debian/patches/mirror-sleep.patch

   1 From 2540abec85433596dd04640b14f75ceb13bbb342 Mon Sep 17 00:00:00 2001
   2 From: Fam Zheng <famz@redhat.com>
   3 Date: Wed, 13 May 2015 11:11:13 +0800
   4 Subject: [PATCH] block/mirror: Sleep periodically during bitmap scanning
   5
   6 Before, we only yield after initializing dirty bitmap, where the QMP
   7 command would return. That may take very long, and guest IO will be
   8 blocked.
   9
  10 Add sleep points like the later mirror iterations.
  11
  12 Signed-off-by: Fam Zheng <famz@redhat.com>
  13 Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
  14 Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
  15 Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
  16 ---
  17  block/mirror.c | 13 ++++++++++++-
  18  1 file changed, 12 insertions(+), 1 deletion(-)
  19
  20 diff --git a/block/mirror.c b/block/mirror.c
  21 index 4056164..0a05971 100644
  22 --- a/block/mirror.c
  23 +++ b/block/mirror.c
  24 @@ -432,11 +432,23 @@ static void coroutine_fn mirror_run(void *opaque)
  25      sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
  26      mirror_free_init(s);
  27
  28 +    last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
  29      if (!s->is_none_mode) {
  30          /* First part, loop on the sectors and initialize the dirty bitmap.  */
  31          BlockDriverState *base = s->base;
  32          for (sector_num = 0; sector_num < end; ) {
  33              int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1;
  34 +            int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
  35 +
  36 +            if (now - last_pause_ns > SLICE_TIME) {
  37 +                last_pause_ns = now;
  38 +                block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0);
  39 +            }
  40 +
  41 +            if (block_job_is_cancelled(&s->common)) {
  42 +                goto immediate_exit;
  43 +            }
  44 +
  45              ret = bdrv_is_allocated_above(bs, base,
  46                                            sector_num, next - sector_num, &n);
  47
  48 @@ -455,7 +467,6 @@ static void coroutine_fn mirror_run(void *opaque)
  49      }
  50
  51      bdrv_dirty_iter_init(bs, s->dirty_bitmap, &s->hbi);
  52 -    last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
  53      for (;;) {
  54          uint64_t delay_ns = 0;
  55          int64_t cnt;
  56 --
  57 2.1.4
  58