here is the reason:
1.clock_systime_timespec(core function) always exist regardless the setting
2.CLOCK_MONOTONIC is a foundamental clock type required by many places
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
In current implementation, the asynchronous call "epoll_ctl()" unable
to wakeup the thread if pending on "epoll_wait()", the newly
added/delete FD cannot be used in the current waiting list,
this patch uses a reserved file object to wake up pending poll internal,
re-traverse the waiting list when a new event comes.
Signed-off-by: chao.an <anchao@xiaomi.com>
https://linux.die.net/man/2/epoll_ctl:
EPOLLONESHOT (since Linux 2.6.2)
Sets the one-shot behavior for the associated file descriptor.
This means that after an event is pulled out with epoll_wait(2)
the associated file descriptor is internally disabled and
no other events will be reported by the epoll interface.
The user must call epoll_ctl() with EPOLL_CTL_MOD to
rearm the file descriptor with a new event mask.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I6c0dc93e1cdae0e8cea5b487c7005de2da2c2ec3
Linux Programmer's Manual
NAME
epoll_create, epoll_create1 - open an epoll file descriptor
...
SYNOPSIS
#include <sys/epoll.h>
int epoll_create1(int flags);
...
epoll_create1()
If flags is 0, then, other than the fact that the obsolete
size argument is dropped, epoll_create1() is the same as
epoll_create(). The following value can be included in flags
to obtain different behavior:
EPOLL_CLOEXEC
Set the close-on-exec (FD_CLOEXEC) flag on the new file
descriptor. See the description of the O_CLOEXEC flag in
open(2) for reasons why this may be useful.
https://man7.org/linux/man-pages/man7/epoll.7.html
arch/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
sched/ audio/ crypto/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
Documentation/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
fs/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
graphics/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
net/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
drivers/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
include/, syscall/, wireless/: Removed all references to CONFIG_DISABLE_POLL. The standard POSIX poll() can not longer be disabled.
configs/: Remove all references to CONFIG_DISABLE_POLL. Standard POSIX poll can no longer be disabled.
