diff options
| -rw-r--r-- | qemu-img.c | 44 | ||||
| -rw-r--r-- | tests/qemu-iotests/122.out | 18 |
2 files changed, 46 insertions, 16 deletions
@@ -1105,11 +1105,15 @@ static int64_t find_nonzero(const uint8_t *buf, int64_t n) * * 'pnum' is set to the number of sectors (including and immediately following * the first one) that are known to be in the same allocated/unallocated state. + * The function will try to align the end offset to alignment boundaries so + * that the request will at least end aligned and consequtive requests will + * also start at an aligned offset. */ -static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum) +static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum, + int64_t sector_num, int alignment) { bool is_zero; - int i; + int i, tail; if (n <= 0) { *pnum = 0; @@ -1122,6 +1126,23 @@ static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum) break; } } + + tail = (sector_num + i) & (alignment - 1); + if (tail) { + if (is_zero && i <= tail) { + /* treat unallocated areas which only consist + * of a small tail as allocated. */ + is_zero = false; + } + if (!is_zero) { + /* align up end offset of allocated areas. */ + i += alignment - tail; + i = MIN(i, n); + } else { + /* align down end offset of zero areas. */ + i -= tail; + } + } *pnum = i; return !is_zero; } @@ -1132,7 +1153,7 @@ static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum) * breaking up write requests for only small sparse areas. */ static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum, - int min) + int min, int64_t sector_num, int alignment) { int ret; int num_checked, num_used; @@ -1141,7 +1162,7 @@ static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum, min = n; } - ret = is_allocated_sectors(buf, n, pnum); + ret = is_allocated_sectors(buf, n, pnum, sector_num, alignment); if (!ret) { return ret; } @@ -1149,13 +1170,15 @@ static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum, num_used = *pnum; buf += BDRV_SECTOR_SIZE * *pnum; n -= *pnum; + sector_num += *pnum; num_checked = num_used; while (n > 0) { - ret = is_allocated_sectors(buf, n, pnum); + ret = is_allocated_sectors(buf, n, pnum, sector_num, alignment); buf += BDRV_SECTOR_SIZE * *pnum; n -= *pnum; + sector_num += *pnum; num_checked += *pnum; if (ret) { num_used = num_checked; @@ -1560,6 +1583,7 @@ typedef struct ImgConvertState { bool wr_in_order; bool copy_range; int min_sparse; + int alignment; size_t cluster_sectors; size_t buf_sectors; long num_coroutines; @@ -1724,7 +1748,8 @@ static int coroutine_fn convert_co_write(ImgConvertState *s, int64_t sector_num, * zeroed. */ if (!s->min_sparse || (!s->compressed && - is_allocated_sectors_min(buf, n, &n, s->min_sparse)) || + is_allocated_sectors_min(buf, n, &n, s->min_sparse, + sector_num, s->alignment)) || (s->compressed && !buffer_is_zero(buf, n * BDRV_SECTOR_SIZE))) { @@ -2368,6 +2393,13 @@ static int img_convert(int argc, char **argv) out_bs->bl.pdiscard_alignment >> BDRV_SECTOR_BITS))); + /* try to align the write requests to the destination to avoid unnecessary + * RMW cycles. */ + s.alignment = MAX(pow2floor(s.min_sparse), + DIV_ROUND_UP(out_bs->bl.request_alignment, + BDRV_SECTOR_SIZE)); + assert(is_power_of_2(s.alignment)); + if (skip_create) { int64_t output_sectors = blk_nb_sectors(s.target); if (output_sectors < 0) { diff --git a/tests/qemu-iotests/122.out b/tests/qemu-iotests/122.out index 6c7ee1d..c576705 100644 --- a/tests/qemu-iotests/122.out +++ b/tests/qemu-iotests/122.out @@ -194,12 +194,12 @@ wrote 1024/1024 bytes at offset 17408 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) convert -S 4k -[{ "start": 0, "length": 1024, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 1024, "length": 7168, "depth": 0, "zero": true, "data": false}, -{ "start": 8192, "length": 1024, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 9216, "length": 8192, "depth": 0, "zero": true, "data": false}, -{ "start": 17408, "length": 1024, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 18432, "length": 67090432, "depth": 0, "zero": true, "data": false}] +[{ "start": 0, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, +{ "start": 4096, "length": 4096, "depth": 0, "zero": true, "data": false}, +{ "start": 8192, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, +{ "start": 12288, "length": 4096, "depth": 0, "zero": true, "data": false}, +{ "start": 16384, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, +{ "start": 20480, "length": 67088384, "depth": 0, "zero": true, "data": false}] convert -c -S 4k [{ "start": 0, "length": 1024, "depth": 0, "zero": false, "data": true}, @@ -210,10 +210,8 @@ convert -c -S 4k { "start": 18432, "length": 67090432, "depth": 0, "zero": true, "data": false}] convert -S 8k -[{ "start": 0, "length": 9216, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 9216, "length": 8192, "depth": 0, "zero": true, "data": false}, -{ "start": 17408, "length": 1024, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, -{ "start": 18432, "length": 67090432, "depth": 0, "zero": true, "data": false}] +[{ "start": 0, "length": 24576, "depth": 0, "zero": false, "data": true, "offset": OFFSET}, +{ "start": 24576, "length": 67084288, "depth": 0, "zero": true, "data": false}] convert -c -S 8k [{ "start": 0, "length": 1024, "depth": 0, "zero": false, "data": true}, |