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tools/vm/page_owner_sort.c: sort by stacktrace before culling

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The contents of page_owner have changed to include more information than
the stack trace.  On a modern kernel, the blocks look like

  Page allocated via order 0, mask 0x0(), pid 1, ts 165564237 ns, free_ts 0 ns
    register_early_stack+0x4b/0x90
    init_page_owner+0x39/0x250
    kernel_init_freeable+0x11e/0x242
    kernel_init+0x16/0x130

Sorting by the contents of .txt will result in almost no repeated pages,
as the pid, ts, and free_ts will almost never be the same.  Instead,
sort by the contents of the stack trace, which we assume to be whatever
is after the first line.

[seanga2@gmail.com: fix NULL-pointer dereference when comparing stack traces]
  Link: https://lkml.kernel.org/r/20211125162653.1855958-1-seanga2@gmail.com

Link: https://lkml.kernel.org/r/20211124193709.1805776-1-seanga2@gmail.com
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Cc: Changhee Han <ch0.han@lge.com>
Cc: Tang Bin <tangbin@cmss.chinamobile.com>
Cc: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Cc: Zhenliang Wei <weizhenliang@huawei.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sean Anderson 2022-03-24 18:08:38 -07:00 committed by Linus Torvalds
parent 52deda9551
commit ba5a396be5
1 changed files with 6 additions and 4 deletions
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10
tools/vm/page_owner_sort.c
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@ -23,6 +23,7 @@
struct block_list {
char *txt;
char *stacktrace;
int len;
int num;
int page_num;
@ -51,11 +52,11 @@ int read_block(char *buf, int buf_size, FILE *fin)
return -1; /* EOF or no space left in buf. */
}
static int compare_txt(const void *p1, const void *p2)
static int compare_stacktrace(const void *p1, const void *p2)
{
const struct block_list *l1 = p1, *l2 = p2;
return strcmp(l1->txt, l2->txt);
return strcmp(l1->stacktrace, l2->stacktrace);
}
static int compare_num(const void *p1, const void *p2)
@ -121,6 +122,7 @@ static void add_list(char *buf, int len)
list[list_size].page_num = get_page_num(buf);
memcpy(list[list_size].txt, buf, len);
list[list_size].txt[len] = 0;
list[list_size].stacktrace = strchr(list[list_size].txt, '\n') ?: "";
list_size++;
if (list_size % 1000 == 0) {
printf("loaded %d\r", list_size);
@ -199,7 +201,7 @@ int main(int argc, char **argv)
printf("sorting ....\n");
qsort(list, list_size, sizeof(list[0]), compare_txt);
qsort(list, list_size, sizeof(list[0]), compare_stacktrace);
list2 = malloc(sizeof(*list) * list_size);
if (!list2) {
@ -211,7 +213,7 @@ int main(int argc, char **argv)
for (i = count = 0; i < list_size; i++) {
if (count == 0 ||
strcmp(list2[count-1].txt, list[i].txt) != 0) {
strcmp(list2[count-1].stacktrace, list[i].stacktrace) != 0) {
list2[count++] = list[i];
} else {
list2[count-1].num += list[i].num;