From: Frederic Weisbecker <frederic@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mel Gorman <mgorman@suse.de>,
Frederic Weisbecker <fweisbecker@suse.de>,
Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [RFC PATCH v2 0/5] allow overriding default preempt mode from command line
Date: Tue, 27 Oct 2020 13:22:41 +0100 [thread overview]
Message-ID: <20201027122241.GA140902@lothringen> (raw)
In-Reply-To: <20201009174554.GS2611@hirez.programming.kicks-ass.net>
On Fri, Oct 09, 2020 at 07:45:54PM +0200, Peter Zijlstra wrote:
> +DEFINE_STATIC_KEY_TRUE(irq_preemption_key);
> +
> +/*
> + * SC:cond_resched
> + * SC:might_resched
> + * SC:preempt_schedule
> + * SC:preempt_schedule_notrace
> + * SB:irq_preemption_key
> + *
> + *
> + * ZERO
> + * cond_resched <- RET0
> + * might_resched <- NOP
> + * preempt_schedule <- NOP
> + * preempt_schedule_notrace <- NOP
> + * irq_preemption_key <- false
> + *
> + * NONE:
> + * cond_resched <- __cond_resched
> + * might_resched <- NOP
> + * preempt_schedule <- NOP
> + * preempt_schedule_notrace <- NOP
> + * irq_preemption_key <- false
> + *
> + * VOLUNTARY:
> + * cond_resched <- __cond_resched
> + * might_resched <- __might_resched
> + * preempt_schedule <- NOP
> + * preempt_schedule_notrace <- NOP
> + * irq_preemption_key <- false
> + *
> + * FULL:
> + * cond_resched <- RET0
> + * might_resched <- NOP
> + * preempt_schedule <- preempt_schedule
> + * preempt_schedule_notrace <- preempt_schedule_notrace
> + * irq_preemption_key <- true
> + */
That's cute! I'll try to end up to that result.
> +static int __init setup_preempt_mode(char *str)
> +{
> + if (!strcmp(str, "zero")) {
> + static_call_update(cond_resched, __static_call_return0);
> + static_call_update(might_resched, (void (*)(void))NULL);
> + static_call_update(preempt_schedule, (void (*)(void))NULL);
> + static_call_update(preempt_schedule_notrace, (void (*)(void))NULL);
> + static_branch_disable(&irq_preemption_key);
> + printk("XXX PREEMPT: %s\n", str);
> + } else if (!strcmp(str, "none")) {
> + static_call_update(cond_resched, __cond_resched);
> + static_call_update(might_resched, (void (*)(void))NULL);
> + static_call_update(preempt_schedule, (void (*)(void))NULL);
> + static_call_update(preempt_schedule_notrace, (void (*)(void))NULL);
> + static_branch_disable(&irq_preemption_key);
> + printk("XXX PREEMPT: %s\n", str);
> + } else if (!strcmp(str, "voluntary")) {
> + static_call_update(cond_resched, __cond_resched);
> + static_call_update(might_resched, __might_resched);
> + static_call_update(preempt_schedule, (void (*)(void))NULL);
> + static_call_update(preempt_schedule_notrace, (void (*)(void))NULL);
> + static_branch_disable(&irq_preemption_key);
> + printk("XXX PREEMPT: %s\n", str);
> + } else if (!strcmp(str, "ponies")) {
> + static_call_update(cond_resched, __cond_resched);
> + static_call_update(might_resched, (void (*)(void))NULL);
> + static_call_update(preempt_schedule, preempt_schedule_thunk);
> + static_call_update(preempt_schedule_notrace, preempt_schedule_notrace_thunk);
> + static_branch_enable(&irq_preemption_key);
> + printk("XXX PREEMPT: %s\n", str);
Why would we need that ponies version?
Thanks!
next prev parent reply other threads:[~2020-10-27 12:22 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 12:04 [RFC PATCH] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line Michal Hocko
2020-10-07 12:19 ` Peter Zijlstra
2020-10-07 12:29 ` Michal Hocko
2020-10-07 13:01 ` Mel Gorman
2020-10-07 12:21 ` Peter Zijlstra
2020-10-07 12:35 ` Michal Hocko
2020-10-09 9:47 ` Peter Zijlstra
2020-10-09 10:14 ` Michal Hocko
2020-10-09 10:20 ` Peter Zijlstra
2020-10-09 10:48 ` Michal Hocko
2020-10-09 11:17 ` Michal Hocko
2020-10-09 11:26 ` Michal Hocko
2020-10-09 11:39 ` Peter Zijlstra
2020-10-09 9:12 ` Michal Hocko
2020-10-09 9:42 ` Peter Zijlstra
2020-10-09 10:10 ` Michal Hocko
2020-10-09 10:14 ` Peter Zijlstra
2020-10-09 10:37 ` Michal Hocko
2020-10-09 11:42 ` Peter Zijlstra
2020-10-09 12:29 ` [RFC PATCH v2 0/5] allow overriding default preempt mode from " Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 1/5] jump_label: split out declaration parts into its own headers Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 2/5] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 3/5] kernel: ARCH_NO_PREEMPT shouldn't exclude PREEMPT_VOLUNTARY Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 4/5] kernel: introduce CONFIG_PREEMPT_DYNAMIC Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 5/5] kernel: drop PREEMPT_NONE compile time option Michal Hocko
2020-10-09 12:50 ` [RFC PATCH v2 0/5] allow overriding default preempt mode from command line Peter Zijlstra
2020-10-09 13:03 ` Michal Hocko
2020-10-09 13:22 ` Peter Zijlstra
2020-10-09 17:45 ` Peter Zijlstra
2020-10-27 12:22 ` Frederic Weisbecker [this message]
2020-10-27 12:28 ` Peter Zijlstra
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