Re: [PATCH] PM: hibernate: Support to select compression algorithm

[Nikhil V]

On 2/13/2024 12:34 AM, Randy Dunlap wrote:
> On 2/12/24 04:32, Nikhil V wrote:
> > Currently the default compression algorithm is selected based on
> > compile time options. Introduce a module parameter "hibernate.compressor"
> > to override this behaviour.
> >
> > Different compression algorithms have different characteristics and
> > hibernation may benefit when it uses any of these algorithms, especially
> > when a secondary algorithm(LZ4) offers better decompression speeds over a
> > default algorithm(LZO), which in turn reduces hibernation image restore
> > time.
> >
> > Users can override the default algorithm in two ways:
> >   1) Passing "hibernate.compressor" as kernel command line parameter.
> >      Usage:
> >      	LZO: hibernate.compressor=lzo
> >      	LZ4: hibernate.compressor=lz4
> >
> >   2) Specifying the algorithm at runtime.
> >      Usage:
> > 	LZO: echo lzo > /sys/module/hibernate/parameters/compressor
> > 	LZ4: echo lz4 > /sys/module/hibernate/parameters/compressor
> >
> > Currently LZO and LZ4 are the supported algorithms. LZO is the default
> > compression algorithm used with hibernation.
> >
> > Signed-off-by: Nikhil V <quic_nprakash@xxxxxxxxxxx>
> > ---
> > This patch is dependent on the patch series, [1] (patches 1/4 to 3/4).
> > This is picked in linux-next, [2].
> >   [1] https://lore.kernel.org/all/cover.1705927916.git.quic_nprakash@xxxxxxxxxxx/
> >   [2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/kernel/power?h=next-20240212
> >
> >   .../admin-guide/kernel-parameters.txt         | 10 ++++
> >   kernel/power/hibernate.c                      | 57 ++++++++++++++++++-
> >   2 files changed, 64 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 31b3a25680d0..522155056645 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -1748,6 +1748,16 @@
> >   				(that will set all pages holding image data
> >   				during restoration read-only).
> >   
>
> Hi,
> Please add something like:
>
>
> > +	hibernate.compressor= 	[HIBERNATION] Compression algorithm to be
> > +				used with hibernation.
> > +				Format: { lzo | lz4 }
> 				Default: lzo
> > +
> > +				lzo: Select LZO compression algorithm to
> > +				compress/decompress hibernation image.
> > +
> > +				lz4: Select LZ4 compression algorithm to
> > +				compress/decompress hibernation image.
> > +
> >   	highmem=nn[KMG]	[KNL,BOOT] forces the highmem zone to have an exact
> >   			size of <nn>. This works even on boxes that have no
> >   			highmem otherwise. This also works to reduce highmem
>
>
> thanks.

Hi @Randy,

Will update the documentation as mentioned and send the patch for review.

Thanks,
Nikhil V