Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: Nishanth Menon <nm@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>,
	Tero Kristo <t-kristo@ti.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Michal Hocko <mhocko@suse.com>, Rik van Riel <riel@surriel.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Santosh Shilimkar <ssantosh@kernel.org>,
	Dave Chinner <david@fromorbit.com>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, Yafang Shao <laoar.shao@gmail.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Johannes Weiner <hannes@cmpxchg.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	kernel-team@fb.com, Kishon Vijay Abraham I <kishon@ti.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU
Date: Sun, 8 Mar 2020 11:58:52 +0100
Message-ID: <CAK8P3a0Gyqu7kzO1JF=j9=jJ0T5ut=hbKepvke-2bppuPNKTuQ@mail.gmail.com> (raw)
In-Reply-To: <20200306203439.peytghdqragjfhdx@kahuna>

On Fri, Mar 6, 2020 at 9:36 PM Nishanth Menon <nm@ti.com> wrote:
> On 13:11-20200226, santosh.shilimkar@oracle.com wrote:

>
> ~few 1000s still relevant spread between 4G and 8G (confirmed that both
> are present, relevant and in use).
>
> I wish we could sunset, but unfortunately, I am told(and agree)
> that we should'nt just leave products (and these are long term
> products stuck in critical parts in our world) hanging in the air, and
> migrations to newer kernel do still take place periodically (the best
> I can talk in public forum at least).

Thank you for the clear answer!

I agree we should certainly not break any such use cases, and for the
8GB case there is not really a good replacement (using zram/zswap
instead of highmem could work for some new workloads, but would be a
rather risky change for an upgrade on already deployed systems).

I hope it's ok to ask the same question every few years until you are
reasonably sure that the users are ready to stop upgrading kernels
beyond the following LTS kernel version. We can also do the same
thing for the other 32-bit platforms that exceed the maximum amount
of lowmem, and document which ones are known.

In the meantime, it would seem useful to increase the amount of
lowmem that can be used by default, using a combination of some
of the changes mentioned earlier

- add a VMSPLIT_2G_OPT config option for non-LPAE ARM kernels
  to handle the common i.MX6 case with 2GB of RAM without highmem

- make VMSPLIT_2G_OPT (without LPAE) or VMSPLIT_2G (with
  LPAE) the default in most ARM defconfig files as well as distros,
  and disable highmem where possible, to see what breaks.

- extend zswap to use all the available high memory for swap space
  when highmem is disabled.

- revisit CONFIG_VMSPLIT_4G_4G for arm32 (and maybe mips32)
  to see if it can be done, and what the overhead is. This is probably
  more work than the others combined, but also the most promising
  as it allows the most user address space and physical ram to be used.

       Arnd

  parent reply index

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-11 17:55 Johannes Weiner
2020-02-11 18:20 ` Johannes Weiner
2020-02-11 19:05 ` Rik van Riel
2020-02-11 19:31   ` Johannes Weiner
2020-02-11 23:44     ` Andrew Morton
2020-02-12  0:28       ` Linus Torvalds
2020-02-12  0:47         ` Andrew Morton
2020-02-12  1:03           ` Linus Torvalds
2020-02-12  8:50             ` Russell King - ARM Linux admin
2020-02-13  9:50               ` Lucas Stach
2020-02-13 16:52               ` Arnd Bergmann
2020-02-15 11:25                 ` Geert Uytterhoeven
2020-02-15 16:59                   ` Arnd Bergmann
2020-02-16  9:44                     ` Geert Uytterhoeven
2020-02-16 19:54                       ` Chris Paterson
2020-02-16 20:38                         ` Arnd Bergmann
2020-02-20 14:35                           ` Chris Paterson
2020-02-26 18:04                 ` santosh.shilimkar
2020-02-26 21:01                   ` Arnd Bergmann
2020-02-26 21:11                     ` santosh.shilimkar
2020-03-06 20:34                       ` Nishanth Menon
2020-03-07  1:08                         ` santosh.shilimkar
2020-03-08 10:58                         ` Arnd Bergmann [this message]
2020-03-08 14:19                           ` Russell King - ARM Linux admin
2020-03-09 13:33                             ` Arnd Bergmann
2020-03-09 14:04                               ` Russell King - ARM Linux admin
2020-03-09 15:04                                 ` Arnd Bergmann
2020-03-10  9:16                                   ` Michal Hocko
2020-03-09 15:59                           ` Catalin Marinas
2020-03-09 16:09                             ` Russell King - ARM Linux admin
2020-03-09 16:57                               ` Catalin Marinas
2020-03-09 19:46                               ` Arnd Bergmann
2020-03-11 14:29                                 ` Catalin Marinas
2020-03-11 16:59                                   ` Arnd Bergmann
2020-03-11 17:26                                     ` Catalin Marinas
2020-03-11 22:21                                       ` Arnd Bergmann
2020-02-12  3:58         ` Matthew Wilcox
2020-02-12  8:09         ` Michal Hocko
2020-02-17 13:31         ` Pavel Machek
2020-02-12 16:35       ` Johannes Weiner
2020-02-12 18:26         ` Andrew Morton
2020-02-12 18:52           ` Johannes Weiner
2020-02-12 12:25 ` Yafang Shao
2020-02-12 16:42   ` Johannes Weiner
2020-02-13  1:47     ` Yafang Shao
2020-02-13 13:46       ` Johannes Weiner
2020-02-14  2:02         ` Yafang Shao
2020-02-13 18:34 ` [PATCH v2] " Johannes Weiner
2020-02-14 16:53 ` [PATCH] " kbuild test robot
2020-02-14 21:30 ` kbuild test robot
2020-02-14 21:30 ` [PATCH] vfs: fix boolreturn.cocci warnings kbuild test robot
2020-05-12 21:29 ` [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU Johannes Weiner
2020-05-13  1:32   ` Yafang Shao
2020-05-13 13:00     ` Johannes Weiner
2020-05-13 21:15   ` Andrew Morton
2020-05-14 11:27     ` Johannes Weiner
2020-05-14  2:24   ` Andrew Morton
2020-05-14 10:37     ` Johannes Weiner

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='CAK8P3a0Gyqu7kzO1JF=j9=jJ0T5ut=hbKepvke-2bppuPNKTuQ@mail.gmail.com' \
    --to=arnd@arndb.de \
    --cc=akpm@linux-foundation.org \
    --cc=catalin.marinas@arm.com \
    --cc=david@fromorbit.com \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=kernel-team@fb.com \
    --cc=kishon@ti.com \
    --cc=laoar.shao@gmail.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux@armlinux.org.uk \
    --cc=mhocko@suse.com \
    --cc=nm@ti.com \
    --cc=riel@surriel.com \
    --cc=santosh.shilimkar@oracle.com \
    --cc=ssantosh@kernel.org \
    --cc=t-kristo@ti.com \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@zeniv.linux.org.uk \
    /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

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git