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linux: remove epoll_pwait() emulation code path (#3936)

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This was removed before in 2018 but then reinstated again in 2019 to
fix building with old Android SDKs. Well, time marches on; this time
it's gone for good.

Refs: https://github.com/libuv/libuv/pull/1372
Refs: https://github.com/libuv/libuv/pull/2358
This commit is contained in:
Ben Noordhuis 2023-03-28 11:58:56 +02:00 committed by GitHub
parent 7b84d5b0ec
commit 0c8eccc3fc
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 8 additions and 50 deletions
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50
src/unix/linux.c
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@ -307,18 +307,14 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
* that being the largest value I have seen in the wild (and only once.)
*/
static const int max_safe_timeout = 1789569;
static int no_epoll_pwait_cached;
static int no_epoll_wait_cached;
int no_epoll_pwait;
int no_epoll_wait;
struct epoll_event events[1024];
struct epoll_event* pe;
struct epoll_event e;
int real_timeout;
QUEUE* q;
uv__io_t* w;
sigset_t* sigmask;
sigset_t sigset;
uint64_t sigmask;
uint64_t base;
int have_signals;
int nevents;
@ -372,11 +368,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
w->events = w->pevents;
}
sigmask = 0;
sigmask = NULL;
if (loop->flags & UV_LOOP_BLOCK_SIGPROF) {
sigemptyset(&sigset);
sigaddset(&sigset, SIGPROF);
sigmask |= 1 << (SIGPROF - 1);
sigmask = &sigset;
}
assert(timeout >= -1);
@ -393,15 +389,6 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
user_timeout = 0;
}
/* You could argue there is a dependency between these two but
* ultimately we don't care about their ordering with respect
* to one another. Worst case, we make a few system calls that
* could have been avoided because another thread already knows
* they fail with ENOSYS. Hardly the end of the world.
*/
no_epoll_pwait = uv__load_relaxed(&no_epoll_pwait_cached);
no_epoll_wait = uv__load_relaxed(&no_epoll_wait_cached);
for (;;) {
/* Only need to set the provider_entry_time if timeout != 0. The function
* will return early if the loop isn't configured with UV_METRICS_IDLE_TIME.
@ -415,34 +402,11 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
if (sizeof(int32_t) == sizeof(long) && timeout >= max_safe_timeout)
timeout = max_safe_timeout;
if (sigmask != 0 && no_epoll_pwait != 0)
if (pthread_sigmask(SIG_BLOCK, &sigset, NULL))
abort();
if (no_epoll_wait != 0 || (sigmask != 0 && no_epoll_pwait == 0)) {
nfds = epoll_pwait(loop->backend_fd,
events,
ARRAY_SIZE(events),
timeout,
&sigset);
if (nfds == -1 && errno == ENOSYS) {
uv__store_relaxed(&no_epoll_pwait_cached, 1);
no_epoll_pwait = 1;
}
} else {
nfds = epoll_wait(loop->backend_fd,
events,
ARRAY_SIZE(events),
timeout);
if (nfds == -1 && errno == ENOSYS) {
uv__store_relaxed(&no_epoll_wait_cached, 1);
no_epoll_wait = 1;
}
}
if (sigmask != 0 && no_epoll_pwait != 0)
if (pthread_sigmask(SIG_UNBLOCK, &sigset, NULL))
abort();
sigmask);
/* Update loop->time unconditionally. It's tempting to skip the update when
* timeout == 0 (i.e. non-blocking poll) but there is no guarantee that the
@ -471,12 +435,6 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
}
if (nfds == -1) {
if (errno == ENOSYS) {
/* epoll_wait() or epoll_pwait() failed, try the other system call. */
assert(no_epoll_wait == 0 || no_epoll_pwait == 0);
continue;
}
if (errno != EINTR)
abort();