From: Sean Anderson <seanga2@xxxxxxxxx> Subject: tools/vm/page_owner_sort.c: sort by stacktrace before culling 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@xxxxxxxxx: fix NULL-pointer dereference when comparing stack traces] Link: https://lkml.kernel.org/r/20211125162653.1855958-1-seanga2@xxxxxxxxx Link: https://lkml.kernel.org/r/20211124193709.1805776-1-seanga2@xxxxxxxxx Signed-off-by: Sean Anderson <seanga2@xxxxxxxxx> Signed-off-by: Sean Anderson <seanga2@xxxxxxxxx> Cc: Changhee Han <ch0.han@xxxxxxx> Cc: Tang Bin <tangbin@xxxxxxxxxxxxxxxxxxxx> Cc: Zhang Shengju <zhangshengju@xxxxxxxxxxxxxxxxxxxx> Cc: Zhenliang Wei <weizhenliang@xxxxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Cc: Yinan Zhang <zhangyinan2019@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/vm/page_owner_sort.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/tools/vm/page_owner_sort.c~tools-vm-page_owner_sortc-sort-by-stacktrace-before-culling +++ a/tools/vm/page_owner_sort.c @@ -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, 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; _
