From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Wed, 4 Jan 2017 13:28:31 +0000 Subject: [PATCH 2/2] arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA In-Reply-To: <1481706707-6211-3-git-send-email-ard.biesheuvel@linaro.org> References: <1481706707-6211-1-git-send-email-ard.biesheuvel@linaro.org> <1481706707-6211-3-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <20170104132831.GD18193@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Dec 14, 2016 at 09:11:47AM +0000, Ard Biesheuvel wrote: > The NUMA code may get confused by the presence of NOMAP regions within > zones, resulting in spurious BUG() checks where the node id deviates > from the containing zone's node id. > > Since the kernel has no business reasoning about node ids of pages it > does not own in the first place, enable CONFIG_HOLES_IN_ZONE to ensure > that such pages are disregarded. > > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/Kconfig | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 111742126897..0472afe64d55 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -614,6 +614,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK > def_bool y > depends on NUMA > > +config HOLES_IN_ZONE > + def_bool y > + depends on NUMA > + > source kernel/Kconfig.preempt > source kernel/Kconfig.hz I'm happy to apply this, but I'll hold off until the first patch is queued somewhere, since this doesn't help without the VM_BUG_ON being moved. Alternatively, I can queue both if somebody from the mm camp acks the first patch. Will