From: Waiman Long <waiman.long@hp.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>, Nathan Zimmer <nzimmer@sgi.com>,
Dave Hansen <dave.hansen@intel.com>,
Scott Norton <scott.norton@hp.com>,
Daniel J Blueman <daniel@numascale.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64
Date: Fri, 24 Apr 2015 10:35:49 -0400 [thread overview]
Message-ID: <553A54C5.3060106@hp.com> (raw)
In-Reply-To: <20150423092327.GJ14842@suse.de>
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<mgorman@suse.de> 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
next prev parent reply other threads:[~2015-04-24 14:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-22 17:07 [RFC PATCH 0/14] Parallel struct page initialisation v5r4 Mel Gorman
2015-04-22 17:07 ` [PATCH 01/13] memblock: Introduce a for_each_reserved_mem_region iterator Mel Gorman
2015-04-22 17:07 ` [PATCH 02/13] mm: meminit: Move page initialization into a separate function Mel Gorman
2015-04-22 17:07 ` [PATCH 03/13] mm: meminit: Only set page reserved in the memblock region Mel Gorman
2015-04-22 17:07 ` [PATCH 04/13] mm: page_alloc: Pass PFN to __free_pages_bootmem Mel Gorman
2015-04-22 17:07 ` [PATCH 05/13] mm: meminit: Make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid Mel Gorman
2015-04-22 17:07 ` [PATCH 06/13] mm: meminit: Inline some helper functions Mel Gorman
2015-04-22 17:07 ` [PATCH 07/13] mm: meminit: Only a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set Mel Gorman
2015-04-22 17:07 ` [PATCH 08/13] mm: meminit: Initialise remaining struct pages in parallel with kswapd Mel Gorman
2015-04-22 17:07 ` [PATCH 09/13] mm: meminit: Minimise number of pfn->page lookups during initialisation Mel Gorman
2015-04-22 17:07 ` [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64 Mel Gorman
2015-04-22 23:45 ` Andrew Morton
2015-04-23 9:23 ` Mel Gorman
2015-04-24 14:35 ` Waiman Long [this message]
2015-04-24 15:20 ` Mel Gorman
2015-04-24 19:04 ` Waiman Long
2015-04-25 17:28 ` Mel Gorman
2015-04-27 20:07 ` Waiman Long
2015-04-22 17:07 ` [PATCH 11/13] mm: meminit: Free pages in large chunks where possible Mel Gorman
2015-04-22 17:07 ` [PATCH 12/13] mm: meminit: Reduce number of times pageblocks are set during struct page init Mel Gorman
2015-04-22 17:07 ` [PATCH 13/13] mm: meminit: Remove mminit_verify_page_links Mel Gorman
2015-04-22 17:11 ` [RFC PATCH 0/14] Parallel struct page initialisation v5r4 Mel Gorman
2015-04-23 10:33 [PATCH 0/13] Parallel struct page initialisation v3 Mel Gorman
2015-04-23 10:33 ` [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64 Mel Gorman
2015-04-28 14:36 [PATCH 0/13] Parallel struct page initialisation v4 Mel Gorman
2015-04-28 14:37 ` [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64 Mel Gorman
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