Re: [Qemu-devel] [PATCH 3/5] Migration thread mutex

[Umesh Deshpande <udeshpan@redhat.com>]

On 08/29/2011 05:04 AM, Stefan Hajnoczi wrote:
> On Sat, Aug 27, 2011 at 7:09 PM, Umesh Deshpande<udeshpan@redhat.com>  wrote:
>> This patch implements migrate_ram mutex, which protects the RAMBlock list
>> traversal in the migration thread during the transfer of a ram from their
>> addition/removal from the iothread.
>>
>> Note: Combination of iothread mutex and migration thread mutex works as a
>> rw-lock. Both mutexes are acquired while modifying the ram_list members or RAM
>> block list.
>>
>> Signed-off-by: Umesh Deshpande<udeshpan@redhat.com>
>> ---
>>   arch_init.c   |   21 +++++++++++++++++++++
>>   cpu-all.h     |    3 +++
>>   exec.c        |   23 +++++++++++++++++++++++
>>   qemu-common.h |    2 ++
>>   4 files changed, 49 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch_init.c b/arch_init.c
>> index 484b39d..9d02270 100644
>> --- a/arch_init.c
>> +++ b/arch_init.c
>> @@ -109,6 +109,7 @@ static int is_dup_page(uint8_t *page, uint8_t ch)
>>
>>   static RAMBlock *last_block;
>>   static ram_addr_t last_offset;
>> +static uint64_t last_version;
> [...]
>>   typedef struct RAMList {
>> +    QemuMutex mutex;    /* Protects RAM block list */
>>      uint8_t *phys_dirty;
>> +    uint32_t version;   /* To detect ram block addition/removal */
> Is there a reason why RAMList.version is uint32_t but last_version is uint64_t?
No, my bad, they both should be consistent.