From cc8c9d6c6f28e4e376a6561a2a31524fd069bc2d Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 21 Mar 2014 13:55:18 +0100 Subject: [PATCH] mirror: fix throttling delay calculation The throttling delay calculation was using an inaccurate sector count to calculate the time to sleep. This broke rate-limiting for the block mirror job. Move the delay calculation into mirror_iteration() where we know how many sectors were transferred. This lets us calculate an accurate delay time. Reported-by: Joaquim Barrera Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- block/mirror.c | 28 +++++++++++++++------------- trace-events | 2 +- 2 files changed, 16 insertions(+), 14 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index dd5ee056b4..adb09cf4ab 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -139,11 +139,12 @@ static void mirror_read_complete(void *opaque, int ret) mirror_write_complete, op); } -static void coroutine_fn mirror_iteration(MirrorBlockJob *s) +static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) { BlockDriverState *source = s->common.bs; int nb_sectors, sectors_per_chunk, nb_chunks; int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; + uint64_t delay_ns; MirrorOp *op; s->sector_num = hbitmap_iter_next(&s->hbi); @@ -231,7 +232,12 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s) nb_chunks += added_chunks; next_sector += added_sectors; next_chunk += added_chunks; - } while (next_sector < end); + if (!s->synced && s->common.speed) { + delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors); + } else { + delay_ns = 0; + } + } while (delay_ns == 0 && next_sector < end); /* Allocate a MirrorOp that is used as an AIO callback. */ op = g_slice_new(MirrorOp); @@ -268,6 +274,7 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s) trace_mirror_one_iteration(s, sector_num, nb_sectors); bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, mirror_read_complete, op); + return delay_ns; } static void mirror_free_init(MirrorBlockJob *s) @@ -362,7 +369,7 @@ static void coroutine_fn mirror_run(void *opaque) 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; + uint64_t delay_ns = 0; int64_t cnt; bool should_complete; @@ -386,8 +393,10 @@ static void coroutine_fn mirror_run(void *opaque) qemu_coroutine_yield(); continue; } else if (cnt != 0) { - mirror_iteration(s); - continue; + delay_ns = mirror_iteration(s); + if (delay_ns == 0) { + continue; + } } } @@ -432,17 +441,10 @@ static void coroutine_fn mirror_run(void *opaque) } ret = 0; - trace_mirror_before_sleep(s, cnt, s->synced); + trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); if (!s->synced) { /* Publish progress */ s->common.offset = (end - cnt) * BDRV_SECTOR_SIZE; - - if (s->common.speed) { - delay_ns = ratelimit_calculate_delay(&s->limit, sectors_per_chunk); - } else { - delay_ns = 0; - } - block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); if (block_job_is_cancelled(&s->common)) { break; diff --git a/trace-events b/trace-events index 002c2604d8..3b7ff4d970 100644 --- a/trace-events +++ b/trace-events @@ -82,7 +82,7 @@ mirror_start(void *bs, void *s, void *co, void *opaque) "bs %p s %p co %p opaque mirror_restart_iter(void *s, int64_t cnt) "s %p dirty count %"PRId64 mirror_before_flush(void *s) "s %p" mirror_before_drain(void *s, int64_t cnt) "s %p dirty count %"PRId64 -mirror_before_sleep(void *s, int64_t cnt, int synced) "s %p dirty count %"PRId64" synced %d" +mirror_before_sleep(void *s, int64_t cnt, int synced, uint64_t delay_ns) "s %p dirty count %"PRId64" synced %d delay %"PRIu64"ns" mirror_one_iteration(void *s, int64_t sector_num, int nb_sectors) "s %p sector_num %"PRId64" nb_sectors %d" mirror_iteration_done(void *s, int64_t sector_num, int nb_sectors, int ret) "s %p sector_num %"PRId64" nb_sectors %d ret %d" mirror_yield(void *s, int64_t cnt, int buf_free_count, int in_flight) "s %p dirty count %"PRId64" free buffers %d in_flight %d"