From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f172.google.com (mail-ob0-f172.google.com [209.85.214.172]) by kanga.kvack.org (Postfix) with ESMTP id 97CD86B0032 for ; Fri, 24 Apr 2015 10:35:57 -0400 (EDT) Received: by oblw8 with SMTP id w8so39136071obl.0 for ; Fri, 24 Apr 2015 07:35:57 -0700 (PDT) Received: from g9t5008.houston.hp.com (g9t5008.houston.hp.com. [15.240.92.66]) by mx.google.com with ESMTPS id h139si8409763oib.70.2015.04.24.07.35.56 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Apr 2015 07:35:56 -0700 (PDT) Message-ID: <553A54C5.3060106@hp.com> Date: Fri, 24 Apr 2015 10:35:49 -0400 From: Waiman Long MIME-Version: 1.0 Subject: Re: [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64 References: <1429722473-28118-1-git-send-email-mgorman@suse.de> <1429722473-28118-11-git-send-email-mgorman@suse.de> <20150422164500.121a355e6b578243cb3650e3@linux-foundation.org> <20150423092327.GJ14842@suse.de> In-Reply-To: <20150423092327.GJ14842@suse.de> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , Linux-MM , Nathan Zimmer , Dave Hansen , Scott Norton , Daniel J Blueman , LKML On 04/23/2015 05:23 AM, Mel Gorman wrote: > On Wed, Apr 22, 2015 at 04:45:00PM -0700, Andrew Morton wrote: >> On Wed, 22 Apr 2015 18:07:50 +0100 Mel Gorman wrote: >> >>> --- a/arch/x86/Kconfig >>> +++ b/arch/x86/Kconfig >>> @@ -32,6 +32,7 @@ config X86 >>> select HAVE_UNSTABLE_SCHED_CLOCK >>> select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 >>> select ARCH_SUPPORTS_INT128 if X86_64 >>> + select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT if X86_64&& NUMA >> Put this in the "config X86_64" section and skip the "X86_64&&"? >> > Done. > >> Can we omit the whole defer_meminit= thing and permanently enable the >> feature? That's simpler, provides better test coverage and is, we >> hope, faster. >> > Yes. The intent was to have a workaround if there were any failures like > Waiman's vmalloc failures in an earlier version but they are bugs that > should be fixed. > >> And can this be used on non-NUMA? Presumably that won't speed things >> up any if we're bandwidth limited but again it's simpler and provides >> better coverage. > Nothing prevents it. There is less opportunity for parallelism but > improving coverage is desirable. > Memory access latency can be more than double for local vs. remote node memory. Bandwidth can also be much lower depending on what kind of interconnect is between the 2 nodes. So it is better to do it in a NUMA-aware way. Within a NUMA node, however, we can split the memory initialization to 2 or more local CPUs if the memory size is big enough. Cheers, Longman -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org