From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46714) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZgZiT-0005Y3-Ri for qemu-devel@nongnu.org; Mon, 28 Sep 2015 10:47:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZgZiS-00034b-Nf for qemu-devel@nongnu.org; Mon, 28 Sep 2015 10:47:45 -0400 Date: Mon, 28 Sep 2015 16:47:36 +0200 From: Kevin Wolf Message-ID: <20150928144736.GB18068@noname.str.redhat.com> References: <0de92b950741a15b9ff085f7b102ef99ef26101c.1443410673.git.jcody@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0de92b950741a15b9ff085f7b102ef99ef26101c.1443410673.git.jcody@redhat.com> Subject: Re: [Qemu-devel] [PATCH 2/3] block: mirror - split out part of mirror_run() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeff Cody Cc: stefanha@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org Am 28.09.2015 um 05:29 hat Jeff Cody geschrieben: > This is code relocation, to pull the part of mirror_run() that > calls mirror_iteration out into a separate function. > > Signed-off-by: Jeff Cody > --- > block/mirror.c | 206 ++++++++++++++++++++++++++++++--------------------------- > 1 file changed, 110 insertions(+), 96 deletions(-) > > diff --git a/block/mirror.c b/block/mirror.c > index 8b3e89b..405e5c4 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -318,6 +318,115 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) > return delay_ns; > } > > +static int mirror_do_iteration(MirrorBlockJob *s, uint64_t last_pause_ns) > +{ > + int ret; > + > + BlockDriverState *bs = s->common.bs; > + > + for (;;) { > + uint64_t delay_ns = 0; > + int64_t cnt; > + bool should_complete; > + > + if (s->ret < 0) { > + ret = s->ret; > + goto immediate_exit; > + } > + > + cnt = bdrv_get_dirty_count(s->dirty_bitmap); > + /* s->common.offset contains the number of bytes already processed so > + * far, cnt is the number of dirty sectors remaining and > + * s->sectors_in_flight is the number of sectors currently being > + * processed; together those are the current total operation length */ > + s->common.len = s->common.offset + > + (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; > + > + /* Note that even when no rate limit is applied we need to yield > + * periodically with no pending I/O so that bdrv_drain_all() returns. > + * We do so every SLICE_TIME nanoseconds, or when there is an error, > + * or when the source is clean, whichever comes first. > + */ > + if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME > + && s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { > + if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 || > + (cnt == 0 && s->in_flight > 0)) { > + trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); > + s->waiting_for_io = true; > + qemu_coroutine_yield(); > + s->waiting_for_io = false; > + continue; > + } else if (cnt != 0) { > + delay_ns = mirror_iteration(s); > + } > + } > + > + should_complete = false; > + if (s->in_flight == 0 && cnt == 0) { > + trace_mirror_before_flush(s); > + ret = bdrv_flush(s->target); > + if (ret < 0) { > + if (mirror_error_action(s, false, -ret) == > + BLOCK_ERROR_ACTION_REPORT) { > + goto immediate_exit; > + } > + } else { > + /* We're out of the streaming phase. From now on, if the job > + * is cancelled we will actually complete all pending I/O and > + * report completion. This way, block-job-cancel will leave > + * the target in a consistent state. > + */ > + if (!s->synced) { > + block_job_event_ready(&s->common); > + s->synced = true; > + } > + > + should_complete = s->should_complete || > + block_job_is_cancelled(&s->common); > + cnt = bdrv_get_dirty_count(s->dirty_bitmap); > + } > + } > + > + if (cnt == 0 && should_complete) { > + /* The dirty bitmap is not updated while operations are pending. > + * If we're about to exit, wait for pending operations before > + * calling bdrv_get_dirty_count(bs), or we may exit while the > + * source has dirty data to copy! > + * > + * Note that I/O can be submitted by the guest while > + * mirror_populate runs. > + */ > + trace_mirror_before_drain(s, cnt); > + bdrv_drain(bs); > + cnt = bdrv_get_dirty_count(s->dirty_bitmap); > + } > + > + ret = 0; > + trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); > + if (!s->synced) { > + block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); > + if (block_job_is_cancelled(&s->common)) { > + break; > + } > + } else if (!should_complete) { > + delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); > + block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); > + } else if (cnt == 0) { > + /* The two disks are in sync. Exit and report successful > + * completion. > + */ > + assert(QLIST_EMPTY(&bs->tracked_requests)); > + s->common.cancelled = false; > + break; > + } > + last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); > + } > + > +immediate_exit: > + return ret; > + > +} Did you leave this additional empty line there intentionally? With or without it removed, and also with or without Paolo's suggestion regarding goto vs. return applied: Reviewed-by: Kevin Wolf