1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * User-space helper to sort the output of /sys/kernel/debug/page_owner
  4 *
  5 * Example use:
  6 * cat /sys/kernel/debug/page_owner > page_owner_full.txt
  7 * grep -v ^PFN page_owner_full.txt > page_owner.txt
  8 * ./page_owner_sort page_owner.txt sorted_page_owner.txt
  9 *
 10 * See Documentation/vm/page_owner.rst
 11*/
 12
 13#include <stdio.h>
 14#include <stdlib.h>
 15#include <sys/types.h>
 16#include <sys/stat.h>
 17#include <fcntl.h>
 18#include <unistd.h>
 19#include <string.h>
 20
 21struct block_list {
 22	char *txt;
 23	int len;
 24	int num;
 25};
 26
 27
 28static struct block_list *list;
 29static int list_size;
 30static int max_size;
 31
 32struct block_list *block_head;
 33
 34int read_block(char *buf, int buf_size, FILE *fin)
 35{
 36	char *curr = buf, *const buf_end = buf + buf_size;
 37
 38	while (buf_end - curr > 1 && fgets(curr, buf_end - curr, fin)) {
 39		if (*curr == '\n') /* empty line */
 40			return curr - buf;
 41		curr += strlen(curr);
 42	}
 43
 44	return -1; /* EOF or no space left in buf. */
 45}
 46
 47static int compare_txt(const void *p1, const void *p2)
 48{
 49	const struct block_list *l1 = p1, *l2 = p2;
 50
 51	return strcmp(l1->txt, l2->txt);
 52}
 53
 54static int compare_num(const void *p1, const void *p2)
 55{
 56	const struct block_list *l1 = p1, *l2 = p2;
 57
 58	return l2->num - l1->num;
 59}
 60
 61static void add_list(char *buf, int len)
 62{
 63	if (list_size != 0 &&
 64	    len == list[list_size-1].len &&
 65	    memcmp(buf, list[list_size-1].txt, len) == 0) {
 66		list[list_size-1].num++;
 67		return;
 68	}
 69	if (list_size == max_size) {
 70		printf("max_size too small??\n");
 71		exit(1);
 72	}
 73	list[list_size].txt = malloc(len+1);
 74	list[list_size].len = len;
 75	list[list_size].num = 1;
 76	memcpy(list[list_size].txt, buf, len);
 77	list[list_size].txt[len] = 0;
 78	list_size++;
 79	if (list_size % 1000 == 0) {
 80		printf("loaded %d\r", list_size);
 81		fflush(stdout);
 82	}
 83}
 84
 85#define BUF_SIZE	(128 * 1024)
 86
 87int main(int argc, char **argv)
 88{
 89	FILE *fin, *fout;
 90	char *buf;
 91	int ret, i, count;
 92	struct block_list *list2;
 93	struct stat st;
 94
 95	if (argc < 3) {
 96		printf("Usage: ./program <input> <output>\n");
 97		perror("open: ");
 98		exit(1);
 99	}
100
101	fin = fopen(argv[1], "r");
102	fout = fopen(argv[2], "w");
103	if (!fin || !fout) {
104		printf("Usage: ./program <input> <output>\n");
105		perror("open: ");
106		exit(1);
107	}
108
109	fstat(fileno(fin), &st);
110	max_size = st.st_size / 100; /* hack ... */
111
112	list = malloc(max_size * sizeof(*list));
113	buf = malloc(BUF_SIZE);
114	if (!list || !buf) {
115		printf("Out of memory\n");
116		exit(1);
117	}
118
119	for ( ; ; ) {
120		ret = read_block(buf, BUF_SIZE, fin);
121		if (ret < 0)
122			break;
123
124		add_list(buf, ret);
125	}
126
127	printf("loaded %d\n", list_size);
128
129	printf("sorting ....\n");
130
131	qsort(list, list_size, sizeof(list[0]), compare_txt);
132
133	list2 = malloc(sizeof(*list) * list_size);
134
135	printf("culling\n");
136
137	for (i = count = 0; i < list_size; i++) {
138		if (count == 0 ||
139		    strcmp(list2[count-1].txt, list[i].txt) != 0) {
140			list2[count++] = list[i];
141		} else {
142			list2[count-1].num += list[i].num;
143		}
144	}
145
146	qsort(list2, count, sizeof(list[0]), compare_num);
147
148	for (i = 0; i < count; i++)
149		fprintf(fout, "%d times:\n%s\n", list2[i].num, list2[i].txt);
150
151	return 0;
152}