| Message ID | 7c1ad306663bcacc60312d4d51ee6d266e075687.1315436097.git.yehuda@hq.newdream.net |
|---|---|
| State | New |
| Headers | show |
On Wed, 7 Sep 2011, Yehuda Sadeh wrote: > In order to improve image conversion process, instead of synchronously > writing the destingation image, we keep a window of async writes. > > Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net> Small fix below: > --- > qemu-img.c | 28 +++++++++++++++++++++++----- > 1 files changed, 23 insertions(+), 5 deletions(-) > > diff --git a/qemu-img.c b/qemu-img.c > index b205e98..0552746 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -622,6 +622,17 @@ static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n, > } > > #define IO_BUF_SIZE (2 * 1024 * 1024) > +#define IO_WRITE_WINDOW_THRESHOLD (32 * 1024 * 1024) > + > +static int write_window = 0; > + > +static void img_write_cb(void *opaque, int ret) > +{ > + QEMUIOVector *qiov = (QEMUIOVector *)opaque; > + write_window -= qiov->iov->iov_len / 512; > + qemu_iovec_destroy(qiov); > + qemu_free(qiov); > +} > > static int img_convert(int argc, char **argv) > { > @@ -980,6 +991,9 @@ static int img_convert(int argc, char **argv) > should add a specific call to have the info to go faster */ > buf1 = buf; > while (n > 0) { > + while (write_window > IO_WRITE_WINDOW_THRESHOLD / 512) { > + qemu_aio_wait(); > + } > /* If the output image is being created as a copy on write image, > copy all sectors even the ones containing only NUL bytes, > because they may differ from the sectors in the base image. > @@ -989,11 +1003,11 @@ static int img_convert(int argc, char **argv) > already there is garbage, not 0s. */ > if (!has_zero_init || out_baseimg || > is_allocated_sectors(buf1, n, &n1)) { > - ret = bdrv_write(out_bs, sector_num, buf1, n1); > - if (ret < 0) { > - error_report("error while writing"); > - goto out; > - } > + QEMUIOVector *qiov = qemu_mallocz(sizeof(QEMUIOVector)); > + qemu_iovec_init(qiov, 1); > + qemu_iovec_add(qiov, (void *)buf1, n1 * 512); > + bdrv_aio_writev(out_bs, sector_num, qiov, n1, img_write_cb, qiov); > + write_window += n1; > } > sector_num += n1; > n -= n1; > @@ -1001,11 +1015,15 @@ static int img_convert(int argc, char **argv) > } > qemu_progress_print(local_progress, 100); > } > + while (write_window > 0) { > + qemu_aio_wait(); > + } > } > out: > qemu_progress_end(); > free_option_parameters(create_options); > free_option_parameters(param); > + bdrv_flush(out_bs); > qemu_free(buf); > if (out_bs) { > bdrv_delete(out_bs); The bdrv_flush() needs to go inside the if or else we get a null dereference on error (e.g. from a bad image name). sage > -- > 1.7.5.1 > > >
diff --git a/qemu-img.c b/qemu-img.c index b205e98..0552746 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -622,6 +622,17 @@ static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n, } #define IO_BUF_SIZE (2 * 1024 * 1024) +#define IO_WRITE_WINDOW_THRESHOLD (32 * 1024 * 1024) + +static int write_window = 0; + +static void img_write_cb(void *opaque, int ret) +{ + QEMUIOVector *qiov = (QEMUIOVector *)opaque; + write_window -= qiov->iov->iov_len / 512; + qemu_iovec_destroy(qiov); + qemu_free(qiov); +} static int img_convert(int argc, char **argv) { @@ -980,6 +991,9 @@ static int img_convert(int argc, char **argv) should add a specific call to have the info to go faster */ buf1 = buf; while (n > 0) { + while (write_window > IO_WRITE_WINDOW_THRESHOLD / 512) { + qemu_aio_wait(); + } /* If the output image is being created as a copy on write image, copy all sectors even the ones containing only NUL bytes, because they may differ from the sectors in the base image. @@ -989,11 +1003,11 @@ static int img_convert(int argc, char **argv) already there is garbage, not 0s. */ if (!has_zero_init || out_baseimg || is_allocated_sectors(buf1, n, &n1)) { - ret = bdrv_write(out_bs, sector_num, buf1, n1); - if (ret < 0) { - error_report("error while writing"); - goto out; - } + QEMUIOVector *qiov = qemu_mallocz(sizeof(QEMUIOVector)); + qemu_iovec_init(qiov, 1); + qemu_iovec_add(qiov, (void *)buf1, n1 * 512); + bdrv_aio_writev(out_bs, sector_num, qiov, n1, img_write_cb, qiov); + write_window += n1; } sector_num += n1; n -= n1; @@ -1001,11 +1015,15 @@ static int img_convert(int argc, char **argv) } qemu_progress_print(local_progress, 100); } + while (write_window > 0) { + qemu_aio_wait(); + } } out: qemu_progress_end(); free_option_parameters(create_options); free_option_parameters(param); + bdrv_flush(out_bs); qemu_free(buf); if (out_bs) { bdrv_delete(out_bs);
In order to improve image conversion process, instead of synchronously writing the destingation image, we keep a window of async writes. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net> --- qemu-img.c | 28 +++++++++++++++++++++++----- 1 files changed, 23 insertions(+), 5 deletions(-)