4 files changed, 159 insertions, 12 deletions
diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst
index 47499a1742bd..6c54718c9d04 100644
--- a/Documentation/admin-guide/sysctl/fs.rst
+++ b/Documentation/admin-guide/sysctl/fs.rst
@@ -38,6 +38,11 @@ requests.  ``aio-max-nr`` allows you to change the maximum value
 ``aio-max-nr`` does not result in the
 pre-allocation or re-sizing of any kernel data structures.
 
+dentry-negative
+----------------------------
+
+Policy for negative dentries. Set to 1 to always delete the dentry when a
+file is removed, and 0 to disable it. By default, this behavior is disabled.
 
 dentry-state
 ------------
@@ -332,3 +337,38 @@ Each "watch" costs roughly 90 bytes on a 32-bit kernel, and roughly 160 bytes
 on a 64-bit one.
 The current default value for ``max_user_watches`` is 4% of the
 available low memory, divided by the "watch" cost in bytes.
+
+5. /proc/sys/fs/fuse - Configuration options for FUSE filesystems
+=====================================================================
+
+This directory contains the following configuration options for FUSE
+filesystems:
+
+``/proc/sys/fs/fuse/max_pages_limit`` is a read/write file for
+setting/getting the maximum number of pages that can be used for servicing
+requests in FUSE.
+
+``/proc/sys/fs/fuse/default_request_timeout`` is a read/write file for
+setting/getting the default timeout (in seconds) for a fuse server to
+reply to a kernel-issued request in the event where the server did not
+specify a timeout at mount. If the server set a timeout,
+then default_request_timeout will be ignored.  The default
+"default_request_timeout" is set to 0. 0 indicates no default timeout.
+The maximum value that can be set is 65535.
+
+``/proc/sys/fs/fuse/max_request_timeout`` is a read/write file for
+setting/getting the maximum timeout (in seconds) for a fuse server to
+reply to a kernel-issued request. A value greater than 0 automatically opts
+the server into a timeout that will be set to at most "max_request_timeout",
+even if the server did not specify a timeout and default_request_timeout is
+set to 0. If max_request_timeout is greater than 0 and the server set a timeout
+greater than max_request_timeout or default_request_timeout is set to a value
+greater than max_request_timeout, the system will use max_request_timeout as the
+timeout. 0 indicates no max request timeout. The maximum value that can be set
+is 65535.
+
+For timeouts, if the server does not respond to the request by the time
+the set timeout elapses, then the connection to the fuse server will be aborted.
+Please note that the timeouts are not 100% precise (eg you may set 60 seconds but
+the timeout may kick in after 70 seconds). The upper margin of error for the
+timeout is roughly FUSE_TIMEOUT_TIMER_FREQ seconds.
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 7fd43947832f..dd49a89a62d3 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -212,6 +212,17 @@ pid>/``).
 This value defaults to 0.
 
 
+core_sort_vma
+=============
+
+The default coredump writes VMAs in address order. By setting
+``core_sort_vma`` to 1, VMAs will be written from smallest size
+to largest size. This is known to break at least elfutils, but
+can be handy when dealing with very large (and truncated)
+coredumps where the more useful debugging details are included
+in the smaller VMAs.
+
+
 core_uses_pid
 =============
 
@@ -401,6 +412,15 @@ The upper bound on the number of tasks that are checked.
 This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled.
 
 
+hung_task_detect_count
+======================
+
+Indicates the total number of tasks that have been detected as hung since
+the system boot.
+
+This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled.
+
+
 hung_task_timeout_secs
 ======================
 
@@ -454,7 +474,7 @@ ignore-unaligned-usertrap
 
 On architectures where unaligned accesses cause traps, and where this
 feature is supported (``CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN``;
-currently, ``arc`` and ``loongarch``), controls whether all
+currently, ``arc``, ``parisc`` and ``loongarch``), controls whether all
 unaligned traps are logged.
 
 = =============================================================
@@ -1535,6 +1555,13 @@ constant ``FUTEX_TID_MASK`` (0x3fffffff).
 If a value outside of this range is written to ``threads-max`` an
 ``EINVAL`` error occurs.
 
+timer_migration
+===============
+
+When set to a non-zero value, attempt to migrate timers away from idle cpus to
+allow them to remain in low power states longer.
+
+Default is set (1).
 
 traceoff_on_warning
 ===================
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst
index 7250c0542828..7b0c4291c686 100644
--- a/Documentation/admin-guide/sysctl/net.rst
+++ b/Documentation/admin-guide/sysctl/net.rst
@@ -72,6 +72,7 @@ two flavors of JITs, the newer eBPF JIT currently supported on:
   - riscv64
   - riscv32
   - loongarch64
+  - arc
 
 And the older cBPF JIT supported on the following archs:
 
diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index c59889de122b..9bef46151d53 100644
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -28,6 +28,7 @@ Currently, these files are in /proc/sys/vm:
 - compact_memory
 - compaction_proactiveness
 - compact_unevictable_allowed
+- defrag_mode
 - dirty_background_bytes
 - dirty_background_ratio
 - dirty_bytes
@@ -36,6 +37,7 @@ Currently, these files are in /proc/sys/vm:
 - dirtytime_expire_seconds
 - dirty_writeback_centisecs
 - drop_caches
+- enable_soft_offline
 - extfrag_threshold
 - highmem_is_dirtyable
 - hugetlb_shm_group
@@ -43,6 +45,7 @@ Currently, these files are in /proc/sys/vm:
 - legacy_va_layout
 - lowmem_reserve_ratio
 - max_map_count
+- mem_profiling         (only if CONFIG_MEM_ALLOC_PROFILING=y)
 - memory_failure_early_kill
 - memory_failure_recovery
 - min_free_kbytes
@@ -72,6 +75,7 @@ Currently, these files are in /proc/sys/vm:
 - unprivileged_userfaultfd
 - user_reserve_kbytes
 - vfs_cache_pressure
+- vfs_cache_pressure_denom
 - watermark_boost_factor
 - watermark_scale_factor
 - zone_reclaim_mode
@@ -128,6 +132,12 @@ to latency spikes in unsuspecting applications. The kernel employs
 various heuristics to avoid wasting CPU cycles if it detects that
 proactive compaction is not being effective.
 
+Setting the value above 80 will, in addition to lowering the acceptable level
+of fragmentation, make the compaction code more sensitive to increases in
+fragmentation, i.e. compaction will trigger more often, but reduce
+fragmentation by a smaller amount.
+This makes the fragmentation level more stable over time.
+
 Be careful when setting it to extreme values like 100, as that may
 cause excessive background compaction activity.
 
@@ -143,6 +153,14 @@ On CONFIG_PREEMPT_RT the default value is 0 in order to avoid a page fault, due
 to compaction, which would block the task from becoming active until the fault
 is resolved.
 
+defrag_mode
+===========
+
+When set to 1, the page allocator tries harder to avoid fragmentation
+and maintain the ability to produce huge pages / higher-order pages.
+
+It is recommended to enable this right after boot, as fragmentation,
+once it occurred, can be long-lasting or even permanent.
 
 dirty_background_bytes
 ======================
@@ -266,6 +284,43 @@ used::
 These are informational only.  They do not mean that anything is wrong
 with your system.  To disable them, echo 4 (bit 2) into drop_caches.
 
+enable_soft_offline
+===================
+Correctable memory errors are very common on servers. Soft-offline is kernel's
+solution for memory pages having (excessive) corrected memory errors.
+
+For different types of page, soft-offline has different behaviors / costs.
+
+- For a raw error page, soft-offline migrates the in-use page's content to
+  a new raw page.
+
+- For a page that is part of a transparent hugepage, soft-offline splits the
+  transparent hugepage into raw pages, then migrates only the raw error page.
+  As a result, user is transparently backed by 1 less hugepage, impacting
+  memory access performance.
+
+- For a page that is part of a HugeTLB hugepage, soft-offline first migrates
+  the entire HugeTLB hugepage, during which a free hugepage will be consumed
+  as migration target.  Then the original hugepage is dissolved into raw
+  pages without compensation, reducing the capacity of the HugeTLB pool by 1.
+
+It is user's call to choose between reliability (staying away from fragile
+physical memory) vs performance / capacity implications in transparent and
+HugeTLB cases.
+
+For all architectures, enable_soft_offline controls whether to soft offline
+memory pages.  When set to 1, kernel attempts to soft offline the pages
+whenever it thinks needed.  When set to 0, kernel returns EOPNOTSUPP to
+the request to soft offline the pages.  Its default value is 1.
+
+It is worth mentioning that after setting enable_soft_offline to 0, the
+following requests to soft offline pages will not be performed:
+
+- Request to soft offline pages from RAS Correctable Errors Collector.
+
+- On ARM, the request to soft offline pages from GHES driver.
+
+- On PARISC, the request to soft offline pages from Page Deallocation Table.
 
 extfrag_threshold
 =================
@@ -425,6 +480,21 @@ e.g., up to one or two maps per allocation.
 The default value is 65530.
 
 
+mem_profiling
+==============
+
+Enable memory profiling (when CONFIG_MEM_ALLOC_PROFILING=y)
+
+1: Enable memory profiling.
+
+0: Disable memory profiling.
+
+Enabling memory profiling introduces a small performance overhead for all
+memory allocations.
+
+The default value depends on CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT.
+
+
 memory_failure_early_kill:
 ==========================
 
@@ -954,19 +1024,28 @@ vfs_cache_pressure
 This percentage value controls the tendency of the kernel to reclaim
 the memory which is used for caching of directory and inode objects.
 
-At the default value of vfs_cache_pressure=100 the kernel will attempt to
-reclaim dentries and inodes at a "fair" rate with respect to pagecache and
-swapcache reclaim.  Decreasing vfs_cache_pressure causes the kernel to prefer
-to retain dentry and inode caches. When vfs_cache_pressure=0, the kernel will
-never reclaim dentries and inodes due to memory pressure and this can easily
-lead to out-of-memory conditions. Increasing vfs_cache_pressure beyond 100
-causes the kernel to prefer to reclaim dentries and inodes.
+At the default value of vfs_cache_pressure=vfs_cache_pressure_denom the kernel
+will attempt to reclaim dentries and inodes at a "fair" rate with respect to
+pagecache and swapcache reclaim.  Decreasing vfs_cache_pressure causes the
+kernel to prefer to retain dentry and inode caches. When vfs_cache_pressure=0,
+the kernel will never reclaim dentries and inodes due to memory pressure and
+this can easily lead to out-of-memory conditions. Increasing vfs_cache_pressure
+beyond vfs_cache_pressure_denom causes the kernel to prefer to reclaim dentries
+and inodes.
 
-Increasing vfs_cache_pressure significantly beyond 100 may have negative
-performance impact. Reclaim code needs to take various locks to find freeable
-directory and inode objects. With vfs_cache_pressure=1000, it will look for
-ten times more freeable objects than there are.
+Increasing vfs_cache_pressure significantly beyond vfs_cache_pressure_denom may
+have negative performance impact. Reclaim code needs to take various locks to
+find freeable directory and inode objects. When vfs_cache_pressure equals
+(10 * vfs_cache_pressure_denom), it will look for ten times more freeable
+objects than there are.
+
+Note: This setting should always be used together with vfs_cache_pressure_denom.
+
+vfs_cache_pressure_denom
+========================
 
+Defaults to 100 (minimum allowed value). Requires corresponding
+vfs_cache_pressure setting to take effect.
 
 watermark_boost_factor
 ======================