From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e39.co.us.ibm.com (e39.co.us.ibm.com [32.97.110.160]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id B1C6C1A003F for ; Fri, 22 Aug 2014 11:10:32 +1000 (EST) Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Aug 2014 19:10:30 -0600 Received: from b01cxnp22033.gho.pok.ibm.com (b01cxnp22033.gho.pok.ibm.com [9.57.198.23]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 64CC838C8059 for ; Thu, 21 Aug 2014 21:10:27 -0400 (EDT) Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id s7M1AR3P66715814 for ; Fri, 22 Aug 2014 01:10:27 GMT Received: from d01av01.pok.ibm.com (localhost [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s7M1APNe026952 for ; Thu, 21 Aug 2014 21:10:27 -0400 Date: Thu, 21 Aug 2014 18:10:11 -0700 From: Nishanth Aravamudan To: Andrew Morton Subject: Re: [RFC PATCH 0/4] Improve slab consumption with memoryless nodes Message-ID: <20140822011011.GF13999@linux.vnet.ibm.com> References: <20140814001301.GI11121@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20140814001301.GI11121@linux.vnet.ibm.com> Cc: Han Pingtian , Matt Mackall , David Rientjes , Pekka Enberg , Linux Memory Management List , Paul Mackerras , Tejun Heo , Joonsoo Kim , linuxppc-dev@lists.ozlabs.org, Christoph Lameter , Wanpeng Li , Anton Blanchard List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 13.08.2014 [17:13:01 -0700], Nishanth Aravamudan wrote: > Anton noticed (http://www.spinics.net/lists/linux-mm/msg67489.html) that > on ppc LPARs with memoryless nodes, a large amount of memory was > consumed by slabs and was marked unreclaimable. He tracked it down to > slab deactivations in the SLUB core when we allocate remotely, leading > to poor efficiency always when memoryless nodes are present. > > After much discussion, Joonsoo provided a few patches that help > significantly. They don't resolve the problem altogether: > > - memory hotplug still needs testing, that is when a memoryless node > becomes memory-ful, we want to dtrt > - there are other reasons for going off-node than memoryless nodes, > e.g., fully exhausted local nodes > > Neither case is resolved with this series, but I don't think that should > block their acceptance, as they can be explored/resolved with follow-on > patches. > > The series consists of: > > [1/4] topology: add support for node_to_mem_node() to determine the fallback node > [2/4] slub: fallback to node_to_mem_node() node if allocating on memoryless node > > - Joonsoo's patches to cache the nearest node with memory for each > NUMA node > > [3/4] Partial revert of 81c98869faa5 (""kthread: ensure locality of task_struct allocations") > > - At Tejun's request, keep the knowledge of memoryless node fallback to > the allocator core. > > [4/4] powerpc: reorder per-cpu NUMA information's initialization > > - Fix what appears to be a bug with when the NUMA topology information > is stored in the powerpc initialization code. Andrew & others, I know kernel summit is going on, so I'll be patient, but was just curious if anyone had any further comments other than Christoph's on the naming. Thanks, Nish > > arch/powerpc/kernel/smp.c | 12 ++++++------ > arch/powerpc/mm/numa.c | 13 ++++++++++--- > include/linux/topology.h | 17 +++++++++++++++++ > kernel/kthread.c | 2 +- > mm/page_alloc.c | 1 + > mm/slub.c | 24 ++++++++++++++++++------ > 6 files changed, 53 insertions(+), 16 deletions(-)