[Qemu-devel] [PATCH v6 4/4] Use cpu_physical_memory_get_dirty_range() to check multiple dirty pages.

[Yoshiaki Tamura]

Modifies ram_save_block() and ram_save_remaining() to use
cpu_physical_memory_get_dirty_range() to check multiple dirty and
non-dirty pages at once.

Signed-off-by: Yoshiaki Tamura <tamura.yoshi...@lab.ntt.co.jp>
Signed-off-by: OHMURA Kei <ohmura....@lab.ntt.co.jp>
---
 arch_init.c |   58 ++++++++++++++++++++++++++++++++++++----------------------
 1 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index eb5b67c..e0cf400 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -108,32 +108,39 @@ static int ram_save_block(QEMUFile *f)
     static ram_addr_t current_addr = 0;
     ram_addr_t saved_addr = current_addr;
     ram_addr_t addr = 0;
-    int bytes_sent = 0;
+    ram_addr_t dirty_rams[HOST_LONG_BITS];
+    int i, found, bytes_sent = 0;
 
     while (addr < ram_list.last_offset) {
-        if (cpu_physical_memory_get_dirty(current_addr, MIGRATION_DIRTY_FLAG)) 
{
+        if ((found = cpu_physical_memory_get_dirty_range(
+                 current_addr, ram_list.last_offset, dirty_rams, 
HOST_LONG_BITS,
+                 MIGRATION_DIRTY_FLAG))) {
             uint8_t *p;
 
-            cpu_physical_memory_reset_dirty(current_addr,
-                                            current_addr + TARGET_PAGE_SIZE,
-                                            MIGRATION_DIRTY_FLAG);
-
-            p = qemu_get_ram_ptr(current_addr);
-
-            if (is_dup_page(p, *p)) {
-                qemu_put_be64(f, current_addr | RAM_SAVE_FLAG_COMPRESS);
-                qemu_put_byte(f, *p);
-                bytes_sent = 1;
-            } else {
-                qemu_put_be64(f, current_addr | RAM_SAVE_FLAG_PAGE);
-                qemu_put_buffer(f, p, TARGET_PAGE_SIZE);
-                bytes_sent = TARGET_PAGE_SIZE;
+            for (i = 0; i < found; i++) {
+                ram_addr_t page_addr = dirty_rams[i];
+                cpu_physical_memory_reset_dirty(page_addr,
+                                                page_addr + TARGET_PAGE_SIZE,
+                                                MIGRATION_DIRTY_FLAG);
+
+                p = qemu_get_ram_ptr(page_addr);
+
+                if (is_dup_page(p, *p)) {
+                    qemu_put_be64(f, page_addr | RAM_SAVE_FLAG_COMPRESS);
+                    qemu_put_byte(f, *p);
+                    bytes_sent++;
+                } else {
+                    qemu_put_be64(f, page_addr | RAM_SAVE_FLAG_PAGE);
+                    qemu_put_buffer(f, p, TARGET_PAGE_SIZE);
+                    bytes_sent += TARGET_PAGE_SIZE;
+                }
             }
 
             break;
+        } else {
+            addr += dirty_rams[0];
+            current_addr = (saved_addr + addr) % ram_list.last_offset;
         }
-        addr += TARGET_PAGE_SIZE;
-        current_addr = (saved_addr + addr) % ram_list.last_offset;
     }
 
     return bytes_sent;
@@ -143,12 +150,19 @@ static uint64_t bytes_transferred;
 
 static ram_addr_t ram_save_remaining(void)
 {
-    ram_addr_t addr;
+    ram_addr_t addr = 0;
     ram_addr_t count = 0;
+    ram_addr_t dirty_rams[HOST_LONG_BITS];
+    int found = 0;
 
-    for (addr = 0; addr < ram_list.last_offset; addr += TARGET_PAGE_SIZE) {
-        if (cpu_physical_memory_get_dirty(addr, MIGRATION_DIRTY_FLAG)) {
-            count++;
+    while (addr < ram_list.last_offset) {
+        if ((found = cpu_physical_memory_get_dirty_range(
+                 addr, ram_list.last_offset, dirty_rams,
+                 HOST_LONG_BITS, MIGRATION_DIRTY_FLAG))) {
+            count += found;
+            addr = dirty_rams[found - 1] + TARGET_PAGE_SIZE;
+        } else {
+            addr += dirty_rams[0];
         }
     }
 
-- 
1.7.0.31.g1df487