| Message ID | 20200527124511.986099-6-rvkagan@yandex-team.ru |
|---|---|
| State | New |
| Headers | show |
| Series | block: enhance handling of size-related BlockConf properties | expand |
On 5/27/20 7:45 AM, Roman Kagan wrote: > Logical and physical block sizes in QEMU are limited to 32 KiB. > > This appears unnecessary tight, and we've seen bigger block sizes handy unnecessarily > at times. > > Lift the limitation up to 2 MiB which appears to be good enough for > everybody, and matches the qcow2 cluster size limit. > > Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> > --- Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c index e7ccd4d276..ecd84262a9 100644 --- a/hw/core/qdev-properties.c +++ b/hw/core/qdev-properties.c @@ -784,9 +784,12 @@ const PropertyInfo qdev_prop_size32 = { /* lower limit is sector size */ #define MIN_BLOCK_SIZE 512 #define MIN_BLOCK_SIZE_STR stringify(MIN_BLOCK_SIZE) -/* upper limit is the max power of 2 that fits in uint16_t */ -#define MAX_BLOCK_SIZE 32768 -#define MAX_BLOCK_SIZE_STR stringify(MAX_BLOCK_SIZE) +/* + * upper limit is arbitrary, 2 MiB looks sufficient for all sensible uses, and + * matches qcow2 cluster size limit + */ +#define MAX_BLOCK_SIZE (2 * MiB) +#define MAX_BLOCK_SIZE_STR "2 MiB" static void set_blocksize(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp)
Logical and physical block sizes in QEMU are limited to 32 KiB. This appears unnecessary tight, and we've seen bigger block sizes handy at times. Lift the limitation up to 2 MiB which appears to be good enough for everybody, and matches the qcow2 cluster size limit. Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> --- v4 -> v5: - split out into separate patch [Philippe] - as this patch has changed significantly lose Eric's r-b hw/core/qdev-properties.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)