memory: add a per-AddressSpace list of listeners

This speeds up MEMORY_LISTENER_CALL noticeably.  Right now,
with many PCI devices you have N regions added to M AddressSpaces
(M = # PCI devices with bus-master enabled) and each call looks
up the whole listener list, with at least M listeners in it.
Because most of the regions in N are BARs, which are also roughly
proportional to M, the whole thing is O(M^3).  This changes it
to O(M^2), which is the best we can do without rewriting the
whole thing.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-09-22 16:23:06 +02:00
parent d45fa784cd
commit 9a54635dcb
2 changed files with 30 additions and 25 deletions

View file

@ -257,6 +257,7 @@ struct MemoryListener {
unsigned priority;
AddressSpace *address_space;
QTAILQ_ENTRY(MemoryListener) link;
QTAILQ_ENTRY(MemoryListener) link_as;
};
/**
@ -278,7 +279,7 @@ struct AddressSpace {
struct AddressSpaceDispatch *dispatch;
struct AddressSpaceDispatch *next_dispatch;
MemoryListener dispatch_listener;
QTAILQ_HEAD(memory_listeners_as, MemoryListener) listeners;
QTAILQ_ENTRY(AddressSpace) address_spaces_link;
};