From 8f0720ecbc3677e13fc7531588fc3831cc972ee4 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 21 Jan 2013 17:09:41 +0100 Subject: block: implement dirty bitmap using HBitmap This actually uses the dirty bitmap in the block layer, and converts mirroring to use an HBitmapIter. Reviewed-by: Laszlo Ersek (except block/mirror.c parts) Reviewed-by: Eric Blake Signed-off-by: Paolo Bonzini Signed-off-by: Kevin Wolf --- block.c | 96 +++++++++++------------------------------------------------------ 1 file changed, 16 insertions(+), 80 deletions(-) (limited to 'block.c') diff --git a/block.c b/block.c index 6fa7c90..e0ff736 100644 --- a/block.c +++ b/block.c @@ -1286,7 +1286,6 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest, bs_dest->iostatus = bs_src->iostatus; /* dirty bitmap */ - bs_dest->dirty_count = bs_src->dirty_count; bs_dest->dirty_bitmap = bs_src->dirty_bitmap; /* job */ @@ -2035,36 +2034,6 @@ int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, return ret; } -#define BITS_PER_LONG (sizeof(unsigned long) * 8) - -static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num, - int nb_sectors, int dirty) -{ - int64_t start, end; - unsigned long val, idx, bit; - - start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK; - end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK; - - for (; start <= end; start++) { - idx = start / BITS_PER_LONG; - bit = start % BITS_PER_LONG; - val = bs->dirty_bitmap[idx]; - if (dirty) { - if (!(val & (1UL << bit))) { - bs->dirty_count++; - val |= 1UL << bit; - } - } else { - if (val & (1UL << bit)) { - bs->dirty_count--; - val &= ~(1UL << bit); - } - } - bs->dirty_bitmap[idx] = val; - } -} - /* Return < 0 if error. Important errors are: -EIO generic I/O error (may happen for all errors) -ENOMEDIUM No media inserted. @@ -4173,7 +4142,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, } if (bs->dirty_bitmap) { - set_dirty_bitmap(bs, sector_num, nb_sectors, 0); + bdrv_reset_dirty(bs, sector_num, nb_sectors); } if (bs->drv->bdrv_co_discard) { @@ -4335,18 +4304,15 @@ void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable) { int64_t bitmap_size; - bs->dirty_count = 0; if (enable) { if (!bs->dirty_bitmap) { - bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) + - BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG - 1; - bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG; - - bs->dirty_bitmap = g_new0(unsigned long, bitmap_size); + bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS); + bs->dirty_bitmap = hbitmap_alloc(bitmap_size, + BDRV_LOG_SECTORS_PER_DIRTY_CHUNK); } } else { if (bs->dirty_bitmap) { - g_free(bs->dirty_bitmap); + hbitmap_free(bs->dirty_bitmap); bs->dirty_bitmap = NULL; } } @@ -4354,67 +4320,37 @@ void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable) int bdrv_get_dirty(BlockDriverState *bs, int64_t sector) { - int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK; - - if (bs->dirty_bitmap && - (sector << BDRV_SECTOR_BITS) < bdrv_getlength(bs)) { - return !!(bs->dirty_bitmap[chunk / BITS_PER_LONG] & - (1UL << (chunk % BITS_PER_LONG))); + if (bs->dirty_bitmap) { + return hbitmap_get(bs->dirty_bitmap, sector); } else { return 0; } } -int64_t bdrv_get_next_dirty(BlockDriverState *bs, int64_t sector) +void bdrv_dirty_iter_init(BlockDriverState *bs, HBitmapIter *hbi) { - int64_t chunk; - int bit, elem; - - /* Avoid an infinite loop. */ - assert(bs->dirty_count > 0); - - sector = (sector | (BDRV_SECTORS_PER_DIRTY_CHUNK - 1)) + 1; - chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK; - - QEMU_BUILD_BUG_ON(sizeof(bs->dirty_bitmap[0]) * 8 != BITS_PER_LONG); - elem = chunk / BITS_PER_LONG; - bit = chunk % BITS_PER_LONG; - for (;;) { - if (sector >= bs->total_sectors) { - sector = 0; - bit = elem = 0; - } - if (bit == 0 && bs->dirty_bitmap[elem] == 0) { - sector += BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG; - elem++; - } else { - if (bs->dirty_bitmap[elem] & (1UL << bit)) { - return sector; - } - sector += BDRV_SECTORS_PER_DIRTY_CHUNK; - if (++bit == BITS_PER_LONG) { - bit = 0; - elem++; - } - } - } + hbitmap_iter_init(hbi, bs->dirty_bitmap, 0); } void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) { - set_dirty_bitmap(bs, cur_sector, nr_sectors, 1); + hbitmap_set(bs->dirty_bitmap, cur_sector, nr_sectors); } void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) { - set_dirty_bitmap(bs, cur_sector, nr_sectors, 0); + hbitmap_reset(bs->dirty_bitmap, cur_sector, nr_sectors); } int64_t bdrv_get_dirty_count(BlockDriverState *bs) { - return bs->dirty_count; + if (bs->dirty_bitmap) { + return hbitmap_count(bs->dirty_bitmap) >> BDRV_LOG_SECTORS_PER_DIRTY_CHUNK; + } else { + return 0; + } } void bdrv_set_in_use(BlockDriverState *bs, int in_use) -- cgit v1.1