: add tests for hbitmap_next_dirty_area

[John Snow]

On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

ACK, and
Tested-by: John Snow <jsnow@redhat.com>

> ---
>  tests/test-hbitmap.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 106 insertions(+)
> 
> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
> index dddb67c3c5..af5142b481 100644
> --- a/tests/test-hbitmap.c
> +++ b/tests/test-hbitmap.c
> @@ -1016,6 +1016,105 @@ static void test_hbitmap_next_zero_4(TestHBitmapData *data, const void *unused)
>      test_hbitmap_next_zero_do(data, 4);
>  }
>  
> +static void test_hbitmap_next_dirty_area_check(TestHBitmapData *data,
> +                                               uint64_t offset,
> +                                               uint64_t count)
> +{
> +    uint64_t off1, off2;
> +    uint64_t len1 = 0, len2 = 0;
> +    bool ret1, ret2;
> +    int64_t end;
> +
> +    off1 = offset;
> +    end = count ? offset + count : 0;
> +    ret1 = hbitmap_next_dirty_area(data->hb, &off1, end, &len1);
> +
> +    end = count ? offset + count : data->size;
> +
> +    for (off2 = offset; off2 < end && !hbitmap_get(data->hb, off2); off2++) {
> +        ;
> +    }
> +
> +    for (len2 = 1; off2 + len2 < end && hbitmap_get(data->hb, off2 + len2);
> +         len2++)
> +    {
> +    }
> +
> +    ret2 = off2 < end;
> +    if (!ret2) {
> +        /* leave unchanged */
> +        off2 = offset;
> +        len2 = 0;
> +    }
> +
> +    g_assert_cmpint(ret1, ==, ret2);
> +    g_assert_cmpint(off1, ==, off2);
> +    g_assert_cmpint(len1, ==, len2);
> +}
> +
> +static void test_hbitmap_next_dirty_area_do(TestHBitmapData *data,
> +                                            int granularity)
> +{
> +    hbitmap_test_init(data, L3, granularity);
> +    test_hbitmap_next_dirty_area_check(data, 0, 0);
> +    test_hbitmap_next_dirty_area_check(data, 0, 1);
> +    test_hbitmap_next_dirty_area_check(data, L3 - 1, 1);
> +
> +    hbitmap_set(data->hb, L2, 1);
> +    test_hbitmap_next_dirty_area_check(data, 0, 1);
> +    test_hbitmap_next_dirty_area_check(data, 0, L2);
> +    test_hbitmap_next_dirty_area_check(data, 0, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 - 1, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 - 1, 1);
> +    test_hbitmap_next_dirty_area_check(data, L2 - 1, 2);
> +    test_hbitmap_next_dirty_area_check(data, L2 - 1, 3);
> +    test_hbitmap_next_dirty_area_check(data, L2, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2, 1);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 1, 1);
> +
> +    hbitmap_set(data->hb, L2 + 5, L1);
> +    test_hbitmap_next_dirty_area_check(data, 0, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 - 2, 8);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 1, 5);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 1, 3);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 4, L1);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 5, L1);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 7, L1);
> +    test_hbitmap_next_dirty_area_check(data, L2 + L1, L1);
> +    test_hbitmap_next_dirty_area_check(data, L2, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 1, 0);
> +
> +    hbitmap_set(data->hb, L2 * 2, L3 - L2 * 2);
> +    test_hbitmap_next_dirty_area_check(data, 0, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 1, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 5 + L1 - 1, 0);
> +    test_hbitmap_next_dirty_area_check(data, L2 + 5 + L1, 5);
> +    test_hbitmap_next_dirty_area_check(data, L2 * 2 - L1, L1 + 1);
> +    test_hbitmap_next_dirty_area_check(data, L2 * 2, L2);
> +
> +    hbitmap_set(data->hb, 0, L3);
> +    test_hbitmap_next_dirty_area_check(data, 0, 0);
> +}
> +
> +static void test_hbitmap_next_dirty_area_0(TestHBitmapData *data,
> +                                           const void *unused)
> +{
> +    test_hbitmap_next_dirty_area_do(data, 0);
> +}
> +
> +static void test_hbitmap_next_dirty_area_1(TestHBitmapData *data,
> +                                           const void *unused)
> +{
> +    test_hbitmap_next_dirty_area_do(data, 1);
> +}
> +
> +static void test_hbitmap_next_dirty_area_4(TestHBitmapData *data,
> +                                           const void *unused)
> +{
> +    test_hbitmap_next_dirty_area_do(data, 4);
> +}
> +
>  int main(int argc, char **argv)
>  {
>      g_test_init(&argc, &argv, NULL);
> @@ -1082,6 +1181,13 @@ int main(int argc, char **argv)
>      hbitmap_test_add("/hbitmap/next_zero/next_zero_4",
>                       test_hbitmap_next_zero_4);
>  
> +    hbitmap_test_add("/hbitmap/next_dirty_area/next_dirty_area_0",
> +                     test_hbitmap_next_dirty_area_0);
> +    hbitmap_test_add("/hbitmap/next_dirty_area/next_dirty_area_1",
> +                     test_hbitmap_next_dirty_area_1);
> +    hbitmap_test_add("/hbitmap/next_dirty_area/next_dirty_area_4",
> +                     test_hbitmap_next_dirty_area_4);
> +
>      g_test_run();
>  
>      return 0;
> 

[Qemu-devel] [PATCH v3 5/8] block/mirror: fix and improve do_sync_target_write

[Vladimir Sementsov-Ogievskiy]

Use bdrv_dirty_bitmap_next_dirty_area() instead of
bdrv_dirty_iter_next_area(), because of the following problems of
bdrv_dirty_iter_next_area():

1. Using HBitmap iterators we should carefully handle unaligned offset,
as first call to hbitmap_iter_next() may return a value less than
original offset (actually, it will be original offset rounded down to
bitmap granularity). This handling is not done in
do_sync_target_write().

2. bdrv_dirty_iter_next_area() handles unaligned max_offset
incorrectly:

look at the code:
    if (max_offset == iter->bitmap->size) {
        /* If max_offset points to the image end, round it up by the
         * bitmap granularity */
        gran_max_offset = ROUND_UP(max_offset, granularity);
    } else {
        gran_max_offset = max_offset;
    }

    ret = hbitmap_iter_next(&iter->hbi, false);
    if (ret < 0 || ret + granularity > gran_max_offset) {
        return false;
    }

and assume that max_offset != iter->bitmap->size but still unaligned.
if 0 < ret < max_offset we found dirty area, but the function can
return false in this case (if ret + granularity > max_offset).

3. bdrv_dirty_iter_next_area() uses inefficient loop to find the end of
the dirty area. Let's use more efficient hbitmap_next_zero instead
(bdrv_dirty_bitmap_next_dirty_area() do so)

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/mirror.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index b48c3f8cf5..d2806812c8 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1167,25 +1167,22 @@ static void do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
                                  uint64_t offset, uint64_t bytes,
                                  QEMUIOVector *qiov, int flags)
 {
-    BdrvDirtyBitmapIter *iter;
     QEMUIOVector target_qiov;
-    uint64_t dirty_offset;
-    int dirty_bytes;
+    uint64_t dirty_offset = offset;
+    uint64_t dirty_bytes;
 
     if (qiov) {
         qemu_iovec_init(&target_qiov, qiov->niov);
     }
 
-    iter = bdrv_dirty_iter_new(job->dirty_bitmap);
-    bdrv_set_dirty_iter(iter, offset);
-
     while (true) {
         bool valid_area;
         int ret;
 
         bdrv_dirty_bitmap_lock(job->dirty_bitmap);
-        valid_area = bdrv_dirty_iter_next_area(iter, offset + bytes,
-                                               &dirty_offset, &dirty_bytes);
+        valid_area = bdrv_dirty_bitmap_next_dirty_area(
+            job->dirty_bitmap, &dirty_offset,
+            MIN(offset + bytes, dirty_offset + INT_MAX), &dirty_bytes);
         if (!valid_area) {
             bdrv_dirty_bitmap_unlock(job->dirty_bitmap);
             break;
@@ -1241,9 +1238,10 @@ static void do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
                 break;
             }
         }
+
+        dirty_offset += dirty_bytes;
     }
 
-    bdrv_dirty_iter_free(iter);
     if (qiov) {
         qemu_iovec_destroy(&target_qiov);
     }
-- 
2.11.1

Re: [Qemu-devel] [PATCH v3 5/8] block/mirror: fix and improve do_sync_target_write

[John Snow]

On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> Use bdrv_dirty_bitmap_next_dirty_area() instead of
> bdrv_dirty_iter_next_area(), because of the following problems of
> bdrv_dirty_iter_next_area():
> 
> 1. Using HBitmap iterators we should carefully handle unaligned offset,
> as first call to hbitmap_iter_next() may return a value less than
> original offset (actually, it will be original offset rounded down to
> bitmap granularity). This handling is not done in
> do_sync_target_write().
> 
> 2. bdrv_dirty_iter_next_area() handles unaligned max_offset
> incorrectly:
> 
> look at the code:
>     if (max_offset == iter->bitmap->size) {
>         /* If max_offset points to the image end, round it up by the
>          * bitmap granularity */
>         gran_max_offset = ROUND_UP(max_offset, granularity);
>     } else {
>         gran_max_offset = max_offset;
>     }
> 
>     ret = hbitmap_iter_next(&iter->hbi, false);
>     if (ret < 0 || ret + granularity > gran_max_offset) {
>         return false;
>     }
> 
> and assume that max_offset != iter->bitmap->size but still unaligned.
> if 0 < ret < max_offset we found dirty area, but the function can
> return false in this case (if ret + granularity > max_offset).
> 
> 3. bdrv_dirty_iter_next_area() uses inefficient loop to find the end of
> the dirty area. Let's use more efficient hbitmap_next_zero instead
> (bdrv_dirty_bitmap_next_dirty_area() do so)
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/mirror.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index b48c3f8cf5..d2806812c8 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -1167,25 +1167,22 @@ static void do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
>                                   uint64_t offset, uint64_t bytes,
>                                   QEMUIOVector *qiov, int flags)
>  {
> -    BdrvDirtyBitmapIter *iter;
>      QEMUIOVector target_qiov;
> -    uint64_t dirty_offset;
> -    int dirty_bytes;
> +    uint64_t dirty_offset = offset;
> +    uint64_t dirty_bytes;
>  
>      if (qiov) {
>          qemu_iovec_init(&target_qiov, qiov->niov);
>      }
>  
> -    iter = bdrv_dirty_iter_new(job->dirty_bitmap);
> -    bdrv_set_dirty_iter(iter, offset);
> -
>      while (true) {
>          bool valid_area;
>          int ret;
>  
>          bdrv_dirty_bitmap_lock(job->dirty_bitmap);
> -        valid_area = bdrv_dirty_iter_next_area(iter, offset + bytes,
> -                                               &dirty_offset, &dirty_bytes);
> +        valid_area = bdrv_dirty_bitmap_next_dirty_area(
> +            job->dirty_bitmap, &dirty_offset,
> +            MIN(offset + bytes, dirty_offset + INT_MAX), &dirty_bytes);

Looks correct, though the invocation looks harder to read now. Might be
a sign that changing the signature is a good idea.... which I think
you're planning to do.

ACK.

>          if (!valid_area) {
>              bdrv_dirty_bitmap_unlock(job->dirty_bitmap);
>              break;
> @@ -1241,9 +1238,10 @@ static void do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
>                  break;
>              }
>          }
> +
> +        dirty_offset += dirty_bytes;
>      }
>  
> -    bdrv_dirty_iter_free(iter);
>      if (qiov) {
>          qemu_iovec_destroy(&target_qiov);
>      }
> 

[Qemu-devel] [PATCH v3 6/8] Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"

[Vladimir Sementsov-Ogievskiy]

This reverts commit 72d10a94213a954ad569095cb4491f2ae0853c40.

The function is unused now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/block/dirty-bitmap.h |  2 --
 block/dirty-bitmap.c         | 55 --------------------------------------------
 2 files changed, 57 deletions(-)

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index cb9162fa7e..20e1d86cb1 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -83,8 +83,6 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
                                     int64_t offset, int64_t bytes);
 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
-bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset,
-                               uint64_t *offset, int *bytes);
 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
 int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap);
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 4af20a1beb..d9333175b3 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -528,61 +528,6 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
     return hbitmap_iter_next(&iter->hbi, true);
 }
 
-/**
- * Return the next consecutively dirty area in the dirty bitmap
- * belonging to the given iterator @iter.
- *
- * @max_offset: Maximum value that may be returned for
- *              *offset + *bytes
- * @offset:     Will contain the start offset of the next dirty area
- * @bytes:      Will contain the length of the next dirty area
- *
- * Returns: True if a dirty area could be found before max_offset
- *          (which means that *offset and *bytes then contain valid
- *          values), false otherwise.
- *
- * Note that @iter is never advanced if false is returned.  If an area
- * is found (which means that true is returned), it will be advanced
- * past that area.
- */
-bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset,
-                               uint64_t *offset, int *bytes)
-{
-    uint32_t granularity = bdrv_dirty_bitmap_granularity(iter->bitmap);
-    uint64_t gran_max_offset;
-    int64_t ret;
-    int size;
-
-    if (max_offset == iter->bitmap->size) {
-        /* If max_offset points to the image end, round it up by the
-         * bitmap granularity */
-        gran_max_offset = ROUND_UP(max_offset, granularity);
-    } else {
-        gran_max_offset = max_offset;
-    }
-
-    ret = hbitmap_iter_next(&iter->hbi, false);
-    if (ret < 0 || ret + granularity > gran_max_offset) {
-        return false;
-    }
-
-    *offset = ret;
-    size = 0;
-
-    assert(granularity <= INT_MAX);
-
-    do {
-        /* Advance iterator */
-        ret = hbitmap_iter_next(&iter->hbi, true);
-        size += granularity;
-    } while (ret + granularity <= gran_max_offset &&
-             hbitmap_iter_next(&iter->hbi, false) == ret + granularity &&
-             size <= INT_MAX - granularity);
-
-    *bytes = MIN(size, max_offset - *offset);
-    return true;
-}
-
 /* Called within bdrv_dirty_bitmap_lock..unlock */
 void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
                                   int64_t offset, int64_t bytes)
-- 
2.11.1

[Qemu-devel] [PATCH v3 7/8] Revert "test-hbitmap: Add non-advancing iter_next tests"

[Vladimir Sementsov-Ogievskiy]

This reverts commit 269576848ec3d57d2d958cf5ac69b08c44adf816.

The functionality is unused. Drop tests.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/test-hbitmap.c | 36 ++++++++++++------------------------
 1 file changed, 12 insertions(+), 24 deletions(-)

diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index af5142b481..5e43056970 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -30,18 +30,6 @@ typedef struct TestHBitmapData {
 } TestHBitmapData;
 
 
-static int64_t check_hbitmap_iter_next(HBitmapIter *hbi)
-{
-    int next0, next1;
-
-    next0 = hbitmap_iter_next(hbi, false);
-    next1 = hbitmap_iter_next(hbi, true);
-
-    g_assert_cmpint(next0, ==, next1);
-
-    return next0;
-}
-
 /* Check that the HBitmap and the shadow bitmap contain the same data,
  * ignoring the same "first" bits.
  */
@@ -58,7 +46,7 @@ static void hbitmap_test_check(TestHBitmapData *data,
 
     i = first;
     for (;;) {
-        next = check_hbitmap_iter_next(&hbi);
+        next = hbitmap_iter_next(&hbi, true);
         if (next < 0) {
             next = data->size;
         }
@@ -447,25 +435,25 @@ static void test_hbitmap_iter_granularity(TestHBitmapData *data,
     /* Note that hbitmap_test_check has to be invoked manually in this test.  */
     hbitmap_test_init(data, 131072 << 7, 7);
     hbitmap_iter_init(&hbi, data->hb, 0);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
 
     hbitmap_test_set(data, ((L2 + L1 + 1) << 7) + 8, 8);
     hbitmap_iter_init(&hbi, data->hb, 0);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
 
     hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);
     g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
 
     hbitmap_test_set(data, (131072 << 7) - 8, 8);
     hbitmap_iter_init(&hbi, data->hb, 0);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), ==, 131071 << 7);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
 
     hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), ==, 131071 << 7);
-    g_assert_cmpint(check_hbitmap_iter_next(&hbi), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
 }
 
 static void hbitmap_test_set_boundary_bits(TestHBitmapData *data, ssize_t diff)
@@ -905,7 +893,7 @@ static void test_hbitmap_serialize_zeroes(TestHBitmapData *data,
     for (i = 0; i < num_positions; i++) {
         hbitmap_deserialize_zeroes(data->hb, positions[i], min_l1, true);
         hbitmap_iter_init(&iter, data->hb, 0);
-        next = check_hbitmap_iter_next(&iter);
+        next = hbitmap_iter_next(&iter, true);
         if (i == num_positions - 1) {
             g_assert_cmpint(next, ==, -1);
         } else {
@@ -931,10 +919,10 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
 
     hbitmap_iter_init(&hbi, data->hb, BITS_PER_LONG - 1);
 
-    check_hbitmap_iter_next(&hbi);
+    hbitmap_iter_next(&hbi, true);
 
     hbitmap_reset_all(data->hb);
-    check_hbitmap_iter_next(&hbi);
+    hbitmap_iter_next(&hbi, true);
 }
 
 static void test_hbitmap_next_zero_check_range(TestHBitmapData *data,
-- 
2.11.1

[Qemu-devel] [PATCH v3 8/8] Revert "hbitmap: Add @advance param to hbitmap_iter_next()"

[Vladimir Sementsov-Ogievskiy]

This reverts commit a33fbb4f8b64226becf502a123733776ce319b24.

The functionality is unused.

Note: in addition to automatic revert, drop second parameter in
hbitmap_iter_next() call from hbitmap_next_dirty_area() too.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/qemu/hbitmap.h |  5 +----
 block/backup.c         |  2 +-
 block/dirty-bitmap.c   |  2 +-
 tests/test-hbitmap.c   | 26 +++++++++++++-------------
 util/hbitmap.c         | 12 ++++--------
 5 files changed, 20 insertions(+), 27 deletions(-)

diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index 7800317bf3..6d205167ce 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -345,14 +345,11 @@ void hbitmap_free_meta(HBitmap *hb);
 /**
  * hbitmap_iter_next:
  * @hbi: HBitmapIter to operate on.
- * @advance: If true, advance the iterator.  Otherwise, the next call
- *           of this function will return the same result (if that
- *           position is still dirty).
  *
  * Return the next bit that is set in @hbi's associated HBitmap,
  * or -1 if all remaining bits are zero.
  */
-int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance);
+int64_t hbitmap_iter_next(HBitmapIter *hbi);
 
 /**
  * hbitmap_iter_next_word:
diff --git a/block/backup.c b/block/backup.c
index 9bfd3f7189..f033148f21 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -421,7 +421,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
     HBitmapIter hbi;
 
     hbitmap_iter_init(&hbi, job->copy_bitmap, 0);
-    while ((cluster = hbitmap_iter_next(&hbi, true)) != -1) {
+    while ((cluster = hbitmap_iter_next(&hbi)) != -1) {
         do {
             if (yield_and_check(job)) {
                 return 0;
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index d9333175b3..d0d602ff52 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -525,7 +525,7 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
 
 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 {
-    return hbitmap_iter_next(&iter->hbi, true);
+    return hbitmap_iter_next(&iter->hbi);
 }
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index 5e43056970..17a3c807de 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -46,7 +46,7 @@ static void hbitmap_test_check(TestHBitmapData *data,
 
     i = first;
     for (;;) {
-        next = hbitmap_iter_next(&hbi, true);
+        next = hbitmap_iter_next(&hbi);
         if (next < 0) {
             next = data->size;
         }
@@ -435,25 +435,25 @@ static void test_hbitmap_iter_granularity(TestHBitmapData *data,
     /* Note that hbitmap_test_check has to be invoked manually in this test.  */
     hbitmap_test_init(data, 131072 << 7, 7);
     hbitmap_iter_init(&hbi, data->hb, 0);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
 
     hbitmap_test_set(data, ((L2 + L1 + 1) << 7) + 8, 8);
     hbitmap_iter_init(&hbi, data->hb, 0);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
 
     hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
 
     hbitmap_test_set(data, (131072 << 7) - 8, 8);
     hbitmap_iter_init(&hbi, data->hb, 0);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, 131071 << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
 
     hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);
-    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, 131071 << 7);
+    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
 }
 
 static void hbitmap_test_set_boundary_bits(TestHBitmapData *data, ssize_t diff)
@@ -893,7 +893,7 @@ static void test_hbitmap_serialize_zeroes(TestHBitmapData *data,
     for (i = 0; i < num_positions; i++) {
         hbitmap_deserialize_zeroes(data->hb, positions[i], min_l1, true);
         hbitmap_iter_init(&iter, data->hb, 0);
-        next = hbitmap_iter_next(&iter, true);
+        next = hbitmap_iter_next(&iter);
         if (i == num_positions - 1) {
             g_assert_cmpint(next, ==, -1);
         } else {
@@ -919,10 +919,10 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
 
     hbitmap_iter_init(&hbi, data->hb, BITS_PER_LONG - 1);
 
-    hbitmap_iter_next(&hbi, true);
+    hbitmap_iter_next(&hbi);
 
     hbitmap_reset_all(data->hb);
-    hbitmap_iter_next(&hbi, true);
+    hbitmap_iter_next(&hbi);
 }
 
 static void test_hbitmap_next_zero_check_range(TestHBitmapData *data,
diff --git a/util/hbitmap.c b/util/hbitmap.c
index bf88c1223e..b00e05a85b 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -144,7 +144,7 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi)
     return cur;
 }
 
-int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance)
+int64_t hbitmap_iter_next(HBitmapIter *hbi)
 {
     unsigned long cur = hbi->cur[HBITMAP_LEVELS - 1] &
             hbi->hb->levels[HBITMAP_LEVELS - 1][hbi->pos];
@@ -157,12 +157,8 @@ int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance)
         }
     }
 
-    if (advance) {
-        /* The next call will resume work from the next bit.  */
-        hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);
-    } else {
-        hbi->cur[HBITMAP_LEVELS - 1] = cur;
-    }
+    /* The next call will resume work from the next bit.  */
+    hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);
     item = ((uint64_t)hbi->pos << BITS_PER_LEVEL) + ctzl(cur);
 
     return item << hbi->granularity;
@@ -256,7 +252,7 @@ bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *offset,
     }
 
     hbitmap_iter_init(&hbi, hb, *offset);
-    off1 = hbitmap_iter_next(&hbi, true);
+    off1 = hbitmap_iter_next(&hbi);
 
     if (off1 < 0 || off1 >= end) {
         return false;
-- 
2.11.1

Re: [Qemu-devel] [PATCH v3 8/8] Revert "hbitmap: Add @advance param to hbitmap_iter_next()"

[John Snow]

On 08/14/2018 08:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> This reverts commit a33fbb4f8b64226becf502a123733776ce319b24.
> 
> The functionality is unused.
> 
> Note: in addition to automatic revert, drop second parameter in
> hbitmap_iter_next() call from hbitmap_next_dirty_area() too.
> 

Hm, it's not really a "revert" in the revision control sense then, but I
don't think I care about that kind of pedantic distinction personally.

6,7,8: Reviewed-by: John Snow <jsnow@redhat.com>

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  include/qemu/hbitmap.h |  5 +----
>  block/backup.c         |  2 +-
>  block/dirty-bitmap.c   |  2 +-
>  tests/test-hbitmap.c   | 26 +++++++++++++-------------
>  util/hbitmap.c         | 12 ++++--------
>  5 files changed, 20 insertions(+), 27 deletions(-)
> 
> diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
> index 7800317bf3..6d205167ce 100644
> --- a/include/qemu/hbitmap.h
> +++ b/include/qemu/hbitmap.h
> @@ -345,14 +345,11 @@ void hbitmap_free_meta(HBitmap *hb);
>  /**
>   * hbitmap_iter_next:
>   * @hbi: HBitmapIter to operate on.
> - * @advance: If true, advance the iterator.  Otherwise, the next call
> - *           of this function will return the same result (if that
> - *           position is still dirty).
>   *
>   * Return the next bit that is set in @hbi's associated HBitmap,
>   * or -1 if all remaining bits are zero.
>   */
> -int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance);
> +int64_t hbitmap_iter_next(HBitmapIter *hbi);
>  
>  /**
>   * hbitmap_iter_next_word:
> diff --git a/block/backup.c b/block/backup.c
> index 9bfd3f7189..f033148f21 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -421,7 +421,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
>      HBitmapIter hbi;
>  
>      hbitmap_iter_init(&hbi, job->copy_bitmap, 0);
> -    while ((cluster = hbitmap_iter_next(&hbi, true)) != -1) {
> +    while ((cluster = hbitmap_iter_next(&hbi)) != -1) {
>          do {
>              if (yield_and_check(job)) {
>                  return 0;
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index d9333175b3..d0d602ff52 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -525,7 +525,7 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
>  
>  int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
>  {
> -    return hbitmap_iter_next(&iter->hbi, true);
> +    return hbitmap_iter_next(&iter->hbi);
>  }
>  
>  /* Called within bdrv_dirty_bitmap_lock..unlock */
> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
> index 5e43056970..17a3c807de 100644
> --- a/tests/test-hbitmap.c
> +++ b/tests/test-hbitmap.c
> @@ -46,7 +46,7 @@ static void hbitmap_test_check(TestHBitmapData *data,
>  
>      i = first;
>      for (;;) {
> -        next = hbitmap_iter_next(&hbi, true);
> +        next = hbitmap_iter_next(&hbi);
>          if (next < 0) {
>              next = data->size;
>          }
> @@ -435,25 +435,25 @@ static void test_hbitmap_iter_granularity(TestHBitmapData *data,
>      /* Note that hbitmap_test_check has to be invoked manually in this test.  */
>      hbitmap_test_init(data, 131072 << 7, 7);
>      hbitmap_iter_init(&hbi, data->hb, 0);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
>  
>      hbitmap_test_set(data, ((L2 + L1 + 1) << 7) + 8, 8);
>      hbitmap_iter_init(&hbi, data->hb, 0);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
>  
>      hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
>  
>      hbitmap_test_set(data, (131072 << 7) - 8, 8);
>      hbitmap_iter_init(&hbi, data->hb, 0);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, 131071 << 7);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
>  
>      hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);
> -    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, 131071 << 7);
> +    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);
>  }
>  
>  static void hbitmap_test_set_boundary_bits(TestHBitmapData *data, ssize_t diff)
> @@ -893,7 +893,7 @@ static void test_hbitmap_serialize_zeroes(TestHBitmapData *data,
>      for (i = 0; i < num_positions; i++) {
>          hbitmap_deserialize_zeroes(data->hb, positions[i], min_l1, true);
>          hbitmap_iter_init(&iter, data->hb, 0);
> -        next = hbitmap_iter_next(&iter, true);
> +        next = hbitmap_iter_next(&iter);
>          if (i == num_positions - 1) {
>              g_assert_cmpint(next, ==, -1);
>          } else {
> @@ -919,10 +919,10 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,
>  
>      hbitmap_iter_init(&hbi, data->hb, BITS_PER_LONG - 1);
>  
> -    hbitmap_iter_next(&hbi, true);
> +    hbitmap_iter_next(&hbi);
>  
>      hbitmap_reset_all(data->hb);
> -    hbitmap_iter_next(&hbi, true);
> +    hbitmap_iter_next(&hbi);
>  }
>  
>  static void test_hbitmap_next_zero_check_range(TestHBitmapData *data,
> diff --git a/util/hbitmap.c b/util/hbitmap.c
> index bf88c1223e..b00e05a85b 100644
> --- a/util/hbitmap.c
> +++ b/util/hbitmap.c
> @@ -144,7 +144,7 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi)
>      return cur;
>  }
>  
> -int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance)
> +int64_t hbitmap_iter_next(HBitmapIter *hbi)
>  {
>      unsigned long cur = hbi->cur[HBITMAP_LEVELS - 1] &
>              hbi->hb->levels[HBITMAP_LEVELS - 1][hbi->pos];
> @@ -157,12 +157,8 @@ int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance)
>          }
>      }
>  
> -    if (advance) {
> -        /* The next call will resume work from the next bit.  */
> -        hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);
> -    } else {
> -        hbi->cur[HBITMAP_LEVELS - 1] = cur;
> -    }
> +    /* The next call will resume work from the next bit.  */
> +    hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);
>      item = ((uint64_t)hbi->pos << BITS_PER_LEVEL) + ctzl(cur);
>  
>      return item << hbi->granularity;
> @@ -256,7 +252,7 @@ bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *offset,
>      }
>  
>      hbitmap_iter_init(&hbi, hb, *offset);
> -    off1 = hbitmap_iter_next(&hbi, true);
> +    off1 = hbitmap_iter_next(&hbi);
>  
>      if (off1 < 0 || off1 >= end) {
>          return false;
> 

Re: [Qemu-devel] [PATCH v3 0/8] dirty-bitmap: rewrite bdrv_dirty_iter_next_area

[no-reply]

Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: 20180814121443.33114-1-vsementsov@virtuozzo.com
Subject: [Qemu-devel] [PATCH v3 0/8] dirty-bitmap: rewrite bdrv_dirty_iter_next_area

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
e8d4951adf Revert "hbitmap: Add @advance param to hbitmap_iter_next()"
f69ec3244d Revert "test-hbitmap: Add non-advancing iter_next tests"
c924e13bbe Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"
da911f4201 block/mirror: fix and improve do_sync_target_write
e4699ed90e tests: add tests for hbitmap_next_dirty_area
ad2af3fae8 dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area
b85dbbed91 tests: add tests for hbitmap_next_zero with specified end parameter
78a802d4d3 dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

=== OUTPUT BEGIN ===
Checking PATCH 1/8: dirty-bitmap: improve bdrv_dirty_bitmap_next_zero...
Checking PATCH 2/8: tests: add tests for hbitmap_next_zero with specified end parameter...
Checking PATCH 3/8: dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area...
Checking PATCH 4/8: tests: add tests for hbitmap_next_dirty_area...
ERROR: suspect code indent for conditional statements (4, 4)
#36: FILE: tests/test-hbitmap.c:1038:
+    for (len2 = 1; off2 + len2 < end && hbitmap_get(data->hb, off2 + len2);
[...]
+    {

total: 1 errors, 0 warnings, 118 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

Checking PATCH 5/8: block/mirror: fix and improve do_sync_target_write...
Checking PATCH 6/8: Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"...
Checking PATCH 7/8: Revert "test-hbitmap: Add non-advancing iter_next tests"...
Checking PATCH 8/8: Revert "hbitmap: Add @advance param to hbitmap_iter_next()"...
=== OUTPUT END ===

Test command exited with code: 1


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