Hi Anshuman,
On 9/21/20 10:05 PM, Anshuman Khandual wrote:
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.mari...@arm.com>
Cc: Will Deacon <w...@kernel.com>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Marc Zyngier <m...@kernel.org>
Cc: Steve Capper <steve.cap...@arm.com>
Cc: Mark Brown <broo...@kernel.org>
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khand...@arm.com>
---
arch/arm64/mm/mmu.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
With the following nit-picky comments resolved:
Reviewed-by: Gavin Shan <gs...@redhat.com>
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 75df62fea1b6..df3b7415b128 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1499,7 +1499,17 @@ 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;
+
+ if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ return ret;
+
+ ret = register_memory_notifier(&prevent_bootmem_remove_nb);
+ if (!ret)
+ return ret;
+
+ pr_err("Notifier registration failed - boot memory can be removed\n");
+ return ret;
}
It might be cleaner if the duplicated return statements can be
avoided. Besides, it's always nice to print the errno even though
zero is always returned from register_memory_notifier(). So I guess
you probably need something like below:
ret = register_memory_notifier(&prevent_bootmem_remove_nb);
if (ret)
pr_err("%s: Error %d registering notifier\n", __func__, ret)
return ret;
register_memory_notifier # 0 is returned on
!CONFIG_MEMORY_HOTPLUG_SPARSE
blocking_notifier_chain_register
notifier_chain_register # 0 is always returned
-device_initcall(prevent_bootmem_remove_init);
+early_initcall(prevent_bootmem_remove_init);
#endif
Cheers,
Gavin
