From: Nam Cao <namcao@linutronix.de>
To: Gabriele Monaco <gmonaco@redhat.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Jonathan Corbet <corbet@lwn.net>,
Masami Hiramatsu <mhiramat@kernel.org>,
linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Cc: Gabriele Monaco <gmonaco@redhat.com>,
Tomas Glozar <tglozar@redhat.com>, Juri Lelli <jlelli@redhat.com>,
Clark Williams <williams@redhat.com>,
John Kacur <jkacur@redhat.com>
Subject: Re: [PATCH v2 15/20] rv: Convert the opid monitor to a hybrid automaton
Date: Fri, 10 Oct 2025 16:29:14 +0200 [thread overview]
Message-ID: <87cy6uygn9.fsf@yellow.woof> (raw)
In-Reply-To: <20250919140954.104920-16-gmonaco@redhat.com>
Gabriele Monaco <gmonaco@redhat.com> writes:
> - | sched_need_resched
> - | sched_waking
> - | irq_entry
> - | +--------------------+
> - v v |
> - +------------------------------------------------------+
> - +----------- | disabled | <+
> - | +------------------------------------------------------+ |
> - | | ^ |
> - | | preempt_disable sched_need_resched |
> - | preempt_enable | +--------------------+ |
> - | v | v | |
> - | +------------------------------------------------------+ |
> - | | irq_disabled | |
> - | +------------------------------------------------------+ |
> - | | | ^ |
> - | irq_entry irq_entry | | |
> - | sched_need_resched v | irq_disable |
> - | sched_waking +--------------+ | | |
> - | +----- | | irq_enable | |
> - | | | in_irq | | | |
> - | +----> | | | | |
> - | +--------------+ | | irq_disable
> - | | | | |
> - | irq_enable | irq_enable | | |
> - | v v | |
> - | #======================================================# |
> - | H enabled H |
> - | #======================================================# |
> - | | ^ ^ preempt_enable | |
> - | preempt_disable preempt_enable +--------------------+ |
> - | v | |
> - | +------------------+ | |
> - +----------> | preempt_disabled | -+ |
> - +------------------+ |
> - | |
> - +-------------------------------------------------------+
> -
> +
> + |
> + |
> + v
> + #=========# sched_need_resched;irq_off == 1
> + H H sched_waking;irq_off == 1 && preempt_off == 1
> + H any H ------------------------------------------------+
> + H H |
> + H H <-----------------------------------------------+
> + #=========#
Nice!
> + * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
> + * preemption (adding one to the preempt_count). Since we are
> + * interested in the preempt_count at the time the tracepoint was
> + * hit, we consider 1 as still enabled.
> + */
> + if (IS_ENABLED(CONFIG_PREEMPTION))
> + return (preempt_count() & PREEMPT_MASK) > 1;
FYI, there is plan to keep preemption enabled during tracepoint
handling. So keep that in mind when this monitor breaks.
Nam
next prev parent reply other threads:[~2025-10-10 14:29 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-19 14:09 [PATCH v2 00/20] rv: Add Hybrid Automata monitor type, per-object and deadline monitors Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 01/20] rv: Refactor da_monitor to minimise macros Gabriele Monaco
2025-10-02 8:45 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 02/20] rv: Cleanup da_monitor after refactor Gabriele Monaco
2025-10-02 8:49 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 03/20] rv: Unify DA event handling functions across monitor types Gabriele Monaco
2025-10-02 9:14 ` Nam Cao
2025-10-02 11:30 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 04/20] Documentation/rv: Adapt documentation after da_monitor refactoring Gabriele Monaco
2025-10-02 9:26 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 05/20] verification/rvgen: Adapt dot2k and templates after refactoring da_monitor.h Gabriele Monaco
2025-10-02 9:34 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 06/20] verification/rvgen: Annotate DA functions with types Gabriele Monaco
2025-10-02 9:39 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 07/20] verification/dot2c: Remove __buff_to_string() and cleanup Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 08/20] verification/dot2c: Remove superfluous enum assignment and add last comma Gabriele Monaco
2025-10-02 9:40 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 09/20] verification/rvgen: Remove unused variable declaration from containers Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 10/20] rv: Add Hybrid Automata monitor type Gabriele Monaco
2025-10-17 8:44 ` Nam Cao
2025-10-17 9:48 ` Gabriele Monaco
2025-10-17 13:05 ` Nam Cao
2025-10-17 15:22 ` Gabriele Monaco
2025-10-20 13:43 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 11/20] verification/rvgen: Allow spaces in and events strings Gabriele Monaco
2025-10-02 11:03 ` Nam Cao
2025-10-02 11:17 ` Gabriele Monaco
2025-10-06 13:20 ` Nam Cao
2025-10-06 15:22 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 12/20] verification/rvgen: Add support for Hybrid Automata Gabriele Monaco
2025-10-17 9:37 ` Nam Cao
2025-10-17 9:53 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 13/20] Documentation/rv: Add documentation about hybrid automata Gabriele Monaco
2025-10-10 13:46 ` Nam Cao
2025-10-13 8:33 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 14/20] rv: Add sample hybrid monitors stall Gabriele Monaco
2025-10-10 14:23 ` Nam Cao
2025-10-13 9:01 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 15/20] rv: Convert the opid monitor to a hybrid automaton Gabriele Monaco
2025-10-10 14:29 ` Nam Cao [this message]
2025-10-13 14:14 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 16/20] sched: Export hidden tracepoints to modules Gabriele Monaco
2025-09-19 15:37 ` Steven Rostedt
2025-09-19 17:07 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 17/20] sched: Add deadline tracepoints Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 18/20] rv: Add support for per-object monitors in DA/HA Gabriele Monaco
2025-10-21 11:55 ` Nam Cao
2025-10-21 15:54 ` Gabriele Monaco
2025-10-23 12:36 ` Nam Cao
2025-10-24 9:20 ` Gabriele Monaco
2025-09-19 14:09 ` [PATCH v2 19/20] verification/rvgen: Add support for per-obj monitors Gabriele Monaco
2025-10-21 12:00 ` Nam Cao
2025-09-19 14:09 ` [PATCH v2 20/20] rv: Add deadline monitors Gabriele Monaco
2025-10-10 15:04 ` Nam Cao
2025-10-13 7:30 ` Gabriele Monaco
2025-10-21 12:05 ` [PATCH v2 00/20] rv: Add Hybrid Automata monitor type, per-object and " Nam Cao
2025-10-21 15:45 ` Gabriele Monaco
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