From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45006) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yn0Ev-0005nG-TA for qemu-devel@nongnu.org; Tue, 28 Apr 2015 03:47:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yn0Es-0004KJ-7h for qemu-devel@nongnu.org; Tue, 28 Apr 2015 03:47:33 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:29194 helo=relay.sw.ru) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yn0Er-0004K5-Ol for qemu-devel@nongnu.org; Tue, 28 Apr 2015 03:47:30 -0400 From: "Denis V. Lunev" Date: Tue, 28 Apr 2015 10:46:59 +0300 Message-Id: <1430207220-24458-27-git-send-email-den@openvz.org> In-Reply-To: <1430207220-24458-1-git-send-email-den@openvz.org> References: <1430207220-24458-1-git-send-email-den@openvz.org> Subject: [Qemu-devel] [PATCH 26/27] block/parallels: optimize linear image expansion List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "Denis V. Lunev" , qemu-devel@nongnu.org, Stefan Hajnoczi 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 Reviewed-by: Roman Karan CC: Kevin Wolf CC: Stefan Hajnoczi --- block/parallels.c | 42 ++++++++++++++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 10 deletions(-) diff --git a/block/parallels.c b/block/parallels.c index 440938e..e7124d9 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); } -- 1.9.1