Re: memory leak in 2.6.11-rc2

[Andrew Tridgell <tridge@osdl.org>]

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 > I'm trying the little leak tracking patch from Alexander Nyberg now.

Here are the results (only backtraces with more than 10k counts
included). The leak was at 1G of memory at the time I ran this, so its
safe to say 10k page allocations ain't enough to explain it :-)

I also attach a hacked version of the pgown sort program that sorts
the output by count, and isn't O(n^2). It took 10 minutes to run the
old version :-)

I'm guessing the leak is in the new xattr code given that is what
dbench and nbench were beating on. Andreas, can you look at the
following and see if you can spot anything?

This was on 2.6.11-rc2 with the pipe leak patch from Linus. The
machine had leaked 1G of ram in 10 minutes, and was idle (only thing
running was sshd).

Cheers, Tridge


175485 times:
Page allocated via order 0
[0xc0132258] generic_file_buffered_write+280
[0xc011b6a9] current_fs_time+77
[0xc0132a1e] __generic_file_aio_write_nolock+642
[0xc0132e70] generic_file_aio_write+100
[0xc017e586] ext3_file_write+38
[0xc014b7f5] do_sync_write+169
[0xc015f6de] fcntl_setlk64+286
[0xc01295a8] autoremove_wake_function+0

141512 times:
Page allocated via order 0
[0xc0132258] generic_file_buffered_write+280
[0xc0132a1e] __generic_file_aio_write_nolock+642
[0xc0132e70] generic_file_aio_write+100
[0xc017e586] ext3_file_write+38
[0xc014b7f5] do_sync_write+169
[0xc015f6de] fcntl_setlk64+286
[0xc01295a8] autoremove_wake_function+0
[0xc014b8d5] vfs_write+157

67641 times:
Page allocated via order 0
[0xc0132258] generic_file_buffered_write+280
[0xc014dc69] __getblk+29
[0xc011b6a9] current_fs_time+77
[0xc0132a1e] __generic_file_aio_write_nolock+642
[0xc018d368] ext3_xattr_user_get+108
[0xc0132e70] generic_file_aio_write+100
[0xc017e586] ext3_file_write+38
[0xc014b7f5] do_sync_write+169

52758 times:
Page allocated via order 0
[0xc0132258] generic_file_buffered_write+280
[0xc014dc69] __getblk+29
[0xc0132a1e] __generic_file_aio_write_nolock+642
[0xc018d368] ext3_xattr_user_get+108
[0xc0132e70] generic_file_aio_write+100
[0xc017e586] ext3_file_write+38
[0xc014b7f5] do_sync_write+169
[0xc0120c0b] kill_proc_info+47

19610 times:
Page allocated via order 0
[0xc0132258] generic_file_buffered_write+280
[0xc011b6a9] current_fs_time+77
[0xc0132a1e] __generic_file_aio_write_nolock+642
[0xc0132c3a] generic_file_aio_write_nolock+54
[0xc0132def] generic_file_write_nolock+151
[0xc011b7cb] __do_softirq+95
[0xc01295a8] autoremove_wake_function+0
[0xc01295a8] autoremove_wake_function+0

16874 times:
Page allocated via order 0
[0xc0132258] generic_file_buffered_write+280
[0xc011b6a9] current_fs_time+77
[0xc0132a1e] __generic_file_aio_write_nolock+642
[0xc0132c3a] generic_file_aio_write_nolock+54
[0xc0132def] generic_file_write_nolock+151
[0xc01295a8] autoremove_wake_function+0
[0xc01295a8] autoremove_wake_function+0
[0xc0152d4a] blkdev_file_write+38


[-- Attachment #2: pgown-fast.c --]
[-- Type: application/octet-stream, Size: 2427 bytes --]

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

struct block_list {
	char *txt;
	int len;
	int num;
};


static struct block_list *list;
static int list_size;
static int max_size;

struct block_list *block_head;

int read_block(char *buf, FILE *fin)
{
	int ret = 0;
	int hit = 0;
	char *curr = buf;
	
	for (;;) {
		*curr = getc(fin);
		if (*curr == EOF) return -1;
		
		ret++;
		if (*curr == '\n' && hit == 1)
			return ret - 1;
		else if (*curr == '\n')
			hit = 1;
		else
			hit = 0;
		curr++;
	}
}

static int compare_txt(struct block_list *l1, struct block_list *l2)
{
	return strcmp(l1->txt, l2->txt);
}

static int compare_num(struct block_list *l1, struct block_list *l2)
{
	return l2->num - l1->num;
}

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++;
		return;
	}
	if (list_size == max_size) {
		printf("max_size too small??\n");
		exit(1);
	}
	list[list_size].txt = malloc(len+1);
	list[list_size].len = len;
	list[list_size].num = 1;
	memcpy(list[list_size].txt, buf, len);
	list[list_size].txt[len] = 0;
	list_size++;
	if (list_size % 1000 == 0) {
		printf("loaded %d\r", list_size);
		fflush(stdout);
	}
}

int main(int argc, char **argv)
{
	FILE *fin, *fout;
	char buf[1024];
	int ret, i, count;
	struct block_list *list2;
	struct stat st;
	
	fin = fopen(argv[1], "r");
	fout = fopen(argv[2], "w");
	if (!fin || !fout) {
		printf("Usage: ./program <input> <output>\n");
		perror("open: ");
		exit(2);
	}

	fstat(fileno(fin), &st);
	max_size = st.st_size / 100; /* hack ... */

	list = malloc(max_size * sizeof(*list));
	
	for(;;) {
		ret = read_block(buf, fin);
		if (ret < 0)
			break;
		
		buf[ret] = '\0';
		add_list(buf, ret);
	}

	printf("loaded %d\n", list_size);

	printf("sorting ....\n");

	qsort(list, list_size, sizeof(list[0]), compare_txt);

	list2 = malloc(sizeof(*list) * list_size);

	printf("culling\n");

	for (i=count=0;i<list_size;i++) {
		if (count == 0 || 
		    strcmp(list2[count-1].txt, list[i].txt) != 0) {
			list2[count++] = list[i];
		} else {
			list2[count-1].num += list[i].num;
		}
	}
	
	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);
	}
	return 0;
}