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signal/timer/event: timerfd core This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
/*
* include/linux/timerfd.h
*
* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
*
*/
#ifndef _LINUX_TIMERFD_H
#define _LINUX_TIMERFD_H
flag parameters: NONBLOCK in timerfd_create This patch adds support for the TFD_NONBLOCK flag to timerfd_create. The additional changes needed are minimal. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <time.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_timerfd_create # ifdef __x86_64__ # define __NR_timerfd_create 283 # elif defined __i386__ # define __NR_timerfd_create 322 # else # error "need __NR_timerfd_create" # endif #endif #define TFD_NONBLOCK O_NONBLOCK int main (void) { int fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, 0); if (fd == -1) { puts ("timerfd_create(0) failed"); return 1; } int fl = fcntl (fd, F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if (fl & O_NONBLOCK) { puts ("timerfd_create(0) set non-blocking mode"); return 1; } close (fd); fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, TFD_NONBLOCK); if (fd == -1) { puts ("timerfd_create(TFD_NONBLOCK) failed"); return 1; } fl = fcntl (fd, F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if ((fl & O_NONBLOCK) == 0) { puts ("timerfd_create(TFD_NONBLOCK) set non-blocking mode"); return 1; } close (fd); puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 12:29:39 +08:00
/* For O_CLOEXEC and O_NONBLOCK */
flag parameters: timerfd_create The timerfd_create syscall already has a flags parameter. It just is unused so far. This patch changes this by introducing the TFD_CLOEXEC flag to set the close-on-exec flag for the returned file descriptor. A new name TFD_CLOEXEC is introduced which in this implementation must have the same value as O_CLOEXEC. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <time.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_timerfd_create # ifdef __x86_64__ # define __NR_timerfd_create 283 # elif defined __i386__ # define __NR_timerfd_create 322 # else # error "need __NR_timerfd_create" # endif #endif #define TFD_CLOEXEC O_CLOEXEC int main (void) { int fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, 0); if (fd == -1) { puts ("timerfd_create(0) failed"); return 1; } int coe = fcntl (fd, F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if (coe & FD_CLOEXEC) { puts ("timerfd_create(0) set close-on-exec flag"); return 1; } close (fd); fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, TFD_CLOEXEC); if (fd == -1) { puts ("timerfd_create(TFD_CLOEXEC) failed"); return 1; } coe = fcntl (fd, F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if ((coe & FD_CLOEXEC) == 0) { puts ("timerfd_create(TFD_CLOEXEC) set close-on-exec flag"); return 1; } close (fd); puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 12:29:26 +08:00
#include <linux/fcntl.h>
signal/timer/event: timerfd core This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
timerfd: Implement timerfd_ioctl method to restore timerfd_ctx::ticks, v3 The read() of timerfd files allows to fetch the number of timer ticks while there is no way to set it back from userspace. To restore the timer's state as it was at checkpoint moment we need a path to bring @ticks back. Initially I thought about writing ticks back via write() interface but it seems such API is somehow obscure. Instead implement timerfd_ioctl() method with TFD_IOC_SET_TICKS command which allows to adjust @ticks into non-zero value waking up the waiters. I wrapped code with CONFIG_CHECKPOINT_RESTORE which can be dropped off if there users except c/r camp appear. v2 (by akpm@): - Use define timerfd_ioctl NULL for non c/r config v3: - Use copy_from_user for @ticks fetching since not all arch support get_user for 8 byte argument Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Andrey Vagin <avagin@openvz.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christopher Covington <cov@codeaurora.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Link: http://lkml.kernel.org/r/20140715215703.285617923@openvz.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-07-16 05:54:54 +08:00
/* For _IO helpers */
#include <linux/ioctl.h>
timerfd: add flags check As requested by Michael, add a missing check for valid flags in timerfd_settime(), and make it return EINVAL in case some extra bits are set. Michael said: If this is to be any use to userland apps that want to check flag support (perhaps it is too late already), then the sooner we get it into the kernel the better: 2.6.29 would be good; earlier stables as well would be even better. [akpm@linux-foundation.org: remove unused TFD_FLAGS_SET] Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: <stable@kernel.org> [2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-19 06:48:18 +08:00
/*
* CAREFUL: Check include/asm-generic/fcntl.h when defining
* new flags, since they might collide with O_* ones. We want
* to re-use O_* flags that couldn't possibly have a meaning
* from eventfd, in order to leave a free define-space for
* shared O_* flags.
*/
signal/timer/event: timerfd core This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
#define TFD_TIMER_ABSTIME (1 << 0)
timerfd: Manage cancelable timers in timerfd Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the timer interrupt. Yes, I did not think about it, because the solution was so elegant. I didn't like the extra list in timerfd when it was proposed some time ago, but with a rcu based list the list walk it's less horrible than the original global lock, which was held over the list iteration. Requested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Peter Zijlstra <peterz@infradead.org>
2011-05-20 22:18:50 +08:00
#define TFD_TIMER_CANCEL_ON_SET (1 << 1)
flag parameters: timerfd_create The timerfd_create syscall already has a flags parameter. It just is unused so far. This patch changes this by introducing the TFD_CLOEXEC flag to set the close-on-exec flag for the returned file descriptor. A new name TFD_CLOEXEC is introduced which in this implementation must have the same value as O_CLOEXEC. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <time.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_timerfd_create # ifdef __x86_64__ # define __NR_timerfd_create 283 # elif defined __i386__ # define __NR_timerfd_create 322 # else # error "need __NR_timerfd_create" # endif #endif #define TFD_CLOEXEC O_CLOEXEC int main (void) { int fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, 0); if (fd == -1) { puts ("timerfd_create(0) failed"); return 1; } int coe = fcntl (fd, F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if (coe & FD_CLOEXEC) { puts ("timerfd_create(0) set close-on-exec flag"); return 1; } close (fd); fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, TFD_CLOEXEC); if (fd == -1) { puts ("timerfd_create(TFD_CLOEXEC) failed"); return 1; } coe = fcntl (fd, F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if ((coe & FD_CLOEXEC) == 0) { puts ("timerfd_create(TFD_CLOEXEC) set close-on-exec flag"); return 1; } close (fd); puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 12:29:26 +08:00
#define TFD_CLOEXEC O_CLOEXEC
flag parameters: NONBLOCK in timerfd_create This patch adds support for the TFD_NONBLOCK flag to timerfd_create. The additional changes needed are minimal. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <time.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_timerfd_create # ifdef __x86_64__ # define __NR_timerfd_create 283 # elif defined __i386__ # define __NR_timerfd_create 322 # else # error "need __NR_timerfd_create" # endif #endif #define TFD_NONBLOCK O_NONBLOCK int main (void) { int fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, 0); if (fd == -1) { puts ("timerfd_create(0) failed"); return 1; } int fl = fcntl (fd, F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if (fl & O_NONBLOCK) { puts ("timerfd_create(0) set non-blocking mode"); return 1; } close (fd); fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, TFD_NONBLOCK); if (fd == -1) { puts ("timerfd_create(TFD_NONBLOCK) failed"); return 1; } fl = fcntl (fd, F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if ((fl & O_NONBLOCK) == 0) { puts ("timerfd_create(TFD_NONBLOCK) set non-blocking mode"); return 1; } close (fd); puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 12:29:39 +08:00
#define TFD_NONBLOCK O_NONBLOCK
signal/timer/event: timerfd core This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
timerfd: add flags check As requested by Michael, add a missing check for valid flags in timerfd_settime(), and make it return EINVAL in case some extra bits are set. Michael said: If this is to be any use to userland apps that want to check flag support (perhaps it is too late already), then the sooner we get it into the kernel the better: 2.6.29 would be good; earlier stables as well would be even better. [akpm@linux-foundation.org: remove unused TFD_FLAGS_SET] Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: <stable@kernel.org> [2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-19 06:48:18 +08:00
#define TFD_SHARED_FCNTL_FLAGS (TFD_CLOEXEC | TFD_NONBLOCK)
/* Flags for timerfd_create. */
#define TFD_CREATE_FLAGS TFD_SHARED_FCNTL_FLAGS
/* Flags for timerfd_settime. */
timerfd: Manage cancelable timers in timerfd Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the timer interrupt. Yes, I did not think about it, because the solution was so elegant. I didn't like the extra list in timerfd when it was proposed some time ago, but with a rcu based list the list walk it's less horrible than the original global lock, which was held over the list iteration. Requested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Peter Zijlstra <peterz@infradead.org>
2011-05-20 22:18:50 +08:00
#define TFD_SETTIME_FLAGS (TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET)
signal/timer/event: timerfd core This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
timerfd: Implement timerfd_ioctl method to restore timerfd_ctx::ticks, v3 The read() of timerfd files allows to fetch the number of timer ticks while there is no way to set it back from userspace. To restore the timer's state as it was at checkpoint moment we need a path to bring @ticks back. Initially I thought about writing ticks back via write() interface but it seems such API is somehow obscure. Instead implement timerfd_ioctl() method with TFD_IOC_SET_TICKS command which allows to adjust @ticks into non-zero value waking up the waiters. I wrapped code with CONFIG_CHECKPOINT_RESTORE which can be dropped off if there users except c/r camp appear. v2 (by akpm@): - Use define timerfd_ioctl NULL for non c/r config v3: - Use copy_from_user for @ticks fetching since not all arch support get_user for 8 byte argument Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Andrey Vagin <avagin@openvz.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christopher Covington <cov@codeaurora.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Link: http://lkml.kernel.org/r/20140715215703.285617923@openvz.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-07-16 05:54:54 +08:00
#define TFD_IOC_SET_TICKS _IOW('T', 0, u64)
signal/timer/event: timerfd core This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 13:23:16 +08:00
#endif /* _LINUX_TIMERFD_H */
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