Revert "mm/vmscan: add sysctl knobs for protecting the working set"

This reverts commit d1ff80f.

Documentation/admin-guide/sysctl/vm.rst

@@ -25,9 +25,6 @@ files can be found in mm/swap.c.
 Currently, these files are in /proc/sys/vm:
 
 - admin_reserve_kbytes
-- anon_min_ratio
-- clean_low_ratio
-- clean_min_ratio
 - compact_memory
 - compaction_proactiveness
 - compact_unevictable_allowed
@@ -109,67 +106,6 @@ On x86_64 this is about 128MB.
 Changing this takes effect whenever an application requests memory.
 
 
-anon_min_ratio
-==============
-
-This knob provides *hard* protection of anonymous pages. The anonymous pages
-on the current node won't be reclaimed under any conditions when their amount
-is below vm.anon_min_ratio.
-
-This knob may be used to prevent excessive swap thrashing when anonymous
-memory is low (for example, when memory is going to be overfilled by
-compressed data of zram module).
-
-Setting this value too high (close to 100) can result in inability to
-swap and can lead to early OOM under memory pressure.
-
-The unit of measurement is the percentage of the total memory of the node.
-
-The default value is 15.
-
-
-clean_low_ratio
-================
-
-This knob provides *best-effort* protection of clean file pages. The file pages
-on the current node won't be reclaimed under memory pressure when the amount of
-clean file pages is below vm.clean_low_ratio *unless* we threaten to OOM.
-
-Protection of clean file pages using this knob may be used when swapping is
-still possible to
-  - prevent disk I/O thrashing under memory pressure;
-  - improve performance in disk cache-bound tasks under memory pressure.
-
-Setting it to a high value may result in a early eviction of anonymous pages
-into the swap space by attempting to hold the protected amount of clean file
-pages in memory.
-
-The unit of measurement is the percentage of the total memory of the node.
-
-The default value is 0.
-
-
-clean_min_ratio
-================
-
-This knob provides *hard* protection of clean file pages. The file pages on the
-current node won't be reclaimed under memory pressure when the amount of clean
-file pages is below vm.clean_min_ratio.
-
-Hard protection of clean file pages using this knob may be used to
-  - prevent disk I/O thrashing under memory pressure even with no free swap space;
-  - improve performance in disk cache-bound tasks under memory pressure;
-  - avoid high latency and prevent livelock in near-OOM conditions.
-
-Setting it to a high value may result in a early out-of-memory condition due to
-the inability to reclaim the protected amount of clean file pages when other
-types of pages cannot be reclaimed.
-
-The unit of measurement is the percentage of the total memory of the node.
-
-The default value is 15.
-
-
 compact_memory
 ==============
 
@@ -974,14 +910,6 @@ be 133 (x + 2x = 200, 2x = 133.33).
 At 0, the kernel will not initiate swap until the amount of free and
 file-backed pages is less than the high watermark in a zone.
 
-This knob has no effect if the amount of clean file pages on the current
-node is below vm.clean_low_ratio or vm.clean_min_ratio. In this case,
-only anonymous pages can be reclaimed.
-
-If the number of anonymous pages on the current node is below
-vm.anon_min_ratio, then only file pages can be reclaimed with
-any vm.swappiness value.
-
 
 unprivileged_userfaultfd
 ========================

include/linux/mm.h

@@ -195,14 +195,6 @@ static inline void __mm_zero_struct_page(struct page *page)
 
 extern int sysctl_max_map_count;
 
-extern bool sysctl_workingset_protection;
-extern u8 sysctl_anon_min_ratio;
-extern u8 sysctl_clean_low_ratio;
-extern u8 sysctl_clean_min_ratio;
-int vm_workingset_protection_update_handler(
-	struct ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos);
-
 extern unsigned long sysctl_user_reserve_kbytes;
 extern unsigned long sysctl_admin_reserve_kbytes;
 

kernel/sysctl.c

@@ -2236,40 +2236,6 @@ static struct ctl_table vm_table[] = {
 		.extra1		= SYSCTL_ZERO,
 	},
 #endif
-	{
-		.procname	= "workingset_protection",
-		.data		= &sysctl_workingset_protection,
-		.maxlen		= sizeof(bool),
-		.mode		= 0644,
-		.proc_handler	= &proc_dobool,
-	},
-	{
-		.procname	= "anon_min_ratio",
-		.data		= &sysctl_anon_min_ratio,
-		.maxlen		= sizeof(u8),
-		.mode		= 0644,
-		.proc_handler	= &vm_workingset_protection_update_handler,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE_HUNDRED,
-	},
-	{
-		.procname	= "clean_low_ratio",
-		.data		= &sysctl_clean_low_ratio,
-		.maxlen		= sizeof(u8),
-		.mode		= 0644,
-		.proc_handler	= &vm_workingset_protection_update_handler,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE_HUNDRED,
-	},
-	{
-		.procname	= "clean_min_ratio",
-		.data		= &sysctl_clean_min_ratio,
-		.maxlen		= sizeof(u8),
-		.mode		= 0644,
-		.proc_handler	= &vm_workingset_protection_update_handler,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE_HUNDRED,
-	},
 	{
 		.procname	= "user_reserve_kbytes",
 		.data		= &sysctl_user_reserve_kbytes,

mm/Kconfig

@@ -509,69 +509,6 @@ config ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
 config ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
 	bool
 
-config ANON_MIN_RATIO
-	int "Default value for vm.anon_min_ratio"
-	depends on SYSCTL
-	range 0 100
-	default 15
-	help
-	  This option sets the default value for vm.anon_min_ratio sysctl knob.
-
-	  The vm.anon_min_ratio sysctl knob provides *hard* protection of
-	  anonymous pages. The anonymous pages on the current node won't be
-	  reclaimed under any conditions when their amount is below
-	  vm.anon_min_ratio. This knob may be used to prevent excessive swap
-	  thrashing when anonymous memory is low (for example, when memory is
-	  going to be overfilled by compressed data of zram module).
-
-	  Setting this value too high (close to MemTotal) can result in
-	  inability to swap and can lead to early OOM under memory pressure.
-
-config CLEAN_LOW_RATIO
-	int "Default value for vm.clean_low_ratio"
-	depends on SYSCTL
-	range 0 100
-	default 0
-	help
-	  This option sets the default value for vm.clean_low_ratio sysctl knob.
-
-	  The vm.clean_low_ratio sysctl knob provides *best-effort*
-	  protection of clean file pages. The file pages on the current node
-	  won't be reclaimed under memory pressure when the amount of clean file
-	  pages is below vm.clean_low_ratio *unless* we threaten to OOM.
-	  Protection of clean file pages using this knob may be used when
-	  swapping is still possible to
-	    - prevent disk I/O thrashing under memory pressure;
-	    - improve performance in disk cache-bound tasks under memory
-	      pressure.
-
-	  Setting it to a high value may result in a early eviction of anonymous
-	  pages into the swap space by attempting to hold the protected amount
-	  of clean file pages in memory.
-
-config CLEAN_MIN_RATIO
-	int "Default value for vm.clean_min_ratio"
-	depends on SYSCTL
-	range 0 100
-	default 15
-	help
-	  This option sets the default value for vm.clean_min_ratio sysctl knob.
-
-	  The vm.clean_min_ratio sysctl knob provides *hard* protection of
-	  clean file pages. The file pages on the current node won't be
-	  reclaimed under memory pressure when the amount of clean file pages is
-	  below vm.clean_min_ratio. Hard protection of clean file pages using
-	  this knob may be used to
-	    - prevent disk I/O thrashing under memory pressure even with no free
-	      swap space;
-	    - improve performance in disk cache-bound tasks under memory
-	      pressure;
-	    - avoid high latency and prevent livelock in near-OOM conditions.
-
-	  Setting it to a high value may result in a early out-of-memory condition
-	  due to the inability to reclaim the protected amount of clean file pages
-	  when other types of pages cannot be reclaimed.
-
 config HAVE_MEMBLOCK_PHYS_MAP
 	bool
 

mm/mm_init.c

@@ -2760,7 +2760,6 @@ static void __init mem_init_print_info(void)
 		, K(totalhigh_pages())
 #endif
 		);
-	printk(KERN_INFO "le9 Unofficial (le9uo) working set protection 1.3 by Masahito Suzuki (forked from hakavlad's original le9 patch)");
 }
 
 /*