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>
since the stdin, stdout and stderr may initialize later
in userspace if CONFIG_DEV_CONSOLE isn't enabled.
Note: it isn't bigger issue here to skip the check because
vfs will check the validation again in read and write syscall
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
The unique minor limit of 255 will overflow easily in
some scenarios where eventfd needs to be create/destroy
frequently:
while (1)
{
fd = eventfd(0, 0); // minor++
sleep(1);
close(fd);
}
remove the unique minor limit.
Change-Id: I0ea1c825ce9b542c883166cb3e72574455ffdd0d
Signed-off-by: chao.an <anchao@xiaomi.com>
There is a good case on sim platform:
When we input some cmd and click enter key to start application in terminal,
this context will change to application from IDLE loop. Althrough entey key '\r'
has been received to recv buffer and complete post semaphore of reader, but
pollnotify may not be called because context change. So when application run
poll function, because no events happend and poll enter wait, context will
again change to IDLE loop, this pollnotify of IDLE loop will run to send poll
events, poll function of applicaton will wake up. It's wrong!
Change-Id: I812a889f2e90781a9c3cb4b0251cccc4d32bebd1
Signed-off-by: dongjiuzhu <dongjiuzhu1@xiaomi.com>
1.Reduce the default size of task_group_s(~512B each task)
2.Scale better between simple and complex application
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ia872137504fddcf64d89c48d6f0593d76d582710
Or close the fd2 return by dup() would segment fault since filep->f_priv
null access.
Change-Id: I285c86f54bbb486d6c2c5aea53952f69083dca72
Signed-off-by: liuhaitao <liuhaitao@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
since these function don't depend on standard input/output function
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I011a387a1e2c1360e8f37716d512bd32f93ad467
since the current implementation is really a symoblic link not hard link
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I59d30d0a620b0b5714fe91bbe90d4405cf53d187
Block and MTD drivers may be opened and managed as though they were character drivers. But this is really sleight of hand; there is a hidden character driver proxy that mediates the interface to the block and MTD drivers in this case.
fstat(), however, did not account for this. It would report the characteristics of the proxy character driver, not of the underlying block or MTD driver.
This change corrects that. fstat now checks if the character driver is such a proxy and, if so, reports the characteristics of the underlying block or MTD driver, not the proxy character driver.
Functions within the OS must never set the errno value. fs_fdopen() was setting the errno value. Now, after some parameter changes, it reports errors via a negated errno integer return value as do most all other internal OS functions.
