Re: [PATCH 1/2] mm: zswap: use separate compression and decompression requests

[Sergey Senozhatsky <senozhatsky@chromium.org>]

On (26/10/06 11:47), Nhat Pham wrote:
> On Tue, Oct 6, 2026 at 2:23 AM Usama Arif <usama.arif@linux.dev> wrote:
> >
> > Stores and loads serialize on the same per-CPU acomp request and mutex.
> > A low-priority store can be preempted as soon as the compressor drops
> > its stream lock, while it still holds the mutex. A higher-priority load
> > on that CPU then waits until the store runs again, which can take a
> > long time when other tasks are runnable.
> >
> > Give compression and decompression their own request, completion wait
> > and mutex. Since commit e2c3b6b21c77f ("mm: zswap: use SG list
> > decompression APIs from zsmalloc"), the per-CPU buffer is only used for
> > compression. The two requests can share the per-CPU transform: no
> > in-tree implementation modifies transform state while (de)compressing,
> > and shared codec state has its own locking. Loads can still wait for
> > each other on the decompression mutex, and stores still serialize on
> > the compression mutex.
> >
> > This follows the proposal from Sergey Senozhatsky for the same split
> > for zram [1].
> 
> Thanks, zram peeps :P

:D