diff options
Diffstat (limited to 'Documentation/admin-guide/mm')
| -rw-r--r-- | Documentation/admin-guide/mm/damon/reclaim.rst | 27 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 186 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/hugetlbpage.rst | 7 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/ksm.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/numa_memory_policy.rst | 9 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/transhuge.rst | 35 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/zswap.rst | 33 |
7 files changed, 166 insertions, 133 deletions
diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index 343e25b252f4..af05ae617018 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -117,6 +117,33 @@ milliseconds. 1 second by default. +quota_mem_pressure_us +--------------------- + +Desired level of memory pressure-stall time in microseconds. + +While keeping the caps that set by other quotas, DAMON_RECLAIM automatically +increases and decreases the effective level of the quota aiming this level of +memory pressure is incurred. System-wide ``some`` memory PSI in microseconds +per quota reset interval (``quota_reset_interval_ms``) is collected and +compared to this value to see if the aim is satisfied. Value zero means +disabling this auto-tuning feature. + +Disabled by default. + +quota_autotune_feedback +----------------------- + +User-specifiable feedback for auto-tuning of the effective quota. + +While keeping the caps that set by other quotas, DAMON_RECLAIM automatically +increases and decreases the effective level of the quota aiming receiving this +feedback of value ``10,000`` from the user. DAMON_RECLAIM assumes the feedback +value and the quota are positively proportional. Value zero means disabling +this auto-tuning feature. + +Disabled by default. + wmarks_interval --------------- diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index 9d23144bf985..e58ceb89ea2a 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -83,10 +83,10 @@ comma (","). │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max - │ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms + │ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms,effective_bytes │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ │ :ref:`goals <sysfs_schemes_quota_goals>`/nr_goals - │ │ │ │ │ │ │ │ │ 0/target_value,current_value + │ │ │ │ │ │ │ │ │ 0/target_metric,target_value,current_value │ │ │ │ │ │ │ :ref:`watermarks <sysfs_watermarks>`/metric,interval_us,high,mid,low │ │ │ │ │ │ │ :ref:`filters <sysfs_filters>`/nr_filters │ │ │ │ │ │ │ │ 0/type,matching,memcg_id @@ -153,6 +153,9 @@ Users can write below commands for the kdamond to the ``state`` file. - ``clear_schemes_tried_regions``: Clear the DAMON-based operating scheme action tried regions directory for each DAMON-based operation scheme of the kdamond. +- ``update_schemes_effective_quotas``: Update the contents of + ``effective_bytes`` files for each DAMON-based operation scheme of the + kdamond. For more details, refer to :ref:`quotas directory <sysfs_quotas>`. If the state is ``on``, reading ``pid`` shows the pid of the kdamond thread. @@ -180,19 +183,14 @@ In each context directory, two files (``avail_operations`` and ``operations``) and three directories (``monitoring_attrs``, ``targets``, and ``schemes``) exist. -DAMON supports multiple types of monitoring operations, including those for -virtual address space and the physical address space. You can get the list of -available monitoring operations set on the currently running kernel by reading +DAMON supports multiple types of :ref:`monitoring operations +<damon_design_configurable_operations_set>`, including those for virtual address +space and the physical address space. You can get the list of available +monitoring operations set on the currently running kernel by reading ``avail_operations`` file. Based on the kernel configuration, the file will -list some or all of below keywords. - - - vaddr: Monitor virtual address spaces of specific processes - - fvaddr: Monitor fixed virtual address ranges - - paddr: Monitor the physical address space of the system - -Please refer to :ref:`regions sysfs directory <sysfs_regions>` for detailed -differences between the operations sets in terms of the monitoring target -regions. +list different available operation sets. Please refer to the :ref:`design +<damon_operations_set>` for the list of all available operation sets and their +brief explanations. You can set and get what type of monitoring operations DAMON will use for the context by writing one of the keywords listed in ``avail_operations`` file and @@ -247,17 +245,11 @@ process to the ``pid_target`` file. targets/<N>/regions ------------------- -When ``vaddr`` monitoring operations set is being used (``vaddr`` is written to -the ``contexts/<N>/operations`` file), DAMON automatically sets and updates the -monitoring target regions so that entire memory mappings of target processes -can be covered. However, users could want to set the initial monitoring region -to specific address ranges. - -In contrast, DAMON do not automatically sets and updates the monitoring target -regions when ``fvaddr`` or ``paddr`` monitoring operations sets are being used -(``fvaddr`` or ``paddr`` have written to the ``contexts/<N>/operations``). -Therefore, users should set the monitoring target regions by themselves in the -cases. +In case of ``fvaddr`` or ``paddr`` monitoring operations sets, users are +required to set the monitoring target address ranges. In case of ``vaddr`` +operations set, it is not mandatory, but users can optionally set the initial +monitoring region to specific address ranges. Please refer to the :ref:`design +<damon_design_vaddr_target_regions_construction>` for more details. For such cases, users can explicitly set the initial monitoring target regions as they want, by writing proper values to the files under this directory. @@ -302,27 +294,8 @@ In each scheme directory, five directories (``access_pattern``, ``quotas``, The ``action`` file is for setting and getting the scheme's :ref:`action <damon_design_damos_action>`. The keywords that can be written to and read -from the file and their meaning are as below. - -Note that support of each action depends on the running DAMON operations set -:ref:`implementation <sysfs_context>`. - - - ``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. - Supported by ``paddr`` operations set. - - ``stat``: Do nothing but count the statistics. - Supported by all operations sets. +from the file and their meaning are same to those of the list on +:ref:`design doc <damon_design_damos_action>`. The ``apply_interval_us`` file is for setting and getting the scheme's :ref:`apply_interval <damon_design_damos>` in microseconds. @@ -350,8 +323,9 @@ schemes/<N>/quotas/ The directory for the :ref:`quotas <damon_design_damos_quotas>` of the given DAMON-based operation scheme. -Under ``quotas`` directory, three files (``ms``, ``bytes``, -``reset_interval_ms``) and two directores (``weights`` and ``goals``) exist. +Under ``quotas`` directory, four files (``ms``, ``bytes``, +``reset_interval_ms``, ``effective_bytes``) and two directores (``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, @@ -359,7 +333,17 @@ respectively. Then, DAMON tries to use only up to ``time quota`` milliseconds for applying the ``action`` to memory regions of the ``access_pattern``, and to apply the action to only up to ``bytes`` bytes of memory regions within the ``reset_interval_ms``. Setting both ``ms`` and ``bytes`` zero disables the -quota limits. +quota limits unless at least one :ref:`goal <sysfs_schemes_quota_goals>` is +set. + +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 +effective size quota is further adjusted. Reading ``effective_bytes`` returns +the current effective size quota. The file is not updated in real time, so +users should ask DAMON sysfs interface to update the content of the file for +the stats by writing a special keyword, ``update_schemes_effective_quotas`` to +the relevant ``kdamonds/<N>/state`` file. Under ``weights`` directory, three files (``sz_permil``, ``nr_accesses_permil``, and ``age_permil``) exist. @@ -382,11 +366,11 @@ number (``N``) to the file creates the number of child directories named ``0`` to ``N-1``. Each directory represents each goal and current achievement. Among the multiple feedback, the best one is used. -Each goal directory contains two files, namely ``target_value`` and -``current_value``. Users can set and get any number to those files to set the -feedback. User space main workload's latency or throughput, system metrics -like free memory ratio or memory pressure stall time (PSI) could be example -metrics for the values. Note that users should write +Each goal directory contains three files, namely ``target_metric``, +``target_value`` and ``current_value``. Users can set and get the three +parameters for the quota auto-tuning goals that specified on the :ref:`design +doc <damon_design_damos_quotas_auto_tuning>` by writing to and reading from each +of the files. Note that users should further write ``commit_schemes_quota_goals`` to the ``state`` file of the :ref:`kdamond directory <sysfs_kdamond>` to pass the feedback to DAMON. @@ -426,19 +410,19 @@ in the numeric order. Each filter directory contains six files, namely ``type``, ``matcing``, ``memcg_path``, ``addr_start``, ``addr_end``, and ``target_idx``. To ``type`` -file, you can write one of four special keywords: ``anon`` for anonymous pages, -``memcg`` for specific memory cgroup, ``addr`` for specific address range (an -open-ended interval), or ``target`` for specific DAMON monitoring target -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. In case of the address range -filtering, you can specify the start and end address of the range to -``addr_start`` and ``addr_end`` files, respectively. For the DAMON monitoring -target filtering, you can specify the index of the target between the list of -the DAMON context's monitoring targets list to ``target_idx`` 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. +file, you can write one of five special keywords: ``anon`` for anonymous pages, +``memcg`` for specific memory cgroup, ``young`` for young pages, ``addr`` for +specific address range (an open-ended interval), or ``target`` for specific +DAMON monitoring target 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. In case of the +address range filtering, you can specify the start and end address of the range +to ``addr_start`` and ``addr_end`` files, respectively. For the DAMON +monitoring target filtering, you can specify the index of the target between +the list of the DAMON context's monitoring targets list to ``target_idx`` 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``.:: @@ -450,7 +434,7 @@ pages of all memory cgroups except ``/having_care_already``.:: # # 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 + echo Y > 1/matching Note that ``anon`` and ``memcg`` filters are currently supported only when ``paddr`` :ref:`implementation <sysfs_context>` is being used. @@ -579,11 +563,11 @@ monitoring results recording. While the monitoring is turned on, you could record the tracepoint events and show results using tracepoint supporting tools like ``perf``. For example:: - # echo on > monitor_on + # echo on > kdamonds/0/state # perf record -e damon:damon_aggregated & # sleep 5 # kill 9 $(pidof perf) - # echo off > monitor_on + # echo off > kdamonds/0/state # perf script kdamond.0 46568 [027] 79357.842179: damon:damon_aggregated: target_id=0 nr_regions=11 122509119488-135708762112: 0 864 [...] @@ -628,9 +612,17 @@ debugfs Interface (DEPRECATED!) 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 -``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``. +DAMON exports nine files, ``DEPRECATED``, ``attrs``, ``target_ids``, +``init_regions``, ``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``, +``mk_contexts`` and ``rm_contexts`` under its debugfs directory, +``<debugfs>/damon/``. + + +``DEPRECATED`` is a read-only file for the DAMON debugfs interface deprecation +notice. Reading it returns the deprecation notice, as below:: + + # cat DEPRECATED + DAMON debugfs interface is deprecated, so users should move to DAMON_SYSFS. If you cannot, please report your usecase to damon@lists.linux.dev and linux-mm@kvack.org. Attributes @@ -755,19 +747,17 @@ Action ~~~~~~ The ``<action>`` is a predefined integer for memory management :ref:`actions -<damon_design_damos_action>`. The supported numbers and their meanings are as -below. - - - 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 +<damon_design_damos_action>`. The mapping between the ``<action>`` values and +the memory management actions is as below. For the detailed meaning of the +action and DAMON operations set supporting each action, please refer to the +list on :ref:`design doc <damon_design_damos_action>`. + + - 0: ``willneed`` + - 1: ``cold`` + - 2: ``pageout`` + - 3: ``hugepage`` + - 4: ``nohugepage`` + - 5: ``stat`` Quota ~~~~~ @@ -848,16 +838,16 @@ Turning On/Off Setting the files as described above doesn't incur effect unless you explicitly start the monitoring. You can start, stop, and check the current status of the -monitoring by writing to and reading from the ``monitor_on`` file. Writing -``on`` to the file starts the monitoring of the targets with the attributes. -Writing ``off`` to the file stops those. DAMON also stops if every target -process is terminated. Below example commands turn on, off, and check the -status of DAMON:: +monitoring by writing to and reading from the ``monitor_on_DEPRECATED`` file. +Writing ``on`` to the file starts the monitoring of the targets with the +attributes. Writing ``off`` to the file stops those. DAMON also stops if +every target process is terminated. Below example commands turn on, off, and +check the status of DAMON:: # cd <debugfs>/damon - # echo on > monitor_on - # echo off > monitor_on - # cat monitor_on + # echo on > monitor_on_DEPRECATED + # echo off > monitor_on_DEPRECATED + # cat monitor_on_DEPRECATED off Please note that you cannot write to the above-mentioned debugfs files while @@ -873,11 +863,11 @@ can get the pid of the thread by reading the ``kdamond_pid`` file. When the monitoring is turned off, reading the file returns ``none``. :: # cd <debugfs>/damon - # cat monitor_on + # cat monitor_on_DEPRECATED off # cat kdamond_pid none - # echo on > monitor_on + # echo on > monitor_on_DEPRECATED # cat kdamond_pid 18594 @@ -907,5 +897,5 @@ directory by putting the name of the context to the ``rm_contexts`` file. :: # ls foo # ls: cannot access 'foo': No such file or directory -Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on`` files are in the -root directory only. +Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on_DEPRECATED`` files +are in the root directory only. diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index e4d4b4a8dc97..f34a0d798d5b 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -376,6 +376,13 @@ Note that the number of overcommit and reserve pages remain global quantities, as we don't know until fault time, when the faulting task's mempolicy is applied, from which node the huge page allocation will be attempted. +The hugetlb may be migrated between the per-node hugepages pool in the following +scenarios: memory offline, memory failure, longterm pinning, syscalls(mbind, +migrate_pages and move_pages), alloc_contig_range() and alloc_contig_pages(). +Now only memory offline, memory failure and syscalls allow fallbacking to allocate +a new hugetlb on a different node if the current node is unable to allocate during +hugetlb migration, that means these 3 cases can break the per-node hugepages pool. + .. _using_huge_pages: Using Huge Pages diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index a639cac12477..ad8e7a41f3b5 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -308,7 +308,7 @@ limited by the ``advisor_max_cpu`` parameter. In addition there is also the ``advisor_target_scan_time`` parameter. This parameter sets the target time to scan all the KSM candidate pages. The parameter ``advisor_target_scan_time`` decides how aggressive the scan time advisor scans candidate pages. Lower -values make the scan time advisor to scan more aggresively. This is the most +values make the scan time advisor to scan more aggressively. This is the most important parameter for the configuration of the scan time advisor. The initial value and the maximum value can be changed with diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst index eca38fa81e0f..a70f20ce1ffb 100644 --- a/Documentation/admin-guide/mm/numa_memory_policy.rst +++ b/Documentation/admin-guide/mm/numa_memory_policy.rst @@ -250,6 +250,15 @@ MPOL_PREFERRED_MANY can fall back to all existing numa nodes. This is effectively MPOL_PREFERRED allowed for a mask rather than a single node. +MPOL_WEIGHTED_INTERLEAVE + This mode operates the same as MPOL_INTERLEAVE, except that + interleaving behavior is executed based on weights set in + /sys/kernel/mm/mempolicy/weighted_interleave/ + + Weighted interleave allocates pages on nodes according to a + weight. For example if nodes [0,1] are weighted [5,2], 5 pages + will be allocated on node0 for every 2 pages allocated on node1. + NUMA memory policy supports the following optional mode flags: MPOL_F_STATIC_NODES diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 04eb45a2f940..076443cc10a6 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -278,7 +278,8 @@ collapsed, resulting fewer pages being collapsed into THPs, and lower memory access performance. ``max_ptes_shared`` specifies how many pages can be shared across multiple -processes. Exceeding the number would block the collapse:: +processes. khugepaged might treat pages of THPs as shared if any page of +that THP is shared. Exceeding the number would block the collapse:: /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_shared @@ -369,7 +370,7 @@ monitor how successfully the system is providing huge pages for use. thp_fault_alloc is incremented every time a huge page is successfully - allocated to handle a page fault. + allocated and charged to handle a page fault. thp_collapse_alloc is incremented by khugepaged when it has found @@ -377,7 +378,7 @@ thp_collapse_alloc successfully allocated a new huge page to store the data. thp_fault_fallback - is incremented if a page fault fails to allocate + is incremented if a page fault fails to allocate or charge a huge page and instead falls back to using small pages. thp_fault_fallback_charge @@ -447,6 +448,34 @@ thp_swpout_fallback Usually because failed to allocate some continuous swap space for the huge page. +In /sys/kernel/mm/transparent_hugepage/hugepages-<size>kB/stats, There are +also individual counters for each huge page size, which can be utilized to +monitor the system's effectiveness in providing huge pages for usage. Each +counter has its own corresponding file. + +anon_fault_alloc + is incremented every time a huge page is successfully + allocated and charged to handle a page fault. + +anon_fault_fallback + is incremented if a page fault fails to allocate or charge + a huge page and instead falls back to using huge pages with + lower orders or small pages. + +anon_fault_fallback_charge + is incremented if a page fault fails to charge a huge page and + instead falls back to using huge pages with lower orders or + small pages even though the allocation was successful. + +anon_swpout + is incremented every time a huge page is swapped out in one + piece without splitting. + +anon_swpout_fallback + is incremented if a huge page has to be split before swapout. + Usually because failed to allocate some continuous swap space + for the huge page. + As the system ages, allocating huge pages may be expensive as the system uses memory compaction to copy data around memory to free a huge page for use. There are some counters in ``/proc/vmstat`` to help diff --git a/Documentation/admin-guide/mm/zswap.rst b/Documentation/admin-guide/mm/zswap.rst index b42132969e31..3598dcd7dbe7 100644 --- a/Documentation/admin-guide/mm/zswap.rst +++ b/Documentation/admin-guide/mm/zswap.rst @@ -111,35 +111,6 @@ checked if it is a same-value filled page before compressing it. If true, the compressed length of the page is set to zero and the pattern or same-filled value is stored. -Same-value filled pages identification feature is enabled by default and can be -disabled at boot time by setting the ``same_filled_pages_enabled`` attribute -to 0, e.g. ``zswap.same_filled_pages_enabled=0``. It can also be enabled and -disabled at runtime using the sysfs ``same_filled_pages_enabled`` -attribute, e.g.:: - - echo 1 > /sys/module/zswap/parameters/same_filled_pages_enabled - -When zswap same-filled page identification is disabled at runtime, it will stop -checking for the same-value filled pages during store operation. -In other words, every page will be then considered non-same-value filled. -However, the existing pages which are marked as same-value filled pages remain -stored unchanged in zswap until they are either loaded or invalidated. - -In some circumstances it might be advantageous to make use of just the zswap -ability to efficiently store same-filled pages without enabling the whole -compressed page storage. -In this case the handling of non-same-value pages by zswap (enabled by default) -can be disabled by setting the ``non_same_filled_pages_enabled`` attribute -to 0, e.g. ``zswap.non_same_filled_pages_enabled=0``. -It can also be enabled and disabled at runtime using the sysfs -``non_same_filled_pages_enabled`` attribute, e.g.:: - - echo 1 > /sys/module/zswap/parameters/non_same_filled_pages_enabled - -Disabling both ``zswap.same_filled_pages_enabled`` and -``zswap.non_same_filled_pages_enabled`` effectively disables accepting any new -pages by zswap. - To prevent zswap from shrinking pool when zswap is full and there's a high pressure on swap (this will result in flipping pages in and out zswap pool without any real benefit but with a performance drop for the system), a @@ -155,7 +126,7 @@ Setting this parameter to 100 will disable the hysteresis. Some users cannot tolerate the swapping that comes with zswap store failures and zswap writebacks. Swapping can be disabled entirely (without disabling -zswap itself) on a cgroup-basis as follows: +zswap itself) on a cgroup-basis as follows:: echo 0 > /sys/fs/cgroup/<cgroup-name>/memory.zswap.writeback @@ -166,7 +137,7 @@ writeback (because the same pages might be rejected again and again). When there is a sizable amount of cold memory residing in the zswap pool, it can be advantageous to proactively write these cold pages to swap and reclaim the memory for other use cases. By default, the zswap shrinker is disabled. -User can enable it as follows: +User can enable it as follows:: echo Y > /sys/module/zswap/parameters/shrinker_enabled |