From: Mel Gorman <mgorman@suse.de>
To: Waiman Long <waiman.long@hp.com>
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: Sat, 25 Apr 2015 18:28:59 +0100 [thread overview]
Message-ID: <20150425172859.GE2449@suse.de> (raw)
In-Reply-To: <553A93BB.1010404@hp.com>
On Fri, Apr 24, 2015 at 03:04:27PM -0400, Waiman Long wrote:
> >>Within a NUMA node, however, we can split the
> >>memory initialization to 2 or more local CPUs if the memory size is
> >>big enough.
> >>
> >I considered it but discarded the idea. It'd be more complex to setup and
> >the two CPUs could simply end up contending on the same memory bus as
> >well as contending on zone->lock.
> >
>
> I don't think we need that now. However, we may have to consider
> this when one day even a single node can have TBs of memory unless
> we move to a page size larger than 4k.
>
We'll cross that bridge when we come to it. I suspect there is more room
for improvement in the initialisation that would be worth trying before
resorting to more threads. With more threads there is a risk that we hit
memory bus contention and a high risk that it actually is worse due to
contending on zone->lock when freeing the pages.
In the meantime, do you mind updating the before/after figures for your
test machine with this series please?
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2015-04-25 17:29 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
2015-04-24 15:20 ` Mel Gorman
2015-04-24 19:04 ` Waiman Long
2015-04-25 17:28 ` Mel Gorman [this message]
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
-- strict thread matches above, loose matches on Subject: below --
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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