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authorFam Zheng <famz@redhat.com>2015-07-09 11:47:58 +0800
committerStefan Hajnoczi <stefanha@redhat.com>2015-07-22 11:14:21 +0100
commit999006975840f8cdf2038a587d852a6cbfe58e3b (patch)
tree1a13ecd7f3f16e0e0e9dd68f182e72029d975b3b /block
parent774ee4772b6838b78741ea52d4bf26b8922244c5 (diff)
mirror: Speed up bitmap initial scanning
Limiting to sectors_per_chunk for each bdrv_is_allocated_above is slow, because the underlying protocol driver would issue much more queries than necessary. We should coalesce the query. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: <1436413678-7114-4-git-send-email-famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/mirror.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/block/mirror.c b/block/mirror.c
index 323f747c75..fc4d8f561e 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -388,7 +388,7 @@ static void coroutine_fn mirror_run(void *opaque)
MirrorBlockJob *s = opaque;
MirrorExitData *data;
BlockDriverState *bs = s->common.bs;
- int64_t sector_num, end, sectors_per_chunk, length;
+ int64_t sector_num, end, length;
uint64_t last_pause_ns;
BlockDriverInfo bdi;
char backing_filename[2]; /* we only need 2 characters because we are only
@@ -442,7 +442,6 @@ static void coroutine_fn mirror_run(void *opaque)
goto immediate_exit;
}
- sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
mirror_free_init(s);
last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
@@ -450,7 +449,9 @@ static void coroutine_fn mirror_run(void *opaque)
/* First part, loop on the sectors and initialize the dirty bitmap. */
BlockDriverState *base = s->base;
for (sector_num = 0; sector_num < end; ) {
- int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1;
+ /* Just to make sure we are not exceeding int limit. */
+ int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS,
+ end - sector_num);
int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
if (now - last_pause_ns > SLICE_TIME) {
@@ -462,8 +463,7 @@ static void coroutine_fn mirror_run(void *opaque)
goto immediate_exit;
}
- ret = bdrv_is_allocated_above(bs, base,
- sector_num, next - sector_num, &n);
+ ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n);
if (ret < 0) {
goto immediate_exit;
@@ -472,10 +472,8 @@ static void coroutine_fn mirror_run(void *opaque)
assert(n > 0);
if (ret == 1) {
bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
- sector_num = next;
- } else {
- sector_num += n;
}
+ sector_num += n;
}
}