[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#940887: marked as done (Integrate ZSTD patches *Kernel compression: add ZSTD, remove LZMA1 and BZIP2*)

Your message dated Tue, 31 May 2022 01:43:24 +0200
with message-id <YpVWnLZ14N4PvRki@angband.pl>
and subject line Re: Bug#940887: Integrate ZSTD patches *Kernel compression: add ZSTD, remove LZMA1 and BZIP2*
has caused the Debian Bug report #940887,
regarding Integrate ZSTD patches *Kernel compression: add ZSTD, remove LZMA1 and BZIP2*
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@bugs.debian.org
immediately.)


-- 
940887: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=940887
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: src:linux
Version: 5.2.9-2
Severity: wishlist


Dear Linux folks,
It’d be awesome, if you applied Adam’s and Nick’s patches for ZSTD support [1] to the Debian kernel, so users can test those early for the next Debian release. 

Here is the cover letter text:


Hi!
As new compressors get invented, they tend to find their way into the
kernel, yet we never prune superseded ones.  It's time to do so.

In particular, BZIP2 is drastically slower than other compressors we
have, even when they achieve smaller sizes.  It takes more memory, too.
And, BZIP2 is not used anywhere else in the kernel -- just for booting
the kernel itself and the initrd.  Thus, we can drop it from the tree
completely, making Linus happier by around 900 lines.

LZMA1 is redundant with XZ (LZMA2), and unlike the latter, it uses its own
copy of code that's not shared with anything else (some drivers use XZ).
Let's drop it as well.  Some bootloaders can use it thus let's keep the
Kconfig option, but I left no piece of code inside the kernel itself.

On the other hand, Nick Terrell has a couple of patches adding ZSTD support
(using code already in use in multiple pieces around the kernel).  ZSTD is
strong and fast, obsoleting all mid-range compressors.  As the removal of
BZIP2 and LZMA1 would be hopelessly entangled with this addition, I'm
resending Nick's patches here.  I've been booting using them since Oct'17
on amd64 (kernel+initrd), armhf and arm64 (initrd) without issues, other
folks tested various other architectures as well.

Thus, I'd recommend people to use:
* XZ for most machines
* ZSTD where speed is important
* maaaaybe LZ4 is some special cases
(grub and u-boot are ridiculously slow at reading, making fast but weak
decompressors a net loss.  On the other hand, XZ decompresses pretty fast
but is very slow at compress time, making ZSTD preferred for rapid devel
cycles.)

* we can't get rid of GZIP in foreseable future
* LZO is obsolete but is used elsewhere in the kernel

Total:
 69 files changed, 518 insertions(+), 1785 deletions(-)

Not sure whose tree this patchset should go through.  I'm also not sure
how finely split into commits you want the arch bits be; I included
defconfig bits all together, yet separated code changes per-arch.


Meow!



Kind regards,

Paul


[1]: https://lore.kernel.org/patchwork/cover/1009317/

--- End Message ---
--- Begin Message --- 
On Mon, May 30, 2022 at 08:39:23PM +0200, Diederik de Haas wrote:
> On Sat, 21 Sep 2019 16:00:55 +0200 Paul Menzel <pmenzel@molgen.mpg.de> wrote:
> > It’d be awesome, if you applied Adam’s and Nick’s patches for ZSTD 
> > support [1] to the Debian kernel, so users can test those early for the 
> > next Debian release.
> > 
> > [1]: https://lore.kernel.org/patchwork/cover/1009317/
> 
> That URL gives a 404. Is there an update patch URL?
> Or is it perhaps already integrated into the (upstream) Linux kernel?

The support for ZSTD has been mainlined years ago.
 
> IOW: what's the current status?

Cleanup of LZMA and BZIP2 on the other hand should probably be refreshed and
resubmitted, but there's no point in picking removals to distro kernels.

Thus, this bug is done.


Meow!
-- 
⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢠⠒⠀⣿⡁ “Exegi monumentum aere perennius” -- “I made a monument more
⢿⡄⠘⠷⠚⠋⠀ durable than bronze”.
⠈⠳⣄⠀⠀⠀⠀               -- Horace (65-8 BC), leaving the loo, constipated

--- End Message ---
Reply to: