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Diffstat (limited to 'Documentation/admin-guide/mm/damon/usage.rst')
| -rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 105 |
1 files changed, 85 insertions, 20 deletions
diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index 1a5b6b71efa1..9b823fec974d 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -25,10 +25,12 @@ DAMON provides below interfaces for different users. interface provides only simple :ref:`statistics <damos_stats>` for the monitoring results. For detailed monitoring results, DAMON provides a :ref:`tracepoint <tracepoint>`. -- *debugfs interface.* +- *debugfs interface. (DEPRECATED!)* :ref:`This <debugfs_interface>` is almost identical to :ref:`sysfs interface - <sysfs_interface>`. This will be removed after next LTS kernel is released, - so users should move to the :ref:`sysfs interface <sysfs_interface>`. + <sysfs_interface>`. This is deprecated, so users should move to the + :ref:`sysfs interface <sysfs_interface>`. If you depend on this and cannot + move, please report your usecase to damon@lists.linux.dev and + linux-mm@kvack.org. - *Kernel Space Programming Interface.* :doc:`This </mm/damon/api>` is for kernel space programmers. Using this, users can utilize every feature of DAMON most flexibly and efficiently by @@ -87,6 +89,8 @@ comma (","). :: │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low + │ │ │ │ │ │ │ filters/nr_filters + │ │ │ │ │ │ │ │ 0/type,matching,memcg_id │ │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds │ │ │ │ │ │ │ tried_regions/ │ │ │ │ │ │ │ │ 0/start,end,nr_accesses,age @@ -151,6 +155,8 @@ number (``N``) to the file creates the number of child directories named as moment, only one context per kdamond is supported, so only ``0`` or ``1`` can be written to the file. +.. _sysfs_contexts: + contexts/<N>/ ------------- @@ -268,21 +274,32 @@ schemes/<N>/ ------------ In each scheme directory, five directories (``access_pattern``, ``quotas``, -``watermarks``, ``stats``, and ``tried_regions``) and one file (``action``) -exist. +``watermarks``, ``filters``, ``stats``, and ``tried_regions``) and one file +(``action``) exist. The ``action`` file is for setting and getting what action you want to apply to memory regions having specific access pattern of the interest. The keywords that can be written to and read from the file and their meaning are as below. - - ``willneed``: Call ``madvise()`` for the region with ``MADV_WILLNEED`` - - ``cold``: Call ``madvise()`` for the region with ``MADV_COLD`` - - ``pageout``: Call ``madvise()`` for the region with ``MADV_PAGEOUT`` - - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE`` - - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE`` +Note that support of each action depends on the running DAMON operations set +`implementation <sysfs_contexts>`. + + - ``willneed``: Call ``madvise()`` for the region with ``MADV_WILLNEED``. + Supported by ``vaddr`` and ``fvaddr`` operations set. + - ``cold``: Call ``madvise()`` for the region with ``MADV_COLD``. + Supported by ``vaddr`` and ``fvaddr`` operations set. + - ``pageout``: Call ``madvise()`` for the region with ``MADV_PAGEOUT``. + Supported by ``vaddr``, ``fvaddr`` and ``paddr`` operations set. + - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``. + Supported by ``vaddr`` and ``fvaddr`` operations set. + - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``. + Supported by ``vaddr`` and ``fvaddr`` operations set. - ``lru_prio``: Prioritize the region on its LRU lists. + Supported by ``paddr`` operations set. - ``lru_deprio``: Deprioritize the region on its LRU lists. - - ``stat``: Do nothing but count the statistics + Supported by ``paddr`` operations set. + - ``stat``: Do nothing but count the statistics. + Supported by all operations sets. schemes/<N>/access_pattern/ --------------------------- @@ -347,6 +364,46 @@ as below. The ``interval`` should written in microseconds unit. +schemes/<N>/filters/ +-------------------- + +Users could know something more than the kernel for specific types of memory. +In the case, users could do their own management for the memory and hence +doesn't want DAMOS bothers that. Users could limit DAMOS by setting the access +pattern of the scheme and/or the monitoring regions for the purpose, but that +can be inefficient in some cases. In such cases, users could set non-access +pattern driven filters using files in this directory. + +In the beginning, this directory has only one file, ``nr_filters``. Writing a +number (``N``) to the file creates the number of child directories named ``0`` +to ``N-1``. Each directory represents each filter. The filters are evaluated +in the numeric order. + +Each filter directory contains three files, namely ``type``, ``matcing``, and +``memcg_path``. You can write one of two special keywords, ``anon`` for +anonymous pages, or ``memcg`` for specific memory cgroup filtering. In case of +the memory cgroup filtering, you can specify the memory cgroup of the interest +by writing the path of the memory cgroup from the cgroups mount point to +``memcg_path`` file. You can write ``Y`` or ``N`` to ``matching`` file to +filter out pages that does or does not match to the type, respectively. Then, +the scheme's action will not be applied to the pages that specified to be +filtered out. + +For example, below restricts a DAMOS action to be applied to only non-anonymous +pages of all memory cgroups except ``/having_care_already``.:: + + # echo 2 > nr_filters + # # filter out anonymous pages + echo anon > 0/type + echo Y > 0/matching + # # further filter out all cgroups except one at '/having_care_already' + echo memcg > 1/type + echo /having_care_already > 1/memcg_path + echo N > 1/matching + +Note that filters are currently supported only when ``paddr`` +`implementation <sysfs_contexts>` is being used. + .. _sysfs_schemes_stats: schemes/<N>/stats/ @@ -432,13 +489,17 @@ the files as above. Above is only for an example. .. _debugfs_interface: -debugfs Interface -================= +debugfs Interface (DEPRECATED!) +=============================== .. note:: - DAMON debugfs interface will be removed after next LTS kernel is released, so - users should move to the :ref:`sysfs interface <sysfs_interface>`. + THIS IS DEPRECATED! + + DAMON debugfs interface is deprecated, so users should move to the + :ref:`sysfs interface <sysfs_interface>`. If you depend on this and cannot + move, please report your usecase to damon@lists.linux.dev and + linux-mm@kvack.org. DAMON exports eight files, ``attrs``, ``target_ids``, ``init_regions``, ``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` and @@ -574,11 +635,15 @@ The ``<action>`` is a predefined integer for memory management actions, which DAMON will apply to the regions having the target access pattern. The supported numbers and their meanings are as below. - - 0: Call ``madvise()`` for the region with ``MADV_WILLNEED`` - - 1: Call ``madvise()`` for the region with ``MADV_COLD`` - - 2: Call ``madvise()`` for the region with ``MADV_PAGEOUT`` - - 3: Call ``madvise()`` for the region with ``MADV_HUGEPAGE`` - - 4: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE`` + - 0: Call ``madvise()`` for the region with ``MADV_WILLNEED``. Ignored if + ``target`` is ``paddr``. + - 1: Call ``madvise()`` for the region with ``MADV_COLD``. Ignored if + ``target`` is ``paddr``. + - 2: Call ``madvise()`` for the region with ``MADV_PAGEOUT``. + - 3: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``. Ignored if + ``target`` is ``paddr``. + - 4: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``. Ignored if + ``target`` is ``paddr``. - 5: Do nothing but count the statistics Quota |