diff options
Diffstat (limited to 'Documentation/admin-guide/sysctl')
| -rw-r--r-- | Documentation/admin-guide/sysctl/fs.rst | 25 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 11 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/vm.rst | 47 |
3 files changed, 72 insertions, 11 deletions
diff --git a/Documentation/admin-guide/sysctl/fs.rst b/Documentation/admin-guide/sysctl/fs.rst index 08e89e031714..6c54718c9d04 100644 --- a/Documentation/admin-guide/sysctl/fs.rst +++ b/Documentation/admin-guide/sysctl/fs.rst @@ -347,3 +347,28 @@ 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 a43b78b4b646..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 ============= diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index f48eaa98d22d..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 @@ -74,6 +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 @@ -130,6 +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. @@ -145,6 +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 ====================== @@ -1008,19 +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 ====================== |