Re: [PATCH v2 2/6] Introduce bit-based phys_ram_dirty for VGA, CODE, MIGRATION and MASTER.

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On 04/06/2010 03:51 AM, Yoshiaki Tamura wrote:
Replaces byte-based phys_ram_dirty bitmap with three bit-based phys_ram_dirty
bitmap.  On allocation, it sets all bits in the bitmap.



index c74b0a4..9733892 100644
--- a/exec.c
+++ b/exec.c
@@ -110,7 +110,7 @@ uint8_t *code_gen_ptr;

  #if !defined(CONFIG_USER_ONLY)
  int phys_ram_fd;
-uint8_t *phys_ram_dirty;
+unsigned long *phys_ram_dirty[NUM_DIRTY_FLAGS];
  static int in_migration;

  typedef struct RAMBlock {
@@ -2825,10 +2825,32 @@ ram_addr_t qemu_ram_alloc(ram_addr_t size)
      new_block->next = ram_blocks;
      ram_blocks = new_block;

-    phys_ram_dirty = qemu_realloc(phys_ram_dirty,
-        (last_ram_offset + size)>>  TARGET_PAGE_BITS);
-    memset(phys_ram_dirty + (last_ram_offset>>  TARGET_PAGE_BITS),
-           0xff, size>>  TARGET_PAGE_BITS);
+/* temporarily copy from qemu-kvm.git/qemu-kvm.h */
+#define ALIGN(x, y)  (((x)+(y)-1)&  ~((y)-1))
+#define BITMAP_SIZE(m) (ALIGN(((m)>>TARGET_PAGE_BITS), HOST_LONG_BITS) / 8)

Please put in some header file, maybe qemu-common.h.

+
+    if (BITMAP_SIZE(last_ram_offset + size) != BITMAP_SIZE(last_ram_offset)) {
+        phys_ram_dirty[MASTER_DIRTY_FLAG] =
+            qemu_realloc(phys_ram_dirty[MASTER_DIRTY_FLAG],
+                         BITMAP_SIZE(last_ram_offset + size));
+        phys_ram_dirty[VGA_DIRTY_FLAG]
+            = qemu_realloc(phys_ram_dirty[VGA_DIRTY_FLAG],
+                           BITMAP_SIZE(last_ram_offset + size));
+        phys_ram_dirty[CODE_DIRTY_FLAG] =
+            qemu_realloc(phys_ram_dirty[CODE_DIRTY_FLAG],
+                         BITMAP_SIZE(last_ram_offset + size));
+        phys_ram_dirty[MIGRATION_DIRTY_FLAG] =
+            qemu_realloc(phys_ram_dirty[MIGRATION_DIRTY_FLAG],
+                         BITMAP_SIZE(last_ram_offset + size));
+        memset((uint8_t *)phys_ram_dirty[MASTER_DIRTY_FLAG] +
+               BITMAP_SIZE(last_ram_offset), 0xff, BITMAP_SIZE(size));
+        memset((uint8_t *)phys_ram_dirty[VGA_DIRTY_FLAG] +
+               BITMAP_SIZE(last_ram_offset), 0xff, BITMAP_SIZE(size));
+        memset((uint8_t *)phys_ram_dirty[CODE_DIRTY_FLAG] +
+               BITMAP_SIZE(last_ram_offset), 0xff, BITMAP_SIZE(size));
+        memset((uint8_t *)phys_ram_dirty[MIGRATION_DIRTY_FLAG] +
+               BITMAP_SIZE(last_ram_offset), 0xff, BITMAP_SIZE(size));
+    }


Should be nicer as a loop calling a helper to allocate each bitmap. This patch won't work by itself, will it? I think you need to merge it with the succeeding patches.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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