On Mon, Jul 27, 2020 at 07:45:43PM +0200, Philippe Mathieu-Daudé wrote:
> When different regions have the same address, we currently
> sort them by the priority. Also sort them by the region
> size.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> ---
> softmmu/memory.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/softmmu/memory.c b/softmmu/memory.c
> index af25987518..c28dcaf4d6 100644
> --- a/softmmu/memory.c
> +++ b/softmmu/memory.c
> @@ -2960,7 +2960,8 @@ static void mtree_print_mr(const MemoryRegion *mr,
> unsigned int level,
> QTAILQ_FOREACH(ml, &submr_print_queue, mrqueue) {
> if (new_ml->mr->addr < ml->mr->addr ||
> (new_ml->mr->addr == ml->mr->addr &&
> - new_ml->mr->priority > ml->mr->priority)) {
> + (MR_SIZE(new_ml->mr->size) > MR_SIZE(ml->mr->size) ||
> + new_ml->mr->priority > ml->mr->priority))) {
> QTAILQ_INSERT_BEFORE(ml, new_ml, mrqueue);
> new_ml = NULL;
> break;
Note that this change could make the outcome unpredictable... Assuming two
memory regions:
mr1: addr=0, size=0x1000, pri=2
mr2: addr=0, size=0x2000, pri=1
Then assuming submr_print_queue only contains these two mrs. Then when
submr_print_queue has mr1 at head, then when we insert mr2 we'll think it
should be inserted before mr1 (because mr2's size bigger), so the result will
be:
mr2:...
mr1:...
If submr_print_queue has mr2 at head, then when we insert mr1 we'll think it
should be inserted before mr2 (because mr1's priority higher). We'll instead
get:
mr1:...
mr2:...
Phil, could I ask what's the case to be fixed?
--
Peter Xu
