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authorAlex Williamson <alex.williamson@redhat.com>2011-05-03 12:36:58 -0600
committerMichael S. Tsirkin <mst@redhat.com>2011-06-12 10:33:27 +0300
commit2173a75fb714193c4df9d5ddf9d015786566b19a (patch)
tree68190158266dade7b802484acd626ba67c799c57 /exec.c
parent69c8944f17cb6c084567a16c080cfa7bc780e668 (diff)
CPUPhysMemoryClient: batch addresses in catchup
When a phys memory client registers and we play catchup by walking the page tables, we can make a huge improvement in the number of times the set_memory callback is called by batching contiguous pages together. With a 4G guest, this reduces the number of callbacks at registration from 1048866 to 296. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'exec.c')
-rw-r--r--exec.c39
1 files changed, 33 insertions, 6 deletions
diff --git a/exec.c b/exec.c
index 308a86dcc0..66c92bc7a5 100644
--- a/exec.c
+++ b/exec.c
@@ -1750,14 +1750,21 @@ static int cpu_notify_migration_log(int enable)
return 0;
}
+struct last_map {
+ target_phys_addr_t start_addr;
+ ram_addr_t size;
+ ram_addr_t phys_offset;
+};
+
/* The l1_phys_map provides the upper P_L1_BITs of the guest physical
* address. Each intermediate table provides the next L2_BITs of guest
* physical address space. The number of levels vary based on host and
* guest configuration, making it efficient to build the final guest
* physical address by seeding the L1 offset and shifting and adding in
* each L2 offset as we recurse through them. */
-static void phys_page_for_each_1(CPUPhysMemoryClient *client,
- int level, void **lp, target_phys_addr_t addr)
+static void phys_page_for_each_1(CPUPhysMemoryClient *client, int level,
+ void **lp, target_phys_addr_t addr,
+ struct last_map *map)
{
int i;
@@ -1769,15 +1776,29 @@ static void phys_page_for_each_1(CPUPhysMemoryClient *client,
addr <<= L2_BITS + TARGET_PAGE_BITS;
for (i = 0; i < L2_SIZE; ++i) {
if (pd[i].phys_offset != IO_MEM_UNASSIGNED) {
- client->set_memory(client, addr | i << TARGET_PAGE_BITS,
- TARGET_PAGE_SIZE, pd[i].phys_offset, false);
+ target_phys_addr_t start_addr = addr | i << TARGET_PAGE_BITS;
+
+ if (map->size &&
+ start_addr == map->start_addr + map->size &&
+ pd[i].phys_offset == map->phys_offset + map->size) {
+
+ map->size += TARGET_PAGE_SIZE;
+ continue;
+ } else if (map->size) {
+ client->set_memory(client, map->start_addr,
+ map->size, map->phys_offset, false);
+ }
+
+ map->start_addr = start_addr;
+ map->size = TARGET_PAGE_SIZE;
+ map->phys_offset = pd[i].phys_offset;
}
}
} else {
void **pp = *lp;
for (i = 0; i < L2_SIZE; ++i) {
phys_page_for_each_1(client, level - 1, pp + i,
- (addr << L2_BITS) | i);
+ (addr << L2_BITS) | i, map);
}
}
}
@@ -1785,9 +1806,15 @@ static void phys_page_for_each_1(CPUPhysMemoryClient *client,
static void phys_page_for_each(CPUPhysMemoryClient *client)
{
int i;
+ struct last_map map = { };
+
for (i = 0; i < P_L1_SIZE; ++i) {
phys_page_for_each_1(client, P_L1_SHIFT / L2_BITS - 1,
- l1_phys_map + i, i);
+ l1_phys_map + i, i, &map);
+ }
+ if (map.size) {
+ client->set_memory(client, map.start_addr, map.size, map.phys_offset,
+ false);
}
}