From: Chris Murphy <lists@colorremedies.com>
To: Linux Memory Management List <linux-mm@kvack.org>
Subject: 5.11 "debug" missing 20-30% memory, and exceptionally high reserved
Date: Sat, 30 Jan 2021 11:48:08 -0700 [thread overview]
Message-ID: <CAJCQCtQ1HKOz6Wun4qM_3jDXJSeUs4g4dKmUp0NMF2NMq4AAog@mail.gmail.com> (raw)
Fedora is seeing a significantly reduced /proc/meminfo MemTotal with
"debug" 5.11 series kernels. The problem isn't happening with
"nodebug" kernels. The other possible instigator is GCC 11.0.0 is
being used (all 5.10 series, nodebug and debug, are built with GCC
10.2.1). We're still doing some tests to narrow it down.
The problem reproduces on x86_64 (no info on other archs yet) both
baremetal and qemu-kvm. And first manifests with this line:
5.11.0-0.rc5.134.fc34.x86_64+debug
Jan 28 13:56:08 flap.local kernel: Memory: 6547356K/8276392K available
(43019K kernel code, 11036K rwdata, 27184K rodata, 5036K init, 31780K
bss, 1728780K reserved, 0K cma-reserved)
5.11.0-0.rc5.134.fc34.x86_64
Jan 28 13:54:19 flap.local kernel: Memory: 7915056K/8276392K available
(16393K kernel code, 3469K rwdata, 26796K rodata, 2544K init, 5484K
bss, 361076K reserved, 0K cma-reserved)
Reserved memory seems quite high in the debug case.
Downstream bug report has dmesg for
5.11.0-0.rc5.134.fc34.x86_64+debug, and kernel config attachments.
Bug 1921923 - Kernel under-reporting or hiding about a third of
available memory in "debug" 5.11 series
https://bugzilla.redhat.com/show_bug.cgi?id=1921923
--
Chris Murphy
next reply other threads:[~2021-01-30 18:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-30 18:48 Chris Murphy [this message]
2021-01-30 23:21 ` Chris Murphy
2021-02-01 11:08 ` David Hildenbrand
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=CAJCQCtQ1HKOz6Wun4qM_3jDXJSeUs4g4dKmUp0NMF2NMq4AAog@mail.gmail.com \
--to=lists@colorremedies.com \
--cc=linux-mm@kvack.org \
/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