Commit b3fbd58f authored by Johannes Weiner's avatar Johannes Weiner Committed by Andrew Morton
Browse files

mm: Kconfig: simplify zswap configuration 

- CONFIG_ZRAM: Zram is a user-facing feature, whereas zsmalloc is
  not. Don't make the user chase down a technical dependency like
  that, just select it in automatically when zram is requested. The
  CONFIG_CRYPTO dependency is redundant due to more specific deps.

- CONFIG_ZPOOL: This is not a user-facing feature. Hide the symbol and
  have it selected in as needed.

- CONFIG_ZSWAP: Select CRYPTO instead of depend. Common pattern.

- Make the ZSWAP suboptions and their descriptions (compression,
  allocation backend) a bit more straight-forward for the user.

Link: https://lkml.kernel.org/r/20220510152847.230957-5-hannes@cmpxchg.org


Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 519bcb79

drivers/block/zram/Kconfig

+2 −1
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

config ZRAM

	tristate "Compressed RAM block device support"

	depends on BLOCK && SYSFS && ZSMALLOC && CRYPTO

	depends on BLOCK && SYSFS

	depends on CRYPTO_LZO || CRYPTO_ZSTD || CRYPTO_LZ4 || CRYPTO_LZ4HC || CRYPTO_842

	select ZSMALLOC

	help

	  Creates virtual block devices called /dev/zramX (X = 0, 1, ...).

	  Pages written to these disks are compressed and stored in memory

mm/Kconfig

+25 −30
Original line number Diff line number Diff line
@@ -9,6 +9,9 @@ menu "Memory Management options" 
config ARCH_NO_SWAP

	bool



config ZPOOL

	bool



menuconfig SWAP

	bool "Support for paging of anonymous memory (swap)"

	depends on MMU && BLOCK && !ARCH_NO_SWAP
@@ -21,8 +24,9 @@ menuconfig SWAP 


config ZSWAP

	bool "Compressed cache for swap pages (EXPERIMENTAL)"

	depends on SWAP && CRYPTO=y

	depends on SWAP

	select FRONTSWAP

	select CRYPTO

	select ZPOOL

	help

	  A lightweight compressed cache for swap pages.  It takes
@@ -38,8 +42,18 @@ config ZSWAP 
	  they have not be fully explored on the large set of potential

	  configurations and workloads that exist.



config ZSWAP_DEFAULT_ON

	bool "Enable the compressed cache for swap pages by default"

	depends on ZSWAP

	help

	  If selected, the compressed cache for swap pages will be enabled

	  at boot, otherwise it will be disabled.



	  The selection made here can be overridden by using the kernel

	  command line 'zswap.enabled=' option.



choice

	prompt "Compressed cache for swap pages default compressor"

	prompt "Default compressor"

	depends on ZSWAP

	default ZSWAP_COMPRESSOR_DEFAULT_LZO

	help
@@ -105,7 +119,7 @@ config ZSWAP_COMPRESSOR_DEFAULT 
       default ""



choice

	prompt "Compressed cache for swap pages default allocator"

	prompt "Default allocator"

	depends on ZSWAP

	default ZSWAP_ZPOOL_DEFAULT_ZBUD

	help
@@ -145,26 +159,9 @@ config ZSWAP_ZPOOL_DEFAULT 
       default "zsmalloc" if ZSWAP_ZPOOL_DEFAULT_ZSMALLOC

       default ""



config ZSWAP_DEFAULT_ON

	bool "Enable the compressed cache for swap pages by default"

	depends on ZSWAP

	help

	  If selected, the compressed cache for swap pages will be enabled

	  at boot, otherwise it will be disabled.



	  The selection made here can be overridden by using the kernel

	  command line 'zswap.enabled=' option.



config ZPOOL

	tristate "Common API for compressed memory storage"

	depends on ZSWAP

	help

	  Compressed memory storage API.  This allows using either zbud or

	  zsmalloc.



config ZBUD

	tristate "Low (Up to 2x) density storage for compressed pages"

	depends on ZPOOL

	tristate "2:1 compression allocator (zbud)"

	depends on ZSWAP

	help

	  A special purpose allocator for storing compressed pages.

	  It is designed to store up to two compressed pages per physical
@@ -173,8 +170,8 @@ config ZBUD 
	  density approach when reclaim will be used.



config Z3FOLD

	tristate "Up to 3x density storage for compressed pages"

	depends on ZPOOL

	tristate "3:1 compression allocator (z3fold)"

	depends on ZSWAP

	help

	  A special purpose allocator for storing compressed pages.

	  It is designed to store up to three compressed pages per physical
@@ -182,15 +179,13 @@ config Z3FOLD 
	  still there.



config ZSMALLOC

	tristate "Memory allocator for compressed pages"

	tristate

	prompt "N:1 compression allocator (zsmalloc)" if ZSWAP

	depends on MMU

	help

	  zsmalloc is a slab-based memory allocator designed to store

	  compressed RAM pages.  zsmalloc uses virtual memory mapping

	  in order to reduce fragmentation.  However, this results in a

	  non-standard allocator interface where a handle, not a pointer, is

	  returned by an alloc().  This handle must be mapped in order to

	  access the allocated space.

	  pages of various compression levels efficiently. It achieves

	  the highest storage density with the least amount of fragmentation.



config ZSMALLOC_STAT

	bool "Export zsmalloc statistics"