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Date:   Mon, 12 Oct 2020 11:37:48 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Rob Clark <robdclark@chromium.org>
Cc:     Rob Clark <robdclark@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Phil Auld <pauld@redhat.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Thara Gopinath <thara.gopinath@linaro.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Vincent Donnefort <vincent.donnefort@arm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jens Axboe <axboe@kernel.dk>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Ilias Stamatis <stamatis.iliass@gmail.com>,
        Liang Chen <cl@rock-chips.com>,
        Ben Dooks <ben.dooks@codethink.co.uk>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        "J. Bruce Fields" <bfields@redhat.com>
Subject: Re: [PATCH] kthread: Add kthread_work tracepoints
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On Mon, 12 Oct 2020 08:14:50 -0700
Rob Clark <robdclark@chromium.org> wrote:

> > DEFINE_EVENT(sched_kthread_work_execute_template, sched_kthread_work_execute_start,
> >         TP_PROTO(struct kthread_work *work),
> >         TP_ARGS(work));
> >
> > DEFINE_EVENT(sched_kthread_work_execute_template, sched_kthread_work_execute_end,
> >         TP_PROTO(struct kthread_work *work),
> >         TP_ARGS(work));
> >
> > As events are cheap, classes are expensive (size wise), and a TRACE_EVENT()
> > is really just a CLASS and EVENT for a single instance.  
> 
> I think we cannot quite do this, because we should not rely on being

Ah I missed seeing that one used work->func and the other passed in the
function.

> able to dereference work after it finishes.  Although I suppose I
> could just define it to explicitly pass the fxn ptr to both
> tracepoints..

But yes, I would rather see that. It could save up to 5K in text and data.

-- Steve