> Как Альт решает проблему неспособности ядра предотвращать фризы при нехватке памяти?

А она есть? Как воспроизвести?

> Используются ли спецпатчи ядра (например, ROSA Linux использует le9 patch)?

Посмотрел, что она там на самом деле использует.

diff --git a/security/altha/altha_lsm.c b/security/altha/altha_lsm.c
new file mode 100644
index 000000000000..7d1cc8f8a1a7
--- /dev/null
+++ b/security/altha/altha_lsm.c
@@ -0,0 +1,325 @@
+/*
+ * AltHa Linux Security Module
+ *
+ * Author: Anton Boyarshinov <boyarsh@altlinux.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ */

Вот тут le9 patch? https://github.com/hakavlad/le9-patch
а вот le9pf.diff

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..8bb82cf5d74e 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 +3097,25 @@ 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,
+    },
+    {
+        .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..1e1fb8ad434a 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: 524288 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: 262144 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 "524288"
+
+config UNEVICTABLE_ACTIVEFILE_KBYTES_MIN
+    int "Default value for vm.unevictable_activefile_kbytes_min"
+    depends on UNEVICTABLE_ACTIVEFILE
+    default "262144"
+
 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..93760769d676 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
@@ -2418,6 +2427,19 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
             BUG();
         }
 
+#if defined(CONFIG_UNEVICTABLE_ACTIVEFILE)
+        if (lru == LRU_ACTIVE_FILE) {
+            unsigned long activefile_kbytes_now = K(global_node_page_state(NR_ACTIVE_FILE));
+            unsigned long low_scan_granularity = SWAP_CLUSTER_MAX >> sc->priority;
+
+            if (activefile_kbytes_now < sysctl_unevictable_activefile_kbytes_low &&
+                activefile_kbytes_now > sysctl_unevictable_activefile_kbytes_min &&
+                scan > low_scan_granularity)
+                scan = low_scan_granularity;
+            else if (activefile_kbytes_now <= sysctl_unevictable_activefile_kbytes_min)
+                scan = 0;
+        }
+#endif
         nr[lru] = scan;
     }
 }