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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, 10 Mar 2015 11:51:18 +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>
CC: Roman Kagan <address@hidden>
CC: Kevin Wolf <address@hidden>
CC: Stefan Hajnoczi <address@hidden>
---
block/parallels.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 44 insertions(+), 6 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index 70445b1..b42bd07 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"
/**************************************************************/
@@ -62,6 +63,9 @@ 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;
@@ -135,7 +139,6 @@ static int64_t allocate_cluster(BlockDriverState *bs,
int64_t sector_num)
BDRVParallelsState *s = bs->opaque;
uint32_t idx, offset;
int64_t pos;
- int ret;
idx = sector_num / s->tracks;
offset = sector_num % s->tracks;
@@ -151,14 +154,43 @@ static int64_t allocate_cluster(BlockDriverState *bs,
int64_t sector_num)
bdrv_truncate(bs->file, (pos + s->tracks) << BDRV_SECTOR_BITS);
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) {
- 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)
{
@@ -536,6 +568,10 @@ 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;
@@ -557,6 +593,7 @@ static void parallels_close(BlockDriverState *bs)
parallels_update_header(bs);
}
+ g_free(s->bat_dirty_bmap);
qemu_vfree(s->header);
}
@@ -586,6 +623,7 @@ static BlockDriver bdrv_parallels = {
.bdrv_open = parallels_open,
.bdrv_close = parallels_close,
.bdrv_co_get_block_status = parallels_co_get_block_status,
+ .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 15/27] block/parallels: keep BAT bitmap data in little endian in memory, (continued)
- [Qemu-devel] [PATCH 15/27] block/parallels: keep BAT bitmap data in little endian in memory, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 11/27] iotests, parallels: test for newly created parallels image via qemu-img, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 26/27] block/parallels: optimize linear image expansion, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 08/27] block/parallels: _co_writev callback for Parallels format, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 18/27] block/parallels: implement parallels_check method of block driver, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 07/27] block/parallels: replace magic constants 4, 64 with proper sizeofs, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 24/27] block/parallels: delay writing to BAT till bdrv_co_flush_to_os,
Denis V. Lunev <=
- [Qemu-devel] [PATCH 21/27] block/parallels: no need to flush on each block allocation table update, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH 02/27] block/parallels: rename parallels_header to ParallelsHeader, Denis V. Lunev, 2015/03/10
- [Qemu-devel] [PATCH v3 0/27] write/create for Parallels images with reasonable performance, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 22/27] block/parallels: improve image reading performance, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 05/27] block/parallels: add get_block_status, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 01/27] iotests, parallels: quote TEST_IMG in 076 test to be path-safe, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 03/27] block/parallels: switch to bdrv_read, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 24/27] block/parallels: delay writing to BAT till bdrv_co_flush_to_os, Denis V. Lunev, 2015/03/11