diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/blockdev/zram.rst | 49 | ||||
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 5 | ||||
| -rw-r--r-- | Documentation/admin-guide/kdump/vmcoreinfo.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 6 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/lru_sort.rst | 13 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/reclaim.rst | 9 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/stat.rst | 5 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 16 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/kho.rst | 53 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/numa_memory_policy.rst | 2 |
10 files changed, 79 insertions, 81 deletions
diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index 451fa00d3004..60b07a7e30cd 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -462,7 +462,7 @@ know it via /sys/block/zram0/bd_stat's 3rd column. recompression ------------- -With CONFIG_ZRAM_MULTI_COMP, zram can recompress pages using alternative +With `CONFIG_ZRAM_MULTI_COMP`, zram can recompress pages using alternative (secondary) compression algorithms. The basic idea is that alternative compression algorithm can provide better compression ratio at a price of (potentially) slower compression/decompression speeds. Alternative compression @@ -471,7 +471,7 @@ that default algorithm failed to compress). Another application is idle pages recompression - pages that are cold and sit in the memory can be recompressed using more effective algorithm and, hence, reduce zsmalloc memory usage. -With CONFIG_ZRAM_MULTI_COMP, zram supports up to 4 compression algorithms: +With `CONFIG_ZRAM_MULTI_COMP`, zram supports up to 4 compression algorithms: one primary and up to 3 secondary ones. Primary zram compressor is explained in "3) Select compression algorithm", secondary algorithms are configured using recomp_algorithm device attribute. @@ -495,56 +495,43 @@ configuration::: #select deflate recompression algorithm, priority 2 echo "algo=deflate priority=2" > /sys/block/zramX/recomp_algorithm -Another device attribute that CONFIG_ZRAM_MULTI_COMP enables is recompress, +Another device attribute that `CONFIG_ZRAM_MULTI_COMP` enables is `recompress`, which controls recompression. Examples::: #IDLE pages recompression is activated by `idle` mode - echo "type=idle" > /sys/block/zramX/recompress + echo "type=idle priority=1" > /sys/block/zramX/recompress #HUGE pages recompression is activated by `huge` mode - echo "type=huge" > /sys/block/zram0/recompress + echo "type=huge priority=2" > /sys/block/zram0/recompress #HUGE_IDLE pages recompression is activated by `huge_idle` mode - echo "type=huge_idle" > /sys/block/zramX/recompress + echo "type=huge_idle priority=1" > /sys/block/zramX/recompress The number of idle pages can be significant, so user-space can pass a size threshold (in bytes) to the recompress knob: zram will recompress only pages of equal or greater size::: #recompress all pages larger than 3000 bytes - echo "threshold=3000" > /sys/block/zramX/recompress + echo "threshold=3000 priority=1" > /sys/block/zramX/recompress #recompress idle pages larger than 2000 bytes - echo "type=idle threshold=2000" > /sys/block/zramX/recompress + echo "type=idle threshold=2000 priority=1" > \ + /sys/block/zramX/recompress It is also possible to limit the number of pages zram re-compression will attempt to recompress::: - echo "type=huge_idle max_pages=42" > /sys/block/zramX/recompress - -During re-compression for every page, that matches re-compression criteria, -ZRAM iterates the list of registered alternative compression algorithms in -order of their priorities. ZRAM stops either when re-compression was -successful (re-compressed object is smaller in size than the original one) -and matches re-compression criteria (e.g. size threshold) or when there are -no secondary algorithms left to try. If none of the secondary algorithms can -successfully re-compressed the page such a page is marked as incompressible, -so ZRAM will not attempt to re-compress it in the future. - -This re-compression behaviour, when it iterates through the list of -registered compression algorithms, increases our chances of finding the -algorithm that successfully compresses a particular page. Sometimes, however, -it is convenient (and sometimes even necessary) to limit recompression to -only one particular algorithm so that it will not try any other algorithms. -This can be achieved by providing a `algo` or `priority` parameter::: - - #use zstd algorithm only (if registered) - echo "type=huge algo=zstd" > /sys/block/zramX/recompress - - #use zstd algorithm only (if zstd was registered under priority 1) - echo "type=huge priority=1" > /sys/block/zramX/recompress + echo "type=huge_idle priority=1 max_pages=42" > \ + /sys/block/zramX/recompress + +It is advised to always specify `priority` parameter. While it is also +possible to specify `algo` parameter, so that `zram` will use algorithm's +name to determine the priority, it is not recommended, since it can lead to +unexpected results when the same algorithm is configured with different +priorities (e.g. different parameters). `priority` is the only way to +guarantee that the expected algorithm will be used. memory tracking =============== diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 91beaa6798ce..8ad0b2781317 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1734,6 +1734,11 @@ The following nested keys are defined. zswpwb Number of pages written from zswap to swap. + zswap_incomp + Number of incompressible pages currently stored in zswap + without compression. These pages could not be compressed to + a size smaller than PAGE_SIZE, so they are stored as-is. + thp_fault_alloc (npn) Number of transparent hugepages which were allocated to satisfy a page fault. This counter is not present when CONFIG_TRANSPARENT_HUGEPAGE diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst index 404a15f6782c..7663c610fe90 100644 --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -141,7 +141,7 @@ nodemask_t The size of a nodemask_t type. Used to compute the number of online nodes. -(page, flags|_refcount|mapping|lru|_mapcount|private|compound_order|compound_head) +(page, flags|_refcount|mapping|lru|_mapcount|private|compound_order|compound_info) ---------------------------------------------------------------------------------- User-space tools compute their values based on the offset of these diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b9a2c649e411..4510b4b3c416 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2970,6 +2970,12 @@ Kernel parameters Format: <bool> Default: CONFIG_KFENCE_DEFERRABLE + kfence.fault= [MM,KFENCE] Controls the behavior when a KFENCE + error is detected. + report - print the error report and continue (default). + oops - print the error report and oops. + panic - print the error report and panic. + kfence.sample_interval= [MM,KFENCE] KFENCE's sample interval in milliseconds. Format: <unsigned integer> diff --git a/Documentation/admin-guide/mm/damon/lru_sort.rst b/Documentation/admin-guide/mm/damon/lru_sort.rst index 20a8378d5a94..a7dea7c75a9b 100644 --- a/Documentation/admin-guide/mm/damon/lru_sort.rst +++ b/Documentation/admin-guide/mm/damon/lru_sort.rst @@ -91,8 +91,8 @@ increases and decreases the effective level of the quota aiming the LRU Disabled by default. -Auto-tune monitoring intervals ------------------------------- +autotune_monitoring_intervals +----------------------------- If this parameter is set as ``Y``, DAMON_LRU_SORT automatically tunes DAMON's sampling and aggregation intervals. The auto-tuning aims to capture meaningful @@ -221,6 +221,10 @@ But, setting this too high could result in increased monitoring overhead. Please refer to the DAMON documentation (:doc:`usage`) for more detail. 10 by default. +Note that this must be 3 or higher. Please refer to the :ref:`Monitoring +<damon_design_monitoring>` section of the design document for the rationale +behind this lower bound. + max_nr_regions -------------- @@ -351,3 +355,8 @@ the LRU-list based page granularity reclamation. :: # echo 400 > wmarks_mid # echo 200 > wmarks_low # echo Y > enabled + +Note that this module (damon_lru_sort) cannot run simultaneously with other +DAMON-based special-purpose modules. Refer to :ref:`DAMON design special +purpose modules exclusivity <damon_design_special_purpose_modules_exclusivity>` +for more details. diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index 8eba3da8dcee..47854c461706 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -204,6 +204,10 @@ monitoring. This can be used to set lower-bound of the monitoring quality. But, setting this too high could result in increased monitoring overhead. Please refer to the DAMON documentation (:doc:`usage`) for more detail. +Note that this must be 3 or higher. Please refer to the :ref:`Monitoring +<damon_design_monitoring>` section of the design document for the rationale +behind this lower bound. + max_nr_regions -------------- @@ -318,6 +322,11 @@ granularity reclamation. :: # echo 200 > wmarks_low # echo Y > enabled +Note that this module (damon_reclaim) cannot run simultaneously with other +DAMON-based special-purpose modules. Refer to :ref:`DAMON design special +purpose modules exclusivity <damon_design_special_purpose_modules_exclusivity>` +for more details. + .. [1] https://research.google/pubs/pub48551/ .. [2] https://lwn.net/Articles/787611/ .. [3] https://www.kernel.org/doc/html/latest/mm/free_page_reporting.html diff --git a/Documentation/admin-guide/mm/damon/stat.rst b/Documentation/admin-guide/mm/damon/stat.rst index e5a5a2c4f803..c4b14daeb2dd 100644 --- a/Documentation/admin-guide/mm/damon/stat.rst +++ b/Documentation/admin-guide/mm/damon/stat.rst @@ -45,6 +45,11 @@ You can enable DAMON_STAT by setting the value of this parameter as ``Y``. Setting it as ``N`` disables DAMON_STAT. The default value is set by ``CONFIG_DAMON_STAT_ENABLED_DEFAULT`` build config option. +Note that this module (damon_stat) cannot run simultaneously with other +DAMON-based special-purpose modules. Refer to :ref:`DAMON design special +purpose modules exclusivity <damon_design_special_purpose_modules_exclusivity>` +for more details. + .. _damon_stat_aggr_interval_us: aggr_interval_us diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index b0f3969b6b3b..534e1199cf09 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -83,7 +83,7 @@ comma (","). │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max - │ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms,effective_bytes + │ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms,effective_bytes,goal_tuner │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ │ :ref:`goals <sysfs_schemes_quota_goals>`/nr_goals │ │ │ │ │ │ │ │ │ 0/target_metric,target_value,current_value,nid,path @@ -377,9 +377,9 @@ schemes/<N>/quotas/ The directory for the :ref:`quotas <damon_design_damos_quotas>` of the given DAMON-based operation scheme. -Under ``quotas`` directory, four files (``ms``, ``bytes``, -``reset_interval_ms``, ``effective_bytes``) and two directories (``weights`` and -``goals``) exist. +Under ``quotas`` directory, five files (``ms``, ``bytes``, +``reset_interval_ms``, ``effective_bytes`` and ``goal_tuner``) and two +directories (``weights`` and ``goals``) exist. You can set the ``time quota`` in milliseconds, ``size quota`` in bytes, and ``reset interval`` in milliseconds by writing the values to the three files, @@ -390,6 +390,14 @@ apply the action to only up to ``bytes`` bytes of memory regions within the quota limits unless at least one :ref:`goal <sysfs_schemes_quota_goals>` is set. +You can set the goal-based effective quota auto-tuning algorithm to use, by +writing the algorithm name to ``goal_tuner`` file. Reading the file returns +the currently selected tuner algorithm. Refer to the design documentation of +:ref:`automatic quota tuning goals <damon_design_damos_quotas_auto_tuning>` for +the background design of the feature and the name of the selectable algorithms. +Refer to :ref:`goals directory <sysfs_schemes_quota_goals>` for the goals +setup. + The time quota is internally transformed to a size quota. Between the transformed size quota and user-specified size quota, smaller one is applied. Based on the user-specified :ref:`goal <sysfs_schemes_quota_goals>`, the diff --git a/Documentation/admin-guide/mm/kho.rst b/Documentation/admin-guide/mm/kho.rst index 6dc18ed4b886..cb9a20f64920 100644 --- a/Documentation/admin-guide/mm/kho.rst +++ b/Documentation/admin-guide/mm/kho.rst @@ -28,20 +28,10 @@ per NUMA node scratch regions on boot. Perform a KHO kexec =================== -First, before you perform a KHO kexec, you need to move the system into -the :ref:`KHO finalization phase <kho-finalization-phase>` :: - - $ echo 1 > /sys/kernel/debug/kho/out/finalize - -After this command, the KHO FDT is available in -``/sys/kernel/debug/kho/out/fdt``. Other subsystems may also register -their own preserved sub FDTs under -``/sys/kernel/debug/kho/out/sub_fdts/``. - -Next, load the target payload and kexec into it. It is important that you -use the ``-s`` parameter to use the in-kernel kexec file loader, as user -space kexec tooling currently has no support for KHO with the user space -based file loader :: +To perform a KHO kexec, load the target payload and kexec into it. It +is important that you use the ``-s`` parameter to use the in-kernel +kexec file loader, as user space kexec tooling currently has no +support for KHO with the user space based file loader :: # kexec -l /path/to/bzImage --initrd /path/to/initrd -s # kexec -e @@ -52,40 +42,19 @@ For example, if you used ``reserve_mem`` command line parameter to create an early memory reservation, the new kernel will have that memory at the same physical address as the old kernel. -Abort a KHO exec -================ - -You can move the system out of KHO finalization phase again by calling :: - - $ echo 0 > /sys/kernel/debug/kho/out/active - -After this command, the KHO FDT is no longer available in -``/sys/kernel/debug/kho/out/fdt``. - debugfs Interfaces ================== +These debugfs interfaces are available when the kernel is compiled with +``CONFIG_KEXEC_HANDOVER_DEBUGFS`` enabled. + Currently KHO creates the following debugfs interfaces. Notice that these interfaces may change in the future. They will be moved to sysfs once KHO is stabilized. -``/sys/kernel/debug/kho/out/finalize`` - Kexec HandOver (KHO) allows Linux to transition the state of - compatible drivers into the next kexec'ed kernel. To do so, - device drivers will instruct KHO to preserve memory regions, - which could contain serialized kernel state. - While the state is serialized, they are unable to perform - any modifications to state that was serialized, such as - handed over memory allocations. - - When this file contains "1", the system is in the transition - state. When contains "0", it is not. To switch between the - two states, echo the respective number into this file. - ``/sys/kernel/debug/kho/out/fdt`` - When KHO state tree is finalized, the kernel exposes the - flattened device tree blob that carries its current KHO - state in this file. Kexec user space tooling can use this + The kernel exposes the flattened device tree blob that carries its + current KHO state in this file. Kexec user space tooling can use this as input file for the KHO payload image. ``/sys/kernel/debug/kho/out/scratch_len`` @@ -100,8 +69,8 @@ stabilized. it should place its payload images. ``/sys/kernel/debug/kho/out/sub_fdts/`` - In the KHO finalization phase, KHO producers register their own - FDT blob under this directory. + KHO producers can register their own FDT or another binary blob under + this directory. ``/sys/kernel/debug/kho/in/fdt`` When the kernel was booted with Kexec HandOver (KHO), diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst index a70f20ce1ffb..90ab26e805a9 100644 --- a/Documentation/admin-guide/mm/numa_memory_policy.rst +++ b/Documentation/admin-guide/mm/numa_memory_policy.rst @@ -217,7 +217,7 @@ MPOL_PREFERRED the MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES flags described below. -MPOL_INTERLEAVED +MPOL_INTERLEAVE This mode specifies that page allocations be interleaved, on a page granularity, across the nodes specified in the policy. This mode also behaves slightly differently, based on the |