From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Wed, 26 Oct 2016 19:36:14 +0100 Subject: [PATCH 2/2] arm64/numa: support HAVE_MEMORYLESS_NODES In-Reply-To: <1477364358-10620-3-git-send-email-thunder.leizhen@huawei.com> References: <1477364358-10620-1-git-send-email-thunder.leizhen@huawei.com> <1477364358-10620-3-git-send-email-thunder.leizhen@huawei.com> Message-ID: <20161026183614.GJ15216@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Oct 25, 2016 at 10:59:18AM +0800, Zhen Lei wrote: > Some numa nodes may have no memory. For example: > 1) a node has no memory bank plugged. > 2) a node has no memory bank slots. > > To ensure percpu variable areas and numa control blocks of the > memoryless numa nodes to be allocated from the nearest available node to > improve performance, defined node_distance_ready. And make its value to be > true immediately after node distances have been initialized. > > Signed-off-by: Zhen Lei > --- > arch/arm64/Kconfig | 4 ++++ > arch/arm64/include/asm/numa.h | 3 +++ > arch/arm64/mm/numa.c | 6 +++++- > 3 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 30398db..648dd13 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -609,6 +609,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK > def_bool y > depends on NUMA > > +config HAVE_MEMORYLESS_NODES > + def_bool y > + depends on NUMA Given that patch 1 and the associated node_distance_ready stuff is all an unqualified performance optimisation, is there any merit in just enabling HAVE_MEMORYLESS_NODES in Kconfig and then optimising things as a separate series when you have numbers to back it up? Will