> On Apr 7, 2021, at 6:53 AM, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > On Thu, Apr 1, 2021 at 4:21 AM Nick Terrell <terrelln@xxxxxx> wrote: >> >> >> >>> On Mar 31, 2021, at 10:48 AM, Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> wrote: >>> >>> Hello. >>> >>> On Wed, Mar 31, 2021 at 05:39:25PM +0000, Nick Terrell wrote: >>>> >>>> >>>>> On Mar 30, 2021, at 4:50 AM, Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> wrote: >>>>> >>>>> On Tue, Mar 30, 2021 at 01:32:35PM +0200, Piotr Gorski wrote: >>>>>> kmod 28 supports modules compressed in zstd format so let's add this possibility to kernel. >>>>>> >>>>>> Signed-off-by: Piotr Gorski <lucjan.lucjanov@xxxxxxxxx> >>>>>> --- >>>>>> Makefile | 7 +++++-- >>>>>> init/Kconfig | 9 ++++++--- >>>>>> 2 files changed, 11 insertions(+), 5 deletions(-) >>>>>> >>>>>> diff --git a/Makefile b/Makefile >>>>>> index 5160ff8903c1..82f4f4cc2955 100644 >>>>>> --- a/Makefile >>>>>> +++ b/Makefile >>>>>> @@ -1156,8 +1156,8 @@ endif # INSTALL_MOD_STRIP >>>>>> export mod_strip_cmd >>>>>> >>>>>> # CONFIG_MODULE_COMPRESS, if defined, will cause module to be compressed >>>>>> -# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP >>>>>> -# or CONFIG_MODULE_COMPRESS_XZ. >>>>>> +# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP, >>>>>> +# CONFIG_MODULE_COMPRESS_XZ, or CONFIG_MODULE_COMPRESS_ZSTD. >>>>>> >>>>>> mod_compress_cmd = true >>>>>> ifdef CONFIG_MODULE_COMPRESS >>>>>> @@ -1167,6 +1167,9 @@ ifdef CONFIG_MODULE_COMPRESS >>>>>> ifdef CONFIG_MODULE_COMPRESS_XZ >>>>>> mod_compress_cmd = $(XZ) --lzma2=dict=2MiB -f >>>>>> endif # CONFIG_MODULE_COMPRESS_XZ >>>>>> + ifdef CONFIG_MODULE_COMPRESS_ZSTD >>>>>> + mod_compress_cmd = $(ZSTD) -T0 --rm -f -q >>>> >>>> This will use the default zstd level, level 3. I think it would make more sense to use a high >>>> compression level. Level 19 would probably be a good choice. That will choose a window >>>> size of up to 8MB, meaning the decompressor needs to allocate that much memory. If that >>>> is unacceptable, you could use `zstd -T0 --rm -f -q -19 --zstd=wlog=21`, which will use a >>>> window size of up to 2MB, to match the XZ command. Note that if the file is smaller than >>>> the window size, it will be shrunk to the smallest power of two at least as large as the file. >>> >>> Please no. We've already done that with initramfs in Arch, and it >>> increased the time to generate it enormously. >>> >>> I understand that building a kernel is a more rare operation than >>> regenerating initramfs, but still I'd go against hard-coding the level. >>> And if it should be specified anyway, I'd opt in for an explicit >>> configuration option. Remember, not all the kernel are built on >>> build farms... >>> >>> FWIW, Piotr originally used level 9 which worked okay, but I insisted >>> on sending the patch initially without specifying level at all like it is >>> done for other compressors. If this is a wrong approach, then oh meh, >>> mea culpa ;). >>> >>> Whatever default non-standard compression level you choose, I'm fine >>> as long as I can change it without editing Makefile. >> >> That makes sense to me. I have a deep seated need to compress files as >> efficiently as possible for widely distributed packages. But, I understand that >> slow compression significantly impacts build times for quick iteration. I’d be >> happy with a compression level parameter that defaults to a happy middle. >> >> I’m also fine with taking this patch as-is if it is easier, and I can put up another >> patch that adds a compression level parameter, since I don’t want to block >> merging this. > > > I do not want to take such a patch. > Meeking everyone's requirement > results in a bad project for everyone. > > > Does this work for you? > > make modules_install ZSTD="zstd -19" Yeah, that’s perfect. Do you think it is worth mentioning in the docs for `MODULE_COMPRESS_ZSTD`? Best, Nick >> Best, >> Nick Terrell >> >>> Thanks! >>> >>>> >>>> Best, >>>> Nick Terrell >>>> >>>>>> + endif # CONFIG_MODULE_COMPRESS_ZSTD >>>>>> endif # CONFIG_MODULE_COMPRESS >>>>>> export mod_compress_cmd >>>>>> >>>>>> diff --git a/init/Kconfig b/init/Kconfig >>>>>> index 8c2cfd88f6ef..86a452bc2747 100644 >>>>>> --- a/init/Kconfig >>>>>> +++ b/init/Kconfig >>>>>> @@ -2250,8 +2250,8 @@ config MODULE_COMPRESS >>>>>> bool "Compress modules on installation" >>>>>> help >>>>>> >>>>>> - Compresses kernel modules when 'make modules_install' is run; gzip or >>>>>> - xz depending on "Compression algorithm" below. >>>>>> + Compresses kernel modules when 'make modules_install' is run; gzip, >>>>>> + xz, or zstd depending on "Compression algorithm" below. >>>>>> >>>>>> module-init-tools MAY support gzip, and kmod MAY support gzip and xz. >>>>>> >>>>>> @@ -2273,7 +2273,7 @@ choice >>>>>> This determines which sort of compression will be used during >>>>>> 'make modules_install'. >>>>>> >>>>>> - GZIP (default) and XZ are supported. >>>>>> + GZIP (default), XZ, and ZSTD are supported. >>>>>> >>>>>> config MODULE_COMPRESS_GZIP >>>>>> bool "GZIP" >>>>>> @@ -2281,6 +2281,9 @@ config MODULE_COMPRESS_GZIP >>>>>> config MODULE_COMPRESS_XZ >>>>>> bool "XZ" >>>>>> >>>>>> +config MODULE_COMPRESS_ZSTD >>>>>> + bool "ZSTD" >>>>>> + >>>>>> endchoice >>>>>> >>>>>> config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS >>>>>> -- >>>>>> 2.31.0.97.g1424303384 >>>>>> >>>>> >>>>> Great! >>>>> >>>>> Reviewed-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> >>>>> >>>>> This works perfectly fine in Arch Linux if accompanied by the >>>>> following mkinitcpio amendment: [1]. >>>>> >>>>> I'm also Cc'ing other people from get_maintainers output just >>>>> to make this submission more visible. >>>>> >>>>> Thanks. >>>>> >>>>> [1] https://github.com/archlinux/mkinitcpio/pull/43 >>>>> >>>>> -- >>>>> Oleksandr Natalenko (post-factum) >>>> >>> >>> -- >>> Oleksandr Natalenko (post-factum) >> > > > -- > Best Regards > Masahiro Yamada
