linux-kernel - [PATCH 2/2] powerpc/mobility: disabling hard lockup watchdog during LPM

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Date:   Wed,  1 Jun 2022 17:53:15 +0200
From:   Laurent Dufour <ldufour@...ux.ibm.com>
To:     mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        nathanl@...ux.ibm.com, haren@...ux.vnet.ibm.com, npiggin@...il.com
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] powerpc/mobility: disabling hard lockup watchdog during LPM

Disabling the Hard Lockup Watchdog until the memory transfer is complete.

This avoids hard lockup seen while the memory is still in progress when the
system is heavily loaded and a lot of pages are still not transferred on
the arrival side.

Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 55612a1b07d6..061d4faefefb 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -701,6 +701,9 @@ static int pseries_migrate_partition(u64 handle)
 
 	vas_migration_handler(VAS_SUSPEND);
 
+	pr_debug("Disabling the NMI watchdog\n");
+	watchdog_nmi_stop();
+
 	ret = pseries_suspend(handle);
 	if (ret == 0) {
 		post_mobility_fixup();
@@ -708,6 +711,9 @@ static int pseries_migrate_partition(u64 handle)
 	} else
 		pseries_cancel_migration(handle, ret);
 
+	pr_debug("Enabling the NMI watchdog again\n");
+	watchdog_nmi_start();
+
 	vas_migration_handler(VAS_RESUME);
 
 	return ret;
-- 
2.36.1