diff options
author | Denis V. Lunev <den@openvz.org> | 2015-04-28 10:46:59 +0300 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2015-05-22 09:37:32 +0100 |
commit | 19f5dc15912dfb6af06c97e4975023e545e85c72 (patch) | |
tree | c78fd046988fc38c113e436b840848f5f12c0363 /block/parallels.c | |
parent | d61790112fa861fbbbb02b53f9c3beb9ca7f8419 (diff) |
block/parallels: optimize linear image expansion
Plain image expansion spends a lot of time to update image file size.
This seriously affects the performance. The following simple test
qemu_img create -f parallels -o cluster_size=64k ./1.hds 64G
qemu_io -n -c "write -P 0x11 0 1024M" ./1.hds
could be improved if the format driver will pre-allocate some space
in the image file with a reasonable chunk.
This patch preallocates 128 Mb using bdrv_write_zeroes, which should
normally use fallocate() call inside. Fallback to older truncate()
could be used as a fallback using image open options thanks to the
previous patch.
The benefit is around 15%.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Roman Karan <rkagan@parallels.com>
Signed-off-by: Roman Kagan <rkagan@parallels.com>
Message-id: 1430207220-24458-27-git-send-email-den@openvz.org
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/parallels.c')
-rw-r--r-- | block/parallels.c | 42 |
1 files changed, 32 insertions, 10 deletions
diff --git a/block/parallels.c b/block/parallels.c index 440938e18a..e7124d97e7 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -88,6 +88,7 @@ typedef struct BDRVParallelsState { uint32_t *bat_bitmap; unsigned int bat_size; + int64_t data_end; uint64_t prealloc_size; ParallelsPreallocMode prealloc_mode; @@ -187,7 +188,6 @@ 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; @@ -200,14 +200,21 @@ static int64_t allocate_cluster(BlockDriverState *bs, int64_t sector_num) } pos = bdrv_getlength(bs->file) >> BDRV_SECTOR_BITS; - if (s->prealloc_mode == PRL_PREALLOC_MODE_TRUNCATE) { - ret = bdrv_truncate(bs->file, (pos + s->tracks) << BDRV_SECTOR_BITS); - } else { - ret = bdrv_write_zeroes(bs->file, pos, s->tracks, 0); - } - if (ret < 0) { - return ret; + if (s->data_end + s->tracks > pos) { + int ret; + if (s->prealloc_mode == PRL_PREALLOC_MODE_FALLOCATE) { + ret = bdrv_write_zeroes(bs->file, s->data_end, + s->prealloc_size, 0); + } else { + ret = bdrv_truncate(bs->file, + (s->data_end + s->prealloc_size) << BDRV_SECTOR_BITS); + } + if (ret < 0) { + return ret; + } } + pos = s->data_end; + s->data_end += s->tracks; s->bat_bitmap[idx] = cpu_to_le32(pos / s->off_multiplier); @@ -549,7 +556,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, { BDRVParallelsState *s = bs->opaque; ParallelsHeader ph; - int ret, size; + int ret, size, i; QemuOpts *opts = NULL; Error *local_err = NULL; char *buf; @@ -599,7 +606,11 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, ret = -ENOMEM; goto fail; } - if (le32_to_cpu(ph.data_off) < s->header_size) { + s->data_end = le32_to_cpu(ph.data_off); + if (s->data_end == 0) { + s->data_end = ROUND_UP(bat_entry_off(s->bat_size), BDRV_SECTOR_SIZE); + } + if (s->data_end < s->header_size) { /* there is not enough unused space to fit to block align between BAT and actual data. We can't avoid read-modify-write... */ s->header_size = size; @@ -611,6 +622,13 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, } s->bat_bitmap = (uint32_t *)(s->header + 1); + for (i = 0; i < s->bat_size; i++) { + int64_t off = bat2sect(s, i); + if (off >= s->data_end) { + s->data_end = off + s->tracks; + } + } + if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) { /* Image was not closed correctly. The check is mandatory */ s->header_unclean = true; @@ -685,6 +703,10 @@ static void parallels_close(BlockDriverState *bs) parallels_update_header(bs); } + if (bs->open_flags & BDRV_O_RDWR) { + bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS); + } + g_free(s->bat_dirty_bmap); qemu_vfree(s->header); } |