yuzu/unicorn
1
0
Fork 0
mirror of https://github.com/yuzu-emu/unicorn.git synced 2024-12-23 00:35:34 +00:00
Code Issues Packages Projects Releases Wiki Activity

memory: seek FlatView sharing candidates among children subregions

Browse source 
A container can be used instead of an alias to allow switching between
multiple subregions. In this case we cannot directly share the
subregions (since they only belong to a single parent), but if the
subregions are aliases we can in turn walk those.

This is not enough to remove all source of quadratic FlatView creation,
but it enables sharing of the PCI bus master FlatViews (and their
AddressSpaceDispatch structures) across all PCI devices. For 112
virtio-net-pci devices, boot time is reduced from 25 to 10 seconds and
memory consumption from 1.4 to 1 G.

Backports commit e673ba9af9bf8fd8e0f44025ac738b8285b3ed27 from qemu
This commit is contained in:
Paolo Bonzini 2018-03-11 22:19:47 -04:00 committed by Lioncash
parent 7eab335b2e
commit 20b1bd767f
No known key found for this signature in database
GPG key ID: 4E3C3CC1031BA9C7
1 changed files with 34 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

40
qemu/memory.c
View file

@ -688,12 +688,40 @@ static void render_memory_region(FlatView *view,
static MemoryRegion *memory_region_get_flatview_root(MemoryRegion *mr)
{
while (mr->alias && !mr->alias_offset &&
int128_ge(mr->size, mr->alias->size)) {
/* The alias is included in its entirety. Use it as
* the "real" root, so that we can share more FlatViews.
*/
mr = mr->alias;
while (mr->enabled) {
if (mr->alias) {
if (!mr->alias_offset && int128_ge(mr->size, mr->alias->size)) {
/* The alias is included in its entirety. Use it as
* the "real" root, so that we can share more FlatViews.
*/
mr = mr->alias;
continue;
}
} else if (!mr->terminates) {
unsigned int found = 0;
MemoryRegion *child, *next = NULL;
QTAILQ_FOREACH(child, &mr->subregions, subregions_link) {
if (child->enabled) {
if (++found > 1) {
next = NULL;
break;
}
if (!child->addr && int128_ge(mr->size, child->size)) {
/* A child is included in its entirety. If it's the only
* enabled one, use it in the hope of finding an alias down the
* way. This will also let us share FlatViews.
*/
next = child;
}
}
}
if (next) {
mr = next;
continue;
}
}
break;
}
return mr;