linux-kernel - [PATCH 2/5] sched/isolation: Add scheduler tick offloading interface

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1515039937-367-3-git-send-email-frederic@kernel.org>
Date:   Thu,  4 Jan 2018 05:25:34 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Chris Metcalf <cmetcalf@...lanox.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Luiz Capitulino <lcapitulino@...hat.com>,
        Christoph Lameter <cl@...ux.com>,
        "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Mike Galbraith <efault@....de>, Rik van Riel <riel@...hat.com>
Subject: [PATCH 2/5] sched/isolation: Add scheduler tick offloading interface

Add the boot option that will allow us to offload the 1Hz scheduler tick
to the housekeeping CPU.

Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Chris Metcalf <cmetcalf@...lanox.com>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Luiz Capitulino <lcapitulino@...hat.com>
Cc: Mike Galbraith <efault@....de>
Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rik van Riel <riel@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Wanpeng Li <kernellwp@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>
---
 include/linux/sched/isolation.h | 3 ++-
 kernel/sched/isolation.c        | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index d849431..c831855 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -11,7 +11,8 @@ enum hk_flags {
 	HK_FLAG_MISC		= (1 << 2),
 	HK_FLAG_SCHED		= (1 << 3),
 	HK_FLAG_TICK		= (1 << 4),
-	HK_FLAG_DOMAIN		= (1 << 5),
+	HK_FLAG_TICK_SCHED	= (1 << 5),
+	HK_FLAG_DOMAIN		= (1 << 6),
 };
 
 #ifdef CONFIG_CPU_ISOLATION
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index b71b436..264ddcd 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -136,6 +136,12 @@ static int __init housekeeping_isolcpus_setup(char *str)
 			continue;
 		}
 
+		if (!strncmp(str, "nohz_offload,", 13)) {
+			str += 13;
+			flags |= HK_FLAG_TICK | HK_FLAG_TICK_SCHED;
+			continue;
+		}
+
 		if (!strncmp(str, "domain,", 7)) {
 			str += 7;
 			flags |= HK_FLAG_DOMAIN;
-- 
2.7.4