[PATCH v2] tools/vm/page_owner_sort.c: count and sort by mem

[Zhenliang Wei]

When viewing page owner information, we may be more concerned about
the total memory rather than the times of stack appears.
Therefore, the following adjustments are made:
1. Added the statistics on the total number of pages.
2. Added the optional parameter "-m" to configure the program to sort by
   memory (total pages).

The general output of page_owner is as follows:

	Page allocated via order XXX, ...
	PFN XXX ...
	 // Detailed stack

	Page allocated via order XXX, ...
	PFN XXX ...
	 // Detailed stack

The original page_owner_sort ignores PFN rows, puts the remaining rows
in buf, counts the times of buf, and finally sorts them according to
the times. General output:

	XXX times:
	Page allocated via order XXX, ...
	 // Detailed stack

Now, we use regexp to extract the page order value from the buf,
and count the total pages for the buf. General output:

	XXX times, XXX pages:
	Page allocated via order XXX, ...
	 // Detailed stack

By default, it is still sorted by the times of buf;
If you want to sort by the pages nums of buf, use the new -m parameter.

Signed-off-by: Zhenliang Wei <weizhenliang@xxxxxxxxxx>
---
 Documentation/vm/page_owner.rst | 23 +++++++++-
 tools/vm/page_owner_sort.c      | 94 +++++++++++++++++++++++++++++++++++++----
 2 files changed, 107 insertions(+), 10 deletions(-)

diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst
index 2175465c9bf2..9837fc8147dd 100644
--- a/Documentation/vm/page_owner.rst
+++ b/Documentation/vm/page_owner.rst
@@ -85,5 +85,26 @@ Usage
 	cat /sys/kernel/debug/page_owner > page_owner_full.txt
 	./page_owner_sort page_owner_full.txt sorted_page_owner.txt
 
+   The general output of ``page_owner_full.txt`` is as follows:
+
+	Page allocated via order XXX, ...
+	PFN XXX ...
+	 // Detailed stack
+
+	Page allocated via order XXX, ...
+	PFN XXX ...
+	 // Detailed stack
+
+   The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows
+   in buf, uses regexp to extract the page order value, counts the times
+   and pages of buf, and finally sorts them according to the times.
+
    See the result about who allocated each page
-   in the ``sorted_page_owner.txt``.
+   in the ``sorted_page_owner.txt``. General output:
+
+	XXX times, XXX pages:
+	Page allocated via order XXX, ...
+	 // Detailed stack
+
+   By default, ``page_owner_sort`` is sorted according to the times of buf.
+   If you want to sort by the pages nums of buf, use the ``-m`` parameter.
diff --git a/tools/vm/page_owner_sort.c b/tools/vm/page_owner_sort.c
index 0e75f22c9475..9ebb84a9c731 100644
--- a/tools/vm/page_owner_sort.c
+++ b/tools/vm/page_owner_sort.c
@@ -5,6 +5,8 @@
  * Example use:
  * cat /sys/kernel/debug/page_owner > page_owner_full.txt
  * ./page_owner_sort page_owner_full.txt sorted_page_owner.txt
+ * Or sort by total memory:
+ * ./page_owner_sort -m page_owner_full.txt sorted_page_owner.txt
  *
  * See Documentation/vm/page_owner.rst
 */
@@ -16,14 +18,18 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <string.h>
+#include <regex.h>
+#include <errno.h>
 
 struct block_list {
 	char *txt;
 	int len;
 	int num;
+	int page_num;
 };
 
-
+static int sort_by_memory;
+static regex_t order_pattern;
 static struct block_list *list;
 static int list_size;
 static int max_size;
@@ -59,12 +65,50 @@ static int compare_num(const void *p1, const void *p2)
 	return l2->num - l1->num;
 }
 
+static int compare_page_num(const void *p1, const void *p2)
+{
+	const struct block_list *l1 = p1, *l2 = p2;
+
+	return l2->page_num - l1->page_num;
+}
+
+static int get_page_num(char *buf)
+{
+	int err, val_len, order_val;
+	char order_str[4] = {0};
+	char *endptr;
+	regmatch_t pmatch[2];
+
+	err = regexec(&order_pattern, buf, 2, pmatch, REG_NOTBOL);
+	if (err != 0 || pmatch[1].rm_so == -1) {
+		printf("no order pattern in %s\n", buf);
+		return 0;
+	}
+	val_len = pmatch[1].rm_eo - pmatch[1].rm_so;
+	if (val_len > 2) /* max_order should not exceed 2 digits */
+		goto wrong_order;
+
+	memcpy(order_str, buf + pmatch[1].rm_so, val_len);
+
+	errno = 0;
+	order_val = strtol(order_str, &endptr, 10);
+	if (errno != 0 || endptr == order_str || *endptr != '\0')
+		goto wrong_order;
+
+	return 1 << order_val;
+
+wrong_order:
+	printf("wrong order in follow buf:\n%s\n", buf);
+	return 0;
+}
+
 static void add_list(char *buf, int len)
 {
 	if (list_size != 0 &&
 	    len == list[list_size-1].len &&
 	    memcmp(buf, list[list_size-1].txt, len) == 0) {
 		list[list_size-1].num++;
+		list[list_size-1].page_num += get_page_num(buf);
 		return;
 	}
 	if (list_size == max_size) {
@@ -74,6 +118,7 @@ static void add_list(char *buf, int len)
 	list[list_size].txt = malloc(len+1);
 	list[list_size].len = len;
 	list[list_size].num = 1;
+	list[list_size].page_num = get_page_num(buf);
 	memcpy(list[list_size].txt, buf, len);
 	list[list_size].txt[len] = 0;
 	list_size++;
@@ -85,6 +130,13 @@ static void add_list(char *buf, int len)
 
 #define BUF_SIZE	(128 * 1024)
 
+static void usage(void)
+{
+	printf("Usage: ./page_owner_sort [-m] <input> <output>\n"
+		"-m	Sort by total memory. If this option is unset, sort by times\n"
+	);
+}
+
 int main(int argc, char **argv)
 {
 	FILE *fin, *fout;
@@ -92,21 +144,39 @@ int main(int argc, char **argv)
 	int ret, i, count;
 	struct block_list *list2;
 	struct stat st;
+	int err;
+	int opt;
 
-	if (argc < 3) {
-		printf("Usage: ./program <input> <output>\n");
-		perror("open: ");
+	while ((opt = getopt(argc, argv, "m")) != -1)
+		switch (opt) {
+		case 'm':
+			sort_by_memory = 1;
+			break;
+		default:
+			usage();
+			exit(1);
+		}
+
+	if (optind >= (argc - 1)) {
+		usage();
 		exit(1);
 	}
 
-	fin = fopen(argv[1], "r");
-	fout = fopen(argv[2], "w");
+	fin = fopen(argv[optind], "r");
+	fout = fopen(argv[optind + 1], "w");
 	if (!fin || !fout) {
-		printf("Usage: ./program <input> <output>\n");
+		usage();
 		perror("open: ");
 		exit(1);
 	}
 
+	err = regcomp(&order_pattern, "order\\s*([0-9]*),", REG_EXTENDED|REG_NEWLINE);
+	if (err != 0 || order_pattern.re_nsub != 1) {
+		printf("%s: Invalid pattern 'order\\s*([0-9]*),' code %d\n",
+			argv[0], err);
+		exit(1);
+	}
+
 	fstat(fileno(fin), &st);
 	max_size = st.st_size / 100; /* hack ... */
 
@@ -145,13 +215,19 @@ int main(int argc, char **argv)
 			list2[count++] = list[i];
 		} else {
 			list2[count-1].num += list[i].num;
+			list2[count-1].page_num += list[i].page_num;
 		}
 	}
 
-	qsort(list2, count, sizeof(list[0]), compare_num);
+	if (sort_by_memory)
+		qsort(list2, count, sizeof(list[0]), compare_page_num);
+	else
+		qsort(list2, count, sizeof(list[0]), compare_num);
 
 	for (i = 0; i < count; i++)
-		fprintf(fout, "%d times:\n%s\n", list2[i].num, list2[i].txt);
+		fprintf(fout, "%d times, %d pages:\n%s\n",
+				list2[i].num, list2[i].page_num, list2[i].txt);
 
+	regfree(&order_pattern);
 	return 0;
 }
-- 
2.12.3