[PATCH] init: add support for zstd compressed modules

[PATCH] init: add support for zstd compressed modules

[Piotr Gorski]

kmod 28 supports modules compressed in zstd format so let's add this possibility to kernel.

Signed-off-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
---
 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
+  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

Re: [PATCH] init: add support for zstd compressed modules

[Oleksandr Natalenko]

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@gmail.com>
> ---
>  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
> +  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@natalenko.name>

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)

Re: [PATCH] init: add support for zstd compressed modules

[Nick Terrell]

> On Mar 30, 2021, at 4:50 AM, Oleksandr Natalenko <oleksandr@natalenko.name> 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@gmail.com>
>> ---
>> 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.

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@natalenko.name>
> 
> 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)

Re: [PATCH] init: add support for zstd compressed modules

[Oleksandr Natalenko]

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@natalenko.name> 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@gmail.com>
> >> ---
> >> 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.

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@natalenko.name>
> > 
> > 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)

Re: [PATCH] init: add support for zstd compressed modules

[Nick Terrell]

> On Mar 31, 2021, at 10:48 AM, Oleksandr Natalenko <oleksandr@natalenko.name> 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@natalenko.name> 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@gmail.com>
>>>> ---
>>>> 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.

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@natalenko.name>
>>> 
>>> 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)

Re: [PATCH] init: add support for zstd compressed modules

[Oleksandr Natalenko]

Hello.

On Wed, Mar 31, 2021 at 07:21:07PM +0000, Nick Terrell wrote:
> 
> 
> > On Mar 31, 2021, at 10:48 AM, Oleksandr Natalenko <oleksandr@natalenko.name> 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@natalenko.name> 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@gmail.com>
> >>>> ---
> >>>> 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.

Well, it seems Andrew already took this into his tree, so feel free to
drop another one on top of that!

> 
> 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@natalenko.name>
> >>> 
> >>> 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)
> 

-- 
  Oleksandr Natalenko (post-factum)

Re: [PATCH] init: add support for zstd compressed modules

[Masahiro Yamada]

On Thu, Apr 1, 2021 at 4:21 AM Nick Terrell <terrelln@fb.com> wrote:
>
>
>
> > On Mar 31, 2021, at 10:48 AM, Oleksandr Natalenko <oleksandr@natalenko.name> 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@natalenko.name> 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@gmail.com>
> >>>> ---
> >>>> 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"












> 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@natalenko.name>
> >>>
> >>> 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

Re: [PATCH] init: add support for zstd compressed modules

[Masahiro Yamada]

On Tue, Mar 30, 2021 at 8:33 PM Piotr Gorski <lucjan.lucjanov@gmail.com> wrote:
>
> kmod 28 supports modules compressed in zstd format so let's add this possibility to kernel.
>
> Signed-off-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
> ---
>  Makefile     | 7 +++++--
>  init/Kconfig | 9 ++++++---
>  2 files changed, 11 insertions(+), 5 deletions(-)



Piort, sorry for bothering you,
but could you rebase on top of this
clean-up patch set?

https://patchwork.kernel.org/project/linux-kbuild/list/?series=458809

or

git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git kbuild


The module compression code should not be placed
in the top Makefile.





> 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
> +  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
>


--
Best Regards
Masahiro Yamada

Re: [PATCH] init: add support for zstd compressed modules

[Nick Terrell]

> On Apr 7, 2021, at 6:53 AM, Masahiro Yamada <masahiroy@kernel.org> wrote:
> 
> On Thu, Apr 1, 2021 at 4:21 AM Nick Terrell <terrelln@fb.com> wrote:
>> 
>> 
>> 
>>> On Mar 31, 2021, at 10:48 AM, Oleksandr Natalenko <oleksandr@natalenko.name> 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@natalenko.name> 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@gmail.com>
>>>>>> ---
>>>>>> 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@natalenko.name>
>>>>> 
>>>>> 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

Re: [PATCH] init: add support for zstd compressed modules

[Nick Terrell]

> On Apr 1, 2021, at 12:54 AM, torvic9@mailbox.org wrote:
> 
> Thanks Piotr, good work!
> Question: Is `-T0` really faster in this particular case than the default `-T1`? Are modules installed sequentially?

The zstd CLI produces deterministic output regardless of the number of threads used. `-T1` (or not specifying `-T`) will produce the same output as `-T0`. `-T0` will be faster for large files (at the default level, multiple jobs will be spawned for files > 8MB), and be just as fast as `-T1` for smaller files.

Best,
Nick

> I also saw that Masahiro did some work on modules_install, moving MODULE_COMPRESS from the base Makefile to scripts/Makefile.modinst, so perhaps this should also be moved there at a later point.
> 
> Tor Vic

Re: [PATCH] init: add support for zstd compressed modules

[torvic9]

Thanks Piotr, good work!
Question: Is `-T0` really faster in this particular case than the default `-T1`? Are modules installed sequentially?
I also saw that Masahiro did some work on modules_install, moving MODULE_COMPRESS from the base Makefile to scripts/Makefile.modinst, so perhaps this should also be moved there at a later point.

(sorry for double post)

Tor Vic

[PATCH] init: add support for zstd compressed modules

[>]

From: Piotr Gorski <lucjan.lucjanov@gmail.com>

kmod 28 supports modules compressed in zstd format so let's add this possibility to kernel.

Signed-off-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
---
 Makefile     | 7 +++++--
 init/Kconfig | 9 ++++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index cf54d33ba863..90986a3f5897 100644
--- a/Makefile
+++ b/Makefile
@@ -1049,8 +1049,8 @@ 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
@@ -1060,6 +1060,9 @@ 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 -9 --rm -f
+  endif # CONFIG_MODULE_COMPRESS_ZSTD
 endif # CONFIG_MODULE_COMPRESS
 export mod_compress_cmd
 
diff --git a/init/Kconfig b/init/Kconfig
index b77c60f8b963..11d7dfea98b6 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2216,8 +2216,8 @@ 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.
 
@@ -2239,7 +2239,7 @@ 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"
@@ -2247,6 +2247,9 @@ config MODULE_COMPRESS_GZIP
 config MODULE_COMPRESS_XZ
 	bool "XZ"
 
+config MODULE_COMPRESS_ZSTD
+	bool "ZSTD"
+
 endchoice
 
 config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
-- 
2.30.0.81.g72c4083ddf