linux/kernel/hrtimer.c

1924 lines
47 KiB

timerfd: new timerfd API This is the new timerfd API as it is implemented by the following patch: int timerfd_create(int clockid, int flags); int timerfd_settime(int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr); int timerfd_gettime(int ufd, struct itimerspec *otmr); The timerfd_create() API creates an un-programmed timerfd fd. The "clockid" parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME. The timerfd_settime() API give new settings by the timerfd fd, by optionally retrieving the previous expiration time (in case the "otmr" parameter is not NULL). The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit is set in the "flags" parameter. Otherwise it's a relative time. The timerfd_gettime() API returns the next expiration time of the timer, or {0, 0} if the timerfd has not been set yet. Like the previous timerfd API implementation, read(2) and poll(2) are supported (with the same interface). Here's a simple test program I used to exercise the new timerfd APIs: http://www.xmailserver.org/timerfd-test2.c [akpm@linux-foundation.org: coding-style cleanups] [akpm@linux-foundation.org: fix ia64 build] [akpm@linux-foundation.org: fix m68k build] [akpm@linux-foundation.org: fix mips build] [akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds] [heiko.carstens@de.ibm.com: fix s390] [akpm@linux-foundation.org: fix powerpc build] [akpm@linux-foundation.org: fix sparc64 more] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-04 22:27:26 -08:00
timerfd: new timerfd API This is the new timerfd API as it is implemented by the following patch: int timerfd_create(int clockid, int flags); int timerfd_settime(int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr); int timerfd_gettime(int ufd, struct itimerspec *otmr); The timerfd_create() API creates an un-programmed timerfd fd. The "clockid" parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME. The timerfd_settime() API give new settings by the timerfd fd, by optionally retrieving the previous expiration time (in case the "otmr" parameter is not NULL). The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit is set in the "flags" parameter. Otherwise it's a relative time. The timerfd_gettime() API returns the next expiration time of the timer, or {0, 0} if the timerfd has not been set yet. Like the previous timerfd API implementation, read(2) and poll(2) are supported (with the same interface). Here's a simple test program I used to exercise the new timerfd APIs: http://www.xmailserver.org/timerfd-test2.c [akpm@linux-foundation.org: coding-style cleanups] [akpm@linux-foundation.org: fix ia64 build] [akpm@linux-foundation.org: fix m68k build] [akpm@linux-foundation.org: fix mips build] [akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds] [heiko.carstens@de.ibm.com: fix s390] [akpm@linux-foundation.org: fix powerpc build] [akpm@linux-foundation.org: fix sparc64 more] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-04 22:27:26 -08:00
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 01:28:13 -08:00
timerfd: new timerfd API This is the new timerfd API as it is implemented by the following patch: int timerfd_create(int clockid, int flags); int timerfd_settime(int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr); int timerfd_gettime(int ufd, struct itimerspec *otmr); The timerfd_create() API creates an un-programmed timerfd fd. The "clockid" parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME. The timerfd_settime() API give new settings by the timerfd fd, by optionally retrieving the previous expiration time (in case the "otmr" parameter is not NULL). The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit is set in the "flags" parameter. Otherwise it's a relative time. The timerfd_gettime() API returns the next expiration time of the timer, or {0, 0} if the timerfd has not been set yet. Like the previous timerfd API implementation, read(2) and poll(2) are supported (with the same interface). Here's a simple test program I used to exercise the new timerfd APIs: http://www.xmailserver.org/timerfd-test2.c [akpm@linux-foundation.org: coding-style cleanups] [akpm@linux-foundation.org: fix ia64 build] [akpm@linux-foundation.org: fix m68k build] [akpm@linux-foundation.org: fix mips build] [akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds] [heiko.carstens@de.ibm.com: fix s390] [akpm@linux-foundation.org: fix powerpc build] [akpm@linux-foundation.org: fix sparc64 more] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-04 22:27:26 -08:00
timerfd: new timerfd API This is the new timerfd API as it is implemented by the following patch: int timerfd_create(int clockid, int flags); int timerfd_settime(int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr); int timerfd_gettime(int ufd, struct itimerspec *otmr); The timerfd_create() API creates an un-programmed timerfd fd. The "clockid" parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME. The timerfd_settime() API give new settings by the timerfd fd, by optionally retrieving the previous expiration time (in case the "otmr" parameter is not NULL). The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit is set in the "flags" parameter. Otherwise it's a relative time. The timerfd_gettime() API returns the next expiration time of the timer, or {0, 0} if the timerfd has not been set yet. Like the previous timerfd API implementation, read(2) and poll(2) are supported (with the same interface). Here's a simple test program I used to exercise the new timerfd APIs: http://www.xmailserver.org/timerfd-test2.c [akpm@linux-foundation.org: coding-style cleanups] [akpm@linux-foundation.org: fix ia64 build] [akpm@linux-foundation.org: fix m68k build] [akpm@linux-foundation.org: fix mips build] [akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds] [heiko.carstens@de.ibm.com: fix s390] [akpm@linux-foundation.org: fix powerpc build] [akpm@linux-foundation.org: fix sparc64 more] Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-04 22:27:26 -08:00
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 01:28:13 -08:00
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 01:28:13 -08:00
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 01:28:13 -08:00
timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context Impact: fix incorrect locking triggered during hotplug-intense stress-tests While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline, we queue them on the cb_pending list, so that they won't go stale. Thus, when the callbacks of the timers run from the softirq context, they could run into potential deadlocks, since these callbacks assume that they're running with irq's disabled, thereby annoying lockdep! Fix this by emulating hardirq context while running these callbacks from the hrtimer softirq. ================================= [ INFO: inconsistent lock state ] 2.6.27 #2 -------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: (&rq->lock){++..}, at: [<c011db84>] sched_rt_period_timer+0x9e/0x1fc {in-hardirq-W} state was registered at: [<c014103c>] __lock_acquire+0x549/0x121e [<c0107890>] native_sched_clock+0x88/0x99 [<c013aa12>] clocksource_get_next+0x39/0x3f [<c0139abc>] update_wall_time+0x616/0x7df [<c0141d6b>] lock_acquire+0x5a/0x74 [<c0121724>] scheduler_tick+0x3a/0x18d [<c047ed45>] _spin_lock+0x1c/0x45 [<c0121724>] scheduler_tick+0x3a/0x18d [<c0121724>] scheduler_tick+0x3a/0x18d [<c012c436>] update_process_times+0x3a/0x44 [<c013c044>] tick_periodic+0x63/0x6d [<c013c062>] tick_handle_periodic+0x14/0x5e [<c010568c>] timer_interrupt+0x44/0x4a [<c0150c9f>] handle_IRQ_event+0x13/0x3d [<c0151c14>] handle_level_irq+0x79/0xbd [<c0105634>] do_IRQ+0x69/0x7d [<c01041e4>] common_interrupt+0x28/0x30 [<c047007b>] aac_probe_one+0x1a3/0x3f3 [<c047ec2d>] _spin_unlock_irqrestore+0x36/0x39 [<c01512b4>] setup_irq+0x1be/0x1f9 [<c065d70b>] start_kernel+0x259/0x2c5 [<ffffffff>] 0xffffffff irq event stamp: 50102 hardirqs last enabled at (50102): [<c047ebf4>] _spin_unlock_irq+0x20/0x23 hardirqs last disabled at (50101): [<c047edc2>] _spin_lock_irq+0xa/0x4b softirqs last enabled at (50088): [<c0128ba6>] do_softirq+0x37/0x4d softirqs last disabled at (50099): [<c0128ba6>] do_softirq+0x37/0x4d other info that might help us debug this: no locks held by ksoftirqd/0/4. stack backtrace: Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2 [<c013f6cb>] print_usage_bug+0x13e/0x147 [<c013fef5>] mark_lock+0x493/0x797 [<c01410b1>] __lock_acquire+0x5be/0x121e [<c0141d6b>] lock_acquire+0x5a/0x74 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c047ed45>] _spin_lock+0x1c/0x45 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c01210fd>] finish_task_switch+0x41/0xbd [<c0107890>] native_sched_clock+0x88/0x99 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0136dda>] run_hrtimer_pending+0x54/0xe5 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0128afb>] __do_softirq+0x7b/0xef [<c0128ba6>] do_softirq+0x37/0x4d [<c0128c12>] ksoftirqd+0x56/0xc5 [<c0128bbc>] ksoftirqd+0x0/0xc5 [<c0134649>] kthread+0x38/0x5d [<c0134611>] kthread+0x0/0x5d [<c0104477>] kernel_thread_helper+0x7/0x10 ======================= Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-25 10:22:38 +05:30
timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context Impact: fix incorrect locking triggered during hotplug-intense stress-tests While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline, we queue them on the cb_pending list, so that they won't go stale. Thus, when the callbacks of the timers run from the softirq context, they could run into potential deadlocks, since these callbacks assume that they're running with irq's disabled, thereby annoying lockdep! Fix this by emulating hardirq context while running these callbacks from the hrtimer softirq. ================================= [ INFO: inconsistent lock state ] 2.6.27 #2 -------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: (&rq->lock){++..}, at: [<c011db84>] sched_rt_period_timer+0x9e/0x1fc {in-hardirq-W} state was registered at: [<c014103c>] __lock_acquire+0x549/0x121e [<c0107890>] native_sched_clock+0x88/0x99 [<c013aa12>] clocksource_get_next+0x39/0x3f [<c0139abc>] update_wall_time+0x616/0x7df [<c0141d6b>] lock_acquire+0x5a/0x74 [<c0121724>] scheduler_tick+0x3a/0x18d [<c047ed45>] _spin_lock+0x1c/0x45 [<c0121724>] scheduler_tick+0x3a/0x18d [<c0121724>] scheduler_tick+0x3a/0x18d [<c012c436>] update_process_times+0x3a/0x44 [<c013c044>] tick_periodic+0x63/0x6d [<c013c062>] tick_handle_periodic+0x14/0x5e [<c010568c>] timer_interrupt+0x44/0x4a [<c0150c9f>] handle_IRQ_event+0x13/0x3d [<c0151c14>] handle_level_irq+0x79/0xbd [<c0105634>] do_IRQ+0x69/0x7d [<c01041e4>] common_interrupt+0x28/0x30 [<c047007b>] aac_probe_one+0x1a3/0x3f3 [<c047ec2d>] _spin_unlock_irqrestore+0x36/0x39 [<c01512b4>] setup_irq+0x1be/0x1f9 [<c065d70b>] start_kernel+0x259/0x2c5 [<ffffffff>] 0xffffffff irq event stamp: 50102 hardirqs last enabled at (50102): [<c047ebf4>] _spin_unlock_irq+0x20/0x23 hardirqs last disabled at (50101): [<c047edc2>] _spin_lock_irq+0xa/0x4b softirqs last enabled at (50088): [<c0128ba6>] do_softirq+0x37/0x4d softirqs last disabled at (50099): [<c0128ba6>] do_softirq+0x37/0x4d other info that might help us debug this: no locks held by ksoftirqd/0/4. stack backtrace: Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2 [<c013f6cb>] print_usage_bug+0x13e/0x147 [<c013fef5>] mark_lock+0x493/0x797 [<c01410b1>] __lock_acquire+0x5be/0x121e [<c0141d6b>] lock_acquire+0x5a/0x74 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c047ed45>] _spin_lock+0x1c/0x45 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c01210fd>] finish_task_switch+0x41/0xbd [<c0107890>] native_sched_clock+0x88/0x99 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0136dda>] run_hrtimer_pending+0x54/0xe5 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0128afb>] __do_softirq+0x7b/0xef [<c0128ba6>] do_softirq+0x37/0x4d [<c0128c12>] ksoftirqd+0x56/0xc5 [<c0128bbc>] ksoftirqd+0x0/0xc5 [<c0134649>] kthread+0x38/0x5d [<c0134611>] kthread+0x0/0x5d [<c0104477>] kernel_thread_helper+0x7/0x10 ======================= Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-25 10:22:38 +05:30
timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context Impact: fix incorrect locking triggered during hotplug-intense stress-tests While migrating the the CB_IRQSAFE_UNLOCKED timers during a cpu-offline, we queue them on the cb_pending list, so that they won't go stale. Thus, when the callbacks of the timers run from the softirq context, they could run into potential deadlocks, since these callbacks assume that they're running with irq's disabled, thereby annoying lockdep! Fix this by emulating hardirq context while running these callbacks from the hrtimer softirq. ================================= [ INFO: inconsistent lock state ] 2.6.27 #2 -------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: (&rq->lock){++..}, at: [<c011db84>] sched_rt_period_timer+0x9e/0x1fc {in-hardirq-W} state was registered at: [<c014103c>] __lock_acquire+0x549/0x121e [<c0107890>] native_sched_clock+0x88/0x99 [<c013aa12>] clocksource_get_next+0x39/0x3f [<c0139abc>] update_wall_time+0x616/0x7df [<c0141d6b>] lock_acquire+0x5a/0x74 [<c0121724>] scheduler_tick+0x3a/0x18d [<c047ed45>] _spin_lock+0x1c/0x45 [<c0121724>] scheduler_tick+0x3a/0x18d [<c0121724>] scheduler_tick+0x3a/0x18d [<c012c436>] update_process_times+0x3a/0x44 [<c013c044>] tick_periodic+0x63/0x6d [<c013c062>] tick_handle_periodic+0x14/0x5e [<c010568c>] timer_interrupt+0x44/0x4a [<c0150c9f>] handle_IRQ_event+0x13/0x3d [<c0151c14>] handle_level_irq+0x79/0xbd [<c0105634>] do_IRQ+0x69/0x7d [<c01041e4>] common_interrupt+0x28/0x30 [<c047007b>] aac_probe_one+0x1a3/0x3f3 [<c047ec2d>] _spin_unlock_irqrestore+0x36/0x39 [<c01512b4>] setup_irq+0x1be/0x1f9 [<c065d70b>] start_kernel+0x259/0x2c5 [<ffffffff>] 0xffffffff irq event stamp: 50102 hardirqs last enabled at (50102): [<c047ebf4>] _spin_unlock_irq+0x20/0x23 hardirqs last disabled at (50101): [<c047edc2>] _spin_lock_irq+0xa/0x4b softirqs last enabled at (50088): [<c0128ba6>] do_softirq+0x37/0x4d softirqs last disabled at (50099): [<c0128ba6>] do_softirq+0x37/0x4d other info that might help us debug this: no locks held by ksoftirqd/0/4. stack backtrace: Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27 #2 [<c013f6cb>] print_usage_bug+0x13e/0x147 [<c013fef5>] mark_lock+0x493/0x797 [<c01410b1>] __lock_acquire+0x5be/0x121e [<c0141d6b>] lock_acquire+0x5a/0x74 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c047ed45>] _spin_lock+0x1c/0x45 [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c011db84>] sched_rt_period_timer+0x9e/0x1fc [<c01210fd>] finish_task_switch+0x41/0xbd [<c0107890>] native_sched_clock+0x88/0x99 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0136dda>] run_hrtimer_pending+0x54/0xe5 [<c011dae6>] sched_rt_period_timer+0x0/0x1fc [<c0128afb>] __do_softirq+0x7b/0xef [<c0128ba6>] do_softirq+0x37/0x4d [<c0128c12>] ksoftirqd+0x56/0xc5 [<c0128bbc>] ksoftirqd+0x0/0xc5 [<c0134649>] kthread+0x38/0x5d [<c0134611>] kthread+0x0/0x5d [<c0104477>] kernel_thread_helper+0x7/0x10 ======================= Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-25 10:22:38 +05:30
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 01:28:13 -08:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00
hrtimer: fix *rmtp handling in hrtimer_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to the local variable which lives in the caller's stack frame. This means that if sys_restart_syscall() actually happens and it is interrupted as well, we don't update the user-space variable, but write into the already dead stack frame. Introduced by commit 04c227140fed77587432667a574b14736a06dd7f hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp. Small problem remains. man 2 nanosleep states that *rtmp should be written if nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp if nanosleep returns 0), but (with or without this patch) we can dirty *rem even if nanosleep() returns 0. NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other bugs. Fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Pavel Emelyanov <xemul@sw.ru> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Toyo Abe <toyoa@mvista.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> include/linux/hrtimer.h | 2 - kernel/hrtimer.c | 51 +++++++++++++++++++++++++----------------------- kernel/posix-timers.c | 14 +------------ 3 files changed, 30 insertions(+), 37 deletions(-)
2008-02-01 17:29:05 +03:00