From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Borntraeger Subject: [PATCH 2/5] stop_machine: yield CPU during stop machine Date: Fri, 21 Oct 2016 13:58:55 +0200 Message-ID: <1477051138-1610-3-git-send-email-borntraeger@de.ibm.com> References: <1477051138-1610-1-git-send-email-borntraeger@de.ibm.com> Return-path: In-Reply-To: <1477051138-1610-1-git-send-email-borntraeger@de.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-Archive: List-Post: To: Peter Zijlstra Cc: Nicholas Piggin , linux-kernel@vger.kernel.org, linux-s390 , linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Heiko Carstens , Martin Schwidefsky , Noam Camus , Christian Borntraeger List-ID: stop_machine can take a very long time if the hypervisor does overcommitment for guest CPUs. When waiting for "the one", lets give up our CPU by using the new cpu_relax_yield. Signed-off-by: Christian Borntraeger --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ec9ab2f..1eb8266 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -194,7 +194,7 @@ static int multi_cpu_stop(void *data) /* Simple state machine */ do { /* Chill out and ensure we re-read multi_stop_state. */ - cpu_relax(); + cpu_relax_yield(); if (msdata->state != curstate) { curstate = msdata->state; switch (curstate) { -- 2.5.5