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[Qemu-devel] [PATCH 24/27] block/parallels: delay writing to BAT till bd
From: |
Denis V. Lunev |
Subject: |
[Qemu-devel] [PATCH 24/27] block/parallels: delay writing to BAT till bdrv_co_flush_to_os |
Date: |
Tue, 28 Apr 2015 10:46:57 +0300 |
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 <address@hidden>
Reviewed-by: Roman Kagan <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
CC: Kevin Wolf <address@hidden>
---
block/parallels.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 44 insertions(+), 6 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index 4d8a0d4..05fe030 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,
--
1.9.1
- [Qemu-devel] [PATCH 14/27] block/parallels: rename catalog_ names to bat_, (continued)
- [Qemu-devel] [PATCH 14/27] block/parallels: rename catalog_ names to bat_, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 15/27] block/parallels: create bat2sect helper, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 16/27] block/parallels: keep BAT bitmap data in little endian in memory, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 17/27] block/parallels: read parallels image header and BAT into single buffer, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 18/27] block/parallels: move parallels_open/probe to the very end of the file, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 19/27] block/parallels: implement parallels_check method of block driver, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 20/27] block/parallels: implement incorrect close detection, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 22/27] block/parallels: improve image reading performance, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 21/27] iotests, parallels: check for incorrectly closed image in tests, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 23/27] block/parallels: create bat_entry_off helper, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 24/27] block/parallels: delay writing to BAT till bdrv_co_flush_to_os,
Denis V. Lunev <=
- [Qemu-devel] [PATCH 25/27] block/parallels: add prealloc-mode and prealloc-size open paramemets, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 26/27] block/parallels: optimize linear image expansion, Denis V. Lunev, 2015/04/28
- [Qemu-devel] [PATCH 27/27] block/parallels: improve image writing performance further, Denis V. Lunev, 2015/04/28