| Message ID | 1432790990-25383-4-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 28/05/2015 07:29, Fam Zheng wrote: > If guest discards a source cluster, mirroring with bdrv_aio_readv is overkill. > Some protocols do zero upon discard, where it's best to use > bdrv_aio_write_zeroes, otherwise, bdrv_aio_discard will be enough. > > Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > --- > block/mirror.c | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/block/mirror.c b/block/mirror.c > index 85995b2..ba33254 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -164,6 +164,8 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) > int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; > uint64_t delay_ns = 0; > MirrorOp *op; > + int pnum; > + int64_t ret; > > s->sector_num = hbitmap_iter_next(&s->hbi); > if (s->sector_num < 0) { > @@ -290,8 +292,22 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) > s->in_flight++; > s->sectors_in_flight += nb_sectors; > trace_mirror_one_iteration(s, sector_num, nb_sectors); > - bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, > - mirror_read_complete, op); > + > + ret = bdrv_get_block_status_above(source, NULL, sector_num, > + nb_sectors, &pnum); > + if (ret < 0 || pnum < nb_sectors || > + (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { > + bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, > + mirror_read_complete, op); > + } else if (ret & BDRV_BLOCK_ZERO) { > + bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, > + s->unmap ? BDRV_REQ_MAY_UNMAP : 0, > + mirror_write_complete, op); > + } else { > + assert(!(ret & BDRV_BLOCK_DATA)); > + bdrv_aio_discard(s->target, sector_num, op->nb_sectors, > + mirror_write_complete, op); > + } > return delay_ns; > } > >
diff --git a/block/mirror.c b/block/mirror.c index 85995b2..ba33254 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -164,6 +164,8 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; uint64_t delay_ns = 0; MirrorOp *op; + int pnum; + int64_t ret; s->sector_num = hbitmap_iter_next(&s->hbi); if (s->sector_num < 0) { @@ -290,8 +292,22 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) s->in_flight++; s->sectors_in_flight += nb_sectors; trace_mirror_one_iteration(s, sector_num, nb_sectors); - bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, - mirror_read_complete, op); + + ret = bdrv_get_block_status_above(source, NULL, sector_num, + nb_sectors, &pnum); + if (ret < 0 || pnum < nb_sectors || + (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { + bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, + mirror_read_complete, op); + } else if (ret & BDRV_BLOCK_ZERO) { + bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, + s->unmap ? BDRV_REQ_MAY_UNMAP : 0, + mirror_write_complete, op); + } else { + assert(!(ret & BDRV_BLOCK_DATA)); + bdrv_aio_discard(s->target, sector_num, op->nb_sectors, + mirror_write_complete, op); + } return delay_ns; }
If guest discards a source cluster, mirroring with bdrv_aio_readv is overkill. Some protocols do zero upon discard, where it's best to use bdrv_aio_write_zeroes, otherwise, bdrv_aio_discard will be enough. Signed-off-by: Fam Zheng <famz@redhat.com> --- block/mirror.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)