Re: [PATCH v6 3/3] lib: zstd: Upgrade to latest upstream zstd version 1.4.6

[David Sterba]

On Thu, Dec 03, 2020 at 07:58:16AM +0800, kernel test robot wrote:
> All warnings (new ones prefixed by >>):
> 
>    lib/zstd/compress/zstd_double_fast.c: In function 'ZSTD_compressBlock_doubleFast_extDict_generic':
> >> lib/zstd/compress/zstd_double_fast.c:501:1: warning: the frame size of 3724 bytes is larger than 1280 bytes [-Wframe-larger-than=]

Frame size 3724?

>    lib/zstd/compress/zstd_double_fast.c: In function 'ZSTD_compressBlock_doubleFast':
>    lib/zstd/compress/zstd_double_fast.c:336:1: warning: the frame size of 3792 bytes is larger than 1280 bytes [-Wframe-larger-than=]

3792

>    lib/zstd/compress/zstd_double_fast.c: In function 'ZSTD_compressBlock_doubleFast_dictMatchState':
>    lib/zstd/compress/zstd_double_fast.c:356:1: warning: the frame size of 3808 bytes is larger than 1280 bytes [-Wframe-larger-than=]

3808

>    lib/zstd/compress/zstd_fast.c: In function 'ZSTD_compressBlock_fast_extDict_generic':
> >> lib/zstd/compress/zstd_fast.c:476:1: warning: the frame size of 2736 bytes is larger than 1280 bytes [-Wframe-larger-than=]

2736

>    lib/zstd/compress/zstd_fast.c: In function 'ZSTD_compressBlock_fast':
>    lib/zstd/compress/zstd_fast.c:204:1: warning: the frame size of 1508 bytes is larger than 1280 bytes [-Wframe-larger-than=]

1508

>    lib/zstd/compress/zstd_fast.c: In function 'ZSTD_compressBlock_fast_dictMatchState':
>    lib/zstd/compress/zstd_fast.c:372:1: warning: the frame size of 1540 bytes is larger than 1280 bytes [-Wframe-larger-than=]

1540

For userspace code it's nothing but in kernel it's a lot for a single
function. The largest number is almost one page, there were days where
this would be one half of the whole stack space. We can't waste precious
resources like that. Taking the userspace code as-is does not seem to
work.