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![Daniel Bristot de Oliveira](/assets/img/avatar_default.png)
The wakeup in preemptive (wip) monitor verifies if the wakeup events always take place with preemption disabled: | | v #==================# H preemptive H <+ #==================# | | | | preempt_disable | preempt_enable v | sched_waking +------------------+ | +--------------- | | | | | non_preemptive | | +--------------> | | -+ +------------------+ The wakeup event always takes place with preemption disabled because of the scheduler synchronization. However, because the preempt_count and its trace event are not atomic with regard to interrupts, some inconsistencies might happen. The documentation illustrates one of these cases. Link: https://lkml.kernel.org/r/c98ca678df81115fddc04921b3c79720c836b18f.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck <wim@linux-watchdog.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Gabriele Paoloni <gpaoloni@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
16 lines
602 B
Text
16 lines
602 B
Text
digraph state_automaton {
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{node [shape = circle] "non_preemptive"};
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{node [shape = plaintext, style=invis, label=""] "__init_preemptive"};
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{node [shape = doublecircle] "preemptive"};
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{node [shape = circle] "preemptive"};
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"__init_preemptive" -> "preemptive";
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"non_preemptive" [label = "non_preemptive"];
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"non_preemptive" -> "non_preemptive" [ label = "sched_waking" ];
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"non_preemptive" -> "preemptive" [ label = "preempt_enable" ];
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"preemptive" [label = "preemptive"];
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"preemptive" -> "non_preemptive" [ label = "preempt_disable" ];
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{ rank = min ;
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"__init_preemptive";
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"preemptive";
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}
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}
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