exec: change ramlist from MRU order to a 1-item cache
Most of the time, only 2 items will be active (from/to for a string operation,
or code/data). But TCG guests likely won't have gigabytes of memory, so
this actually goes down to 1 item.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
diff --git a/exec.c b/exec.c
index 28abd7e..78bae1c 100644
--- a/exec.c
+++ b/exec.c
@@ -43,6 +43,7 @@
#include "sysemu/xen-mapcache.h"
#include "trace.h"
#endif
+#include "exec/cpu-all.h"
#include "exec/cputlb.h"
#include "translate-all.h"
@@ -1043,6 +1044,7 @@
new_block->length = size;
QLIST_INSERT_HEAD(&ram_list.blocks, new_block, next);
+ ram_list.mru_block = NULL;
ram_list.phys_dirty = g_realloc(ram_list.phys_dirty,
last_ram_offset() >> TARGET_PAGE_BITS);
@@ -1071,6 +1073,7 @@
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (addr == block->offset) {
QLIST_REMOVE(block, next);
+ ram_list.mru_block = NULL;
g_free(block);
return;
}
@@ -1084,6 +1087,7 @@
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (addr == block->offset) {
QLIST_REMOVE(block, next);
+ ram_list.mru_block = NULL;
if (block->flags & RAM_PREALLOC_MASK) {
;
} else if (mem_path) {
@@ -1189,37 +1193,40 @@
{
RAMBlock *block;
+ block = ram_list.mru_block;
+ if (block && addr - block->offset < block->length) {
+ goto found;
+ }
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (addr - block->offset < block->length) {
- /* Move this entry to to start of the list. */
- if (block != QLIST_FIRST(&ram_list.blocks)) {
- QLIST_REMOVE(block, next);
- QLIST_INSERT_HEAD(&ram_list.blocks, block, next);
- }
- if (xen_enabled()) {
- /* We need to check if the requested address is in the RAM
- * because we don't want to map the entire memory in QEMU.
- * In that case just map until the end of the page.
- */
- if (block->offset == 0) {
- return xen_map_cache(addr, 0, 0);
- } else if (block->host == NULL) {
- block->host =
- xen_map_cache(block->offset, block->length, 1);
- }
- }
- return block->host + (addr - block->offset);
+ goto found;
}
}
fprintf(stderr, "Bad ram offset %" PRIx64 "\n", (uint64_t)addr);
abort();
- return NULL;
+found:
+ ram_list.mru_block = block;
+ if (xen_enabled()) {
+ /* We need to check if the requested address is in the RAM
+ * because we don't want to map the entire memory in QEMU.
+ * In that case just map until the end of the page.
+ */
+ if (block->offset == 0) {
+ return xen_map_cache(addr, 0, 0);
+ } else if (block->host == NULL) {
+ block->host =
+ xen_map_cache(block->offset, block->length, 1);
+ }
+ }
+ return block->host + (addr - block->offset);
}
-/* Return a host pointer to ram allocated with qemu_ram_alloc.
- * Same as qemu_get_ram_ptr but avoid reordering ramblocks.
+/* Return a host pointer to ram allocated with qemu_ram_alloc. Same as
+ * qemu_get_ram_ptr but do not touch ram_list.mru_block.
+ *
+ * ??? Is this still necessary?
*/
static void *qemu_safe_ram_ptr(ram_addr_t addr)
{
