Re: [RFC PATCH 0/5] mm: support zswap-backed anonymous large folio swapin

[Alexandre Ghiti]

Hi,

On Tue, May 12, 2026 at 9:46 AM Fujunjie <fujunjie1@xxxxxx> wrote:
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> On 5/12/2026 12:20 PM, Alexandre Ghiti wrote:
> > So I have been working on the exact same thing for some weeks now. My work is based on Usama's series [1].
> >
> > The problem with large folio swapin is that it can create swap thrashing: to swap in a large folio, swap out may be necessary, as reported in [2].
> >
> > I implemented quite a few throttling algorithms on top to try to avoid this issue and so far, I have had mixed/inconsistent results.
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> > How did you test this series? Did you encounter thrashing? Do you have performance numbers?
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> > Happy to talk more about this, thanks for your series!
> >
> > Alex
> >
> > [1] https://lore.kernel.org/all/20241018105026.2521366-1-usamaarif642@xxxxxxxxx/  <https://lore.kernel.org/all/20241018105026.2521366-1-usamaarif642@xxxxxxxxx/ >
> > [2] https://lore.kernel.org/all/SJ0PR11MB5678A864244B09FDE4D914EEC9402@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/  <https://lore.kernel.org/all/SJ0PR11MB5678A864244B09FDE4D914EEC9402@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ >
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> Thanks Alexandre.
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> My RFC only had correctness testing so far. I tested the all-zswap path
> and fallback cases under QEMU, but I don't have bare-metal
> performance numbers yet.
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> If you are already actively working on this, I don't want to duplicate the
> same effort. I will pause this RFC for now and wait for your series.
>
> After your series is posted, I will take another look and see if there is
> anything that still needs follow-up work.
>
> Thanks for letting me know.

Sorry for the late answer. I took a break because of the inconsistent
results that I had, perhaps a fresh look could help so no worries if
you give it a try on your end.

Happy to discuss further results if you continue.

Alex

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