[PATCH v4] Improve the performance of --num-threads -d 31

Minfei Huang mhuang at redhat.com
Wed Mar 16 01:24:13 PDT 2016


On 03/16/16 at 04:04pm, Minfei Huang wrote:
> On 03/16/16 at 09:55am, "Zhou, Wenjian/周文剑" wrote:
> > Hi Minfei,
> > 
> > I have some questions.
> > 
> > If the value of num-threads is 8,
> > 1. How much is the free memory before running makedumpfile failed?
> 
> Hmm, this machine is reserved by other, I have no access to take a look
> about reserved memory. All of the configuration are set by default.
> Maybe it's about 420M.
> 
> > 
> > 2. How much is the free memory before running makedumpfile success?
> 
> I don't memtion this during testing it.

I don't notice the issue during test it.

> 
> > 
> > 
> > And the following result is very strange if all cache has been dropped.
> > makedumpfile --num-threads 30 -d 31
> >     real    0m0.006s
> >     user    0m0.002s
> >     sys 0m0.004s
> 
> For this case, makedumpfile fails to dump vmcore with option
> --num-threads 30.
> 
> I suspect the following output from strace.
> 
> > >1313 mmap(NULL, 18446744048584388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)
> > >1314 mmap(NULL, 18446744048584523776, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)
> > >1315 mmap(NULL, 134217728, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0) = 0x7f5927bb2000
> 
> Thanks
> Minfei
> 
> > 
> > -- 
> > Thanks
> > Zhou
> > 
> > On 03/15/2016 05:33 PM, Minfei Huang wrote:
> > >On 03/15/16 at 03:12pm, "Zhou, Wenjian/周文剑" wrote:
> > >>Hello Minfei,
> > >>
> > >>I guess the result is affected by the caches.
> > >>How about executing the following command before running makedumpfile each time?
> > >># echo 3 > /proc/sys/vm/drop_caches
> > >
> > >Hi, Zhou.
> > >
> > >Seem there is a bug during dumping vmcore with option num-threads.
> > >
> > >1307 open("/proc/meminfo", O_RDONLY)         = 4
> > >1308 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
> > >1309 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f59322d3000
> > >1310 read(4, "MemTotal:         385452 kB\nMemF"..., 1024) = 1024
> > >1311 close(4)                                = 0
> > >1312 munmap(0x7f59322d3000, 4096)            = 0
> > >1313 mmap(NULL, 18446744048584388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)
> > >1314 mmap(NULL, 18446744048584523776, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)
> > >1315 mmap(NULL, 134217728, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0) = 0x7f5927bb2000
> > >1316 munmap(0x7f5927bb2000, 4513792)         = 0
> > >1317 munmap(0x7f592c000000, 62595072)        = 0
> > >1318 mprotect(0x7f5928000000, 135168, PROT_READ|PROT_WRITE) = 0
> > >1319 mmap(NULL, 18446744048584388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)
> > >
> > >Thanks
> > >Minfei
> > >
> > >>
> > >>--
> > >>Thanks
> > >>Zhou
> > >>
> > >>On 03/15/2016 02:34 PM, Minfei Huang wrote:
> > >>>Hi, Zhou.
> > >>>
> > >>>I have applied this patch base on 1.5.9. There are several testcases I
> > >>>have tested.
> > >>>
> > >>>- makedumpfile --num-threads 64 -d 31
> > >>>     real    0m0.010s
> > >>>     user    0m0.002s
> > >>>     sys 0m0.009s
> > >>>
> > >>>- makedumpfile --num-threads 31 -d 31
> > >>>     real    2m40.915s
> > >>>     user    10m50.900s
> > >>>     sys 23m9.664s
> > >>>
> > >>>makedumpfile --num-threads 30 -d 31
> > >>>     real    0m0.006s
> > >>>     user    0m0.002s
> > >>>     sys 0m0.004s
> > >>>
> > >>>makedumpfile --num-threads 32 -d 31
> > >>>     real    0m0.007s
> > >>>     user    0m0.002s
> > >>>     sys 0m0.005s
> > >>>
> > >>>- makedumpfile --num-threads 8 -d 31
> > >>>     real    2m32.692s
> > >>>     user    7m4.630s
> > >>>     sys 2m0.369s
> > >>>
> > >>>- makedumpfile --num-threads 1 -d 31
> > >>>     real    4m42.423s
> > >>>     user    7m27.153s
> > >>>     sys 0m22.490s
> > >>>
> > >>>- makedumpfile.orig -d 31
> > >>>     real    4m1.297s
> > >>>     user    3m39.696s
> > >>>     sys 0m15.200s
> > >>>
> > >>>This patch has a huge increment to the filter performance under 31. But
> > >>>it is not stable, since makedumpfile fails to dump vmcore intermittently.
> > >>>You can find the above test result, makedumpfile fails to dump vmcore
> > >>>with option --num-threads 64, also it may occur with option
> > >>>--number-threads 8.
> > >>>
> > >>>Thanks
> > >>>Minfei
> > >>>
> > >>>On 03/09/16 at 08:27am, Zhou Wenjian wrote:
> > >>>>v4:
> > >>>>         1. fix a bug caused by the logic
> > >>>>v3:
> > >>>>         1. remove some unused variables
> > >>>>         2. fix a bug caused by the wrong logic
> > >>>>         3. fix a bug caused by optimising
> > >>>>         4. improve more performance by using Minoru Usui's code
> > >>>>
> > >>>>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: Minoru Usui <min-usui at ti.jp.nec.com>
> > >>>>Signed-off-by: Zhou Wenjian <zhouwj-fnst at cn.fujitsu.com>
> > >>>>---
> > >>>>  makedumpfile.c | 298 +++++++++++++++++++++++++++++++++++----------------------
> > >>>>  makedumpfile.h |  35 ++++---
> > >>>>  2 files changed, 202 insertions(+), 131 deletions(-)
> > >>>>
> > >>>>diff --git a/makedumpfile.c b/makedumpfile.c
> > >>>>index fa0b779..2b0864a 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);
> > >>>>
> > >>>>@@ -3560,10 +3561,16 @@ initial_for_parallel()
> > >>>>
> > >>>>  	limit_size = (get_free_memory_size()
> > >>>>  		      - MAP_REGION * info->num_threads) * 0.6;
> > >>>>+	if (limit_size < 0) {
> > >>>>+		MSG("Free memory is not enough for multi-threads\n");
> > >>>>+		return FALSE;
> > >>>>+	}
> > >>>>
> > >>>>  	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 +3595,36 @@ 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] = calloc(1, sizeof(struct page_flag))) == NULL) {
> > >>>>+			MSG("Can't allocate memory for page_flag. %s\n",
> > >>>>+				strerror(errno));
> > >>>>+			return FALSE;
> > >>>>+		}
> > >>>>+		current = info->page_flag_buf[i];
> > >>>>+
> > >>>>+		for (j = 1; j < NUM_BUFFERS; j++) {
> > >>>>+			if ((current->next = calloc(1, sizeof(struct page_flag))) == NULL) {
> > >>>>+				MSG("Can't allocate memory for page_flag. %s\n",
> > >>>>+					strerror(errno));
> > >>>>+				return FALSE;
> > >>>>+			}
> > >>>>+			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 +3649,8 @@ 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 +3693,19 @@ 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;
> > >>>>
> > >>>>@@ -7075,11 +7126,11 @@ void *
> > >>>>  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;
> > >>>>+	volatile struct page_data *page_data_buf = kdump_thread_args->page_data_buf;
> > >>>>+	volatile 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;
> > >>>>+	mdf_pfn_t pfn = cycle->start_pfn;
> > >>>>+	int index = kdump_thread_args->thread_num;
> > >>>>  	int buf_ready;
> > >>>>  	int dumpable;
> > >>>>  	int fd_memory = 0;
> > >>>>@@ -7125,47 +7176,48 @@ 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);
> > >>>>-
> > >>>>-		if (pfn >= kdump_thread_args->end_pfn)
> > >>>>-			break;
> > >>>>-
> > >>>>-		index = -1;
> > >>>>+	/*
> > >>>>+	 * 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 (pfn < cycle->end_pfn) {
> > >>>>  		buf_ready = FALSE;
> > >>>>
> > >>>>+		pthread_mutex_lock(&info->page_data_mutex);
> > >>>>+		while (page_data_buf[index].used != FALSE) {
> > >>>>+			index = (index + 1) % info->num_buffers;
> > >>>>+		}
> > >>>>+		page_data_buf[index].used = TRUE;
> > >>>>+		pthread_mutex_unlock(&info->page_data_mutex);
> > >>>>+
> > >>>>  		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;
> > >>>>
> > >>>>-			if (page_data_buf[index].ready != 0)
> > >>>>-				continue;
> > >>>>-
> > >>>>-			pthread_mutex_lock(&page_data_buf[index].mutex);
> > >>>>-
> > >>>>-			if (page_data_buf[index].ready != 0)
> > >>>>-				goto unlock;
> > >>>>-
> > >>>>-			buf_ready = TRUE;
> > >>>>+			/* get next dumpable pfn */
> > >>>>+			pthread_mutex_lock(&info->current_pfn_mutex);
> > >>>>+			for (pfn = info->current_pfn; pfn < cycle->end_pfn; pfn++) {
> > >>>>+				dumpable = is_dumpable(
> > >>>>+					info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> > >>>>+					pfn,
> > >>>>+					cycle);
> > >>>>+				if (dumpable)
> > >>>>+					break;
> > >>>>+			}
> > >>>>+			info->current_pfn = pfn + 1;
> > >>>>
> > >>>>-			page_data_buf[index].pfn = pfn;
> > >>>>-			page_data_buf[index].ready = 1;
> > >>>>+			page_flag_buf->pfn = pfn;
> > >>>>+			page_flag_buf->ready = FLAG_FILLING;
> > >>>>+			pthread_mutex_unlock(&info->current_pfn_mutex);
> > >>>>+			sem_post(&info->page_flag_buf_sem);
> > >>>>
> > >>>>-			dumpable = is_dumpable(
> > >>>>-				info->fd_bitmap ? &bitmap_parallel : info->bitmap2,
> > >>>>-				pfn,
> > >>>>-				cycle);
> > >>>>-			page_data_buf[index].dumpable = dumpable;
> > >>>>-			if (!dumpable)
> > >>>>-				goto unlock;
> > >>>>+			if (pfn >= cycle->end_pfn) {
> > >>>>+				info->current_pfn = cycle->end_pfn;
> > >>>>+				page_data_buf[index].used = FALSE;
> > >>>>+				break;
> > >>>>+			}
> > >>>>
> > >>>>  			if (!read_pfn_parallel(fd_memory, pfn, buf,
> > >>>>  					       &bitmap_memory_parallel,
> > >>>>@@ -7178,11 +7230,11 @@ 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;
> > >>>>  			}
> > >>>>
> > >>>>-			page_data_buf[index].zero = FALSE;
> > >>>>+			page_flag_buf->zero = FALSE;
> > >>>>
> > >>>>  			/*
> > >>>>  			 * Compress the page data.
> > >>>>@@ -7210,6 +7262,7 @@ kdump_thread_function_cyclic(void *arg) {
> > >>>>  				page_data_buf[index].flags =
> > >>>>  							DUMP_DH_COMPRESSED_LZO;
> > >>>>  				page_data_buf[index].size  = size_out;
> > >>>>+
> > >>>>  				memcpy(page_data_buf[index].buf, buf_out, size_out);
> > >>>>  #endif
> > >>>>  #ifdef USESNAPPY
> > >>>>@@ -7232,12 +7285,14 @@ 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;
> > >>>>
> > >>>>  		}
> > >>>>  	}
> > >>>>-
> > >>>>  	retval = NULL;
> > >>>>
> > >>>>  fail:
> > >>>>@@ -7265,14 +7320,15 @@ 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;
> > >>>>@@ -7284,13 +7340,6 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> > >>>>  		goto out;
> > >>>>  	}
> > >>>>
> > >>>>-	res = pthread_mutex_init(&info->consumed_pfn_mutex, NULL);
> > >>>>-	if (res != 0) {
> > >>>>-		ERRMSG("Can't initialize consumed_pfn_mutex. %s\n",
> > >>>>-				strerror(res));
> > >>>>-		goto out;
> > >>>>-	}
> > >>>>-
> > >>>>  	res = pthread_mutex_init(&info->filter_mutex, NULL);
> > >>>>  	if (res != 0) {
> > >>>>  		ERRMSG("Can't initialize filter_mutex. %s\n", strerror(res));
> > >>>>@@ -7314,36 +7363,23 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> > >>>>  	end_pfn   = cycle->end_pfn;
> > >>>>
> > >>>>  	info->current_pfn = start_pfn;
> > >>>>-	info->consumed_pfn = start_pfn - 1;
> > >>>>
> > >>>>  	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;
> > >>>>+	pthread_mutex_init(&info->page_data_mutex, NULL);
> > >>>>+	sem_init(&info->page_flag_buf_sem, 0, 0);
> > >>>>
> > >>>>-	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;
> > >>>>-		res = pthread_mutex_init(&page_data_buf[i].mutex, NULL);
> > >>>>-		if (res != 0) {
> > >>>>-			ERRMSG("Can't initialize mutex of page_data_buf. %s\n",
> > >>>>-					strerror(res));
> > >>>>-			goto out;
> > >>>>-		}
> > >>>>-	}
> > >>>>+	for (i = 0; i < page_buf_num; i++)
> > >>>>+		page_data_buf[i].used = FALSE;
> > >>>>
> > >>>>  	for (i = 0; i < info->num_threads; i++) {
> > >>>>  		kdump_thread_args[i].thread_num = i;
> > >>>>  		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_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 +7392,88 @@ write_kdump_pages_parallel_cyclic(struct cache_data *cd_header,
> > >>>>  		}
> > >>>>  	}
> > >>>>
> > >>>>-	consuming_pfn = start_pfn;
> > >>>>-	index = -1;
> > >>>>+	end_count = 0;
> > >>>>+	while (1) {
> > >>>>+		consuming = 0;
> > >>>>+		check_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.
> > >>>>+		 */
> > >>>>+		sem_wait(&info->page_flag_buf_sem);
> > >>>>+		gettimeofday(&last, NULL);
> > >>>>+		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) {
> > >>>>+					info->page_flag_buf[i]->ready = FLAG_UNUSED;
> > >>>>+					end_count++;
> > >>>>+					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;
> > >>>>+			}
> > >>>>
> > >>>>-		/* 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 all the threads have reached the end, we will finish writing.
> > >>>>+			 */
> > >>>>+			if (end_count >= info->num_threads)
> > >>>>+				goto finish;
> > >>>>+
> > >>>>+			/*
> > >>>>+			 * If the page_flag_buf is not ready, the pfn recorded may be changed.
> > >>>>+			 * So we should recheck.
> > >>>>+			 */
> > >>>>+			if (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;
> > >>>>+				}
> > >>>>+				continue;
> > >>>>+			}
> > >>>>+
> > >>>>+			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 +7489,12 @@ 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 = FALSE;
> > >>>>  		}
> > >>>>-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 %]
> > >>>>@@ -7463,15 +7532,9 @@ out:
> > >>>>  		}
> > >>>>  	}
> > >>>>
> > >>>>-	if (page_data_buf != NULL) {
> > >>>>-		for (i = 0; i < page_data_num; i++) {
> > >>>>-			pthread_mutex_destroy(&page_data_buf[i].mutex);
> > >>>>-		}
> > >>>>-	}
> > >>>>-
> > >>>>+	sem_destroy(&info->page_flag_buf_sem);
> > >>>>  	pthread_rwlock_destroy(&info->usemmap_rwlock);
> > >>>>  	pthread_mutex_destroy(&info->filter_mutex);
> > >>>>-	pthread_mutex_destroy(&info->consumed_pfn_mutex);
> > >>>>  	pthread_mutex_destroy(&info->current_pfn_mutex);
> > >>>>
> > >>>>  	return ret;
> > >>>>@@ -7564,6 +7627,7 @@ 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..4b315c0 100644
> > >>>>--- a/makedumpfile.h
> > >>>>+++ b/makedumpfile.h
> > >>>>@@ -44,6 +44,7 @@
> > >>>>  #include "print_info.h"
> > >>>>  #include "sadump_mod.h"
> > >>>>  #include <pthread.h>
> > >>>>+#include <semaphore.h>
> > >>>>
> > >>>>  /*
> > >>>>   * Result of command
> > >>>>@@ -977,7 +978,7 @@ 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 +986,33 @@ 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;
> > >>>>  	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;
> > >>>>  	struct cycle *cycle;
> > >>>>  	struct page_data *page_data_buf;
> > >>>>+	struct page_flag *page_flag_buf;
> > >>>>  };
> > >>>>
> > >>>>  /*
> > >>>>@@ -1295,11 +1301,12 @@ struct DumpInfo {
> > >>>>  	pthread_t **threads;
> > >>>>  	struct thread_args *kdump_thread_args;
> > >>>>  	struct page_data *page_data_buf;
> > >>>>+	struct page_flag **page_flag_buf;
> > >>>>+	sem_t page_flag_buf_sem;
> > >>>>  	pthread_rwlock_t usemmap_rwlock;
> > >>>>  	mdf_pfn_t current_pfn;
> > >>>>  	pthread_mutex_t current_pfn_mutex;
> > >>>>-	mdf_pfn_t consumed_pfn;
> > >>>>-	pthread_mutex_t consumed_pfn_mutex;
> > >>>>+	pthread_mutex_t page_data_mutex;
> > >>>>  	pthread_mutex_t filter_mutex;
> > >>>>  };
> > >>>>  extern struct DumpInfo		*info;
> > >>>>--
> > >>>>1.8.3.1
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>_______________________________________________
> > >>>>kexec mailing list
> > >>>>kexec at lists.infradead.org
> > >>>>http://lists.infradead.org/mailman/listinfo/kexec
> > >>>
> > >>>
> > >>
> > >>
> > >>
> > >>_______________________________________________
> > >>kexec mailing list
> > >>kexec at lists.infradead.org
> > >>http://lists.infradead.org/mailman/listinfo/kexec
> > 
> > 
> > 



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