On Sat, Dec 25, 2021 at 2:41 AM Christoph Hellwig <hch@xxxxxx> wrote:
> The cleancache subsystem is unused since the removal of Xen tmem driver
> in commit 814bbf49dcd0 ("xen: remove tmem driver").
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> arch/m68k/configs/amiga_defconfig | 1 -
> arch/m68k/configs/apollo_defconfig | 1 -
> arch/m68k/configs/atari_defconfig | 1 -
> arch/m68k/configs/bvme6000_defconfig | 1 -
> arch/m68k/configs/hp300_defconfig | 1 -
> arch/m68k/configs/mac_defconfig | 1 -
> arch/m68k/configs/multi_defconfig | 1 -
> arch/m68k/configs/mvme147_defconfig | 1 -
> arch/m68k/configs/mvme16x_defconfig | 1 -
> arch/m68k/configs/q40_defconfig | 1 -
> arch/m68k/configs/sun3_defconfig | 1 -
> arch/m68k/configs/sun3x_defconfig | 1 -
Although this would be removed during the next refresh anyway:
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -444,28 +444,6 @@ config USE_PERCPU_NUMA_NODE_ID
> config HAVE_SETUP_PER_CPU_AREA
> bool
>
> -config CLEANCACHE
> - bool "Enable cleancache driver to cache clean pages if tmem is present"
> - help
> - Cleancache can be thought of as a page-granularity victim cache
> - for clean pages that the kernel's pageframe replacement algorithm
> - (PFRA) would like to keep around, but can't since there isn't enough
> - memory. So when the PFRA "evicts" a page, it first attempts to use
> - cleancache code to put the data contained in that page into
> - "transcendent memory", memory that is not directly accessible or
> - addressable by the kernel and is of unknown and possibly
> - time-varying size. And when a cleancache-enabled
> - filesystem wishes to access a page in a file on disk, it first
> - checks cleancache to see if it already contains it; if it does,
> - the page is copied into the kernel and a disk access is avoided.
> - When a transcendent memory driver is available (such as zcache or
> - Xen transcendent memory), a significant I/O reduction
> - may be achieved. When none is available, all cleancache calls
> - are reduced to a single pointer-compare-against-NULL resulting
> - in a negligible performance hit.
> -
> - If unsure, say Y to enable cleancache
Ah, the joy of good advice...
> -
> config FRONTSWAP
> bool "Enable frontswap to cache swap pages if tmem is present"
> depends on SWAP
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
