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From: Josh Triplett <josh@joshtriplett.org>
To: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Steffen Klassert <steffen.klassert@secunet.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Alexander Duyck <alexander.h.duyck@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	David Hildenbrand <david@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>, Jonathan Corbet <corbet@lwn.net>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	Michal Hocko <mhocko@kernel.org>, Pavel Machek <pavel@ucw.cz>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Shile Zhang <shile.zhang@linux.alibaba.com>,
	Tejun Heo <tj@kernel.org>, Zi Yan <ziy@nvidia.com>,
	linux-crypto@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/7] padata: parallelize deferred page init
Date: Thu, 30 Apr 2020 18:09:35 -0700
Message-ID: <20200501010935.GB104377@localhost> (raw)
In-Reply-To: <20200430201125.532129-1-daniel.m.jordan@oracle.com>

On Thu, Apr 30, 2020 at 04:11:18PM -0400, Daniel Jordan wrote:
> Sometimes the kernel doesn't take full advantage of system memory
> bandwidth, leading to a single CPU spending excessive time in
> initialization paths where the data scales with memory size.
> 
> Multithreading naturally addresses this problem, and this series is the
> first step.
> 
> It extends padata, a framework that handles many parallel singlethreaded
> jobs, to handle multithreaded jobs as well by adding support for
> splitting up the work evenly, specifying a minimum amount of work that's
> appropriate for one helper thread to do, load balancing between helpers,
> and coordinating them.  More documentation in patches 4 and 7.
> 
> The first user is deferred struct page init, a large bottleneck in
> kernel boot--actually the largest for us and likely others too.  This
> path doesn't require concurrency limits, resource control, or priority
> adjustments like future users will (vfio, hugetlb fallocate, munmap)
> because it happens during boot when the system is otherwise idle and
> waiting on page init to finish.
> 
> This has been tested on a variety of x86 systems and speeds up kernel
> boot by 6% to 49% by making deferred init 63% to 91% faster.  Patch 6
> has detailed numbers.  Test results from other systems appreciated.
> 
> This series is based on v5.6 plus these three from mmotm:
> 
>   mm-call-touch_nmi_watchdog-on-max-order-boundaries-in-deferred-init.patch
>   mm-initialize-deferred-pages-with-interrupts-enabled.patch
>   mm-call-cond_resched-from-deferred_init_memmap.patch
> 
> All of the above can be found in this branch:
> 
>   git://oss.oracle.com/git/linux-dmjordan.git padata-mt-definit-v1
>   https://oss.oracle.com/git/gitweb.cgi?p=linux-dmjordan.git;a=shortlog;h=refs/heads/padata-mt-definit-v1

For the series (and the three prerequisite patches):

Tested-by: Josh Triplett <josh@joshtriplett.org>

Thank you for writing this, and thank you for working towards
upstreaming it!

  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 20:11 Daniel Jordan
2020-04-30 20:11 ` [PATCH 1/7] padata: remove exit routine Daniel Jordan
2020-04-30 20:11 ` [PATCH 2/7] padata: initialize earlier Daniel Jordan
2020-04-30 20:11 ` [PATCH 3/7] padata: allocate work structures for parallel jobs from a pool Daniel Jordan
2020-04-30 20:11 ` [PATCH 4/7] padata: add basic support for multithreaded jobs Daniel Jordan
2020-04-30 20:11 ` [PATCH 5/7] mm: move zone iterator outside of deferred_init_maxorder() Daniel Jordan
2020-04-30 21:43   ` Alexander Duyck
2020-05-01  2:45     ` Daniel Jordan
2020-05-04 22:10       ` Alexander Duyck
2020-05-05  0:54         ` Daniel Jordan
2020-05-05 15:27           ` Alexander Duyck
2020-05-06 22:39             ` Daniel Jordan
2020-05-07 15:26               ` Alexander Duyck
2020-05-07 20:20                 ` Daniel Jordan
2020-05-07 21:18                   ` Alexander Duyck
2020-05-07 22:15                     ` Daniel Jordan
2020-04-30 20:11 ` [PATCH 6/7] mm: parallelize deferred_init_memmap() Daniel Jordan
2020-05-04 22:33   ` Alexander Duyck
2020-05-04 23:38     ` Josh Triplett
2020-05-05  0:40       ` Alexander Duyck
2020-05-05  1:48         ` Daniel Jordan
2020-05-05  2:09           ` Daniel Jordan
2020-05-05 14:55             ` Alexander Duyck
2020-05-06 22:21               ` Daniel Jordan
2020-05-06 22:36                 ` Alexander Duyck
2020-05-06 22:43                   ` Daniel Jordan
2020-05-06 23:01                     ` Daniel Jordan
2020-05-05  1:26     ` Daniel Jordan
2020-04-30 20:11 ` [PATCH 7/7] padata: document multithreaded jobs Daniel Jordan
2020-04-30 21:31 ` [PATCH 0/7] padata: parallelize deferred page init Andrew Morton
2020-04-30 21:40   ` Pavel Tatashin
2020-05-01  2:40     ` Daniel Jordan
2020-05-01  0:50   ` Josh Triplett
2020-05-01  1:09 ` Josh Triplett [this message]
2020-05-01  2:48   ` Daniel Jordan

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