All of lore.kernel.org
 help / color / mirror / Atom feed
From: David Hildenbrand <david@redhat.com>
To: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: linux-mm@kvack.org, Arjan van de Ven <arjan@linux.intel.com>,
	Feng Tang <feng.tang@intel.com>
Subject: Re: Deferred Memory Init: How to bring rest of memory online after limiting it with `mem=XG`?
Date: Thu, 3 Dec 2020 14:06:05 +0100	[thread overview]
Message-ID: <7692e410-886e-a1bb-4158-e02305fcd013@redhat.com> (raw)
In-Reply-To: <8a395c1a-764b-9d82-0a12-b1a9254f8d53@molgen.mpg.de>

On 03.12.20 13:52, Paul Menzel wrote:
> Dear David,
> 
> 
> Thank you for the quick response.
> 
> 
> Am 03.12.20 um 13:25 schrieb David Hildenbrand:
>> On 03.12.20 11:51, Paul Menzel wrote:
> 
>>> I am trying to reduce the startup time of Debian’s Linux 5.9.9 on a
>>> Intel Kaby Lake system with 32 GB of memory (TUXEDO Book BU1406 (Clevo
>>> N240BU)).
> 
> […]
> 
>> We do have deferred meminit in the kernel during boot that can
>> initialize memory in parallel.
> 
> Is that used automatically, or do I need to activate it somehow?

If your kernel is compiled with

CONFIG_DEFERRED_STRUCT_PAGE_INIT

it should be enabled automatically.


config DEFERRED_STRUCT_PAGE_INIT
	bool "Defer initialisation of struct pages to kthreads"
	depends on SPARSEMEM
	depends on !NEED_PER_CPU_KM
	depends on 64BIT
	select PADATA
	help
	  Ordinarily all struct pages are initialised during early boot in a
	  single thread. On very large machines this can take a considerable
	  amount of time. If this option is set, large machines will bring up
	  a subset of memmap at boot and then initialise the rest in parallel.
	  This has a potential performance impact on tasks running early in the
	  lifetime of the system until these kthreads finish the
	  initialisation.

-- 
Thanks,

David / dhildenb



  reply	other threads:[~2020-12-03 13:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03 10:51 Deferred Memory Init: How to bring rest of memory online after limiting it with `mem=XG`? Paul Menzel
2020-12-03 12:25 ` David Hildenbrand
2020-12-03 12:52   ` Paul Menzel
2020-12-03 13:06     ` David Hildenbrand [this message]
2020-12-03 20:58       ` Daniel Jordan
2020-12-04  7:31         ` Paul Menzel
2020-12-04 19:50           ` Daniel Jordan
2020-12-04  1:17   ` Feng Tang
2020-12-04  8:05 ` Feng Tang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7692e410-886e-a1bb-4158-e02305fcd013@redhat.com \
    --to=david@redhat.com \
    --cc=arjan@linux.intel.com \
    --cc=feng.tang@intel.com \
    --cc=linux-mm@kvack.org \
    --cc=pmenzel@molgen.mpg.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.