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block: per caller dirty bitmap
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Previously a BlockDriverState has only one dirty bitmap, so only one
caller (e.g. a block job) can keep track of writing. This changes the
dirty bitmap to a list and creates a BdrvDirtyBitmap for each caller, the
lifecycle is managed with these new functions:

    bdrv_create_dirty_bitmap
    bdrv_release_dirty_bitmap

Where BdrvDirtyBitmap is a linked list wrapper structure of HBitmap.

In place of bdrv_set_dirty_tracking, a BdrvDirtyBitmap pointer argument
is added to these functions, since each caller has its own dirty bitmap:

    bdrv_get_dirty
    bdrv_dirty_iter_init
    bdrv_get_dirty_count

bdrv_set_dirty and bdrv_reset_dirty prototypes are unchanged but will
internally walk the list of all dirty bitmaps and set them one by one.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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@kevmw
Fam Zheng authored and kevmw committed Nov 29, 2013
1 parent f4a193e commit e4654d2
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Showing 6 changed files with 86 additions and 63 deletions.
22 changes: 16 additions & 6 deletions block-migration.c
View file
Expand Up @@ -58,6 +58,7 @@ typedef struct BlkMigDevState {
/* Protected by block migration lock. */
unsigned long *aio_bitmap;
int64_t completed_sectors;
BdrvDirtyBitmap *dirty_bitmap;
} BlkMigDevState;

typedef struct BlkMigBlock {
Expand Down Expand Up @@ -309,12 +310,21 @@ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)

/* Called with iothread lock taken. */

static void set_dirty_tracking(int enable)
static void set_dirty_tracking(void)
{
BlkMigDevState *bmds;

QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
bdrv_set_dirty_tracking(bmds->bs, enable ? BLOCK_SIZE : 0);
bmds->dirty_bitmap = bdrv_create_dirty_bitmap(bmds->bs, BLOCK_SIZE);
}
}

static void unset_dirty_tracking(void)
{
BlkMigDevState *bmds;

QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
bdrv_release_dirty_bitmap(bmds->bs, bmds->dirty_bitmap);
}
}

Expand Down Expand Up @@ -432,7 +442,7 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
} else {
blk_mig_unlock();
}
if (bdrv_get_dirty(bmds->bs, sector)) {
if (bdrv_get_dirty(bmds->bs, bmds->dirty_bitmap, sector)) {

if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
nr_sectors = total_sectors - sector;
Expand Down Expand Up @@ -554,7 +564,7 @@ static int64_t get_remaining_dirty(void)
int64_t dirty = 0;

QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) {
dirty += bdrv_get_dirty_count(bmds->bs);
dirty += bdrv_get_dirty_count(bmds->bs, bmds->dirty_bitmap);
}

return dirty << BDRV_SECTOR_BITS;
Expand All @@ -569,7 +579,7 @@ static void blk_mig_cleanup(void)

bdrv_drain_all();

set_dirty_tracking(0);
unset_dirty_tracking();

blk_mig_lock();
while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
Expand Down Expand Up @@ -604,7 +614,7 @@ static int block_save_setup(QEMUFile *f, void *opaque)
init_blk_migration(f);

/* start track dirty blocks */
set_dirty_tracking(1);
set_dirty_tracking();
qemu_mutex_unlock_iothread();

ret = flush_blks(f);
Expand Down
83 changes: 49 additions & 34 deletions block.c
View file
Expand Up @@ -49,6 +49,11 @@
#include <windows.h>
#endif

struct BdrvDirtyBitmap {
HBitmap *bitmap;
QLIST_ENTRY(BdrvDirtyBitmap) list;
};

#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */

static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
Expand Down Expand Up @@ -318,6 +323,7 @@ BlockDriverState *bdrv_new(const char *device_name)
BlockDriverState *bs;

bs = g_malloc0(sizeof(BlockDriverState));
QLIST_INIT(&bs->dirty_bitmaps);
pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
if (device_name[0] != '\0') {
QTAILQ_INSERT_TAIL(&bdrv_states, bs, list);
Expand Down Expand Up @@ -1617,7 +1623,7 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
bs_dest->iostatus = bs_src->iostatus;

/* dirty bitmap */
bs_dest->dirty_bitmap = bs_src->dirty_bitmap;
bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps;

/* reference count */
bs_dest->refcnt = bs_src->refcnt;
Expand Down Expand Up @@ -1650,7 +1656,7 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old)

/* bs_new must be anonymous and shouldn't have anything fancy enabled */
assert(bs_new->device_name[0] == '\0');
assert(bs_new->dirty_bitmap == NULL);
assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
assert(bs_new->job == NULL);
assert(bs_new->dev == NULL);
assert(bs_new->in_use == 0);
Expand Down Expand Up @@ -1711,6 +1717,7 @@ static void bdrv_delete(BlockDriverState *bs)
assert(!bs->job);
assert(!bs->in_use);
assert(!bs->refcnt);
assert(QLIST_EMPTY(&bs->dirty_bitmaps));

bdrv_close(bs);

Expand Down Expand Up @@ -2858,9 +2865,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
ret = bdrv_co_flush(bs);
}

if (bs->dirty_bitmap) {
bdrv_set_dirty(bs, sector_num, nb_sectors);
}
bdrv_set_dirty(bs, sector_num, nb_sectors);

if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
bs->wr_highest_sector = sector_num + nb_sectors - 1;
Expand Down Expand Up @@ -3431,7 +3436,7 @@ int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
if (bdrv_check_request(bs, sector_num, nb_sectors))
return -EIO;

assert(!bs->dirty_bitmap);
assert(QLIST_EMPTY(&bs->dirty_bitmaps));

return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
}
Expand Down Expand Up @@ -4296,9 +4301,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
return -EROFS;
}

if (bs->dirty_bitmap) {
bdrv_reset_dirty(bs, sector_num, nb_sectors);
}
bdrv_reset_dirty(bs, sector_num, nb_sectors);

/* Do nothing if disabled. */
if (!(bs->open_flags & BDRV_O_UNMAP)) {
Expand Down Expand Up @@ -4490,58 +4493,70 @@ bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
return true;
}

void bdrv_set_dirty_tracking(BlockDriverState *bs, int granularity)
BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity)
{
int64_t bitmap_size;
BdrvDirtyBitmap *bitmap;

assert((granularity & (granularity - 1)) == 0);

if (granularity) {
granularity >>= BDRV_SECTOR_BITS;
assert(!bs->dirty_bitmap);
bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS);
bs->dirty_bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1);
} else {
if (bs->dirty_bitmap) {
hbitmap_free(bs->dirty_bitmap);
bs->dirty_bitmap = NULL;
granularity >>= BDRV_SECTOR_BITS;
assert(granularity);
bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS);
bitmap = g_malloc0(sizeof(BdrvDirtyBitmap));
bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1);
QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
return bitmap;
}

void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
{
BdrvDirtyBitmap *bm, *next;
QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
if (bm == bitmap) {
QLIST_REMOVE(bitmap, list);
hbitmap_free(bitmap->bitmap);
g_free(bitmap);
return;
}
}
}

int bdrv_get_dirty(BlockDriverState *bs, int64_t sector)
int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector)
{
if (bs->dirty_bitmap) {
return hbitmap_get(bs->dirty_bitmap, sector);
if (bitmap) {
return hbitmap_get(bitmap->bitmap, sector);
} else {
return 0;
}
}

void bdrv_dirty_iter_init(BlockDriverState *bs, HBitmapIter *hbi)
void bdrv_dirty_iter_init(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
{
hbitmap_iter_init(hbi, bs->dirty_bitmap, 0);
hbitmap_iter_init(hbi, bitmap->bitmap, 0);
}

void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
int nr_sectors)
{
hbitmap_set(bs->dirty_bitmap, cur_sector, nr_sectors);
BdrvDirtyBitmap *bitmap;
QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
}
}

void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
int nr_sectors)
void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors)
{
hbitmap_reset(bs->dirty_bitmap, cur_sector, nr_sectors);
BdrvDirtyBitmap *bitmap;
QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
}
}

int64_t bdrv_get_dirty_count(BlockDriverState *bs)
int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
{
if (bs->dirty_bitmap) {
return hbitmap_count(bs->dirty_bitmap);
} else {
return 0;
}
return hbitmap_count(bitmap->bitmap);
}

/* Get a reference to bs */
Expand Down
23 changes: 13 additions & 10 deletions block/mirror.c
View file
Expand Up @@ -39,6 +39,7 @@ typedef struct MirrorBlockJob {
int64_t granularity;
size_t buf_size;
unsigned long *cow_bitmap;
BdrvDirtyBitmap *dirty_bitmap;
HBitmapIter hbi;
uint8_t *buf;
QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
Expand Down Expand Up @@ -145,9 +146,10 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s)

s->sector_num = hbitmap_iter_next(&s->hbi);
if (s->sector_num < 0) {
bdrv_dirty_iter_init(source, &s->hbi);
bdrv_dirty_iter_init(source, s->dirty_bitmap, &s->hbi);
s->sector_num = hbitmap_iter_next(&s->hbi);
trace_mirror_restart_iter(s, bdrv_get_dirty_count(source));
trace_mirror_restart_iter(s,
bdrv_get_dirty_count(source, s->dirty_bitmap));
assert(s->sector_num >= 0);
}

Expand Down Expand Up @@ -183,7 +185,7 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
do {
int added_sectors, added_chunks;

if (!bdrv_get_dirty(source, next_sector) ||
if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) ||
test_bit(next_chunk, s->in_flight_bitmap)) {
assert(nb_sectors > 0);
break;
Expand Down Expand Up @@ -249,7 +251,8 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
/* Advance the HBitmapIter in parallel, so that we do not examine
* the same sector twice.
*/
if (next_sector > hbitmap_next_sector && bdrv_get_dirty(source, next_sector)) {
if (next_sector > hbitmap_next_sector
&& bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) {
hbitmap_next_sector = hbitmap_iter_next(&s->hbi);
}

Expand Down Expand Up @@ -355,7 +358,7 @@ static void coroutine_fn mirror_run(void *opaque)
}
}

bdrv_dirty_iter_init(bs, &s->hbi);
bdrv_dirty_iter_init(bs, s->dirty_bitmap, &s->hbi);
last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
for (;;) {
uint64_t delay_ns;
Expand All @@ -367,7 +370,7 @@ static void coroutine_fn mirror_run(void *opaque)
goto immediate_exit;
}

cnt = bdrv_get_dirty_count(bs);
cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap);

/* Note that even when no rate limit is applied we need to yield
* periodically with no pending I/O so that qemu_aio_flush() returns.
Expand Down Expand Up @@ -409,7 +412,7 @@ static void coroutine_fn mirror_run(void *opaque)

should_complete = s->should_complete ||
block_job_is_cancelled(&s->common);
cnt = bdrv_get_dirty_count(bs);
cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap);
}
}

Expand All @@ -424,7 +427,7 @@ static void coroutine_fn mirror_run(void *opaque)
*/
trace_mirror_before_drain(s, cnt);
bdrv_drain_all();
cnt = bdrv_get_dirty_count(bs);
cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap);
}

ret = 0;
Expand Down Expand Up @@ -471,7 +474,7 @@ static void coroutine_fn mirror_run(void *opaque)
qemu_vfree(s->buf);
g_free(s->cow_bitmap);
g_free(s->in_flight_bitmap);
bdrv_set_dirty_tracking(bs, 0);
bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
bdrv_iostatus_disable(s->target);
if (s->should_complete && ret == 0) {
if (bdrv_get_flags(s->target) != bdrv_get_flags(s->common.bs)) {
Expand Down Expand Up @@ -575,7 +578,7 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target,
s->granularity = granularity;
s->buf_size = MAX(buf_size, granularity);

bdrv_set_dirty_tracking(bs, granularity);
s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity);
bdrv_set_enable_write_cache(s->target, true);
bdrv_set_on_error(s->target, on_target_error, on_target_error);
bdrv_iostatus_enable(s->target);
Expand Down
8 changes: 0 additions & 8 deletions block/qapi.c
View file
Expand Up @@ -204,14 +204,6 @@ void bdrv_query_info(BlockDriverState *bs,
info->io_status = bs->iostatus;
}

if (bs->dirty_bitmap) {
info->has_dirty = true;
info->dirty = g_malloc0(sizeof(*info->dirty));
info->dirty->count = bdrv_get_dirty_count(bs) * BDRV_SECTOR_SIZE;
info->dirty->granularity =
((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bs->dirty_bitmap));
}

if (bs->drv) {
info->has_inserted = true;
info->inserted = g_malloc0(sizeof(*info->inserted));
Expand Down
11 changes: 7 additions & 4 deletions include/block/block.h
View file
Expand Up @@ -419,12 +419,15 @@ void *qemu_blockalign(BlockDriverState *bs, size_t size);
bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);

struct HBitmapIter;
void bdrv_set_dirty_tracking(BlockDriverState *bs, int granularity);
int bdrv_get_dirty(BlockDriverState *bs, int64_t sector);
typedef struct BdrvDirtyBitmap BdrvDirtyBitmap;
BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity);
void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector);
void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors);
void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors);
void bdrv_dirty_iter_init(BlockDriverState *bs, struct HBitmapIter *hbi);
int64_t bdrv_get_dirty_count(BlockDriverState *bs);
void bdrv_dirty_iter_init(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);

void bdrv_enable_copy_on_read(BlockDriverState *bs);
void bdrv_disable_copy_on_read(BlockDriverState *bs);
Expand Down
2 changes: 1 addition & 1 deletion include/block/block_int.h
View file
Expand Up @@ -318,7 +318,7 @@ struct BlockDriverState {
bool iostatus_enabled;
BlockDeviceIoStatus iostatus;
char device_name[32];
HBitmap *dirty_bitmap;
QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
int refcnt;
int in_use; /* users other than guest access, eg. block migration */
QTAILQ_ENTRY(BlockDriverState) list;
Expand Down

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