niansa-misc/musl
1
0
Fork 0
mirror of git://git.musl-libc.org/musl synced 2025-03-06 20:48:29 +01:00
Code Issues Projects Releases Packages Wiki Activity

drop use of pthread_once for aio thread stack size init

Browse source 
pthread_once is not compatible with MT-fork constraints (commit
167390f055) and is not needed here
anyway; we already have a lock suitable for initialization.

while changing this, fix a corner case where AT_MINSIGSTKSZ gives a
value that's more than MINSIGSTKSZ but by a margin of less than
2048, thereby causing the size to be reduced. it shouldn't matter but
the intent was to be the larger of a 2048-byte margin over the legacy
fixed minimum stack requirement or a 512-byte margin over the minimum
the kernel reports at runtime.
This commit is contained in:
Rich Felker 2020-12-08 18:02:39 -05:00
parent 90ff016996
commit b67d56c7b3
1 changed files with 8 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
src/aio/aio.c
View file

@ -76,6 +76,10 @@ static struct aio_queue *****map;
static volatile int aio_fd_cnt;
volatile int __aio_fut;
static size_t io_thread_stack_size;
#define MAX(a,b) ((a)>(b) ? (a) : (b))
static struct aio_queue *__aio_get_queue(int fd, int need)
{
if (fd < 0) {
@ -90,6 +94,10 @@ static struct aio_queue *__aio_get_queue(int fd, int need)
pthread_rwlock_unlock(&maplock);
if (fcntl(fd, F_GETFD) < 0) return 0;
pthread_rwlock_wrlock(&maplock);
if (!io_thread_stack_size) {
unsigned long val = __getauxval(AT_MINSIGSTKSZ);
io_thread_stack_size = MAX(MINSIGSTKSZ+2048, val+512);
}
if (!map) map = calloc(sizeof *map, (-1U/2+1)>>24);
if (!map) goto out;
if (!map[a]) map[a] = calloc(sizeof **map, 256);
@ -265,15 +273,6 @@ static void *io_thread_func(void *ctx)
return 0;
}
static size_t io_thread_stack_size = MINSIGSTKSZ+2048;
static pthread_once_t init_stack_size_once;
static void init_stack_size()
{
unsigned long val = __getauxval(AT_MINSIGSTKSZ);
if (val > MINSIGSTKSZ) io_thread_stack_size = val + 512;
}
static int submit(struct aiocb *cb, int op)
{
int ret = 0;
@ -299,7 +298,6 @@ static int submit(struct aiocb *cb, int op)
else
pthread_attr_init(&a);
} else {
pthread_once(&init_stack_size_once, init_stack_size);
pthread_attr_init(&a);
pthread_attr_setstacksize(&a, io_thread_stack_size);
pthread_attr_setguardsize(&a, 0);