From 2173a75fb714193c4df9d5ddf9d015786566b19a Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Tue, 3 May 2011 12:36:58 -0600 Subject: [PATCH] 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 Signed-off-by: Michael S. Tsirkin --- exec.c | 39 +++++++++++++++++++++++++++++++++------ 1 file changed, 33 insertions(+), 6 deletions(-) diff --git a/exec.c b/exec.c index 308a86dcc..66c92bc7a 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); } } -- 2.39.5