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[Qemu-block] [PATCH 3/3] mirror: Speed up bitmap initial scanning
From: |
Fam Zheng |
Subject: |
[Qemu-block] [PATCH 3/3] mirror: Speed up bitmap initial scanning |
Date: |
Thu, 9 Jul 2015 11:47:58 +0800 |
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 <address@hidden>
---
block/mirror.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c
index ca55578..e8cb592 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -371,7 +371,7 @@ 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
@@ -425,7 +425,6 @@ 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);
@@ -433,7 +432,9 @@ 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) {
@@ -444,9 +445,7 @@ static void coroutine_fn mirror_run(void *opaque)
if (block_job_is_cancelled(&s->common)) {
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;
@@ -455,10 +454,8 @@ 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;
}
}
--
2.4.3
[Qemu-block] [PATCH 2/3] mirror: Use block_job_relax_cpu during bitmap scanning, Fam Zheng, 2015/07/08
[Qemu-block] [PATCH 3/3] mirror: Speed up bitmap initial scanning,
Fam Zheng <=
Re: [Qemu-block] [Qemu-devel] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan, Alexandre DERUMIER, 2015/07/09
Re: [Qemu-block] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan, Stefan Hajnoczi, 2015/07/09