Re: [PATCH v6 02/17] zram: permit preemption with active compression stream

[Yosry Ahmed]

On Fri, Feb 14, 2025 at 01:50:14PM +0900, Sergey Senozhatsky wrote:
> Currently, per-CPU stream access is done from a non-preemptible
> (atomic) section, which imposes the same atomicity requirements on
> compression backends as entry spin-lock, and makes it impossible
> to use algorithms that can schedule/wait/sleep during compression
> and decompression.
> 
> Switch to preemptible per-CPU model, similar to the one used
> in zswap.  Instead of a per-CPU local lock, each stream carries
> a mutex which is locked throughout entire time zram uses it
> for compression or decompression, so that cpu-dead event waits
> for zram to stop using a particular per-CPU stream and release
> it.
> 
> Suggested-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>

Reviewed-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>