Re: [PATCH] pstore: migrate to crypto acomp interface (take 2)

From: Ard Biesheuvel
Date: Mon Oct 17 2022 - 17:16:57 EST


On Mon, 17 Oct 2022 at 23:10, Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx> wrote:
>
> On 17/10/2022 18:01, Ard Biesheuvel wrote:
> > [...]
> >
> > In summary, we're better off sticking with the legacy comp interface,
> > but unfortunately, due to the way that has been plumbed into the
> > scomp/acomp with scatterlists version, that doesn't really help us get
> > rid of the memory overhead.
> >
>
> Out of curiosity, do you have a number here, like X kilobytes per active
> CPU?

2x128 KB per CPU, which makes 128 KB also the maximum input/output
size per request when using this interface. (SCOMP_SCRATCH_SIZE)

On my 32x4 CPU workstation, this amounts to 32 MB permanently locked
up for nothing when the pstore driver is loaded (with compression
enabled)