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Re: [Qemu-devel] [PATCH 3/3] block: per caller dirty bitmap
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 3/3] block: per caller dirty bitmap |
Date: |
Wed, 30 Oct 2013 08:49:36 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130923 Thunderbird/17.0.9 |
Il 30/10/2013 08:08, Fam Zheng ha scritto:
> 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 one HBitmap for each caller, the
> lifecycle is managed with these new functions:
>
> bdrv_create_dirty_bitmap
> bdrv_release_dirty_bitmap
>
> In place of this one:
>
> bdrv_set_dirty_tracking
>
> An HBitmap 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
>
> While bdrv_set_dirty and bdrv_reset_dirty prototypes unchanged but
> internally walk the list of all dirty bitmaps and set them one by one.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> block-migration.c | 22 ++++++++++----
> block.c | 74
> ++++++++++++++++++++++++++---------------------
> block/mirror.c | 23 ++++++++-------
> block/qapi.c | 8 -----
> include/block/block.h | 11 ++++---
> include/block/block_int.h | 2 +-
> 6 files changed, 78 insertions(+), 62 deletions(-)
>
> diff --git a/block-migration.c b/block-migration.c
> index daf9ec1..08df056 100644
> --- a/block-migration.c
> +++ b/block-migration.c
> @@ -58,6 +58,7 @@ typedef struct BlkMigDevState {
> /* Protected by block migration lock. */
> unsigned long *aio_bitmap;
> int64_t completed_sectors;
> + HBitmap *dirty_bitmap;
> } BlkMigDevState;
>
> typedef struct BlkMigBlock {
> @@ -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);
> }
> }
>
> @@ -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;
> @@ -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;
> @@ -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) {
> @@ -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);
> diff --git a/block.c b/block.c
> index fd05a80..9975428 100644
> --- a/block.c
> +++ b/block.c
> @@ -323,6 +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);
> @@ -1614,7 +1615,7 @@ 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;
> @@ -1647,7 +1648,7 @@ 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);
> @@ -1708,6 +1709,7 @@ 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);
>
> @@ -2784,9 +2786,7 @@ 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);
> - }
>
> if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
> bs->wr_highest_sector = sector_num + nb_sectors - 1;
> @@ -3321,7 +3321,7 @@ 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);
> }
> @@ -4181,9 +4181,7 @@ 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)) {
> @@ -4345,58 +4343,68 @@ bool bdrv_qiov_is_aligned(BlockDriverState *bs,
> QEMUIOVector *qiov)
> return true;
> }
>
> -void bdrv_set_dirty_tracking(BlockDriverState *bs, int granularity)
> +HBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity)
> {
> int64_t bitmap_size;
> + HBitmap *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 = hbitmap_alloc(bitmap_size, ffs(granularity) - 1);
> + QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
> + return bitmap;
> +}
> +
> +void bdrv_release_dirty_bitmap(BlockDriverState *bs, HBitmap *bitmap)
> +{
> + HBitmap *bm, *next;
> + QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
> + if (bm == bitmap) {
> + QLIST_REMOVE(bitmap, list);
> + hbitmap_free(bitmap);
> + return;
> }
> }
> }
>
> -int bdrv_get_dirty(BlockDriverState *bs, int64_t sector)
> +int bdrv_get_dirty(BlockDriverState *bs, HBitmap *bitmap, int64_t sector)
> {
> - if (bs->dirty_bitmap) {
> - return hbitmap_get(bs->dirty_bitmap, sector);
> + if (bitmap) {
> + return hbitmap_get(bitmap, sector);
> } else {
> return 0;
> }
> }
>
> -void bdrv_dirty_iter_init(BlockDriverState *bs, HBitmapIter *hbi)
> +void bdrv_dirty_iter_init(BlockDriverState *bs,
> + HBitmap *bitmap, HBitmapIter *hbi)
> {
> - hbitmap_iter_init(hbi, bs->dirty_bitmap, 0);
> + hbitmap_iter_init(hbi, bitmap, 0);
> }
>
> void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
> int nr_sectors)
> {
> - hbitmap_set(bs->dirty_bitmap, cur_sector, nr_sectors);
> + HBitmap *bitmap;
> + QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
> + hbitmap_set(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);
> + HBitmap *bitmap;
> + QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
> + hbitmap_reset(bitmap, cur_sector, nr_sectors);
> + }
> }
I think callers outside block.c should only call
hbitmap_set/hbitmap_reset; resetting is typically done before processing
sectors and setting after an error (both of which happen privately to
each task).
Thus you probably should add a fourth patch which makes
bdrv_(re)set_dirty static and remove
bdrv_get_dirty/bdrv_dirty_iter_init/bdrv_get_dirty_count.
Otherwise, this is a very nice patch. Great work!
Paolo
> -int64_t bdrv_get_dirty_count(BlockDriverState *bs)
> +int64_t bdrv_get_dirty_count(BlockDriverState *bs, HBitmap *bitmap)
> {
> - if (bs->dirty_bitmap) {
> - return hbitmap_count(bs->dirty_bitmap);
> - } else {
> - return 0;
> - }
> + return hbitmap_count(bitmap);
> }
>
> /* Get a reference to bs */
> diff --git a/block/mirror.c b/block/mirror.c
> index 7b95acf..65e274b 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -39,6 +39,7 @@ typedef struct MirrorBlockJob {
> int64_t granularity;
> size_t buf_size;
> unsigned long *cow_bitmap;
> + HBitmap *dirty_bitmap;
> HBitmapIter hbi;
> uint8_t *buf;
> QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
> @@ -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);
> }
>
> @@ -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;
> @@ -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);
> }
>
> @@ -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;
> @@ -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.
> @@ -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);
> }
> }
>
> @@ -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;
> @@ -471,7 +474,7 @@ immediate_exit:
> 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)) {
> @@ -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);
> diff --git a/block/qapi.c b/block/qapi.c
> index 5880b3e..6b0cdcf 100644
> --- a/block/qapi.c
> +++ b/block/qapi.c
> @@ -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));
> diff --git a/include/block/block.h b/include/block/block.h
> index 3560deb..bfc494a 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -388,12 +388,15 @@ 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 HBitmap HBitmap;
> +HBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity);
> +void bdrv_release_dirty_bitmap(BlockDriverState *bs, HBitmap *bitmap);
> +int bdrv_get_dirty(BlockDriverState *bs, HBitmap *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,
> + HBitmap *bitmap, struct HBitmapIter *hbi);
> +int64_t bdrv_get_dirty_count(BlockDriverState *bs, HBitmap *bitmap);
>
> void bdrv_enable_copy_on_read(BlockDriverState *bs);
> void bdrv_disable_copy_on_read(BlockDriverState *bs);
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index a48731d..1dc5bb7 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -298,7 +298,7 @@ struct BlockDriverState {
> bool iostatus_enabled;
> BlockDeviceIoStatus iostatus;
> char device_name[32];
> - HBitmap *dirty_bitmap;
> + QLIST_HEAD(, HBitmap) dirty_bitmaps;
> int refcnt;
> int in_use; /* users other than guest access, eg. block migration */
> QTAILQ_ENTRY(BlockDriverState) list;
>