From: Michael Ellerman <mpe@ellerman.id.au>
To: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Cc: Gal Pressman <gal@nvidia.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/64s: Increase default stack size to 32KB
Date: Thu, 15 Feb 2024 08:56:59 +1100 [thread overview]
Message-ID: <87cysy7lqs.fsf@mail.lhotse> (raw)
In-Reply-To: <87ttmau5mg.fsf@nvidia.com>
Rahul Rameshbabu <rrameshbabu@nvidia.com> writes:
> On Fri, 15 Dec, 2023 23:44:49 +1100 Michael Ellerman <mpe@ellerman.id.au> wrote:
>> There are reports of kernels crashing due to stack overflow while
>> running OpenShift (Kubernetes). The primary contributor to the stack
>> usage seems to be openvswitch, which is used by OVN-Kubernetes (based on
>> OVN (Open Virtual Network)), but NFS also contributes in some stack
>> traces.
>>
>> There may be some opportunities to reduce stack usage in the openvswitch
>> code, but doing so potentially require tradeoffs vs performance, and
>> also requires testing across architectures.
>>
>> Looking at stack usage across the kernel (using -fstack-usage), shows
>> that ppc64le stack frames are on average 50-100% larger than the
>> equivalent function built for x86-64. Which is not surprising given the
>> minimum stack frame size is 32 bytes on ppc64le vs 16 bytes on x86-64.
>>
>> So increase the default stack size to 32KB for the modern 64-bit Book3S
>> platforms, ie. pseries (virtualised) and powernv (bare metal). That
>> leaves the older systems like G5s, and the AmigaOne (pasemi) with a 16KB
>> stack which should be sufficient on those machines.
>>
>> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
>> ---
>
> We noticed this change is causing assembler issues for us when building
> the kernel.
>
> make ARCH=powerpc KERNELRELEASE=6.8.0-rc2_for_upstream_debug_2024_02_06_20_01 KBUILD_BUILD_VERSION=1
> arch/powerpc/kernel/switch.S: Assembler messages:
> arch/powerpc/kernel/switch.S:249: Error: operand out of range (0x000000000000fe50 is not between 0xffffffffffff8000 and 0x0000000000007fff)
> make[6]: *** [scripts/Makefile.build:361: arch/powerpc/kernel/switch.o] Error 1
> make[5]: *** [scripts/Makefile.build:481: arch/powerpc/kernel] Error 2
> make[5]: *** Waiting for unfinished jobs....
> make[4]: *** [scripts/Makefile.build:481: arch/powerpc] Error 2
> make[4]: *** Waiting for unfinished jobs....
> make[3]: *** [Makefile:1921: .] Error 2
There's a fix in my fixes branch:
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=fixes&id=f1acb109505d983779bbb7e20a1ee6244d2b5736
I'll send it to Linus this week.
cheers
prev parent reply other threads:[~2024-02-14 21:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-15 12:44 [PATCH] powerpc/64s: Increase default stack size to 32KB Michael Ellerman
2023-12-19 12:32 ` Michael Ellerman
2024-02-14 20:47 ` Rahul Rameshbabu
2024-02-14 21:56 ` Michael Ellerman [this message]
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=87cysy7lqs.fsf@mail.lhotse \
--to=mpe@ellerman.id.au \
--cc=gal@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=rrameshbabu@nvidia.com \
/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;
as well as URLs for NNTP newsgroup(s).