Re: [PATCH v2 0/2] zswap pool per-CPU acomp_ctx simplifications

["Kanchana P. Sridhar" <kanchanapsridhar2026@gmail.com>]

On Tue, Mar 17, 2026 at 12:48 PM Yosry Ahmed <yosry@kernel.org> wrote:
>
> On Tue, Mar 17, 2026 at 12:45 PM Andrew Morton
> <akpm@linux-foundation.org> wrote:
> >
> > On Mon, 16 Mar 2026 18:48:00 -0700 "Kanchana P. Sridhar" <kanchanapsridhar2026@gmail.com> wrote:
> >
> > > This patchset first removes redundant checks on the acomp_ctx and its
> > > "req" member in zswap_cpu_comp_dead().
> > >
> > > Next, it persists the zswap pool's per-CPU acomp_ctx resources to
> > > last until the pool is destroyed. It then simplifies the per-CPU
> > > acomp_ctx mutex locking in zswap_compress()/zswap_decompress().
> > >
> > > Code comments added after allocation and before checking to deallocate
> > > the per-CPU acomp_ctx's members, based on expected crypto API return
> > > values and zswap changes this patchset makes.
> > >
> > > Patch 2 is an independent submission of patch 23 from [1], to
> > > facilitate merging.
> >
> > Thanks.
> >
> > What happened with "mm: zswap: Consistently use IS_ERR_OR_NULL() to
> > check acomp_ctx resources"?  Still relevant?
> >
> > https://lkml.kernel.org/r/20260314051632.17931-3-kanchanapsridhar2026@gmail.com
>
> We decided to drop it (and patch 1 here kinda sorta takes its place):
> https://lore.kernel.org/all/CACpmpoeo0LhxkoA5Wx6q+9=2scn_az0u=3bar-JgBvTA-ZBkZg@mail.gmail.com/

Thanks for the clarification, Yosry!

Thanks Andrew, for adding the two patches in v2 to mm-new! Thanks also
for obsoleting the "mm: zswap: Consistently use IS_ERR_OR_NULL() to
check acomp_ctx resources" patch - we decided to replace this with the
"[v2,1/2] mm: zswap: Remove redundant checks in
zswap_cpu_comp_dead().", which makes the acomp_ctx consistency checks
changes in the original mainline code, before refactoring that code
into the new acomp_ctx_free() in "[v2,2/2] mm: zswap: Tie per-CPU
acomp_ctx lifetime to the pool."

Best regards,
Kanchana