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Re: [Qemu-block] [PATCH v3 14/20] backup: Switch BackupBlockJob to byte-
From: |
Jeff Cody |
Subject: |
Re: [Qemu-block] [PATCH v3 14/20] backup: Switch BackupBlockJob to byte-based |
Date: |
Fri, 30 Jun 2017 17:18:01 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Tue, Jun 27, 2017 at 02:24:52PM -0500, Eric Blake wrote:
> We are gradually converting to byte-based interfaces, as they are
> easier to reason about than sector-based. Continue by converting an
> internal structure (no semantic change), and all references to
> tracking progress. Drop a redundant local variable bytes_per_cluster.
>
> Signed-off-by: Eric Blake <address@hidden>
> Reviewed-by: John Snow <address@hidden>
>
Reviewed-by: Jeff Cody <address@hidden>
> ---
> v2: no change
> ---
> block/backup.c | 33 +++++++++++++++------------------
> 1 file changed, 15 insertions(+), 18 deletions(-)
>
> diff --git a/block/backup.c b/block/backup.c
> index 06431ac..4e64710 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -39,7 +39,7 @@ typedef struct BackupBlockJob {
> BlockdevOnError on_source_error;
> BlockdevOnError on_target_error;
> CoRwlock flush_rwlock;
> - uint64_t sectors_read;
> + uint64_t bytes_read;
> unsigned long *done_bitmap;
> int64_t cluster_size;
> bool compress;
> @@ -102,16 +102,15 @@ static int coroutine_fn backup_do_cow(BackupBlockJob
> *job,
> void *bounce_buffer = NULL;
> int ret = 0;
> int64_t sectors_per_cluster = cluster_size_sectors(job);
> - int64_t bytes_per_cluster = sectors_per_cluster * BDRV_SECTOR_SIZE;
> - int64_t start, end;
> - int n;
> + int64_t start, end; /* clusters */
> + int n; /* bytes */
>
> qemu_co_rwlock_rdlock(&job->flush_rwlock);
>
> start = sector_num / sectors_per_cluster;
> end = DIV_ROUND_UP(sector_num + nb_sectors, sectors_per_cluster);
>
> - trace_backup_do_cow_enter(job, start * bytes_per_cluster,
> + trace_backup_do_cow_enter(job, start * job->cluster_size,
> sector_num * BDRV_SECTOR_SIZE,
> nb_sectors * BDRV_SECTOR_SIZE);
>
> @@ -120,28 +119,27 @@ static int coroutine_fn backup_do_cow(BackupBlockJob
> *job,
>
> for (; start < end; start++) {
> if (test_bit(start, job->done_bitmap)) {
> - trace_backup_do_cow_skip(job, start * bytes_per_cluster);
> + trace_backup_do_cow_skip(job, start * job->cluster_size);
> continue; /* already copied */
> }
>
> - trace_backup_do_cow_process(job, start * bytes_per_cluster);
> + trace_backup_do_cow_process(job, start * job->cluster_size);
>
> - n = MIN(sectors_per_cluster,
> - job->common.len / BDRV_SECTOR_SIZE -
> - start * sectors_per_cluster);
> + n = MIN(job->cluster_size,
> + job->common.len - start * job->cluster_size);
>
> if (!bounce_buffer) {
> bounce_buffer = blk_blockalign(blk, job->cluster_size);
> }
> iov.iov_base = bounce_buffer;
> - iov.iov_len = n * BDRV_SECTOR_SIZE;
> + iov.iov_len = n;
> qemu_iovec_init_external(&bounce_qiov, &iov, 1);
>
> ret = blk_co_preadv(blk, start * job->cluster_size,
> bounce_qiov.size, &bounce_qiov,
> is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
> if (ret < 0) {
> - trace_backup_do_cow_read_fail(job, start * bytes_per_cluster,
> ret);
> + trace_backup_do_cow_read_fail(job, start * job->cluster_size,
> ret);
> if (error_is_read) {
> *error_is_read = true;
> }
> @@ -157,7 +155,7 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
> job->compress ? BDRV_REQ_WRITE_COMPRESSED :
> 0);
> }
> if (ret < 0) {
> - trace_backup_do_cow_write_fail(job, start * bytes_per_cluster,
> ret);
> + trace_backup_do_cow_write_fail(job, start * job->cluster_size,
> ret);
> if (error_is_read) {
> *error_is_read = false;
> }
> @@ -169,8 +167,8 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
> /* Publish progress, guest I/O counts as progress too. Note that the
> * offset field is an opaque progress value, it is not a disk offset.
> */
> - job->sectors_read += n;
> - job->common.offset += n * BDRV_SECTOR_SIZE;
> + job->bytes_read += n;
> + job->common.offset += n;
> }
>
> out:
> @@ -363,9 +361,8 @@ static bool coroutine_fn yield_and_check(BackupBlockJob
> *job)
> */
> if (job->common.speed) {
> uint64_t delay_ns = ratelimit_calculate_delay(&job->limit,
> - job->sectors_read *
> - BDRV_SECTOR_SIZE);
> - job->sectors_read = 0;
> + job->bytes_read);
> + job->bytes_read = 0;
> block_job_sleep_ns(&job->common, QEMU_CLOCK_REALTIME, delay_ns);
> } else {
> block_job_sleep_ns(&job->common, QEMU_CLOCK_REALTIME, 0);
> --
> 2.9.4
>
- [Qemu-block] [PATCH v3 11/20] mirror: Switch mirror_do_read() to byte-based, (continued)
- [Qemu-block] [PATCH v3 11/20] mirror: Switch mirror_do_read() to byte-based, Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 12/20] mirror: Switch mirror_iteration() to byte-based, Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 13/20] block: Drop unused bdrv_round_sectors_to_clusters(), Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 15/20] backup: Switch block_backup.h to byte-based, Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 14/20] backup: Switch BackupBlockJob to byte-based, Eric Blake, 2017/06/27
- Re: [Qemu-block] [PATCH v3 14/20] backup: Switch BackupBlockJob to byte-based,
Jeff Cody <=
- [Qemu-block] [PATCH v3 16/20] backup: Switch backup_do_cow() to byte-based, Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 17/20] backup: Switch backup_run() to byte-based, Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 18/20] block: Make bdrv_is_allocated() byte-based, Eric Blake, 2017/06/27
- [Qemu-block] [PATCH v3 19/20] block: Minimize raw use of bds->total_sectors, Eric Blake, 2017/06/27