Re: [PATCH] lib: zstd: update to latest Linux zstd 1.5.7

On Fri, Aug 14, 2026 at 06:34:42PM +0000, Cole Munz wrote:

> Alexey asked which boards actually carry this and what it costs them, so
> here is the data.
> 
> Nothing selects ZSTD except fs/btrfs/Kconfig, and nothing selects FS_BTRFS
> except CMD_BTRFS in cmd/Kconfig. So a board pays for zstd only if its
> defconfig sets CONFIG_ZSTD, CONFIG_FS_BTRFS or CONFIG_CMD_BTRFS, either
> directly or through an included .config fragment. Resolving those includes
> transitively, that is 41 of 1550 defconfigs:

Note that qconfig.py can do all of this for you.

[snip]
> Text growth, measured base vs this patch:
> 
>   turris_mox                  +1920
>   mvebu_espressobin-88f3720   +1920
>   am62x_evm_a53               +2072
>   kontron-sl-mx8mm            +2072
>   imx8mp_dhcom_pdk2           +2072
>   sandbox                     +2888
> 
> data and bss are unchanged on every one of them. ZSTD_LIB_MINIFY is default y
> under ZSTD and none of the affected defconfigs turn it off, so those are the
> numbers boards actually ship. The three i.MX8MP/AM62x figures come from the
> linked ELF; those builds stop later at binman for want of vendor blobs I do
> not have, with no compile errors.
> 
> On a board without zstd there is no change at all. I built qemu_arm64 at the
> parent commit and at this patch with SOURCE_DATE_EPOCH pinned: .text and
> .text_rest are byte for byte identical.
> 
> It is also not in xPL. SPL_ZSTD is a separate symbol, no defconfig enables it
> and nothing selects it, so this only lands in U-Boot proper.
> 
> I did not measure the RISC-V, PowerPC or 32-bit ARM boards in that list, as I
> have no toolchain for them here.

If you use buildman, you can tell it to fetch the normal cross
toolchains from kernel.org. It can also be used with something like:
https://git.u-boot-project.org/u-boot/u-boot-extras/-/blob/master/contrib/trini/u-boot-size-test.sh?ref_type=heads
to give a more detailed growth report. Thanks for digging in to this, it
is a question I had as well.

-- 
Tom

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