[PATCH V4 1/3] arm64/mm/hotplug: Register boot memory hot remove notifier earlier

Anshuman Khandual anshuman.khandual at arm.com
Tue Sep 29 09:54:45 EDT 2020

This moves memory notifier registration earlier in the boot process from
device_initcall() to early_initcall() which will help in guarding against
potential early boot memory offline requests. Even though there should not
be any actual offlinig requests till memory block devices are initialized
with memory_dev_init() but then generic init sequence might just change in
future. Hence an early registration for the memory event notifier would be
helpful. While here, just skip the registration if CONFIG_MEMORY_HOTREMOVE
is not enabled and also call out when memory notifier registration fails.

Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Steve Capper <steve.capper at arm.com>
Cc: Mark Brown <broonie at kernel.org>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Reviewed-by: Gavin Shan <gshan at redhat.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
 arch/arm64/mm/mmu.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 75df62fea1b6..4e70f4fea06c 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1499,7 +1499,16 @@ static struct notifier_block prevent_bootmem_remove_nb = {
 static int __init prevent_bootmem_remove_init(void)
-	return register_memory_notifier(&prevent_bootmem_remove_nb);
+	int ret = 0;
+		return ret;
+	ret = register_memory_notifier(&prevent_bootmem_remove_nb);
+	if (ret)
+		pr_err("%s: Notifier registration failed %d\n", __func__, ret);
+	return ret;

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