Tune kernel config:

* disable Atom ISP as recommended by RussianNeuroMancer because it does not make cameras work on x86 Intel-based tablets where cameras are connected on i2c bus, but makes the camera consome power without working
* enable zswap by default and use the default allocator as in Arch Linux where zswap is enabled by default
  https://wiki.archlinux.org/index.php/Zswap
* tune values of sysctls from le9 patch to make it have at least some effect on typical desktop and server systems but avoid too agressive OOM killer on systems with 2 GB RAM and less where OOM killer kills too many process
  See discussion and my comments in the thread https://www.linux.org.ru/news/kernel/16052362
* remove not used variant of the patch which did not have any effect

kernel-arm64.config

@@ -961,6 +961,9 @@ CONFIG_COREDUMP=y
 #
 CONFIG_SELECT_MEMORY_MODEL=y
 CONFIG_SPARSEMEM_MANUAL=y
+CONFIG_UNEVICTABLE_ACTIVEFILE=y
+CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW=102400
+CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN=51200
 CONFIG_SPARSEMEM=y
 CONFIG_NEED_MULTIPLE_NODES=y
 CONFIG_SPARSEMEM_EXTREME=y
@@ -1006,14 +1009,14 @@ CONFIG_ZSWAP=y
 # CONFIG_ZSWAP_COMPRESSOR_DEFAULT_LZ4HC is not set
 CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD=y
 CONFIG_ZSWAP_COMPRESSOR_DEFAULT="zstd"
-CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD=y
+# CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD is not set
-# CONFIG_ZSWAP_ZPOOL_DEFAULT_Z3FOLD is not set
+CONFIG_ZSWAP_ZPOOL_DEFAULT_Z3FOLD=y
 # CONFIG_ZSWAP_ZPOOL_DEFAULT_ZSMALLOC is not set
-CONFIG_ZSWAP_ZPOOL_DEFAULT="zbud"
+CONFIG_ZSWAP_ZPOOL_DEFAULT="z3fold"
-# CONFIG_ZSWAP_DEFAULT_ON is not set
+CONFIG_ZSWAP_DEFAULT_ON=y
 CONFIG_ZPOOL=y
 CONFIG_ZBUD=y
-CONFIG_Z3FOLD=m
+CONFIG_Z3FOLD=y
 CONFIG_ZSMALLOC=y
 # CONFIG_ZSMALLOC_STAT is not set
 CONFIG_GENERIC_EARLY_IOREMAP=y

kernel-i586.config

@@ -974,6 +974,9 @@ CONFIG_COREDUMP=y
 #
 CONFIG_SELECT_MEMORY_MODEL=y
 CONFIG_SPARSEMEM_MANUAL=y
+CONFIG_UNEVICTABLE_ACTIVEFILE=y
+CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW=102400
+CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN=51200
 CONFIG_SPARSEMEM=y
 CONFIG_NEED_MULTIPLE_NODES=y
 CONFIG_SPARSEMEM_EXTREME=y
@@ -1023,14 +1026,14 @@ CONFIG_ZSWAP=y
 # CONFIG_ZSWAP_COMPRESSOR_DEFAULT_LZ4HC is not set
 CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD=y
 CONFIG_ZSWAP_COMPRESSOR_DEFAULT="zstd"
-CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD=y
+# CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD is not set
-# CONFIG_ZSWAP_ZPOOL_DEFAULT_Z3FOLD is not set
+CONFIG_ZSWAP_ZPOOL_DEFAULT_Z3FOLD=y
 # CONFIG_ZSWAP_ZPOOL_DEFAULT_ZSMALLOC is not set
-CONFIG_ZSWAP_ZPOOL_DEFAULT="zbud"
+CONFIG_ZSWAP_ZPOOL_DEFAULT="z3fold"
-# CONFIG_ZSWAP_DEFAULT_ON is not set
+CONFIG_ZSWAP_DEFAULT_ON=y
 CONFIG_ZPOOL=y
 CONFIG_ZBUD=y
-CONFIG_Z3FOLD=m
+CONFIG_Z3FOLD=y
 CONFIG_ZSMALLOC=y
 # CONFIG_ZSMALLOC_STAT is not set
 CONFIG_GENERIC_EARLY_IOREMAP=y
@@ -8501,7 +8504,7 @@ CONFIG_AD2S1210=m
 
 CONFIG_FB_SM750=m
 CONFIG_STAGING_MEDIA=y
-CONFIG_INTEL_ATOMISP=y
+# CONFIG_INTEL_ATOMISP is not set
 # CONFIG_VIDEO_ZORAN is not set
 CONFIG_VIDEO_IPU3_IMGU=m
 
@@ -8647,6 +8650,7 @@ CONFIG_THINKPAD_ACPI_DEBUGFACILITIES=y
 CONFIG_THINKPAD_ACPI_VIDEO=y
 CONFIG_THINKPAD_ACPI_HOTKEY_POLL=y
 CONFIG_INTEL_ATOMISP2_LED=m
+CONFIG_INTEL_ATOMISP2_PM=m
 CONFIG_INTEL_CHT_INT33FE=m
 CONFIG_INTEL_HID_EVENT=m
 CONFIG_INTEL_INT0002_VGPIO=m

kernel-x86_64.config

@@ -982,6 +982,9 @@ CONFIG_COREDUMP=y
 #
 CONFIG_SELECT_MEMORY_MODEL=y
 CONFIG_SPARSEMEM_MANUAL=y
+CONFIG_UNEVICTABLE_ACTIVEFILE=y
+CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW=102400
+CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN=51200
 CONFIG_SPARSEMEM=y
 CONFIG_NEED_MULTIPLE_NODES=y
 CONFIG_SPARSEMEM_EXTREME=y
@@ -1031,14 +1034,14 @@ CONFIG_ZSWAP=y
 # CONFIG_ZSWAP_COMPRESSOR_DEFAULT_LZ4HC is not set
 CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD=y
 CONFIG_ZSWAP_COMPRESSOR_DEFAULT="zstd"
-CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD=y
+# CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD is not set
-# CONFIG_ZSWAP_ZPOOL_DEFAULT_Z3FOLD is not set
+CONFIG_ZSWAP_ZPOOL_DEFAULT_Z3FOLD=y
 # CONFIG_ZSWAP_ZPOOL_DEFAULT_ZSMALLOC is not set
-CONFIG_ZSWAP_ZPOOL_DEFAULT="zbud"
+CONFIG_ZSWAP_ZPOOL_DEFAULT="z3fold"
-# CONFIG_ZSWAP_DEFAULT_ON is not set
+CONFIG_ZSWAP_DEFAULT_ON=y
 CONFIG_ZPOOL=y
 CONFIG_ZBUD=y
-CONFIG_Z3FOLD=m
+CONFIG_Z3FOLD=y
 CONFIG_ZSMALLOC=y
 # CONFIG_ZSMALLOC_STAT is not set
 CONFIG_GENERIC_EARLY_IOREMAP=y
@@ -8510,7 +8513,7 @@ CONFIG_AD2S1210=m
 
 CONFIG_FB_SM750=m
 CONFIG_STAGING_MEDIA=y
-CONFIG_INTEL_ATOMISP=y
+# CONFIG_INTEL_ATOMISP is not set
 # CONFIG_VIDEO_ZORAN is not set
 CONFIG_VIDEO_IPU3_IMGU=m
 
@@ -8656,6 +8659,7 @@ CONFIG_THINKPAD_ACPI_DEBUGFACILITIES=y
 CONFIG_THINKPAD_ACPI_VIDEO=y
 CONFIG_THINKPAD_ACPI_HOTKEY_POLL=y
 CONFIG_INTEL_ATOMISP2_LED=m
+CONFIG_INTEL_ATOMISP2_PM=m
 CONFIG_INTEL_CHT_INT33FE=m
 CONFIG_INTEL_HID_EVENT=m
 CONFIG_INTEL_INT0002_VGPIO=m

kernel.spec

@@ -24,7 +24,7 @@
 %define sublevel	2
 
 # Release number. Increase this before a rebuild.
-%define rpmrel		4
+%define rpmrel		5
 %define fullrpmrel	%{rpmrel}
 
 %define rpmtag		%{disttag}
@@ -309,8 +309,16 @@ Patch302:	0001-sign-file-full-functionality-with-modern-LibreSSL.patch
 Patch305:	0001-crypto-support-loading-GOST-signed-kernel-modules.patch
 # Allow to off modules signature check dynamically
 Patch306:	0001-ROSA-ima-allow-to-off-modules-signature-check-dynami.patch
-# (WIP, experimantal) https://www.linux.org.ru/news/kernel/16052362
+# Experimental patch to reduce freezes in low memory conditions
-#Patch307:	rosa-le9.diff
+# Config values are the following:
+# CONFIG_UNEVICTABLE_ACTIVEFILE=y
+# CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW=102400 (100 MB)
+# CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN=51200 (50 MB)
+# + zswap is enabled by default
+# 50 MB is default value of min_filelist_kbytes in Chromium OS
+# https://chromium.googlesource.com/chromiumos/third_party/kernel-next/+/545e2917dbd863760a51379de8c26631e667c563%5E!/
+# 256 and 512 MB values are too big as a distro default because many systems have 512MB-2GB RAM
+# TODO: tune 50 and 100 MB to some not random and mathemetically explainable values
 # https://www.linux.org.ru/news/kernel/16052362?cid=16075323
 Patch307:	le9pf.diff
 

rosa-le9.diff

@@ -1,216 +0,0 @@
-diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
-index f455fa00c00f..a6146e0fc88a 100644
---- a/Documentation/admin-guide/sysctl/vm.rst
-+++ b/Documentation/admin-guide/sysctl/vm.rst
-@@ -69,6 +69,8 @@ Currently, these files are in /proc/sys/vm:
- - stat_refresh
- - numa_stat
- - swappiness
-+- unevictable_activefile_kbytes_low
-+- unevictable_activefile_kbytes_min
- - unprivileged_userfaultfd
- - user_reserve_kbytes
- - vfs_cache_pressure
-@@ -881,6 +883,31 @@ privileged users (with SYS_CAP_PTRACE capability).
- The default value is 1.
- 
- 
-+unevictable_activefile_kbytes_low
-+=================================
-+
-+Keep some active file pages still mapped under memory pressure to avoid
-+potential disk thrashing that may occur due to evicting running executables
-+code. This implements soft eviction throttling, and some file pages can still
-+be discarded.
-+
-+Setting it to 0 effectively disables this feature.
-+
-+The default value is 512 MiB.
-+
-+
-+unevictable_activefile_kbytes_min
-+=================================
-+
-+Keep all active file pages still mapped under memory pressure to avoid
-+potential disk thrashing that may occur due to evicting running executables
-+code. This is the hard limit.
-+
-+Setting it to 0 effectively disables this feature.
-+
-+The default value is 256 MiB.
-+
-+
- user_reserve_kbytes
- ===================
- 
-diff --git a/kernel/sysctl.c b/kernel/sysctl.c
-index afad085960b8..1a2423c7f4a3 100644
---- a/kernel/sysctl.c
-+++ b/kernel/sysctl.c
-@@ -111,6 +111,22 @@
- static int sixty = 60;
- #endif
- 
-+#if defined(CONFIG_UNEVICTABLE_ACTIVEFILE)
-+#if CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW < 0
-+#error "CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW should be >= 0"
-+#endif
-+#if CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN < 0
-+#error "CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN should be >= 0"
-+#endif
-+#if CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW < CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN
-+#error "CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW should be >= CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN"
-+#endif
-+unsigned long sysctl_unevictable_activefile_kbytes_low __read_mostly =
-+	CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_LOW;
-+unsigned long sysctl_unevictable_activefile_kbytes_min __read_mostly =
-+	CONFIG_UNEVICTABLE_ACTIVEFILE_KBYTES_MIN;
-+#endif
-+
- static int __maybe_unused neg_one = -1;
- static int __maybe_unused two = 2;
- static int __maybe_unused four = 4;
-@@ -3081,6 +3097,26 @@ static struct ctl_table vm_table[] = {
- 		.extra1		= SYSCTL_ZERO,
- 		.extra2		= SYSCTL_ONE,
- 	},
-+#endif
-+#if defined(CONFIG_UNEVICTABLE_ACTIVEFILE)
-+	{
-+		.procname	= "unevictable_activefile_kbytes_low",
-+		.data		= &sysctl_unevictable_activefile_kbytes_low,
-+		.maxlen		= sizeof(sysctl_unevictable_activefile_kbytes_low),
-+		.mode		= 0644,
-+		.proc_handler	= proc_doulongvec_minmax,
-+		.extra1		= &sysctl_unevictable_activefile_kbytes_min,
-+		.extra2		= &long_max,
-+	},
-+	{
-+		.procname	= "unevictable_activefile_kbytes_min",
-+		.data		= &sysctl_unevictable_activefile_kbytes_min,
-+		.maxlen		= sizeof(sysctl_unevictable_activefile_kbytes_min),
-+		.mode		= 0644,
-+		.proc_handler	= proc_doulongvec_minmax,
-+		.extra1		= &zero_ul,
-+		.extra2		= &sysctl_unevictable_activefile_kbytes_low,
-+	},
- #endif
- 	{
- 		.procname	= "user_reserve_kbytes",
-diff --git a/mm/Kconfig b/mm/Kconfig
-index 390165ffbb0f..055b8b4a893f 100644
---- a/mm/Kconfig
-+++ b/mm/Kconfig
-@@ -63,6 +63,41 @@ config SPARSEMEM_MANUAL
- 
- endchoice
- 
-+config UNEVICTABLE_ACTIVEFILE
-+	bool "Keep some active file pages under memory pressure"
-+	depends on SYSCTL
-+	def_bool y
-+	help
-+	  Keep some active file pages still mapped under memory pressure to avoid
-+	  potential disk thrashing that may occur due to evicting running executables
-+	  code.
-+
-+	  The UNEVICTABLE_ACTIVEFILE_KBYTES_LOW value defines a threshold to activate
-+	  file pages eviction throttling. The vm.unevictable_activefile_kbytes_low
-+	  sysctl knob is used to change the amount in the runtime (setting it to 0
-+	  effectively disables this feature).
-+
-+	  Recommended value: 153600 for typical desktop workload.
-+
-+	  The UNEVICTABLE_ACTIVEFILE_KBYTES_MIN value sets the amount of pages to keep
-+	  as a hard limit. The vm.unevictable_activefile_kbytes_min sysctl knob is used
-+	  to change the amount in the runtime (setting it to 0 effectively disables
-+	  this feature).
-+
-+	  Recommended value: 51200 for typical desktop workload.
-+
-+	  See also: Documentation/admin-guide/sysctl/vm.rst
-+
-+config UNEVICTABLE_ACTIVEFILE_KBYTES_LOW
-+	int "Default value for vm.unevictable_activefile_kbytes_low"
-+	depends on UNEVICTABLE_ACTIVEFILE
-+	default "153600"
-+
-+config UNEVICTABLE_ACTIVEFILE_KBYTES_MIN
-+	int "Default value for vm.unevictable_activefile_kbytes_min"
-+	depends on UNEVICTABLE_ACTIVEFILE
-+	default "51200"
-+
- config DISCONTIGMEM
- 	def_bool y
- 	depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
-diff --git a/mm/vmscan.c b/mm/vmscan.c
-index 7b4e31eac2cf..a14daf648df1 100644
---- a/mm/vmscan.c
-+++ b/mm/vmscan.c
-@@ -166,6 +166,11 @@ struct scan_control {
- #define prefetchw_prev_lru_page(_page, _base, _field) do { } while (0)
- #endif
- 
-+#if defined(CONFIG_UNEVICTABLE_ACTIVEFILE)
-+extern unsigned long sysctl_unevictable_activefile_kbytes_low;
-+extern unsigned long sysctl_unevictable_activefile_kbytes_min;
-+#endif
-+
- /*
-  * From 0 .. 200.  Higher means more swappy.
-  */
-@@ -2225,6 +2230,10 @@ enum scan_balance {
- 	SCAN_FILE,
- };
- 
-+#if defined(CONFIG_UNEVICTABLE_ACTIVEFILE)
-+#define K(x) ((x) << (PAGE_SHIFT - 10))
-+#endif
-+
- /*
-  * Determine how aggressively the anon and file LRU lists should be
-  * scanned.  The relative value of each set of LRU lists is determined
-@@ -2290,7 +2299,32 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
- 		scan_balance = SCAN_FILE;
- 		goto out;
- 	}
-+	
-+#ifdef CONFIG_UNEVICTABLE_ACTIVEFILE
-+	bool skip_evecting_active_file;
-+	skip_evecting_active_file = false;
-+	unsigned long kib_active_file_now = K(global_node_page_state(NR_ACTIVE_FILE));
-+	if (kib_active_file_now <= sysctl_unevictable_activefile_kbytes_min) {
-+		skip_evecting_active_file = true;
-+		goto cua_done;
-+	} else if (kib_active_file_now < sysctl_unevictable_activefile_kbytes_low &&
-+		       kib_active_file_now > sysctl_unevictable_activefile_kbytes_min) {
-+		/* Integer division: taking decision whether to skip evicting active file or not */
-+		if ((
-+		    (kib_active_file_now - sysctl_unevictable_activefile_kbytes_min) /
-+		    (sysctl_unevictable_activefile_kbytes_low - sysctl_unevictable_activefile_kbytes_min)
-+		   ) < 1)
-+				skip_evecting_active_file = true;
-+	} else {
-+		goto scan_fract;
-+	}
-+cua_done:
-+	/* Skip not needed calculations */
-+	scan_balance = SCAN_ANON;
-+	goto out;
-+#endif
- 
-+scan_fract:
- 	scan_balance = SCAN_FRACT;
- 	/*
- 	 * Calculate the pressure balance between anon and file pages.
-@@ -2412,6 +2446,10 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
- 			/* Scan one type exclusively */
- 			if ((scan_balance == SCAN_FILE) != file)
- 				scan = 0;
-+#ifdef CONFIG_UNEVICTABLE_ACTIVEFILE
-+			if ((skip_evecting_active_file) && (lru == LRU_ACTIVE_FILE))
-+				scan = 0;
-+#endif
- 			break;
- 		default:
- 			/* Look ma, no brain */