Re: [PATCHv2 00/17] zram: convert to custom comp API and allow algorithms configuration

[Sergey Senozhatsky <senozhatsky@chromium.org>]

On (24/05/06 16:58), Sergey Senozhatsky wrote:
> 	This patch set moves zram from crypto API to a custom compression
> API which allows us to tune and configure compression algorithms,
> something that crypto API, unfortunately, doesn't support. Basically,
> this seroes brings back the bits of comp "backend" code that we had
> many years ago. This means that if we want zram to support new
> compression algorithms we need to implement corresponding backends.
> 
>         Currently, zram supports a pretty decent number of comp backends:
> lzo, lzorle, lz4, lz4hc, 842, deflate, zstd
> 
>         At this point we handle 2 parameters: a compression level and
> a pre-trained compression dictionary. Which seems like a good enough
> start. The list will be extended in the future.
> 
> Examples:
> 
> - changes default compression level
>         echo "algo=zstd level=11" > /sys/block/zram0/comp_algorithm
> 
> - passes path to a pre-trained dictionary
>         echo "algo=zstd dict=/etc/dictionary" > /sys/block/zram0/comp_algorithm

I'll send v3 shortly, which adds pre-trained dictionary support to
lz4 and lz4hc compression backends. Apparently lz4/lz4hc can use
dictionaries pre-trained with zstd --init, just like zstd.