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authorRich Felker <dalias@aerifal.cx>2020-12-08 18:02:39 -0500
committerRich Felker <dalias@aerifal.cx>2020-12-08 18:02:39 -0500
commitb67d56c7b3b0f84360db749aa6f431a07761d9c8 (patch)
treeebb174d2dc4c9a912e9870c8601d32a81ff30718
parent90ff016996753d83263445940710c87d9afa71f3 (diff)
downloadmusl-b67d56c7b3b0f84360db749aa6f431a07761d9c8.tar.gz
drop use of pthread_once for aio thread stack size init
pthread_once is not compatible with MT-fork constraints (commit 167390f05564e0a4d3fcb4329377fd7743267560) 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.
-rw-r--r--src/aio/aio.c18
1 files changed, 8 insertions, 10 deletions
diff --git a/src/aio/aio.c b/src/aio/aio.c
index e004f98b..a1a3e791 100644
--- a/src/aio/aio.c
+++ b/src/aio/aio.c
@@ -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);