Re: [Qemu-devel] [PATCH V2] add migration capability to bypass the shared memory

[Lai Jiangshan]

On Wed, Aug 10, 2016 at 10:22 AM, Li, Liang Z <address@hidden> wrote:
> Hi Jiangshan,
>
> Glad to see your patch. It's a simple implementation which could provide very 
> useful functions.
>
>> +static void migration_bitmap_init(unsigned long *bitmap) {
>> +    RAMBlock *block;
>> +
>> +    bitmap_clear(bitmap, 0, last_ram_offset() >> TARGET_PAGE_BITS);
>> +    rcu_read_lock();
>> +    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
>> +        if (!migrate_bypass_shared_memory()
>> || !qemu_ram_is_shared(block)) {
>> +            bitmap_set(bitmap, block->offset >> TARGET_PAGE_BITS,
>
> You should use (block->offset >> TARGET_PAGE_BITS )/ BITS_PER_LONG here.

Hello, Li

I might have missed something, could you tell me more?

void bitmap_set(unsigned long *map, long start, long nr);
I think the @start and @nr are both the number of the bits.

thanks,
Lai


>
>> +                       block->used_length >> TARGET_PAGE_BITS);
>> +
>> +            /*
>> +             * Count the total number of pages used by ram blocks not 
>> including
>> +             * any gaps due to alignment or unplugs.
>> +             */
>> +            migration_dirty_pages += block->used_length >>
>> TARGET_PAGE_BITS;
>> +        }
>> +    }
>> +    rcu_read_unlock();
>>  }
>
> Liang