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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
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3
include/exec/memory.h
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;
};

52
memory.c
View File

@ -97,12 +97,6 @@ static AddrRange addrrange_intersection(AddrRange r1, AddrRange r2)
enum ListenerDirection { Forward, Reverse };
static bool memory_listener_match(MemoryListener *listener,
MemoryRegionSection *section)
{
return listener->address_space == section->address_space;
}
#define MEMORY_LISTENER_CALL_GLOBAL(_callback, _direction, _args...) \
do { \
MemoryListener *_listener; \
@ -128,24 +122,23 @@ static bool memory_listener_match(MemoryListener *listener,
} \
} while (0)
#define MEMORY_LISTENER_CALL(_callback, _direction, _section, _args...) \
#define MEMORY_LISTENER_CALL(_as, _callback, _direction, _section, _args...) \
do { \
MemoryListener *_listener; \
struct memory_listeners_as *list = &(_as)->listeners; \
\
switch (_direction) { \
case Forward: \
QTAILQ_FOREACH(_listener, &memory_listeners, link) { \
if (_listener->_callback \
&& memory_listener_match(_listener, _section)) { \
QTAILQ_FOREACH(_listener, list, link_as) { \
if (_listener->_callback) { \
_listener->_callback(_listener, _section, ##_args); \
} \
} \
break; \
case Reverse: \
QTAILQ_FOREACH_REVERSE(_listener, &memory_listeners, \
memory_listeners, link) { \
if (_listener->_callback \
&& memory_listener_match(_listener, _section)) { \
QTAILQ_FOREACH_REVERSE(_listener, list, memory_listeners_as, \
link_as) { \
if (_listener->_callback) { \
_listener->_callback(_listener, _section, ##_args); \
} \
} \
@ -159,7 +152,7 @@ static bool memory_listener_match(MemoryListener *listener,
#define MEMORY_LISTENER_UPDATE_REGION(fr, as, dir, callback, _args...) \
do { \
MemoryRegionSection mrs = section_from_flat_range(fr, as); \
MEMORY_LISTENER_CALL(callback, dir, &mrs, ##_args); \
MEMORY_LISTENER_CALL(as, callback, dir, &mrs, ##_args); \
} while(0)
struct CoalescedMemoryRange {
@ -748,7 +741,7 @@ static void address_space_add_del_ioeventfds(AddressSpace *as,
.offset_within_address_space = int128_get64(fd->addr.start),
.size = fd->addr.size,
};
MEMORY_LISTENER_CALL(eventfd_del, Forward, &section,
MEMORY_LISTENER_CALL(as, eventfd_del, Forward, &section,
fd->match_data, fd->data, fd->e);
++iold;
} else if (inew < fds_new_nb
@ -761,7 +754,7 @@ static void address_space_add_del_ioeventfds(AddressSpace *as,
.offset_within_address_space = int128_get64(fd->addr.start),
.size = fd->addr.size,
};
MEMORY_LISTENER_CALL(eventfd_add, Reverse, &section,
MEMORY_LISTENER_CALL(as, eventfd_add, Reverse, &section,
fd->match_data, fd->data, fd->e);
++inew;
} else {
@ -1773,7 +1766,7 @@ static void memory_region_update_coalesced_range_as(MemoryRegion *mr, AddressSpa
.size = fr->addr.size,
};
MEMORY_LISTENER_CALL(coalesced_mmio_del, Reverse, &section,
MEMORY_LISTENER_CALL(as, coalesced_mmio_del, Reverse, &section,
int128_get64(fr->addr.start),
int128_get64(fr->addr.size));
QTAILQ_FOREACH(cmr, &mr->coalesced, link) {
@ -1784,7 +1777,7 @@ static void memory_region_update_coalesced_range_as(MemoryRegion *mr, AddressSpa
continue;
}
tmp = addrrange_intersection(tmp, fr->addr);
MEMORY_LISTENER_CALL(coalesced_mmio_add, Forward, &section,
MEMORY_LISTENER_CALL(as, coalesced_mmio_add, Forward, &section,
int128_get64(tmp.start),
int128_get64(tmp.size));
}
@ -2265,12 +2258,26 @@ void memory_listener_register(MemoryListener *listener, AddressSpace *as)
QTAILQ_INSERT_BEFORE(other, listener, link);
}
if (QTAILQ_EMPTY(&as->listeners)
|| listener->priority >= QTAILQ_LAST(&as->listeners,
memory_listeners)->priority) {
QTAILQ_INSERT_TAIL(&as->listeners, listener, link_as);
} else {
QTAILQ_FOREACH(other, &as->listeners, link_as) {
if (listener->priority < other->priority) {
break;
}
}
QTAILQ_INSERT_BEFORE(other, listener, link_as);
}
listener_add_address_space(listener, as);
}
void memory_listener_unregister(MemoryListener *listener)
{
QTAILQ_REMOVE(&memory_listeners, listener, link);
QTAILQ_REMOVE(&listener->address_space->listeners, listener, link_as);
}
void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
@ -2284,6 +2291,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
flatview_init(as->current_map);
as->ioeventfd_nb = 0;
as->ioeventfds = NULL;
QTAILQ_INIT(&as->listeners);
QTAILQ_INSERT_TAIL(&address_spaces, as, address_spaces_link);
as->name = g_strdup(name ? name : "anonymous");
address_space_init_dispatch(as);
@ -2293,14 +2301,10 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
static void do_address_space_destroy(AddressSpace *as)
{
MemoryListener *listener;
bool do_free = as->malloced;
address_space_destroy_dispatch(as);
QTAILQ_FOREACH(listener, &memory_listeners, link) {
assert(listener->address_space != as);
}
assert(QTAILQ_EMPTY(&as->listeners));
flatview_unref(as->current_map);
g_free(as->name);