Re: [RFC PATCH v3 6/7] scripts/sorttable: Add ORC unwind tables sort concurrently

Peter Zijlstra
2019-11-15T09:19:56Z

On Fri, Nov 15, 2019 at 02:47:49PM +0800, Shile Zhang wrote:

> @@ -141,21 +306,44 @@ static int do_sort(Elf_Ehdr *ehdr,
> if (r(&s->sh_type) == SHT_SYMTAB_SHNDX)
> symtab_shndx = (Elf32_Word *)((const char *)ehdr +
> _r(&s->sh_offset));
> - }
>
> +#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
> + /* locate the ORC unwind tables */
> + if (!strcmp(secstrings + idx, ".orc_unwind_ip")) {
> + orctable.orc_ip_size = s->sh_size;
> + g_orc_ip_table = (int *)((void *)ehdr +
> + s->sh_offset);
> + }
> + if (!strcmp(secstrings + idx, ".orc_unwind")) {
> + orctable.orc_size = s->sh_size;
> + g_orc_table = (struct orc_entry *)((void *)ehdr +
> + s->sh_offset);
> + }
> +#endif
> + } /* for loop */
> +
> +#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)

Maybe something like:

if (g_orc_table && g_orc_ip_table) {
if (pthread_create(...))
...
} else if (g_orc_table || g_orc_up_table) {
fprintf(stderr, "incomplete ORC tables...\n");
}

> + /* create thread to sort ORC unwind tables concurrently */
> + if (pthread_create(&orc_sort_thread, NULL, sort_orctable, &orctable)) {
> + fprintf(stderr,
> + "pthread_create orc_sort_thread failed '%s': %s\n",
> + strerror(errno), fname);
> + goto out;
> + }
> +#endif
> if (!extab_sec) {
> fprintf(stderr, "no __ex_table in file: %s\n", fname);
> - return -1;
> + goto out;
> }
>
> if (!symtab_sec) {
> fprintf(stderr, "no .symtab in file: %s\n", fname);
> - return -1;
> + goto out;
> }
>
> if (!strtab_sec) {
> fprintf(stderr, "no .strtab in file: %s\n", fname);
> - return -1;
> + goto out;
> }
>
> extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
> @@ -192,7 +380,7 @@ static int do_sort(Elf_Ehdr *ehdr,
> fprintf(stderr,
> "no main_extable_sort_needed symbol in file: %s\n",
> fname);
> - return -1;
> + goto out;
> }
>
> sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
> @@ -205,6 +393,20 @@ static int do_sort(Elf_Ehdr *ehdr,
>
> /* extable has been sorted, clear the flag */
> w(0, sort_needed_loc);
> + rc = 0;
>
> - return 0;
> +out:
> +#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
> + { /* to avoid gcc warning about declaration */
> + void *retval = NULL;

and then here:

if (orc_sort_thread) {
void *retval = NULL;
pthread_join(...);
...
}

> +
> + /* wait for ORC tables sort done */
> + pthread_join(orc_sort_thread, &retval);
> + if (retval) {
> + fprintf(stderr, "%s in file: %s\n", (char *)retval, fname);
> + rc = -1;
> + }
> + }
> +#endif
> + return rc;
> }