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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Rik van Riel <riel@surriel.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>, Wang <wang.yi59@zte.com.cn>,
	zhong.weidong@zte.com.cn, Yi Liu <liu.yi24@zte.com.cn>,
	Frederic Weisbecker <frederic@kernel.org>
Subject: [PATCH v3 3/3] sched/core: Error out if cpumask has a mix of isolcpus and housekeeping CPUs
Date: Fri, 26 Oct 2018 00:12:23 +0530	[thread overview]
Message-ID: <1540492943-17147-4-git-send-email-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1540492943-17147-1-git-send-email-srikar@linux.vnet.ibm.com>

Return EINVAL, if the user has passed a mix of isolcpus and housekeeping
CPUs in cpumask to sched_setaffinity(). This will ensure that users are
notified so that they can take corrective actions to ensure consistent
behaviour. This might cause a change in sched_setaffinity behaviour when
isolcpus is set.

Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 kernel/sched/core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 37e62b8..3842471 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4798,9 +4798,12 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
 	 * housekeeping_cpumask
 	 */
 	if (!cpumask_subset(new_mask, hk_mask) &&
-			cpumask_intersects(new_mask, hk_mask))
+			cpumask_intersects(new_mask, hk_mask)) {
 		pr_warn("pid %d: Mix of isolcpus and non-isolcpus provided\n",
 			p->pid);
+		retval = -EINVAL;
+		goto out_free_new_mask;
+	}
 
 	/*
 	 * Since bandwidth control happens on root_domain basis,
-- 
1.8.3.1


      parent reply	other threads:[~2018-10-25 18:42 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-25 18:42 [PATCH v3 0/3] isolcpus Srikar Dronamraju
2018-10-25 18:42 ` [PATCH v3 1/3] sched/core: Warn if cpumask has a mix of isolcpus and housekeeping CPUs Srikar Dronamraju
2018-10-26  8:32   ` Peter Zijlstra
2018-10-25 18:42 ` [PATCH v3 2/3] sched/core: Don't mix " Srikar Dronamraju
2018-10-26  8:33   ` Peter Zijlstra
2018-10-25 18:42 ` Srikar Dronamraju [this message]

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