Re: [PATCH v1] Improve the performance of --num-threads -d 31

["\"Zhou, Wenjian/周文剑\"" <zhouwj-fnst@cn.fujitsu.com>]

On 02/23/2016 10:16 AM, Minoru Usui wrote:
> Hello Zhou
>
> I'm sorry for late reply, too.
>
>> -----Original Message-----
>> From: "Zhou, Wenjian/周文剑" [mailto:zhouwj-fnst@cn.fujitsu.com]
>> Sent: Monday, February 15, 2016 11:15 AM
>> To: Usui Minoru(碓井 成) <min-usui@ti.jp.nec.com>; kexec@lists.infradead.org
>> Subject: Re: [PATCH v1] Improve the performance of --num-threads -d 31
>>
>> Hello Usui,
>>
>> Thanks very much for your comments.
>> And sorry for the late reply.
>>
>> See below.
>>
>> On 02/08/2016 01:00 PM, Minoru Usui wrote:
>>> Hello,
>>>
>>>> -----Original Message-----
>>>> From: kexec [mailto:kexec-bounces@lists.infradead.org] On Behalf Of Minoru Usui
>>>> Sent: Thursday, February 04, 2016 8:52 AM
>>>> To: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>; kexec@lists.infradead.org
>>>> Subject: Re: [PATCH v1] Improve the performance of --num-threads -d 31
>>>>
>>>> Hi, Zhou
>>>>
>>>> I have some comments.
>>>> I'm sorry if I have misunderstood your code.
>>>>
>>>>> -----Original Message-----
>>>>> From: kexec [mailto:kexec-bounces@lists.infradead.org] On Behalf Of Zhou Wenjian
>>>>> Sent: Monday, February 01, 2016 3:22 PM
>>>>> To: kexec@lists.infradead.org
>>>>> Subject: [PATCH v1] Improve the performance of --num-threads -d 31
>>>>>
>>>>> v1:
>>>>>           1. change page_flag.ready's value to enum
>>>>>           2. change the patch description
>>>>>           3. cleanup some codes
>>>>> 	4. fix a bug in cyclic mode
>>>>>
>>>>> multi-threads implementation will introduce extra cost when handling
>>>>> each page. The origin implementation will also do the extra work for
>>>>> filtered pages. So there is a big performance degradation in
>>>>> --num-threads -d 31.
>>>>> The new implementation won't do the extra work for filtered pages any
>>>>> more. So the performance of -d 31 is close to that of serial processing.
>>>>>
>>>>> The new implementation is just like the following:
>>>>>           * The basic idea is producer producing page and consumer writing page.
>>>>>           * Each producer have a page_flag_buf list which is used for storing
>>>>>             page's description.
>>>>>           * The size of page_flag_buf is little so it won't take too much memory.
>>>>>           * And all producers will share a page_data_buf array which is
>>>>>             used for storing page's compressed data.
>>>>>           * The main thread is the consumer. It will find the next pfn and write
>>>>>             it into file.
>>>>>           * The next pfn is smallest pfn in all page_flag_buf.
>>>>>
>>>>> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
>>>>> ---
>>>>>    makedumpfile.c | 258 ++++++++++++++++++++++++++++++++++++++-------------------
>>>>>    makedumpfile.h |  31 ++++---
>>>>>    2 files changed, 193 insertions(+), 96 deletions(-)
>>>>>
>>>>> diff --git a/makedumpfile.c b/makedumpfile.c
>>>>> index fa0b779..0ecd065 100644
>>>>> --- a/makedumpfile.c
>>>>> +++ b/makedumpfile.c
>>>>> @@ -3483,7 +3483,8 @@ initial_for_parallel()
>>>>>    	unsigned long page_data_buf_size;
>>>>>    	unsigned long limit_size;
>>>>>    	int page_data_num;
>>>>> -	int i;
>>>>> +	struct page_flag *current;
>>>>> +	int i, j;
>>>>>
>>>>>    	len_buf_out = calculate_len_buf_out(info->page_size);
>>>>>
>>>>> @@ -3562,8 +3563,10 @@ initial_for_parallel()
>>>>>    		      - MAP_REGION * info->num_threads) * 0.6;
>>>>>
>>>>>    	page_data_num = limit_size / page_data_buf_size;
>>>>> +	info->num_buffers = 3 * info->num_threads;
>>>>>
>>>>> -	info->num_buffers = MIN(NUM_BUFFERS, page_data_num);
>>>>> +	info->num_buffers = MAX(info->num_buffers, NUM_BUFFERS);
>>>>> +	info->num_buffers = MIN(info->num_buffers, page_data_num);
>>>>>
>>>>>    	DEBUG_MSG("Number of struct page_data for produce/consume: %d\n",
>>>>>    			info->num_buffers);
>>>>> @@ -3588,6 +3591,36 @@ initial_for_parallel()
>>>>>    	}
>>>>>
>>>>>    	/*
>>>>> +	 * initial page_flag for each thread
>>>>> +	 */
>>>>> +	if ((info->page_flag_buf = malloc(sizeof(void *) * info->num_threads))
>>>>> +	    == NULL) {
>>>>> +		MSG("Can't allocate memory for page_flag_buf. %s\n",
>>>>> +				strerror(errno));
>>>>> +		return FALSE;
>>>>> +	}
>>>>> +	memset(info->page_flag_buf, 0, sizeof(void *) * info->num_threads);
>>>>> +
>>>>> +	for (i = 0; i < info->num_threads; i++) {
>>>>> +		if ((info->page_flag_buf[i] = malloc(sizeof(struct page_flag))) == NULL) {
>>>>
>>>> Fist element of struct page_flag in circular list is allocated by malloc(),
>>>> but other elements are allocated by calloc().(see below)
>>>> I think both elements should be allocated by calloc().
>>>>
>>
>> Yes, you are right.
>> I have made a mistake.
>>
>>>>> +			MSG("Can't allocate memory for page_flag_buf. %s\n",
>>>>> +				strerror(errno));
>>>>> +			return FALSE;
>>>>> +		}
>>>>> +		current = info->page_flag_buf[i];
>>>>> +
>>>>> +		for (j = 1; j < NUM_BUFFERS; j++) {
>>>>> +			if ((current->next = calloc(0, sizeof(struct page_flag))) == NULL) {
>>>>> +				MSG("Can't allocate memory for data of page_data_buf. %s\n",
>>>>> +					strerror(errno));
>>>>> +				return FALSE;
>>>>> +			}
>>>>
>>>>
>>>> First argument of calloc() should be 1, not 0.
>>>> And there is typo in error message.
>>>> Allocated element is not page_data_buf.
>>>>
>>
>> I agree.
>>
>>>>> +			current = current->next;
>>>>> +		}
>>>>> +		current->next = info->page_flag_buf[i];
>>>>> +	}
>>>>> +
>>>>> +	/*
>>>>>    	 * initial fd_memory for threads
>>>>>    	 */
>>>>>    	for (i = 0; i < info->num_threads; i++) {
>>>>> @@ -3612,7 +3645,8 @@ initial_for_parallel()
>>>>>    void
>>>>>    free_for_parallel()
>>>>>    {
>>>>> -	int i;
>>>>> +	int i, j;
>>>>> +	struct page_flag *current;
>>>>>
>>>>>    	if (info->threads != NULL) {
>>>>>    		for (i = 0; i < info->num_threads; i++) {
>>>>> @@ -3655,6 +3689,19 @@ free_for_parallel()
>>>>>    		free(info->page_data_buf);
>>>>>    	}
>>>>>
>>>>> +	if (info->page_flag_buf != NULL) {
>>>>> +		for (i = 0; i < info->num_threads; i++) {
>>>>> +			for (j = 0; j < NUM_BUFFERS; j++) {
>>>>> +				if (info->page_flag_buf[i] != NULL) {
>>>>> +					current = info->page_flag_buf[i];
>>>>> +					info->page_flag_buf[i] = current->next;
>>>>> +					free(current);
>>>>> +				}
>>>>> +			}
>>>>> +		}
>>>>> +		free(info->page_flag_buf);
>>>>> +	}
>>>>> +
>>>>>    	if (info->parallel_info == NULL)
>>>>>    		return;
>>>>>
>>>>> @@ -7076,10 +7123,10 @@ kdump_thread_function_cyclic(void *arg) {
>>>>>    	void *retval = PTHREAD_FAIL;
>>>>>    	struct thread_args *kdump_thread_args = (struct thread_args *)arg;
>>>>>    	struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
>>>>> +	struct page_flag *page_flag_buf = kdump_thread_args->page_flag_buf;
>>>>>    	struct cycle *cycle = kdump_thread_args->cycle;
>>>>> -	int page_data_num = kdump_thread_args->page_data_num;
>>>>>    	mdf_pfn_t pfn;
>>>>> -	int index;
>>>>> +	int index = kdump_thread_args->thread_num;
>>>>>    	int buf_ready;
>>>>>    	int dumpable;
>>>>>    	int fd_memory = 0;
>>>>> @@ -7125,47 +7172,47 @@ kdump_thread_function_cyclic(void *arg) {
>>>>>    						kdump_thread_args->thread_num);
>>>>>    	}
>>>>>
>>>>> -	while (1) {
>>>>> -		/* get next pfn */
>>>>> -		pthread_mutex_lock(&info->current_pfn_mutex);
>>>>> -		pfn = info->current_pfn;
>>>>> -		info->current_pfn++;
>>>>> -		pthread_mutex_unlock(&info->current_pfn_mutex);
>>>>> +	/*
>>>>> +	 * filtered page won't take anything
>>>>> +	 * unfiltered zero page will only take a page_flag_buf
>>>>> +	 * unfiltered non-zero page will take a page_flag_buf and a page_data_buf
>>>>> +	 */
>>>>> +	while (page_flag_buf->pfn < kdump_thread_args->end_pfn) {
>>>>
>>>> At first, page_flag_buf->pfn is not initialized.
>>>> I think this block should be replaced with the following code.
>>>>
>>>> ===
>>>>     do {
>>>>       :
>>>>     } while(page_flag_buf->pfn < kdump_thread_args->end_pfn)
>>>> ===
>>>
>>> I'm sorry, above suggestion is meaningless in terms of page_flag_buf->pfn is uninitialized.
>>> It should be replaced like following.
>>>
>>> ===
>>>     while (1) {
>>>       :
>>>       while (buf_ready == FALSE) {
>>>          :
>>>         if (pfn >= kdump_thread_args->end_pfn) {
>>>            :
>>>           goto finish;
>>>         }
>>>         :
>>>       }
>>>       :
>>>     }
>>> finish:
>>> ===
>>>
>>
>> page_flag_buf is allocated by calloc().
>> The page_flag_buf->pfn's value is 0.
>> So I think it is not necessary to modify the code.
>>
>>> Thanks,
>>> Minoru Usui
>>>
>>>
>>>>> +		buf_ready = FALSE;
>>>>>
>>>>> -		if (pfn >= kdump_thread_args->end_pfn)
>>>>> -			break;
>>>>> +		while (page_data_buf[index].used != 0 ||
>>>>> +				pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
>>>>> +			index = (index + 1) % info->num_buffers;
>>>>>
>>>>> -		index = -1;
>>>>> -		buf_ready = FALSE;
>>>>> +		page_data_buf[index].used = 1;
>>>>
>>>> "1" is a magic number.
>>>> It should be changed TRUE or FALSE.
>>>>
>>
>> I see.
>>
>>>>>    		while (buf_ready == FALSE) {
>>>>>    			pthread_testcancel();
>>>>> -
>>>>> -			index = pfn % page_data_num;
>>>>> -
>>>>> -			if (pfn - info->consumed_pfn > info->num_buffers)
>>>>> +			if (page_flag_buf->ready == FLAG_READY)
>>>>>    				continue;
>>>>
>>>> At first, page_flag_buf->ready is uninitialized, too.
>>>> Should it be initialized in head part of this function, even if FLAG_UNUSED is defined 0?
>>>>
>>>>
>>
>> The same topic as the page_flag_buf is allocated by calloc().
>>
>>>>>
>>>>> -			if (page_data_buf[index].ready != 0)
>>>>> -				continue;
>>>>> -
>>>>> -			pthread_mutex_lock(&page_data_buf[index].mutex);
>>>>> +			/* get next pfn */
>>>>> +			pthread_mutex_lock(&info->current_pfn_mutex);
>>>>> +			pfn = info->current_pfn;
>>>>> +			info->current_pfn++;
>>>>> +			page_flag_buf->ready = FLAG_FILLING;
>>>>> +			pthread_mutex_unlock(&info->current_pfn_mutex);
>>>>>
>>>>> -			if (page_data_buf[index].ready != 0)
>>>>> -				goto unlock;
>>>>> +			page_flag_buf->pfn = pfn;
>>>>
>>>> It set FLAG_FILLING to page_flag_buf->ready before setting pfn to page_flag_buf->pfn.
>>>> But consumer gets page_flag_buf->pfn after checking page_flag_buf->ready != FLAG_UNUSED
>>>> in getting minimum pfn of each thread block.
>>>> Should it set page_flag_buf->pfn first?
>>>>
>>
>> Have you noticed the following code in the consumer?
>> <cut>
>>                           if (current_pfn == info->page_flag_buf[consuming]->pfn)
>>                                   break;
>> <cut>
>
> No, I pointed following code.
> This part accesses info->page_flag_buf[i]->ready, then it accesses info->page_flag_buf[i]->pfn immediately.
> So, temp_pfn may be wrong pfn at this moment.
>
> ---
>                          for (i = 0; i < info->num_threads; i++) {
>                                  if (info->page_flag_buf[i]->ready == FLAG_UNUSED)
>                                          continue;
>                                  temp_pfn = info->page_flag_buf[i]->pfn;
> ---
>
>> The consumer will check if the pfn is changed after the page_flag_buf->ready turns to be FLAG_READY.
>> So it's not important whether setting page_flag_buf->pfn first or not.
>
> As you said, consumer checks pfn which is changed.
> So it works well.
>
>> In the other hand, even setting page_flag_buf->pfn first, if the pfn is not dumpable, the producer
>> will also reset the page_flag_buf->pfn.
>
> Thank you for your explanation.
> I didn't notice that pfn can be undumpable.
>
>>>>>
>>>>> -			buf_ready = TRUE;
>>>>> -
>>>>> -			page_data_buf[index].pfn = pfn;
>>>>> -			page_data_buf[index].ready = 1;
>>>>> +			if (pfn >= kdump_thread_args->end_pfn) {
>>>>> +				page_data_buf[index].used = 0;
>>>>> +				page_flag_buf->ready = FLAG_READY;
>>>>> +				info->current_pfn--;
>>>>> +				break;
>>>>> +			}
>>>>
>>>> This block decrements info->current_pfn without info->current_pfn_mutex.
>>>> I think this block should be moved into previous pthread_mutex_lock(info->current_pfn_mutex) block, so it can remove.
>>>>
>>
>> Why do you think it should have current_pfn_mutex?
>>
>> If pfn >= kdump_thread_args->end_pfn, info->current_pfn will always larger than
>> kdump_thread_args->end_pfn. info->current_pfn-- won't affect anything.
>>
>> The decrement operation is for cyclic mode.
>>
>>>>>
>>>>>    			dumpable = is_dumpable(
>>>>>    				info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
>>>>>    				pfn,
>>>>>    				cycle);
>>>>> -			page_data_buf[index].dumpable = dumpable;
>>>>>    			if (!dumpable)
>>>>> -				goto unlock;
>>>>> +				continue;
>>>>>
>>>>>    			if (!read_pfn_parallel(fd_memory, pfn, buf,
>>>>>    					       &bitmap_memory_parallel,
>>>>> @@ -7178,11 +7225,11 @@ kdump_thread_function_cyclic(void *arg) {
>>>>>
>>>>>    			if ((info->dump_level & DL_EXCLUDE_ZERO)
>>>>>    			    && is_zero_page(buf, info->page_size)) {
>>>>> -				page_data_buf[index].zero = TRUE;
>>>>> -				goto unlock;
>>>>> +				page_flag_buf->zero = TRUE;
>>>>> +				goto next;
>>>>>    			}
>>>>
>>>> First, this code gets page_data_buf, then it gets page_flag_buf.
>>>> However, if processed pfn is zero page,
>>>> it processes next pfn while keeping page_data_buf.
>>>>
>>>> I think it should get page_flag_buf, then get page_data_buf
>>>> in order to shorten the holding period of the page_data_buf[index].mutex.
>>>>
>>
>> Do you mean the following logic?
>> 1. get the page_flag_buf first
>> 2. if the pfn is not zero page, then get the page_data_buf.
>
> Yes.
>
>> Think about the following case.
>> A producer get the page_flag_buf, and the pfn is not zero page.
>> It wants to get a page_data_buf, but there is no more page_data_buf.
>> Then ...
>
> It's not a problem.
> In not zero page case, this logic needs both page_flag_buf and page_data_buf,
> so waiting buffer is obvious when it isn't able to get page_flag_buf or page_data_buf.
>

Of course, waiting is not a problem.
But if other page_data_bufs are all used by later pfns, it will
wait forever. That's the problem.

-- 
Thanks
Zhou

>> Since there are several page_data_bufs, it's not a problem that each producer
>> will always hold a page_data_buf.
>
> It depends on the speed of consumer and producer.
> It's not possible to predict it.
>
> In zero page case, I think each producer executes more parallel theoretically
> if page_data_buf doesn't get.
>
> Thanks,
> Minoru Usui
>
>>
>> Thanks again for your comments.
>> And I will post the next version later.
>>
>> --
>> Thanks
>> Zhou
>>
>>>> Thanks,
>>>> Minoru Usui
>>>>
>>>>>
>>>>> -			page_data_buf[index].zero = FALSE;
>>>>> +			page_flag_buf->zero = FALSE;
>>>>>
>>>>>    			/*
>>>>>    			 * Compress the page data.
>>>>> @@ -7232,12 +7279,16 @@ kdump_thread_function_cyclic(void *arg) {
>>>>>    				page_data_buf[index].size  = info->page_size;
>>>>>    				memcpy(page_data_buf[index].buf, buf, info->page_size);
>>>>>    			}
>>>>> -unlock:
>>>>> -			pthread_mutex_unlock(&page_data_buf[index].mutex);
>>>>> +			page_flag_buf->index = index;
>>>>> +			buf_ready = TRUE;
>>>>> +next:
>>>>> +			page_flag_buf->ready = FLAG_READY;
>>>>> +			page_flag_buf = page_flag_buf->next;
>>>>>
>>>>>    		}
>>>>> -	}
>>>>>
>>>>> +		pthread_mutex_unlock(&page_data_buf[index].mutex);
>>>>> +	}
>>>>>    	retval = NULL;
>>>>>
>>>>>    fail:
>>>>> @@ -7265,14 +7316,15 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
>>>>>    	struct page_desc pd;
>>>>>    	struct timeval tv_start;
>>>>>    	struct timeval last, new;
>>>>> -	unsigned long long consuming_pfn;
>>>>>    	pthread_t **threads = NULL;
>>>>>    	struct thread_args *kdump_thread_args = NULL;
>>>>>    	void *thread_result;
>>>>> -	int page_data_num;
>>>>> +	int page_buf_num;
>>>>>    	struct page_data *page_data_buf = NULL;
>>>>>    	int i;
>>>>>    	int index;
>>>>> +	int end_count, consuming, check_count;
>>>>> +	mdf_pfn_t current_pfn, temp_pfn;
>>>>>
>>>>>    	if (info->flag_elf_dumpfile)
>>>>>    		return FALSE;
>>>>> @@ -7319,16 +7371,11 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
>>>>>    	threads = info->threads;
>>>>>    	kdump_thread_args = info->kdump_thread_args;
>>>>>
>>>>> -	page_data_num = info->num_buffers;
>>>>> +	page_buf_num = info->num_buffers;
>>>>>    	page_data_buf = info->page_data_buf;
>>>>>
>>>>> -	for (i = 0; i < page_data_num; i++) {
>>>>> -		/*
>>>>> -		 * producer will use pfn in page_data_buf to decide the
>>>>> -		 * consumed pfn
>>>>> -		 */
>>>>> -		page_data_buf[i].pfn = start_pfn - 1;
>>>>> -		page_data_buf[i].ready = 0;
>>>>> +	for (i = 0; i < page_buf_num; i++) {
>>>>> +		page_data_buf[i].used = 0;
>>>>>    		res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
>>>>>    		if (res != 0) {
>>>>>    			ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
>>>>> @@ -7342,8 +7389,9 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
>>>>>    		kdump_thread_args[i].len_buf_out = len_buf_out;
>>>>>    		kdump_thread_args[i].start_pfn = start_pfn;
>>>>>    		kdump_thread_args[i].end_pfn = end_pfn;
>>>>> -		kdump_thread_args[i].page_data_num = page_data_num;
>>>>> +		kdump_thread_args[i].page_buf_num = page_buf_num;
>>>>>    		kdump_thread_args[i].page_data_buf = page_data_buf;
>>>>> +		kdump_thread_args[i].page_flag_buf = info->page_flag_buf[i];
>>>>>    		kdump_thread_args[i].cycle = cycle;
>>>>>
>>>>>    		res = pthread_create(threads[i], NULL,
>>>>> @@ -7356,55 +7404,94 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
>>>>>    		}
>>>>>    	}
>>>>>
>>>>> -	consuming_pfn = start_pfn;
>>>>> -	index = -1;
>>>>> +	while (1) {
>>>>> +		consuming = 0;
>>>>> +		check_count = 0;
>>>>> +		end_count = 0;
>>>>>
>>>>> -	gettimeofday(&last, NULL);
>>>>> +		/*
>>>>> +		 * The basic idea is producer producing page and consumer writing page.
>>>>> +		 * Each producer have a page_flag_buf list which is used for storing page's description.
>>>>> +		 * The size of page_flag_buf is little so it won't take too much memory.
>>>>> +		 * And all producers will share a page_data_buf array which is used for storing page's compressed data.
>>>>> +		 * The main thread is the consumer. It will find the next pfn and write it into file.
>>>>> +		 * The next pfn is smallest pfn in all page_flag_buf.
>>>>> +		 */
>>>>> +		while (1) {
>>>>> +			current_pfn = end_pfn;
>>>>>
>>>>> -	while (consuming_pfn < end_pfn) {
>>>>> -		index = consuming_pfn % page_data_num;
>>>>> +			/*
>>>>> +			 * page_flag_buf is in circular linked list.
>>>>> +			 * The array info->page_flag_buf[] records the current page_flag_buf in each thread's
>>>>> +			 * page_flag_buf list.
>>>>> +			 * consuming is used for recording in which thread the pfn is the smallest.
>>>>> +			 * current_pfn is used for recording the value of pfn when checking the pfn.
>>>>> +			 */
>>>>> +			for (i = 0; i < info->num_threads; i++) {
>>>>> +				if (info->page_flag_buf[i]->ready == FLAG_UNUSED)
>>>>> +					continue;
>>>>> +				temp_pfn = info->page_flag_buf[i]->pfn;
>>>>>
>>>>> -		gettimeofday(&new, NULL);
>>>>> -		if (new.tv_sec - last.tv_sec > WAIT_TIME) {
>>>>> -			ERRMSG("Can't get data of pfn %llx.\n", consuming_pfn);
>>>>> -			goto out;
>>>>> -		}
>>>>> +				/*
>>>>> +				 * count how many threads have reached the end.
>>>>> +				 */
>>>>> +				if (temp_pfn >= end_pfn) {
>>>>> +					end_count++;
>>>>> +					info->page_flag_buf[i]->ready = FLAG_UNUSED;
>>>>> +					continue;
>>>>> +				}
>>>>>
>>>>> -		/*
>>>>> -		 * check pfn first without mutex locked to reduce the time
>>>>> -		 * trying to lock the mutex
>>>>> -		 */
>>>>> -		if (page_data_buf[index].pfn != consuming_pfn)
>>>>> -			continue;
>>>>> +				if (current_pfn < temp_pfn)
>>>>> +					continue;
>>>>>
>>>>> -		if (pthread_mutex_trylock(&page_data_buf[index].mutex) != 0)
>>>>> -			continue;
>>>>> +				check_count++;
>>>>> +				consuming = i;
>>>>> +				current_pfn = temp_pfn;
>>>>> +			}
>>>>> +
>>>>> +			/*
>>>>> +			 * If all the threads have reached the end, we will finish writing.
>>>>> +			 */
>>>>> +			if (end_count >= info->num_threads)
>>>>> +				goto finish;
>>>>> +
>>>>> +			/*
>>>>> +			 * Since it has the probabilty that there is no page_flag_buf being ready,
>>>>> +			 * we should recheck if it happens.
>>>>> +			 */
>>>>> +			if (check_count == 0)
>>>>> +				continue;
>>>>> +
>>>>> +			/*
>>>>> +			 * When we check the pfn in page_flag_buf, it may be being produced.
>>>>> +			 * So we should wait until it is ready to use. And if the pfn is
>>>>> +			 * different from the value when we check, we should rechoose the buf.
>>>>> +			 */
>>>>> +			gettimeofday(&last, NULL);
>>>>> +			while (info->page_flag_buf[consuming]->ready != FLAG_READY) {
>>>>> +				gettimeofday(&new, NULL);
>>>>> +				if (new.tv_sec - last.tv_sec > WAIT_TIME) {
>>>>> +					ERRMSG("Can't get data of pfn.\n");
>>>>> +					goto out;
>>>>> +				}
>>>>> +			}
>>>>>
>>>>> -		/* check whether the found one is ready to be consumed */
>>>>> -		if (page_data_buf[index].pfn != consuming_pfn ||
>>>>> -		    page_data_buf[index].ready != 1) {
>>>>> -			goto unlock;
>>>>> +			if (current_pfn == info->page_flag_buf[consuming]->pfn)
>>>>> +				break;
>>>>>    		}
>>>>>
>>>>>    		if ((num_dumped % per) == 0)
>>>>>    			print_progress(PROGRESS_COPY, num_dumped, info->num_dumpable);
>>>>>
>>>>> -		/* next pfn is found, refresh last here */
>>>>> -		last = new;
>>>>> -		consuming_pfn++;
>>>>> -		info->consumed_pfn++;
>>>>> -		page_data_buf[index].ready = 0;
>>>>> -
>>>>> -		if (page_data_buf[index].dumpable == FALSE)
>>>>> -			goto unlock;
>>>>> -
>>>>>    		num_dumped++;
>>>>>
>>>>> -		if (page_data_buf[index].zero == TRUE) {
>>>>> +
>>>>> +		if (info->page_flag_buf[consuming]->zero == TRUE) {
>>>>>    			if (!write_cache(cd_header, pd_zero, sizeof(page_desc_t)))
>>>>>    				goto out;
>>>>>    			pfn_zero++;
>>>>>    		} else {
>>>>> +			index = info->page_flag_buf[consuming]->index;
>>>>>    			pd.flags      = page_data_buf[index].flags;
>>>>>    			pd.size       = page_data_buf[index].size;
>>>>>    			pd.page_flags = 0;
>>>>> @@ -7420,12 +7507,12 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
>>>>>    			 */
>>>>>    			if (!write_cache(cd_page, page_data_buf[index].buf, pd.size))
>>>>>    				goto out;
>>>>> -
>>>>> +			page_data_buf[index].used = 0;
>>>>>    		}
>>>>> -unlock:
>>>>> -		pthread_mutex_unlock(&page_data_buf[index].mutex);
>>>>> +		info->page_flag_buf[consuming]->ready = FLAG_UNUSED;
>>>>> +		info->page_flag_buf[consuming] = info->page_flag_buf[consuming]->next;
>>>>>    	}
>>>>> -
>>>>> +finish:
>>>>>    	ret = TRUE;
>>>>>    	/*
>>>>>    	 * print [100 %]
>>>>> @@ -7464,7 +7551,7 @@ out:
>>>>>    	}
>>>>>
>>>>>    	if (page_data_buf != NULL) {
>>>>> -		for (i = 0; i < page_data_num; i++) {
>>>>> +		for (i = 0; i < page_buf_num; i++) {
>>>>>    			pthread_mutex_destroy(&page_data_buf[i].mutex);
>>>>>    		}
>>>>>    	}
>>>>> @@ -7564,6 +7651,7 @@ write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_pag
>>>>>    		num_dumped++;
>>>>>    		if (!read_pfn(pfn, buf))
>>>>>    			goto out;
>>>>> +
>>>>>    		filter_data_buffer(buf, pfn_to_paddr(pfn), info->page_size);
>>>>>
>>>>>    		/*
>>>>> diff --git a/makedumpfile.h b/makedumpfile.h
>>>>> index e0b5bbf..8a9a5b2 100644
>>>>> --- a/makedumpfile.h
>>>>> +++ b/makedumpfile.h
>>>>> @@ -977,7 +977,7 @@ typedef unsigned long long int ulonglong;
>>>>>    #define PAGE_DATA_NUM	(50)
>>>>>    #define WAIT_TIME	(60 * 10)
>>>>>    #define PTHREAD_FAIL	((void *)-2)
>>>>> -#define NUM_BUFFERS	(50)
>>>>> +#define NUM_BUFFERS	(20)
>>>>>
>>>>>    struct mmap_cache {
>>>>>    	char	*mmap_buf;
>>>>> @@ -985,28 +985,36 @@ struct mmap_cache {
>>>>>    	off_t   mmap_end_offset;
>>>>>    };
>>>>>
>>>>> +enum {
>>>>> +	FLAG_UNUSED,
>>>>> +	FLAG_READY,
>>>>> +	FLAG_FILLING
>>>>> +};
>>>>> +struct page_flag {
>>>>> +	mdf_pfn_t pfn;
>>>>> +	char zero;
>>>>> +	char ready;
>>>>> +	short index;
>>>>> +	struct page_flag *next;
>>>>> +};
>>>>> +
>>>>>    struct page_data
>>>>>    {
>>>>> -	mdf_pfn_t pfn;
>>>>> -	int dumpable;
>>>>> -	int zero;
>>>>> -	unsigned int flags;
>>>>> +	pthread_mutex_t mutex;
>>>>>    	long size;
>>>>>    	unsigned char *buf;
>>>>> -	pthread_mutex_t mutex;
>>>>> -	/*
>>>>> -	 * whether the page_data is ready to be consumed
>>>>> -	 */
>>>>> -	int ready;
>>>>> +	int flags;
>>>>> +	int used;
>>>>>    };
>>>>>
>>>>>    struct thread_args {
>>>>>    	int thread_num;
>>>>>    	unsigned long len_buf_out;
>>>>>    	mdf_pfn_t start_pfn, end_pfn;
>>>>> -	int page_data_num;
>>>>> +	int page_buf_num;
>>>>>    	struct cycle *cycle;
>>>>>    	struct page_data *page_data_buf;
>>>>> +	struct page_flag *page_flag_buf;
>>>>>    };
>>>>>
>>>>>    /*
>>>>> @@ -1295,6 +1303,7 @@ struct DumpInfo {
>>>>>    	pthread_t **threads;
>>>>>    	struct thread_args *kdump_thread_args;
>>>>>    	struct page_data *page_data_buf;
>>>>> +	struct page_flag **page_flag_buf;
>>>>>    	pthread_rwlock_t usemmap_rwlock;
>>>>>    	mdf_pfn_t current_pfn;
>>>>>    	pthread_mutex_t current_pfn_mutex;
>>>>> --
>>>>> 1.8.3.1
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> kexec mailing list
>>>>> kexec@lists.infradead.org
>>>>> http://lists.infradead.org/mailman/listinfo/kexec
>>>>
>>>> _______________________________________________
>>>> kexec mailing list
>>>> kexec@lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/kexec
>>>
>>>
>>




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