Re: [PATCH v3 12/13] mm: Add sysctl vm.compress-batching switch for compress batching during swapout.

[Andrew Morton <akpm@linux-foundation.org>]

On Wed,  6 Nov 2024 11:21:04 -0800 Kanchana P Sridhar <kanchana.p.sridhar@intel.com> wrote:

>  extern int sysctl_legacy_va_layout;
> +extern unsigned int compress_batching;

nit: I suggest calling this "sysctl_compress_batching".  See how we
treated sysctl_legacy_va_layout.

> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -47,6 +47,9 @@
>  int page_cluster;
>  const int page_cluster_max = 31;
>  
> +/* Enable/disable compress batching during swapout. */
> +unsigned int compress_batching;
> +
>  struct cpu_fbatches {
>  	/*
>  	 * The following folio batches are grouped together because they are protected
> @@ -1074,4 +1077,7 @@ void __init swap_setup(void)
>  	 * Right now other parts of the system means that we
>  	 * _really_ don't want to cluster much more
>  	 */
> +
> +	/* Disable compress batching during swapout by default. */
> +	compress_batching = 0;

Not really needed?  The compiler already did that.

>  }