Messages in this thread | | | Subject | Re: [PATCH v2 1/2] tools/vm/page_owner_sort.c: Sort by stacktrace before culling | From | Sean Anderson <> | Date | Thu, 25 Nov 2021 11:26:59 -0500 |
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On 11/25/21 4:46 AM, weizhenliang wrote: > On 2021/11/25 3:37, Sean Anderson <seanga2@gmail.com> wrote: > >> 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'); > > When read_block gets an empty line, buf is "\n", then the stacktrace is NULL > >> 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) { > > And when stacktrace is NULL, a segmentation fault will be triggered here.
Ah, whoops. Looks like I check for this in compare_stacktrace but not here.
>> list2[count++] = list[i]; >> } else { >> list2[count-1].num += list[i].num; > > 1. Maybe you can check whether the ret of read_block is 0 before add_list, > or whether the len of buf is 0 in add_list
I think this is the best route.
Since this seems to have already been applied I've sent a follow-up patch.
--Sean
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