diff options
Diffstat (limited to 'Documentation/admin-guide/mm')
18 files changed, 124 insertions, 84 deletions
diff --git a/Documentation/admin-guide/mm/concepts.rst b/Documentation/admin-guide/mm/concepts.rst index c79f1e336222..e796b0a7e4a5 100644 --- a/Documentation/admin-guide/mm/concepts.rst +++ b/Documentation/admin-guide/mm/concepts.rst @@ -1,5 +1,3 @@ -.. _mm_concepts: - ================= Concepts overview ================= @@ -86,16 +84,15 @@ memory with the huge pages. The first one is `HugeTLB filesystem`, or hugetlbfs. It is a pseudo filesystem that uses RAM as its backing store. For the files created in this filesystem the data resides in the memory and mapped using huge pages. The hugetlbfs is described at -:ref:`Documentation/admin-guide/mm/hugetlbpage.rst <hugetlbpage>`. +Documentation/admin-guide/mm/hugetlbpage.rst. Another, more recent, mechanism that enables use of the huge pages is called `Transparent HugePages`, or THP. Unlike the hugetlbfs that requires users and/or system administrators to configure what parts of the system memory should and can be mapped by the huge pages, THP manages such mappings transparently to the user and hence the -name. See -:ref:`Documentation/admin-guide/mm/transhuge.rst <admin_guide_transhuge>` -for more details about THP. +name. See Documentation/admin-guide/mm/transhuge.rst for more details +about THP. Zones ===== @@ -125,8 +122,8 @@ processor. Each bank is referred to as a `node` and for each node Linux constructs an independent memory management subsystem. A node has its own set of zones, lists of free and used pages and various statistics counters. You can find more details about NUMA in -:ref:`Documentation/mm/numa.rst <numa>` and in -:ref:`Documentation/admin-guide/mm/numa_memory_policy.rst <numa_memory_policy>`. +Documentation/mm/numa.rst` and in +Documentation/admin-guide/mm/numa_memory_policy.rst. Page cache ========== diff --git a/Documentation/admin-guide/mm/damon/lru_sort.rst b/Documentation/admin-guide/mm/damon/lru_sort.rst index c09cace80651..7b0775d281b4 100644 --- a/Documentation/admin-guide/mm/damon/lru_sort.rst +++ b/Documentation/admin-guide/mm/damon/lru_sort.rst @@ -54,7 +54,7 @@ that is built with ``CONFIG_DAMON_LRU_SORT=y``. To let sysadmins enable or disable it and tune for the given system, DAMON_LRU_SORT utilizes module parameters. That is, you can put ``damon_lru_sort.<parameter>=<value>`` on the kernel boot command line or write -proper values to ``/sys/modules/damon_lru_sort/parameters/<parameter>`` files. +proper values to ``/sys/module/damon_lru_sort/parameters/<parameter>`` files. Below are the description of each parameter. @@ -283,7 +283,7 @@ doesn't make progress and therefore the free memory rate becomes lower than 20%, it asks DAMON_LRU_SORT to do nothing again, so that we can fall back to the LRU-list based page granularity reclamation. :: - # cd /sys/modules/damon_lru_sort/parameters + # cd /sys/module/damon_lru_sort/parameters # echo 500 > hot_thres_access_freq # echo 120000000 > cold_min_age # echo 10 > quota_ms diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index 4f1479a11e63..343e25b252f4 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -46,7 +46,7 @@ that is built with ``CONFIG_DAMON_RECLAIM=y``. To let sysadmins enable or disable it and tune for the given system, DAMON_RECLAIM utilizes module parameters. That is, you can put ``damon_reclaim.<parameter>=<value>`` on the kernel boot command line or write -proper values to ``/sys/modules/damon_reclaim/parameters/<parameter>`` files. +proper values to ``/sys/module/damon_reclaim/parameters/<parameter>`` files. Below are the description of each parameter. @@ -205,6 +205,15 @@ The end physical address of memory region that DAMON_RECLAIM will do work against. That is, DAMON_RECLAIM will find cold memory regions in this region and reclaims. By default, biggest System RAM is used as the region. +skip_anon +--------- + +Skip anonymous pages reclamation. + +If this parameter is set as ``Y``, DAMON_RECLAIM does not reclaim anonymous +pages. By default, ``N``. + + kdamond_pid ----------- @@ -251,7 +260,7 @@ therefore the free memory rate becomes lower than 20%, it asks DAMON_RECLAIM to do nothing again, so that we can fall back to the LRU-list based page granularity reclamation. :: - # cd /sys/modules/damon_reclaim/parameters + # cd /sys/module/damon_reclaim/parameters # echo 30000000 > min_age # echo $((1 * 1024 * 1024 * 1024)) > quota_sz # echo 1000 > quota_reset_interval_ms 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 diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index 19f27c0d92e0..e4d4b4a8dc97 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -1,5 +1,3 @@ -.. _hugetlbpage: - ============= HugeTLB Pages ============= @@ -86,7 +84,7 @@ by increasing or decreasing the value of ``nr_hugepages``. Note: When the feature of freeing unused vmemmap pages associated with each hugetlb page is enabled, we can fail to free the huge pages triggered by -the user when ths system is under memory pressure. Please try again later. +the user when the system is under memory pressure. Please try again later. Pages that are used as huge pages are reserved inside the kernel and cannot be used for other purposes. Huge pages cannot be swapped out under @@ -313,7 +311,7 @@ memory policy mode--bind, preferred, local or interleave--may be used. The resulting effect on persistent huge page allocation is as follows: #. Regardless of mempolicy mode [see - :ref:`Documentation/admin-guide/mm/numa_memory_policy.rst <numa_memory_policy>`], + Documentation/admin-guide/mm/numa_memory_policy.rst], persistent huge pages will be distributed across the node or nodes specified in the mempolicy as if "interleave" had been specified. However, if a node in the policy does not contain sufficient contiguous @@ -461,13 +459,13 @@ Examples .. _map_hugetlb: ``map_hugetlb`` - see tools/testing/selftests/vm/map_hugetlb.c + see tools/testing/selftests/mm/map_hugetlb.c ``hugepage-shm`` - see tools/testing/selftests/vm/hugepage-shm.c + see tools/testing/selftests/mm/hugepage-shm.c ``hugepage-mmap`` - see tools/testing/selftests/vm/hugepage-mmap.c + see tools/testing/selftests/mm/hugepage-mmap.c The `libhugetlbfs`_ library provides a wide range of userspace tools to help with huge page usability, environment setup, and control. diff --git a/Documentation/admin-guide/mm/idle_page_tracking.rst b/Documentation/admin-guide/mm/idle_page_tracking.rst index df9394fb39c2..16fcf38dac56 100644 --- a/Documentation/admin-guide/mm/idle_page_tracking.rst +++ b/Documentation/admin-guide/mm/idle_page_tracking.rst @@ -1,5 +1,3 @@ -.. _idle_page_tracking: - ================== Idle Page Tracking ================== @@ -65,14 +63,13 @@ workload one should: are not reclaimable, he or she can filter them out using ``/proc/kpageflags``. -The page-types tool in the tools/vm directory can be used to assist in this. +The page-types tool in the tools/mm directory can be used to assist in this. If the tool is run initially with the appropriate option, it will mark all the queried pages as idle. Subsequent runs of the tool can then show which pages have their idle flag cleared in the interim. -See :ref:`Documentation/admin-guide/mm/pagemap.rst <pagemap>` for more -information about ``/proc/pid/pagemap``, ``/proc/kpageflags``, and -``/proc/kpagecgroup``. +See Documentation/admin-guide/mm/pagemap.rst for more information about +``/proc/pid/pagemap``, ``/proc/kpageflags``, and ``/proc/kpagecgroup``. .. _impl_details: diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst index d1064e0ba34a..1f883abf3f00 100644 --- a/Documentation/admin-guide/mm/index.rst +++ b/Documentation/admin-guide/mm/index.rst @@ -16,8 +16,7 @@ are described in Documentation/admin-guide/sysctl/vm.rst and in `man 5 proc`_. .. _man 5 proc: http://man7.org/linux/man-pages/man5/proc.5.html Linux memory management has its own jargon and if you are not yet -familiar with it, consider reading -:ref:`Documentation/admin-guide/mm/concepts.rst <mm_concepts>`. +familiar with it, consider reading Documentation/admin-guide/mm/concepts.rst. Here we document in detail how to interact with various mechanisms in the Linux memory management. diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index fb6ba2002a4b..eed51a910c94 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -1,5 +1,3 @@ -.. _admin_guide_ksm: - ======================= Kernel Samepage Merging ======================= diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst index a3c9e8ad8fa0..1b02fe5807cc 100644 --- a/Documentation/admin-guide/mm/memory-hotplug.rst +++ b/Documentation/admin-guide/mm/memory-hotplug.rst @@ -1,5 +1,3 @@ -.. _admin_guide_memory_hotplug: - ================== Memory Hot(Un)Plug ================== diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst index 5a6afecbb0d0..46515ad2337f 100644 --- a/Documentation/admin-guide/mm/numa_memory_policy.rst +++ b/Documentation/admin-guide/mm/numa_memory_policy.rst @@ -1,5 +1,3 @@ -.. _numa_memory_policy: - ================== NUMA Memory Policy ================== @@ -246,7 +244,7 @@ MPOL_INTERLEAVED interleaved system default policy works in this mode. MPOL_PREFERRED_MANY - This mode specifices that the allocation should be preferrably + This mode specifies that the allocation should be preferably satisfied from the nodemask specified in the policy. If there is a memory pressure on all nodes in the nodemask, the allocation can fall back to all existing numa nodes. This is effectively @@ -360,7 +358,7 @@ and NUMA nodes. "Usage" here means one of the following: 2) examination of the policy to determine the policy mode and associated node or node lists, if any, for page allocation. This is considered a "hot path". Note that for MPOL_BIND, the "usage" extends across the entire - allocation process, which may sleep during page reclaimation, because the + allocation process, which may sleep during page reclamation, because the BIND policy nodemask is used, by reference, to filter ineligible nodes. We can avoid taking an extra reference during the usages listed above as diff --git a/Documentation/admin-guide/mm/numaperf.rst b/Documentation/admin-guide/mm/numaperf.rst index 166697325947..90a12b6a8bfc 100644 --- a/Documentation/admin-guide/mm/numaperf.rst +++ b/Documentation/admin-guide/mm/numaperf.rst @@ -1,6 +1,7 @@ -.. _numaperf: +======================= +NUMA Memory Performance +======================= -============= NUMA Locality ============= @@ -61,7 +62,6 @@ that are CPUs and hence suitable for generic task scheduling, and IO initiators such as GPUs and NICs. Unlike access class 0, only nodes containing CPUs are considered. -================ NUMA Performance ================ @@ -96,7 +96,6 @@ for the platform. Access class 1 takes the same form but only includes values for CPU to memory activity. -========== NUMA Cache ========== @@ -170,7 +169,6 @@ The "size" is the number of bytes provided by this cache level. The "write_policy" will be 0 for write-back, and non-zero for write-through caching. -======== See Also ======== diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index 6e2e416af783..b5f970dc91e7 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -1,5 +1,3 @@ -.. _pagemap: - ============================= Examining Process Page Tables ============================= @@ -19,10 +17,10 @@ There are four components to pagemap: * Bits 0-4 swap type if swapped * Bits 5-54 swap offset if swapped * Bit 55 pte is soft-dirty (see - :ref:`Documentation/admin-guide/mm/soft-dirty.rst <soft_dirty>`) + Documentation/admin-guide/mm/soft-dirty.rst) * Bit 56 page exclusively mapped (since 4.2) * Bit 57 pte is uffd-wp write-protected (since 5.13) (see - :ref:`Documentation/admin-guide/mm/userfaultfd.rst <userfaultfd>`) + Documentation/admin-guide/mm/userfaultfd.rst) * Bits 58-60 zero * Bit 61 page is file-page or shared-anon (since 3.5) * Bit 62 page swapped @@ -46,7 +44,7 @@ There are four components to pagemap: * ``/proc/kpagecount``. This file contains a 64-bit count of the number of times each page is mapped, indexed by PFN. -The page-types tool in the tools/vm directory can be used to query the +The page-types tool in the tools/mm directory can be used to query the number of times a page is mapped. * ``/proc/kpageflags``. This file contains a 64-bit set of flags for each @@ -105,8 +103,7 @@ Short descriptions to the page flags A compound page with order N consists of 2^N physically contiguous pages. A compound page with order 2 takes the form of "HTTT", where H donates its head page and T donates its tail page(s). The major consumers of compound - pages are hugeTLB pages - (:ref:`Documentation/admin-guide/mm/hugetlbpage.rst <hugetlbpage>`), + pages are hugeTLB pages (Documentation/admin-guide/mm/hugetlbpage.rst), the SLUB etc. memory allocators and various device drivers. However in this interface, only huge/giga pages are made visible to end users. @@ -128,7 +125,7 @@ Short descriptions to the page flags Zero page for pfn_zero or huge_zero page. 25 - IDLE The page has not been accessed since it was marked idle (see - :ref:`Documentation/admin-guide/mm/idle_page_tracking.rst <idle_page_tracking>`). + Documentation/admin-guide/mm/idle_page_tracking.rst). Note that this flag may be stale in case the page was accessed via a PTE. To make sure the flag is up-to-date one has to read ``/sys/kernel/mm/page_idle/bitmap`` first. @@ -173,7 +170,7 @@ LRU related page flags 14 - SWAPBACKED The page is backed by swap/RAM. -The page-types tool in the tools/vm directory can be used to query the +The page-types tool in the tools/mm directory can be used to query the above flags. Using pagemap to do something useful diff --git a/Documentation/admin-guide/mm/shrinker_debugfs.rst b/Documentation/admin-guide/mm/shrinker_debugfs.rst index 3887f0b294fe..c582033bd113 100644 --- a/Documentation/admin-guide/mm/shrinker_debugfs.rst +++ b/Documentation/admin-guide/mm/shrinker_debugfs.rst @@ -1,5 +1,3 @@ -.. _shrinker_debugfs: - ========================== Shrinker Debugfs Interface ========================== diff --git a/Documentation/admin-guide/mm/soft-dirty.rst b/Documentation/admin-guide/mm/soft-dirty.rst index cb0cfd6672fa..aeea936caa44 100644 --- a/Documentation/admin-guide/mm/soft-dirty.rst +++ b/Documentation/admin-guide/mm/soft-dirty.rst @@ -1,5 +1,3 @@ -.. _soft_dirty: - =============== Soft-Dirty PTEs =============== diff --git a/Documentation/admin-guide/mm/swap_numa.rst b/Documentation/admin-guide/mm/swap_numa.rst index e0466f2db8fa..2e630627bcee 100644 --- a/Documentation/admin-guide/mm/swap_numa.rst +++ b/Documentation/admin-guide/mm/swap_numa.rst @@ -1,5 +1,3 @@ -.. _swap_numa: - =========================================== Automatically bind swap device to numa node =========================================== diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 8ee78ec232eb..b0cc8243e093 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -1,5 +1,3 @@ -.. _admin_guide_transhuge: - ============================ Transparent Hugepage Support ============================ diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst index 83f31919ebb3..7dc823b56ca4 100644 --- a/Documentation/admin-guide/mm/userfaultfd.rst +++ b/Documentation/admin-guide/mm/userfaultfd.rst @@ -1,5 +1,3 @@ -.. _userfaultfd: - =========== Userfaultfd =========== diff --git a/Documentation/admin-guide/mm/zswap.rst b/Documentation/admin-guide/mm/zswap.rst index f67de481c7f6..c5c2c7dbb155 100644 --- a/Documentation/admin-guide/mm/zswap.rst +++ b/Documentation/admin-guide/mm/zswap.rst @@ -1,5 +1,3 @@ -.. _zswap: - ===== zswap ===== @@ -70,9 +68,7 @@ e.g. ``zswap.zpool=zbud``. It can also be changed at runtime using the sysfs The zbud type zpool allocates exactly 1 page to store 2 compressed pages, which means the compression ratio will always be 2:1 or worse (because of half-full zbud pages). The zsmalloc type zpool has a more complex compressed page -storage method, and it can achieve greater storage densities. However, -zsmalloc does not implement compressed page eviction, so once zswap fills it -cannot evict the oldest page, it can only reject new pages. +storage method, and it can achieve greater storage densities. When a swap page is passed from frontswap to zswap, zswap maintains a mapping of the swap entry, a combination of the swap type and swap offset, to the zpool |