On 2020/8/31 17:13, David Edmondson wrote:
> On Saturday, 2020-08-29 at 10:52:55 +08, Chuan Zheng wrote:
>
>> Implement calculate_dirtyrate() function.
>>
>> Signed-off-by: Chuan Zheng <[email protected]>
>> Signed-off-by: YanYing Zhuang <[email protected]>
>> ---
>> migration/dirtyrate.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 43 insertions(+), 2 deletions(-)
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index 850126d..95ee23e 100644
>> --- a/migration/dirtyrate.c
>> +++ b/migration/dirtyrate.c
>> @@ -162,6 +162,21 @@ static void get_ramblock_dirty_info(RAMBlock *block,
>> strcpy(info->idstr, qemu_ram_get_idstr(block));
>> }
>>
>> +static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int
>> count)
>> +{
>> + int i;
>> +
>> + if (!infos) {
>> + return;
>> + }
>> +
>> + for (i = 0; i < count; i++) {
>> + g_free(infos[i].sample_page_vfn);
>> + g_free(infos[i].hash_result);
>> + }
>> + g_free(infos);
>> +}
>> +
>> static struct RamblockDirtyInfo *
>> alloc_ramblock_dirty_info(int *block_index,
>> struct RamblockDirtyInfo *block_dinfo)
>> @@ -301,8 +316,34 @@ static int compare_page_hash_info(struct
>> RamblockDirtyInfo *info,
>>
>> static void calculate_dirtyrate(struct DirtyRateConfig config)
>> {
>> - /* todo */
>> - return;
>> + struct RamblockDirtyInfo *block_dinfo = NULL;
>> + int block_index = 0;
>> + int64_t msec = 0;
>> + int64_t initial_time;
>> +
>> + rcu_register_thread();
>> + reset_dirtyrate_stat();
>> + rcu_read_lock();
>> + initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>> + if (record_ramblock_hash_info(&block_dinfo, config, &block_index) < 0) {
>> + goto out;
>> + }
>> + rcu_read_unlock();
>> +
>> + msec = config.sample_period_seconds * 1000;
>> + msec = set_sample_page_period(msec, initial_time);
>> +
>> + rcu_read_lock();
>> + if (compare_page_hash_info(block_dinfo, block_index) < 0) {
>> + goto out;
>> + }
>> +
>> + update_dirtyrate(msec);
>> +
>> +out:
>> + rcu_read_unlock();
>
> This still holds the RCU lock across update_dirtyrate(), which I
> understood to be unnecessary.
>It does need to update_dirtyrate if we goto out when erro happens.
In order to remove update_dirtyrate out of RCU, it need to add flag
like is_need_update, like:
if (record_ramblock_hash_info(&block_dinfo, config, &block_index) < 0) {
is_need_update = false;
goto out;
}
if (is_need_update)
update_dirtyrate(msec);
I doubt it is worth doing that or it will does any hurt if i holds
the RCU lock across update_dirtyrate()?
>> + free_ramblock_dirty_info(block_dinfo, block_index + 1);
>> + rcu_unregister_thread();
>> }
>>
>> void *get_dirtyrate_thread(void *arg)
>> --
>> 1.8.3.1
>
> dme.
>
