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Date: Sun, 12 Feb 2017 16:03:35 +0000
From: Chris Wilson <chris@chris-wilson.co.uk>
To: linux-kernel@vger.kernel.org
Cc: intel-gfx@lists.freedesktop.org,
        Tvrtko Ursulin <tvrtko.ursulin@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>, Hannes Reinecke <hare@suse.com>,
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        Ingo Molnar <mingo@kernel.org>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Emese Revfy <re.emese@gmail.com>, Sagi Grimberg <sagi@grimberg.me>,
        Eric Dumazet <edumazet@google.com>, Tom Herbert <therbert@google.com>,
        Ben Hutchings <bhutchings@solarflare.com>
Subject: Re: [PATCH v3] softirq: Prevent looping on disabled tasklets
Message-ID: <20170212160335.GD14326@nuc-i3427.alporthouse.com>
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References: <20170212140019.3450-1-chris@chris-wilson.co.uk>
 <20170212154609.20238-1-chris@chris-wilson.co.uk>
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On Sun, Feb 12, 2017 at 03:46:09PM +0000, Chris Wilson wrote:
> +void tasklet_enable(struct tasklet_struct *t)
> +{
> +	if (!atomic_dec_and_test(&t->count))
> +		return;
> +
> +	if (test_bit(TASKLET_STATE_SCHED, &t->state))
> +		raise_softirq(HI_SOFTIRQ | TASKLET_SOFTIRQ);

And of course this can't work as raise_softirq() is local to the cpu.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre