Re: [Qemu-devel] [PATCH] Revert "memory: syncronize kvm bitmap using bitmaps operations"

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 01/29/2014 06:30 PM, Paolo Bonzini wrote:
> Il 29/01/2014 06:50, Alexey Kardashevskiy ha scritto:
>> Since 64K system page size is quite popular configuration on PPC64,
>> the original patch breaks migration.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>>  include/exec/ram_addr.h | 54
>> +++++++++++++++++--------------------------------
>>  1 file changed, 18 insertions(+), 36 deletions(-)
>>
>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
>> index 33c8acc..c6736ed 100644
>> --- a/include/exec/ram_addr.h
>> +++ b/include/exec/ram_addr.h
>> @@ -83,47 +83,29 @@ static inline void
>> cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
>>                                                            ram_addr_t start,
>>                                                            ram_addr_t pages)
>>  {
>> -    unsigned long i, j;
>> +    unsigned int i, j;
>>      unsigned long page_number, c;
>>      hwaddr addr;
>>      ram_addr_t ram_addr;
>> -    unsigned long len = (pages + HOST_LONG_BITS - 1) / HOST_LONG_BITS;
>> +    unsigned int len = (pages + HOST_LONG_BITS - 1) / HOST_LONG_BITS;
>>      unsigned long hpratio = getpagesize() / TARGET_PAGE_SIZE;
>> -    unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
>>
>> -    /* start address is aligned at the start of a word? */
>> -    if (((page * BITS_PER_LONG) << TARGET_PAGE_BITS) == start) {
> 
> Why not just add " && hpratio == 1" here?


Or fix dirty map to make it 1 bit per system page size (may be the fix is
coming, who knows, but I am just not ready to do this now). Or do tricks
with bits and support hpratio!=1. I could not choose and decided to revert
it for now :)

Do we really earn a lot here?


-- 
Alexey