summaryrefslogtreecommitdiff
path: root/include/linux
AgeCommit message (Collapse)Author
2011-12-28tasklet: Prevent tasklets from going into infinite spin in RTIngo Molnar
When CONFIG_PREEMPT_RT_FULL is enabled, tasklets run as threads, and spinlocks turn are mutexes. But this can cause issues with tasks disabling tasklets. A tasklet runs under ksoftirqd, and if a tasklets are disabled with tasklet_disable(), the tasklet count is increased. When a tasklet runs, it checks this counter and if it is set, it adds itself back on the softirq queue and returns. The problem arises in RT because ksoftirq will see that a softirq is ready to run (the tasklet softirq just re-armed itself), and will not sleep, but instead run the softirqs again. The tasklet softirq will still see that the count is non-zero and will not execute the tasklet and requeue itself on the softirq again, which will cause ksoftirqd to run it again and again and again. It gets worse because ksoftirqd runs as a real-time thread. If it preempted the task that disabled tasklets, and that task has migration disabled, or can't run for other reasons, the tasklet softirq will never run because the count will never be zero, and ksoftirqd will go into an infinite loop. As an RT task, it this becomes a big problem. This is a hack solution to have tasklet_disable stop tasklets, and when a tasklet runs, instead of requeueing the tasklet softirqd it delays it. When tasklet_enable() is called, and tasklets are waiting, then the tasklet_enable() will kick the tasklets to continue. This prevents the lock up from ksoftirq going into an infinite loop. [ rostedt@goodmis.org: ported to 3.0-rt ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28softirq-disable-softirq-stacks-for-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28hardirq.h: Define softirq_count() as OUL to kill build warningYong Zhang
kernel/lockdep.c: In function ‘print_bad_irq_dependency’: kernel/lockdep.c:1476:3: warning: format ‘%lu’ expects type ‘long unsigned int’, but argument 7 has type ‘unsigned int’ kernel/lockdep.c: In function ‘print_usage_bug’: kernel/lockdep.c:2193:3: warning: format ‘%lu’ expects type ‘long unsigned int’, but argument 7 has type ‘unsigned int’ kernel/lockdep.i show this: printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", curr->comm, task_pid_nr(curr), curr->hardirq_context, ((current_thread_info()->preempt_count) & (((1UL << (10))-1) << ((0 + 8) + 8))) >> ((0 + 8) + 8), curr->softirq_context, (0U) >> (0 + 8), curr->hardirqs_enabled, curr->softirqs_enabled); Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Link: http://lkml.kernel.org/r/20111013091909.GA32739@zhy Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28softirq-local-lock.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28lockdep-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28softirq: Sanitize softirq pending for NOHZ/RTThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched: teach migrate_disable about atomic contextsPeter Zijlstra
<NMI> [<ffffffff812dafd8>] spin_bug+0x94/0xa8 [<ffffffff812db07f>] do_raw_spin_lock+0x43/0xea [<ffffffff814fa9be>] _raw_spin_lock_irqsave+0x6b/0x85 [<ffffffff8106ff9e>] ? migrate_disable+0x75/0x12d [<ffffffff81078aaf>] ? pin_current_cpu+0x36/0xb0 [<ffffffff8106ff9e>] migrate_disable+0x75/0x12d [<ffffffff81115b9d>] pagefault_disable+0xe/0x1f [<ffffffff81047027>] copy_from_user_nmi+0x74/0xe6 [<ffffffff810489d7>] perf_callchain_user+0xf3/0x135 Now clearly we can't go around taking locks from NMI context, cure this by short-circuiting migrate_disable() when we're in an atomic context already. Add some extra debugging to avoid things like: preempt_disable() migrate_disable(); preempt_enable(); migrate_enable(); Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1314967297.1301.14.camel@twins Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-wbot4vsmwhi8vmbf83hsclk6@git.kernel.org
2011-12-28sched: Generic migrate_disablePeter Zijlstra
Make migrate_disable() be a preempt_disable() for !rt kernels. This allows generic code to use it but still enforces that these code sections stay relatively small. A preemptible migrate_disable() accessible for general use would allow people growing arbitrary per-cpu crap instead of clean these things up. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-275i87sl8e1jcamtchmehonm@git.kernel.org
2011-12-28migrate-disable-rt-variant.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28ftrace-migrate-disable-tracing.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched-migrate-disable.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28hotplug: Lightweight get online cpusThomas Gleixner
get_online_cpus() is a heavy weight function which involves a global mutex. migrate_disable() wants a simpler construct which prevents only a CPU from going doing while a task is in a migrate disabled section. Implement a per cpu lockless mechanism, which serializes only in the real unplug case on a global mutex. That serialization affects only tasks on the cpu which should be brought down. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28stomp-machine-mark-stomper-thread.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28cond-resched-lock-rt-tweak.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched-no-work-when-pi-blocked.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28cond-resched-softirq-fix.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched-might-sleep-do-not-account-rcu-depth.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched-rt-mutex-wakeup.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched-mmdrop-delayed.patchThomas Gleixner
Needs thread context (pgd_lock) -> ifdeffed. workqueues wont work with RT Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sched-delay-put-task.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28posix-timers: thread posix-cpu-timers on -rtJohn Stultz
posix-cpu-timer code takes non -rt safe locks in hard irq context. Move it to a thread. [ 3.0 fixes from Peter Zijlstra <peterz@infradead.org> ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28hrtimer: fixup hrtimer callback changes for preempt-rtThomas Gleixner
In preempt-rt we can not call the callbacks which take sleeping locks from the timer interrupt context. Bring back the softirq split for now, until we fixed the signal delivery problem for real. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-28hrtimers: prepare full preemptionIngo Molnar
Make cancellation of a running callback in softirq context safe against preemption. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28timers: prepare for full preemptionIngo Molnar
When softirqs can be preempted we need to make sure that cancelling the timer from the active thread can not deadlock vs. a running timer callback. Add a waitqueue to resolve that. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28radix-tree-rt-aware.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28mm: shrink the page frame to !-rt sizePeter Zijlstra
He below is a boot-tested hack to shrink the page frame size back to normal. Should be a net win since there should be many less PTE-pages than page-frames. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28mm: make vmstat -rt awareIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28cpu-rt-variants.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28rt-local-irq-lock.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28local-var.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28genirq-force-threading.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28fs: jbd/jbd2: Make state lock and journal head lock rt safeThomas Gleixner
bit_spin_locks break under RT. Based on a previous patch from Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> -- include/linux/buffer_head.h | 10 ++++++++++ include/linux/jbd_common.h | 24 ++++++++++++++++++++++++ 2 files changed, 34 insertions(+)
2011-12-28buffer_head: Replace bh_uptodate_lock for -rtThomas Gleixner
Wrap the bit_spin_lock calls into a separate inline and add the RT replacements with a real spinlock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28mm: Replace cgroup_page bit spinlockThomas Gleixner
Bit spinlocks are not working on RT. Replace them. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28preempt: Provide preempt_*_(no)rt variantsThomas Gleixner
RT needs a few preempt_disable/enable points which are not necessary otherwise. Implement variants to avoid #ifdeffery. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28rt: local_irq_* variants depending on RT/!RTThomas Gleixner
Add local_irq_*_(no)rt variant which are mainly used to break interrupt disabled sections on PREEMPT_RT or to explicitely disable interrupts on PREEMPT_RT. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28printk-kill.patchIngo Molnar
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28early-printk-consolidate.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28latency-hist.patchCarsten Emde
This patch provides a recording mechanism to store data of potential sources of system latencies. The recordings separately determine the latency caused by a delayed timer expiration, by a delayed wakeup of the related user space program and by the sum of both. The histograms can be enabled and reset individually. The data are accessible via the debug filesystem. For details please consult Documentation/trace/histograms.txt. Signed-off-by: Carsten Emde <C.Emde@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28seqlock: Create raw_seqlockThomas Gleixner
raw_seqlock_t will be used to annotate seqlocks which can not be converted to sleeping locks in preempt-rt Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28wait: Provide __wake_up_all_lockedThomas Gleixner
For code which protects the waitqueue itself with another lock it makes no sense to acquire the waitqueue lock for wakeup all. Provide __wake_up_all_locked. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2011-12-28seqlock-use-seqcount.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28seqlock-remove-unused-functions.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28locking-various-init-fixes.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28softirq-thread-do-softirq.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28sysctl-include-fix.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28rwsem-inlcude-fix.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28list-add-list-last-entry.patchPeter Zijlstra
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28of-convert-devtree-lock.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-12-28suspend: Prevent might sleep splatsThomas Gleixner
timekeeping suspend/resume calls read_persistant_clock() which takes rtc_lock. That results in might sleep warnings because at that point we run with interrupts disabled. We cannot convert rtc_lock to a raw spinlock as that would trigger other might sleep warnings. As a temporary workaround we disable the might sleep warnings by setting system_state to SYSTEM_SUSPEND before calling sysdev_suspend() and restoring it to SYSTEM_RUNNING afer sysdev_resume(). Needs to be revisited. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
generated by cgit v1.2.3 (git 2.0.4) at 2025-05-28 00:52:50 +0000