From: Randy Dunlap <rdunlap@infradead.org>
To: Mikko Rantalainen <mikko.rantalainen@peda.net>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Why is Shmem included in Cached in /proc/meminfo?
Date: Mon, 30 Aug 2021 07:34:38 -0700 [thread overview]
Message-ID: <0d11f620-0562-e150-259d-85de8d10cd7a@infradead.org> (raw)
In-Reply-To: <5a42eb2b-fd7b-6296-f5d6-619661ad1418@peda.net>
[add linux-mm mailing list]
On 8/30/21 12:44 AM, Mikko Rantalainen wrote:
> It's not immediately obvious from fs/proc/meminfo.c function
> meminfo_proc_show() but the output of Cached: field seems to always
> include all of Shmem: field, too.
>
> Is this intentional? Usually cache is something that can be discarded if
> needed but shared memory (e.g. used to contain files in tmpfs) cannot be
> discarded without a data-loss. As such, I'd argue that it shouldn't be
> included in the Cached: output.
>
> A simple fix could be
>
> - cached = global_node_page_state(NR_FILE_PAGES) -
> - total_swapcache_pages() - i.bufferram;
> + cached = global_node_page_state(NR_FILE_PAGES) -
> + total_swapcache_pages()
> + - i.bufferram - i.sharedram;
>
--
~Randy
next parent reply other threads:[~2021-08-30 14:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5a42eb2b-fd7b-6296-f5d6-619661ad1418@peda.net>
2021-08-30 14:34 ` Randy Dunlap [this message]
2021-08-30 14:41 ` Matthew Wilcox
2021-08-30 16:05 ` Vlastimil Babka
2021-08-30 16:17 ` Matthew Wilcox
2021-08-30 17:26 ` Mikko Rantalainen
2021-08-30 19:38 ` Khalid Aziz
2021-09-01 8:57 ` Mikko Rantalainen
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=0d11f620-0562-e150-259d-85de8d10cd7a@infradead.org \
--to=rdunlap@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mikko.rantalainen@peda.net \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox