linux-kernel - Re: [PATCH 0/3] Update LZ4 compressor module

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Date:   Thu, 22 Dec 2016 18:29:37 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Sven Schmidt <4sschmid@...ormatik.uni-hamburg.de>
Cc:     akpm@...ux-foundation.org, bongkyu.kim@....com,
        sergey.senozhatsky@...il.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] Update LZ4 compressor module

On Tue, Dec 20, 2016 at 07:53:09PM +0100, Sven Schmidt wrote:
> 
> This patchset is for updating the LZ4 compression module to a version based
> on LZ4 v1.7.2 allowing to use the fast compression algorithm aka LZ4 fast
> which provides an "acceleration" parameter as a tradeoff between
> compression ratio and compression speed.

But why do this?

> We will use LZ4 fast in order to support compression in lustre. LZ4 fast empowers
> us to do client-side as well as server-side compression/decompression while
> being able to provide appropriate parameters to enable users to tune lustre's
> behaviour to obtain the best performance/compression/etc. on their behalf
> (adapative compression).

We don't care about lustre, especially as it is not merged into the main
portion of the kernel tree :)

Seriously, work on fixing up the known issues in lustre before adding
additional features, I've only been saying this for a few _years_ now...

> Also, it will be useful for other users of LZ4 compression,
> as with LZ4 fast it is possible to enable applications to use fast and/or high
> compression depending of the usecase. E.g. a developer can use very
> high compression (low acceleration) for sending data over a network with
> limited rate of transmission or he trades the compression ratio for higher
> compression speed.

This whole patch series is broken, always test-build your code, there's
nothing we could do with these patches even if we wanted to :(

greg k-h