linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Catalin Marinas <catalin.marinas@arm.com>
To: Christoph Lameter <cl@linux.com>
Cc: Sudarshan Rajagopalan <sudaraja@codeaurora.org>,
	linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	David Hildenbrand <david@redhat.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Logan Gunthorpe <logang@deltatee.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Steven Price <steven.price@arm.com>,
	Suren Baghdasaryan <surenb@google.com>
Subject: Re: [PATCH 1/1] arm64/sparsemem: reduce SECTION_SIZE_BITS
Date: Thu, 21 Jan 2021 15:54:10 +0000	[thread overview]
Message-ID: <20210121155410.GH21811@gaia> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2101211004540.100764@www.lameter.com>

On Thu, Jan 21, 2021 at 10:08:17AM +0000, Christoph Lameter wrote:
> On Wed, 20 Jan 2021, Sudarshan Rajagopalan wrote:
> 
> > But there are other problems in reducing SECTION_SIZE_BIT. Reducing it by too
> > much would over populate /sys/devices/system/memory/ and also consume too many
> > page->flags bits in the !vmemmap case. Also section size needs to be multiple
> > of 128MB to have PMD based vmemmap mapping with CONFIG_ARM64_4K_PAGES.
> 
> There is also the issue of requiring more space in the TLB cache with
> smaller page sizes. Or does ARM resolve these into smaller TLB entries
> anyways (going on my x86 kwon how here)? Anyways if there are only a few
> TLB entries then the effect could
> be significant.

There is indeed more TLB pressure with smaller page sizes but this patch
doesn't change this.

-- 
Catalin


  reply	other threads:[~2021-01-21 15:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21  5:29 [PATCH 0/1] " Sudarshan Rajagopalan
2021-01-21  5:29 ` [PATCH 1/1] " Sudarshan Rajagopalan
2021-01-21 10:08   ` Christoph Lameter
2021-01-21 15:54     ` Catalin Marinas [this message]
2021-01-21 13:36   ` Will Deacon
2021-01-22  2:58     ` Anshuman Khandual
2021-01-21 13:45   ` David Hildenbrand
2021-01-21 14:16   ` Mike Rapoport
2021-01-21 16:04     ` David Hildenbrand
2021-01-21 15:51   ` Catalin Marinas
2021-01-21 18:26 ` [PATCH 0/1] " Will Deacon
2021-01-29  0:17   ` Pavel Tatashin

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=20210121155410.GH21811@gaia \
    --to=catalin.marinas@arm.com \
    --cc=akpm@linux-foundation.org \
    --cc=anshuman.khandual@arm.com \
    --cc=cl@linux.com \
    --cc=david@redhat.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=logang@deltatee.com \
    --cc=mark.rutland@arm.com \
    --cc=rppt@linux.ibm.com \
    --cc=steven.price@arm.com \
    --cc=sudaraja@codeaurora.org \
    --cc=surenb@google.com \
    --cc=will@kernel.org \
    --subject='Re: [PATCH 1/1] arm64/sparsemem: reduce SECTION_SIZE_BITS' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).