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authorDenis V. Lunev <den@openvz.org>2015-04-28 10:46:57 +0300
committerStefan Hajnoczi <stefanha@redhat.com>2015-05-22 09:37:32 +0100
commit0d31c7c200b3dca2aeeaa6f74ff3fd539aad803a (patch)
treee8b2a49fe7133c5c81387cbcc1406518789e6b2a /block/parallels.c
parent2d68e22e94e8bc5a0d32a38b53c592c320db8261 (diff)
block/parallels: delay writing to BAT till bdrv_co_flush_to_os
The idea is that we do not need to immediately sync BAT to the image as from the guest point of view there is a possibility that IO is lost even in the physical controller until flush command was finished. bdrv_co_flush_to_os is exactly the right place for this purpose. Technically the patch uses loaded BAT data as a cache and performs actual on-disk metadata updates in parallels_co_flush_to_os callback. This patch speed ups qemu-img create -f parallels -o cluster_size=64k ./1.hds 64G qemu-io -f parallels -c "write -P 0x11 0 1024k" 1.hds writing from 50-60 Mb/sec to 80-90 Mb/sec on rotational media and from 160 Mb/sec to 190 Mb/sec on SSD disk. Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Roman Kagan <rkagan@parallels.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Roman Kagan <rkagan@parallels.com> Message-id: 1430207220-24458-25-git-send-email-den@openvz.org CC: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/parallels.c')
-rw-r--r--block/parallels.c50
1 files changed, 44 insertions, 6 deletions
diff --git a/block/parallels.c b/block/parallels.c
index 4d8a0d48aa..05fe030f05 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -30,6 +30,7 @@
#include "qemu-common.h"
#include "block/block_int.h"
#include "qemu/module.h"
+#include "qemu/bitmap.h"
/**************************************************************/
@@ -66,6 +67,9 @@ typedef struct BDRVParallelsState {
uint32_t header_size;
bool header_unclean;
+ unsigned long *bat_dirty_bmap;
+ unsigned int bat_dirty_block;
+
uint32_t *bat_bitmap;
unsigned int bat_size;
@@ -165,15 +169,43 @@ static int64_t allocate_cluster(BlockDriverState *bs, int64_t sector_num)
}
s->bat_bitmap[idx] = cpu_to_le32(pos / s->off_multiplier);
- ret = bdrv_pwrite(bs->file, bat_entry_off(idx), s->bat_bitmap + idx,
- sizeof(s->bat_bitmap[idx]));
- if (ret < 0) {
- s->bat_bitmap[idx] = 0;
- return ret;
- }
+
+ bitmap_set(s->bat_dirty_bmap, bat_entry_off(idx) / s->bat_dirty_block, 1);
return bat2sect(s, idx) + offset;
}
+
+static coroutine_fn int parallels_co_flush_to_os(BlockDriverState *bs)
+{
+ BDRVParallelsState *s = bs->opaque;
+ unsigned long size = DIV_ROUND_UP(s->header_size, s->bat_dirty_block);
+ unsigned long bit;
+
+ qemu_co_mutex_lock(&s->lock);
+
+ bit = find_first_bit(s->bat_dirty_bmap, size);
+ while (bit < size) {
+ uint32_t off = bit * s->bat_dirty_block;
+ uint32_t to_write = s->bat_dirty_block;
+ int ret;
+
+ if (off + to_write > s->header_size) {
+ to_write = s->header_size - off;
+ }
+ ret = bdrv_pwrite(bs->file, off, (uint8_t *)s->header + off, to_write);
+ if (ret < 0) {
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+ }
+ bit = find_next_bit(s->bat_dirty_bmap, size, bit + 1);
+ }
+ bitmap_zero(s->bat_dirty_bmap, size);
+
+ qemu_co_mutex_unlock(&s->lock);
+ return 0;
+}
+
+
static int64_t coroutine_fn parallels_co_get_block_status(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum)
{
@@ -557,6 +589,10 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
}
}
+ s->bat_dirty_block = 4 * getpagesize();
+ s->bat_dirty_bmap =
+ bitmap_new(DIV_ROUND_UP(s->header_size, s->bat_dirty_block));
+
qemu_co_mutex_init(&s->lock);
return 0;
@@ -578,6 +614,7 @@ static void parallels_close(BlockDriverState *bs)
parallels_update_header(bs);
}
+ g_free(s->bat_dirty_bmap);
qemu_vfree(s->header);
}
@@ -608,6 +645,7 @@ static BlockDriver bdrv_parallels = {
.bdrv_close = parallels_close,
.bdrv_co_get_block_status = parallels_co_get_block_status,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
+ .bdrv_co_flush_to_os = parallels_co_flush_to_os,
.bdrv_co_readv = parallels_co_readv,
.bdrv_co_writev = parallels_co_writev,