Re: [PATCH v3 01/10] migration/dirtyrate: Add get_dirtyrate_thread() function

[Zheng Chuan]

On 2020/8/21 0:11, Dr. David Alan Gilbert wrote:
> * Chuan Zheng (zhengchuan@huawei.com) wrote:
>> Add get_dirtyrate_thread() functions
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
>> ---
>>  migration/Makefile.objs |  1 +
>>  migration/dirtyrate.c   | 64 
>> +++++++++++++++++++++++++++++++++++++++++++++++++
>>  migration/dirtyrate.h   | 44 ++++++++++++++++++++++++++++++++++
>>  3 files changed, 109 insertions(+)
>>  create mode 100644 migration/dirtyrate.c
>>  create mode 100644 migration/dirtyrate.h
>>
>> diff --git a/migration/Makefile.objs b/migration/Makefile.objs
>> index 0fc619e..12ae98c 100644
>> --- a/migration/Makefile.objs
>> +++ b/migration/Makefile.objs
>> @@ -6,6 +6,7 @@ common-obj-y += qemu-file.o global_state.o
>>  common-obj-y += qemu-file-channel.o
>>  common-obj-y += xbzrle.o postcopy-ram.o
>>  common-obj-y += qjson.o
>> +common-obj-y += dirtyrate.o
>>  common-obj-y += block-dirty-bitmap.o
>>  common-obj-y += multifd.o
>>  common-obj-y += multifd-zlib.o
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> new file mode 100644
>> index 0000000..bb0ebe9
>> --- /dev/null
>> +++ b/migration/dirtyrate.c
>> @@ -0,0 +1,64 @@
>> +/*
>> + * Dirtyrate implement code
>> + *
>> + * Copyright (c) 2017-2020 HUAWEI TECHNOLOGIES CO.,LTD.
>> + *
>> + * Authors:
>> + *  Chuan Zheng <zhengchuan@huawei.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
>> + * See the COPYING file in the top-level directory.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "qapi/error.h"
>> +#include "crypto/hash.h"
>> +#include "crypto/random.h"
>> +#include "qemu/config-file.h"
>> +#include "exec/memory.h"
>> +#include "exec/ramblock.h"
>> +#include "exec/target_page.h"
>> +#include "qemu/rcu_queue.h"
>> +#include "qapi/qapi-commands-migration.h"
>> +#include "migration.h"
>> +#include "dirtyrate.h"
>> +
>> +CalculatingDirtyRateState CalculatingState = CAL_DIRTY_RATE_INIT;
>> +
>> +static int dirty_rate_set_state(int new_state)
>> +{
>> +    int old_state = CalculatingState;
>> +
>> +    if (new_state == old_state) {
>> +        return -1;
>> +    }
>> +
>> +    if (atomic_cmpxchg(&CalculatingState, old_state, new_state) != 
>> old_state) {
>> +        return -1;
>> +    }
> 
> This is a little unusual; this has removed your comment from v1 about
> what you're trying to protect; but not quite being clear about what it's
> doing.
> 
> I think what you want here is closer to migrate_set_state, ie you
> pass what you think the old state is, and the state you want to go to.
> 
Hi, Dave.
Thank you for your review.

Yes, what I want to do is to protect concurrent scene lockless, i'll rewrite
according to migrate_set_state().


>> +    return 0;
>> +}
>> +
>> +static void calculate_dirtyrate(struct DirtyRateConfig config)
>> +{
>> +    /* todo */
>> +    return;
>> +}
>> +
>> +void *get_dirtyrate_thread(void *arg)
>> +{
>> +    struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
>> +    int ret;
>> +
>> +    ret = dirty_rate_set_state(CAL_DIRTY_RATE_ACTIVE);
> 
> so this would become:
>     ret = dirty_rate_set_state(CAL_DIRTY_RATE_INIT,
>               CAL_DIRTY_RATE_ACTIVE);
> 
>> +    if (ret == -1) {
>> +        return NULL;
>> +    }
>> +
>> +    calculate_dirtyrate(config);
>> +
>> +    ret = dirty_rate_set_state(CAL_DIRTY_RATE_END);
>> +
>> +    return NULL;
>> +}
>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
>> new file mode 100644
>> index 0000000..914c363
>> --- /dev/null
>> +++ b/migration/dirtyrate.h
>> @@ -0,0 +1,44 @@
>> +/*
>> + *  Dirtyrate common functions
>> + *
>> + *  Copyright (c) 2020 HUAWEI TECHNOLOGIES CO., LTD.
>> + *
>> + *  Authors:
>> + *  Chuan Zheng <zhengchuan@huawei.com>
>> + *
>> + *  This work is licensed under the terms of the GNU GPL, version 2 or 
>> later.
>> + *  See the COPYING file in the top-level directory.
>> + */
>> +
>> +#ifndef QEMU_MIGRATION_DIRTYRATE_H
>> +#define QEMU_MIGRATION_DIRTYRATE_H
>> +
>> +/*
>> + * Sample 256 pages per GB as default.
>> + * TODO: Make it configurable.
>> + */
>> +#define DIRTYRATE_DEFAULT_SAMPLE_PAGES            256
>> +
>> +/* Take 1s as default for calculation duration */
>> +#define DEFAULT_FETCH_DIRTYRATE_TIME_SEC          1
>> +
>> +struct DirtyRateConfig {
>> +    uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
>> +    int64_t sample_period_seconds; /* time duration between two sampling */
>> +};
>> +
>> +/*
>> + *  To record calculate dirty_rate status:
>> + *  0: initial status, calculating thread is not be created here.
>> + *  1: calculating thread is created.
>> + *  2: calculating thread is end, we can get result.
>> + */
>> +typedef enum {
>> +    CAL_DIRTY_RATE_INIT = 0,
>> +    CAL_DIRTY_RATE_ACTIVE,
>> +    CAL_DIRTY_RATE_END,
>> +} CalculatingDirtyRateState;
>> +
>> +void *get_dirtyrate_thread(void *arg);
>> +#endif
>> +
>> -- 
>> 1.8.3.1
>>