unicorn/include
Alexey Kardashevskiy b90333a531
memory: Share special empty FlatView
This shares an cached empty FlatView among address spaces. The empty
FV is used every time when a root MR renders into a FV without memory
sections which happens when MR or its children are not enabled or
zero-sized. The empty_view is not NULL to keep the rest of memory
API intact; it also has a dispatch tree for the same reason.

On POWER8 with 255 CPUs, 255 virtio-net, 40 PCI bridges guest this halves
the amount of FlatView's in use (557 -> 260) and dispatch tables
(~800000 -> ~370000). In an unrelated experiment with 112 non-virtio
devices on x86 ("-M pc"), only 4 FlatViews are alive, and about ~2000
are created at startup.

Backports commit 092aa2fc65b7a35121616aad8f39d47b8f921618 from qemu
2018-03-11 22:34:28 -04:00
..
unicorn
list.h
qemu.h
uc_priv.h memory: Share special empty FlatView 2018-03-11 22:34:28 -04:00