I had hoped it wouldn't come to this :)
On 01/27/2015 05:56 AM, Vladimir Sementsov-Ogievskiy wrote:
A dirty-dirty bitmap is a dirty bitmap for BdrvDirtyBitmap. It tracks
set/unset changes of BdrvDirtyBitmap.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@parallels.com>
---
block.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
include/block/block.h | 5 +++++
2 files changed, 49 insertions(+)
diff --git a/block.c b/block.c
index 9860fc1..8ab724b 100644
--- a/block.c
+++ b/block.c
@@ -53,6 +53,7 @@
struct BdrvDirtyBitmap {
HBitmap *bitmap;
+ HBitmap *dirty_dirty_bitmap;
Just opinions: Maybe we can call it the "meta_bitmap" to help keep the
name less confusing, and accompany it with a good structure comment here
to explain what the heck it's for.
If you feel that's a good idea; s/dirty_dirty_/meta_/g below.
Regardless, let's make sure this patch adds documentation for it.
BdrvDirtyBitmap *originator;
int64_t size;
int64_t granularity;
@@ -5373,6 +5374,30 @@ BdrvDirtyBitmap
*bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
return originator;
}
+HBitmap *bdrv_create_dirty_dirty_bitmap(BdrvDirtyBitmap *bitmap,
+ uint64_t granularity)
+{
+ uint64_t sector_granularity;
+
+ assert((granularity & (granularity - 1)) == 0);
+
+ granularity *= 8 * bitmap->granularity;
+ sector_granularity = granularity >> BDRV_SECTOR_BITS;
+ assert(sector_granularity);
+
+ bitmap->dirty_dirty_bitmap =
+ hbitmap_alloc(bitmap->size, ffsll(sector_granularity) - 1);
+
+ return bitmap->dirty_dirty_bitmap;
+}
+
+void bdrv_release_dirty_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_free(bitmap->dirty_dirty_bitmap);
+ bitmap->dirty_dirty_bitmap = NULL;
+ }
+}
void bdrv_print_dirty_bitmap(BdrvDirtyBitmap *bitmap)
{
@@ -5447,6 +5472,9 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap)
if (bm == bitmap) {
QLIST_REMOVE(bitmap, list);
hbitmap_free(bitmap->bitmap);
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_free(bitmap->dirty_dirty_bitmap);
+ }
g_free(bitmap->name);
g_free(bitmap);
return;
@@ -5534,6 +5562,10 @@ void bdrv_set_dirty_bitmap(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap,
{
if (bitmap->enabled) {
hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_set(bitmap->dirty_dirty_bitmap, cur_sector, nr_sectors);
+ }
}
}
@@ -5541,6 +5573,9 @@ void bdrv_reset_dirty_bitmap(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap,
int64_t cur_sector, int nr_sectors)
{
hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_set(bitmap->dirty_dirty_bitmap, cur_sector, nr_sectors);
+ }
}
/**
@@ -5550,6 +5585,9 @@ void bdrv_reset_dirty_bitmap(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap,
void bdrv_clear_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
{
hbitmap_reset(bitmap->bitmap, 0, bitmap->size);
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_set(bitmap->dirty_dirty_bitmap, 0, bitmap->size);
+ }
}
const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)
@@ -5597,6 +5635,9 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t
cur_sector,
continue;
}
hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_set(bitmap->dirty_dirty_bitmap, cur_sector, nr_sectors);
+ }
}
}
@@ -5606,6 +5647,9 @@ static void bdrv_reset_dirty(BlockDriverState *bs,
int64_t cur_sector,
BdrvDirtyBitmap *bitmap;
QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
+ if (bitmap->dirty_dirty_bitmap) {
+ hbitmap_set(bitmap->dirty_dirty_bitmap, cur_sector, nr_sectors);
+ }
}
}
diff --git a/include/block/block.h b/include/block/block.h
index 0890cd2..648b0a9 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -4,6 +4,7 @@
#include "block/aio.h"
#include "qemu-common.h"
#include "qemu/option.h"
+#include "qemu/hbitmap.h"
#include "block/coroutine.h"
#include "block/accounting.h"
#include "qapi/qmp/qobject.h"
@@ -473,6 +474,10 @@ void bdrv_dirty_bitmap_deserialize_part0(BdrvDirtyBitmap
*bitmap,
uint64_t start, uint64_t count);
void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap);
+HBitmap *bdrv_create_dirty_dirty_bitmap(BdrvDirtyBitmap *bitmap,
+ uint64_t granularity);
+void bdrv_release_dirty_dirty_bitmap(BdrvDirtyBitmap *bitmap);
+
void bdrv_enable_copy_on_read(BlockDriverState *bs);
void bdrv_disable_copy_on_read(BlockDriverState *bs);
Looks correct, it just needs documentation in my opinion to help explain
what this extra bitmap is for.
Musings / opinions:
I also think that at this point, we may want to make bdrv_reset_dirty
and bdrv_set_dirty call the bdrv_reset_dirty_bitmap and
bdrv_set_dirty_bitmap functions instead of re-implementing the behavior.
I used to think it was fine as-is, but the more conditions we add to how
these bitmaps should be accessed, the more I think limiting the
interface to as few functions as possible is a good idea.
Maybe I'll even do that myself. It might even be nice to split off all
the bitmap functions off into something like block/dirty_bitmaps.c as
the complexity creeps up and we're trying to improve the maintainability
of block.c.
Anyway, we can worry about that in a later series.
