[Qemu-commits] [qemu/qemu] 76d570: dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: 76d570dc495c56bbdcc4574bfc6d512dcb8e9aa9
      
https://github.com/qemu/qemu/commit/76d570dc495c56bbdcc4574bfc6d512dcb8e9aa9
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M block/backup.c
    M block/dirty-bitmap.c
    M include/block/dirty-bitmap.h
    M include/qemu/hbitmap.h
    M nbd/server.c
    M tests/test-hbitmap.c
    M util/hbitmap.c

  Log Message:
  -----------
  dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

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

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>


  Commit: fa9c2da29404be9baeb7b8f88fed3cb232688cd9
      
https://github.com/qemu/qemu/commit/fa9c2da29404be9baeb7b8f88fed3cb232688cd9
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M tests/test-hbitmap.c

  Log Message:
  -----------
  tests: add tests for hbitmap_next_zero with specified end parameter

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>


  Commit: a78a1a48cd1a2e86f23f113bb05e2d3dd8ae0bf6
      
https://github.com/qemu/qemu/commit/a78a1a48cd1a2e86f23f113bb05e2d3dd8ae0bf6
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M block/dirty-bitmap.c
    M include/block/dirty-bitmap.h
    M include/qemu/hbitmap.h
    M util/hbitmap.c

  Log Message:
  -----------
  dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area

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 <address@hidden>


  Commit: bb6a0ec10ee3f791835f1479a8a3226f64cb6d75
      
https://github.com/qemu/qemu/commit/bb6a0ec10ee3f791835f1479a8a3226f64cb6d75
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M tests/test-hbitmap.c

  Log Message:
  -----------
  tests: add tests for hbitmap_next_dirty_area

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>


  Commit: 1eaf1b0fdf41069b4b3e67eae88da0d781261792
      
https://github.com/qemu/qemu/commit/1eaf1b0fdf41069b4b3e67eae88da0d781261792
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M block/mirror.c

  Log Message:
  -----------
  block/mirror: fix and improve do_sync_target_write

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 <address@hidden>


  Commit: 166cd551254f4ea6226d7e687b19928747247500
      
https://github.com/qemu/qemu/commit/166cd551254f4ea6226d7e687b19928747247500
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M block/dirty-bitmap.c
    M include/block/dirty-bitmap.h

  Log Message:
  -----------
  Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"

This reverts commit 72d10a94213a954ad569095cb4491f2ae0853c40.

The function is unused now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Reviewed-by: John Snow <address@hidden>


  Commit: 4294c4ab4825a2ce4d816e52f95a6f08b56aa69c
      
https://github.com/qemu/qemu/commit/4294c4ab4825a2ce4d816e52f95a6f08b56aa69c
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M tests/test-hbitmap.c

  Log Message:
  -----------
  Revert "test-hbitmap: Add non-advancing iter_next tests"

This reverts commit 269576848ec3d57d2d958cf5ac69b08c44adf816.

The functionality is unused. Drop tests.

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Reviewed-by: John Snow <address@hidden>


  Commit: 19c021e1948a81c4ba19b3ff735432b45b6aebee
      
https://github.com/qemu/qemu/commit/19c021e1948a81c4ba19b3ff735432b45b6aebee
  Author: Vladimir Sementsov-Ogievskiy <address@hidden>
  Date:   2019-01-15 (Tue, 15 Jan 2019)

  Changed paths:
    M block/backup.c
    M block/dirty-bitmap.c
    M include/qemu/hbitmap.h
    M tests/test-hbitmap.c
    M util/hbitmap.c

  Log Message:
  -----------
  Revert "hbitmap: Add @advance param to hbitmap_iter_next()"

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 <address@hidden>
Reviewed-by: John Snow <address@hidden>


  Commit: 681d61362d3f766a00806b89d6581869041f73cb
      
https://github.com/qemu/qemu/commit/681d61362d3f766a00806b89d6581869041f73cb
  Author: Peter Maydell <address@hidden>
  Date:   2019-01-17 (Thu, 17 Jan 2019)

  Changed paths:
    M block/backup.c
    M block/dirty-bitmap.c
    M block/mirror.c
    M include/block/dirty-bitmap.h
    M include/qemu/hbitmap.h
    M nbd/server.c
    M tests/test-hbitmap.c
    M util/hbitmap.c

  Log Message:
  -----------
  Merge remote-tracking branch 'remotes/jnsnow/tags/bitmaps-pull-request' into 
staging

Pull request

# gpg: Signature made Wed 16 Jan 2019 01:00:25 GMT
# gpg:                using RSA key 7DEF8106AAFC390E
# gpg: Good signature from "John Snow (John Huston) <address@hidden>"
# Primary key fingerprint: FAEB 9711 A12C F475 812F  18F2 88A9 064D 1835 61EB
#      Subkey fingerprint: F9B7 ABDB BCAC DF95 BE76  CBD0 7DEF 8106 AAFC 390E

* remotes/jnsnow/tags/bitmaps-pull-request:
  Revert "hbitmap: Add @advance param to hbitmap_iter_next()"
  Revert "test-hbitmap: Add non-advancing iter_next tests"
  Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"
  block/mirror: fix and improve do_sync_target_write
  tests: add tests for hbitmap_next_dirty_area
  dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area
  tests: add tests for hbitmap_next_zero with specified end parameter
  dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

Signed-off-by: Peter Maydell <address@hidden>


Compare: https://github.com/qemu/qemu/compare/6f2f34177a25...681d61362d3f
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