Anthony Liguori wrote:
On 03/16/2010 07:45 AM, Avi Kivity wrote:
On 03/16/2010 12:53 PM, Yoshiaki Tamura wrote:
Modifies wrapper functions for byte-based phys_ram_dirty bitmap to
bit-based phys_ram_dirty bitmap, and adds more wrapper functions to
prevent
direct access to the phys_ram_dirty bitmap.
+
+static inline int cpu_physical_memory_get_dirty_flags(ram_addr_t addr)
+{
+ unsigned long mask;
+ int index = (addr>> TARGET_PAGE_BITS) / HOST_LONG_BITS;
+ int offset = (addr>> TARGET_PAGE_BITS)& (HOST_LONG_BITS - 1);
+ int ret = 0;
+
+ mask = 1UL<< offset;
+ if (phys_ram_vga_dirty[index]& mask)
+ ret |= VGA_DIRTY_FLAG;
+ if (phys_ram_code_dirty[index]& mask)
+ ret |= CODE_DIRTY_FLAG;
+ if (phys_ram_migration_dirty[index]& mask)
+ ret |= MIGRATION_DIRTY_FLAG;
+
+ return ret;
}
static inline int cpu_physical_memory_get_dirty(ram_addr_t addr,
int dirty_flags)
{
- return phys_ram_dirty[addr>> TARGET_PAGE_BITS]& dirty_flags;
+ return cpu_physical_memory_get_dirty_flags(addr)& dirty_flags;
}
This turns one cacheline access into three. If the dirty bitmaps were
in an array, you could do
return dirty_bitmaps[dirty_index][addr >> (TARGET_PAGE_BITS +
BITS_IN_LONG)] & mask;
with one cacheline access.
As far as I can tell, we only ever call with a single flag so your
suggestion makes sense.
I'd suggest introducing these functions before splitting the bitmap up.
It makes review a bit easier.
Thanks for your advise.
I'll post the wrapper functions for existing byte-based phys_ram_dirty first.
Yoshi
