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

Shile Zhang
2019-11-15T09:45:57Z

On 2019/11/15 17:19, Peter Zijlstra wrote:
> 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(...);
> ...
> }

Thank you for your kindly advice! I'll change it in next version.

>> +
>> + /* 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;
>> }