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

[Sergey Senozhatsky]

On (26/10/05 17:22), Usama Arif 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].

Greetings zswap peeps,
We pushed things a little further for even more gains [1]

Catch me if you can ;P

[1] https://lore.kernel.org/all/20261009071157.3730698-12-senozhatsky@xxxxxxxxxxxx