Commit 150dfee9 authored Oct 27, 2017 by Frederic Weisbecker Committed by Ingo Molnar Oct 27, 2017

sched/isolation: Add basic isolcpus flags



Add flags to control NOHZ and domain isolation from "isolcpus=", in
order to centralize the isolation features to a common interface. Domain
isolation remains the default so not to break the existing isolcpus
boot paramater behaviour.

Further flags in the future may include 0hz (1hz tick offload) and timers,
workqueue, RCU, kthread, watchdog, likely all merged together in a
common flag ("async"?). In any case, this will have to be modifiable by
cpusets.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1509072159-31808-12-git-send-email-frederic@kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent edb93821

kernel/sched/isolation.c

+25 −1

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@
		#include <linux/init.h>
		#include <linux/kernel.h>
		#include <linux/static_key.h>
		#include <linux/ctype.h>

		DEFINE_STATIC_KEY_FALSE(housekeeping_overriden);
		EXPORT_SYMBOL_GPL(housekeeping_overriden);
		@@ -126,6 +127,29 @@ __setup("nohz_full=", housekeeping_nohz_full_setup);

		static int __init housekeeping_isolcpus_setup(char *str)
		{
		return housekeeping_setup(str, HK_FLAG_DOMAIN);
		unsigned int flags = 0;

		while (isalpha(*str)) {
		if (!strncmp(str, "nohz,", 5)) {
		str += 5;
		flags \|= HK_FLAG_TICK;
		continue;
		}

		if (!strncmp(str, "domain,", 7)) {
		str += 7;
		flags \|= HK_FLAG_DOMAIN;
		continue;
		}

		pr_warn("isolcpus: Error, unknown flag\n");
		return 0;
		}

		/* Default behaviour for isolcpus without flags */
		if (!flags)
		flags \|= HK_FLAG_DOMAIN;

		return housekeeping_setup(str, flags);
		}
		__setup("isolcpus=", housekeeping_isolcpus_setup);

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