Build regressions/improvements in v5.16-rc1

[Nick Terrell]

> On Nov 17, 2021, at 3:22 AM, Helge Deller <deller at gmx.de> wrote:
> 
> On 11/17/21 03:19, Nick Terrell wrote:
>> 
>> 
>>> On Nov 16, 2021, at 6:05 PM, Randy Dunlap <rdunlap at infradead.org> wrote:
>>> 
>>> On 11/16/21 5:59 PM, Nick Terrell wrote:
>>>>> On Nov 15, 2021, at 8:44 AM, Helge Deller <deller at gmx.de> wrote:
>>>>> 
>>>>> On 11/15/21 17:12, Geert Uytterhoeven wrote:
>>>>>> On Mon, Nov 15, 2021 at 4:54 PM Geert Uytterhoeven <geert at linux-m68k.org> wrote:
>>>>>>> Below is the list of build error/warning regressions/improvements in
>>>>>>> v5.16-rc1[1] compared to v5.15[2].
>>>>>>> 
>>>>>>> Summarized:
>>>>>>> - build errors: +20/-13
>>>>>>> - build warnings: +3/-28
>>>>>>> 
>>>>>>> Happy fixing! ;-)
>>>>>>> 
>>>>>>> Thanks to the linux-next team for providing the build service.
>>>>>>> 
>>>>>>> [1] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf/    (all 90 configs)
>>>>>>> [2] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/8bb7eca972ad531c9b149c0a51ab43a417385813/    (all 90 configs)
>>>>>>> 
>>>>>>> 
>>>>>>> *** ERRORS ***
>>>>>>> 
>>>>>>> 20 error regressions:
>>>>>>> + /kisskb/src/arch/parisc/include/asm/jump_label.h: error: expected ':' before '__stringify':  => 33:4, 18:4
>>>>>>> + /kisskb/src/arch/parisc/include/asm/jump_label.h: error: label 'l_yes' defined but not used [-Werror=unused-label]:  => 38:1, 23:1
>>>>>> 
>>>>>>   due to static_branch_likely() in crypto/api.c
>>>>>> 
>>>>>> parisc-allmodconfig
>>>>> 
>>>>> fixed now in the parisc for-next git tree.
>>>>> 
>>>>> 
>>>>>>> + /kisskb/src/drivers/gpu/drm/msm/msm_drv.h: error: "COND" redefined [-Werror]:  => 531
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_double_fast.c: error: the frame size of 3252 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 47:1
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_double_fast.c: error: the frame size of 3360 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 499:1
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_double_fast.c: error: the frame size of 5344 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 334:1
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_double_fast.c: error: the frame size of 5380 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 354:1
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_fast.c: error: the frame size of 1824 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 372:1
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_fast.c: error: the frame size of 2224 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 204:1
>>>>>>> + /kisskb/src/lib/zstd/compress/zstd_fast.c: error: the frame size of 3800 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]:  => 476:1
>>>>>> 
>>>>>> parisc-allmodconfig
>>>>> 
>>>>> parisc needs much bigger frame sizes, so I'm not astonished here.
>>>>> During the v5.15 cycl I increased it to 1536 (from 1280), so I'm simply tempted to
>>>>> increase it this time to 4096, unless someone has a better idea....
>>>> This patch set should fix the zstd stack size warnings [0]. I’ve
>>>> verified the fix using the same tooling: gcc-8-hppa-linux-gnu.
>>>> I’ll send the PR to Linus tomorrow. I’ve been informed that it
>>>> isn't strictly necessary to send the patches to the mailing list
>>>> for bug fixes, but its already done, so I’ll wait and see if there
>>>> is any feedback.
>>> 
>>> IMO several (or many more) people would disagree with that.
>>> 
>>> "strictly?"  OK, it's probably possible that almost any patch
>>> could be merged without being on a mailing list, but it's not
>>> desirable (except in the case of "security" patches).
>> 
>> Good to know! Thanks for the advice, I wasn’t really sure what
>> the best practice is for sending patches to your own tree, as I
>> didn't see anything about it in the maintainer guide.
> 
> Nick, thanks a lot for your efforts to get the frame size usage down!
> 
> I've applied your patch series to the parisc for-next tree [1], so that it
> gets some testing in the upstream for-next tree.
> My tests so far are good, although I'm only using gcc-11.
> 
> If you don't mind, and if it doesn't generate issues for other
> platforms & architectures I could submit them upstream to Linus when
> I send the next pull request.

Sure, I’m fine with that. The only other major goal of this patch series
is to reduce code size bloat. But, that isn’t blocking development of
anyone.

I do have an update to make for patch 1 though, after some comments
from Linus. So I’ll send out a V2 shortly.

Best,
Nick Terrell

> Helge
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/log/?h=for-next