Re: [PATCH v6 09/13] zram: split zcomp into separate R/W streams

[Hillf Danton]

On Wed, 21 Oct 2026 13:56:17 +0900 Sergey Senozhatsky wrote:
>On (26/10/21 12:23), Hillf Danton wrote:
>> On Wed, 21 Oct 2026 11:42:19 +0900 Sergey Senozhatsky wrote:
>> > Split struct zcomp_strm into separate compression (Write zcomp_cstrm)
>> > and decompression (Read zcomp_dstrm) streams, and split zcomp_ops
>> > context creation/destruction into create_cctx/destroy_cctx and
>> > optional create_dctx/destroy_dctx callbacks.
>> > 
>> > This decouples Read (decompression) and Write (compression) paths so
>> > they no longer contend on the same per-CPU stream mutex (Writer vs
>> > Reader priority inversion).  Currently, a (low priority) Writer that
>> > holds the stream mutex can be preempted by a (higher priority) Reader
>> > on the same CPU, which then blocks on that mutex until the Writer gets
>> > to run again and releases it, which can take a long time when there
>> > are other runnable tasks on that CPU.
>> >
>> Given lock like mutex, priority inversion happens from Monday to Friday,
>> but I wonder if you are inventing some wheels in 2026 if proxy excution
>> works for you.
>
> Reader-Writer split is a foundation for further improvements (like
> singleton recompression stream and so on).
>
But that split is not needed at all if PE works, yes?