diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-02-23 17:09:35 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-02-23 17:09:35 -0800 |
| commit | 3822a7c40997dc86b1458766a3f146d62393f084 (patch) | |
| tree | 4473720ecbfaabeedfe58484425be77d0f89f736 /Documentation | |
| parent | e4bc15889506723d7b93c053ad4a75cd58248d74 (diff) | |
| parent | f9366f4c2a29d14f5992b195e268240c2deb116e (diff) | |
| download | linux-3822a7c40997dc86b1458766a3f146d62393f084.tar.gz linux-3822a7c40997dc86b1458766a3f146d62393f084.tar.bz2 linux-3822a7c40997dc86b1458766a3f146d62393f084.zip | |
Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
Diffstat (limited to 'Documentation')
24 files changed, 684 insertions, 178 deletions
diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node index 8db67aa472f1..402af4b2b905 100644 --- a/Documentation/ABI/stable/sysfs-devices-node +++ b/Documentation/ABI/stable/sysfs-devices-node @@ -182,3 +182,42 @@ Date: November 2021 Contact: Jarkko Sakkinen <jarkko@kernel.org> Description: The total amount of SGX physical memory in bytes. + +What: /sys/devices/system/node/nodeX/memory_failure/total +Date: January 2023 +Contact: Jiaqi Yan <jiaqiyan@google.com> +Description: + The total number of raw poisoned pages (pages containing + corrupted data due to memory errors) on a NUMA node. + +What: /sys/devices/system/node/nodeX/memory_failure/ignored +Date: January 2023 +Contact: Jiaqi Yan <jiaqiyan@google.com> +Description: + Of the raw poisoned pages on a NUMA node, how many pages are + ignored by memory error recovery attempt, usually because + support for this type of pages is unavailable, and kernel + gives up the recovery. + +What: /sys/devices/system/node/nodeX/memory_failure/failed +Date: January 2023 +Contact: Jiaqi Yan <jiaqiyan@google.com> +Description: + Of the raw poisoned pages on a NUMA node, how many pages are + failed by memory error recovery attempt. This usually means + a key recovery operation failed. + +What: /sys/devices/system/node/nodeX/memory_failure/delayed +Date: January 2023 +Contact: Jiaqi Yan <jiaqiyan@google.com> +Description: + Of the raw poisoned pages on a NUMA node, how many pages are + delayed by memory error recovery attempt. Delayed poisoned + pages usually will be retried by kernel. + +What: /sys/devices/system/node/nodeX/memory_failure/recovered +Date: January 2023 +Contact: Jiaqi Yan <jiaqiyan@google.com> +Description: + Of the raw poisoned pages on a NUMA node, how many pages are + recovered by memory error recovery attempt. diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon index 13397b853692..2744f21b5a6b 100644 --- a/Documentation/ABI/testing/sysfs-kernel-mm-damon +++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon @@ -258,6 +258,35 @@ Contact: SeongJae Park <sj@kernel.org> Description: Writing to and reading from this file sets and gets the low watermark of the scheme in permil. +What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/nr_filters +Date: Dec 2022 +Contact: SeongJae Park <sj@kernel.org> +Description: Writing a number 'N' to this file creates the number of + directories for setting filters of the scheme named '0' to + 'N-1' under the filters/ directory. + +What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/type +Date: Dec 2022 +Contact: SeongJae Park <sj@kernel.org> +Description: Writing to and reading from this file sets and gets the type of + the memory of the interest. 'anon' for anonymous pages, or + 'memcg' for specific memory cgroup can be written and read. + +What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/memcg_path +Date: Dec 2022 +Contact: SeongJae Park <sj@kernel.org> +Description: If 'memcg' is written to the 'type' file, writing to and + reading from this file sets and gets the path to the memory + cgroup of the interest. + +What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/matching +Date: Dec 2022 +Contact: SeongJae Park <sj@kernel.org> +Description: Writing 'Y' or 'N' to this file sets whether to filter out + pages that do or do not match to the 'type' and 'memcg_path', + respectively. Filter out means the action of the scheme will + not be applied to. + What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/stats/nr_tried Date: Mar 2022 Contact: SeongJae Park <sj@kernel.org> diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 27d89495ac88..47d1d7d932a8 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -87,6 +87,8 @@ Brief summary of control files. memory.swappiness set/show swappiness parameter of vmscan (See sysctl's vm.swappiness) memory.move_charge_at_immigrate set/show controls of moving charges + This knob is deprecated and shouldn't be + used. memory.oom_control set/show oom controls. memory.numa_stat show the number of memory usage per numa node @@ -727,8 +729,15 @@ If we want to change this to 1G, we can at any time use:: .. _cgroup-v1-memory-move-charges: -8. Move charges at task migration -================================= +8. Move charges at task migration (DEPRECATED!) +=============================================== + +THIS IS DEPRECATED! + +It's expensive and unreliable! It's better practice to launch workload +tasks directly from inside their target cgroup. Use dedicated workload +cgroups to allow fine-grained policy adjustments without having to +move physical pages between control domains. Users can move charges associated with a task along with task migration, that is, uncharge task's pages from the old cgroup and charge them to the new cgroup. diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index d2ccd9c21b9a..343e25b252f4 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -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 ----------- 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 bca00cb6f43a..e4d4b4a8dc97 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -459,13 +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 b5a285bd73fd..16fcf38dac56 100644 --- a/Documentation/admin-guide/mm/idle_page_tracking.rst +++ b/Documentation/admin-guide/mm/idle_page_tracking.rst @@ -63,7 +63,7 @@ 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. diff --git a/Documentation/admin-guide/mm/numaperf.rst b/Documentation/admin-guide/mm/numaperf.rst index 24e63e740420..90a12b6a8bfc 100644 --- a/Documentation/admin-guide/mm/numaperf.rst +++ b/Documentation/admin-guide/mm/numaperf.rst @@ -1,4 +1,7 @@ -============= +======================= +NUMA Memory Performance +======================= + NUMA Locality ============= @@ -59,7 +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 ================ @@ -94,7 +96,6 @@ for the platform. Access class 1 takes the same form but only includes values for CPU to memory activity. -========== NUMA Cache ========== @@ -168,7 +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 1a22674ab18e..b5f970dc91e7 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -44,7 +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 @@ -170,7 +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/core-api/pin_user_pages.rst b/Documentation/core-api/pin_user_pages.rst index b18416f4500f..9fb0b1080d3b 100644 --- a/Documentation/core-api/pin_user_pages.rst +++ b/Documentation/core-api/pin_user_pages.rst @@ -55,18 +55,17 @@ flags the caller provides. The caller is required to pass in a non-null struct pages* array, and the function then pins pages by incrementing each by a special value: GUP_PIN_COUNTING_BIAS. -For compound pages, the GUP_PIN_COUNTING_BIAS scheme is not used. Instead, -an exact form of pin counting is achieved, by using the 2nd struct page -in the compound page. A new struct page field, compound_pincount, has -been added in order to support this. - -This approach for compound pages avoids the counting upper limit problems that -are discussed below. Those limitations would have been aggravated severely by -huge pages, because each tail page adds a refcount to the head page. And in -fact, testing revealed that, without a separate compound_pincount field, -page overflows were seen in some huge page stress tests. - -This also means that huge pages and compound pages do not suffer +For large folios, the GUP_PIN_COUNTING_BIAS scheme is not used. Instead, +the extra space available in the struct folio is used to store the +pincount directly. + +This approach for large folios avoids the counting upper limit problems +that are discussed below. Those limitations would have been aggravated +severely by huge pages, because each tail page adds a refcount to the +head page. And in fact, testing revealed that, without a separate pincount +field, refcount overflows were seen in some huge page stress tests. + +This also means that huge pages and large folios do not suffer from the false positives problem that is mentioned below.:: Function @@ -221,7 +220,7 @@ Unit testing ============ This file:: - tools/testing/selftests/vm/gup_test.c + tools/testing/selftests/mm/gup_test.c has the following new calls to exercise the new pin*() wrapper functions: @@ -264,9 +263,9 @@ place.) Other diagnostics ================= -dump_page() has been enhanced slightly, to handle these new counting -fields, and to better report on compound pages in general. Specifically, -for compound pages, the exact (compound_pincount) pincount is reported. +dump_page() has been enhanced slightly to handle these new counting +fields, and to better report on large folios in general. Specifically, +for large folios, the exact pincount is reported. References ========== diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 5c93ab915049..e66916a483cd 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -140,6 +140,23 @@ disabling KASAN altogether or controlling its features: - ``kasan.vmalloc=off`` or ``=on`` disables or enables tagging of vmalloc allocations (default: ``on``). +- ``kasan.page_alloc.sample=<sampling interval>`` makes KASAN tag only every + Nth page_alloc allocation with the order equal or greater than + ``kasan.page_alloc.sample.order``, where N is the value of the ``sample`` + parameter (default: ``1``, or tag every such allocation). + This parameter is intended to mitigate the performance overhead introduced + by KASAN. + Note that enabling this parameter makes Hardware Tag-Based KASAN skip checks + of allocations chosen by sampling and thus miss bad accesses to these + allocations. Use the default value for accurate bug detection. + +- ``kasan.page_alloc.sample.order=<minimum page order>`` specifies the minimum + order of allocations that are affected by sampling (default: ``3``). + Only applies when ``kasan.page_alloc.sample`` is set to a value greater + than ``1``. + This parameter is intended to allow sampling only large page_alloc + allocations, which is the biggest source of the performance overhead. + Error reports ~~~~~~~~~~~~~ diff --git a/Documentation/mm/balance.rst b/Documentation/mm/balance.rst index 6cd0127154ac..abaa78561c31 100644 --- a/Documentation/mm/balance.rst +++ b/Documentation/mm/balance.rst @@ -4,7 +4,7 @@ Memory Balancing Started Jan 2000 by Kanoj Sarcar <kanoj@sgi.com> -Memory balancing is needed for !__GFP_ATOMIC and !__GFP_KSWAPD_RECLAIM as +Memory balancing is needed for !__GFP_HIGH and !__GFP_KSWAPD_RECLAIM as well as for non __GFP_IO allocations. The first reason why a caller may avoid reclaim is that the caller can not diff --git a/Documentation/mm/damon/index.rst b/Documentation/mm/damon/index.rst index 48c0bbff98b2..5e0a50583500 100644 --- a/Documentation/mm/damon/index.rst +++ b/Documentation/mm/damon/index.rst @@ -4,8 +4,9 @@ DAMON: Data Access MONitor ========================== -DAMON is a data access monitoring framework subsystem for the Linux kernel. -The core mechanisms of DAMON (refer to :doc:`design` for the detail) make it +DAMON is a Linux kernel subsystem that provides a framework for data access +monitoring and the monitoring results based system operations. The core +monitoring mechanisms of DAMON (refer to :doc:`design` for the detail) make it - *accurate* (the monitoring output is useful enough for DRAM level memory management; It might not appropriate for CPU Cache levels, though), @@ -14,12 +15,16 @@ The core mechanisms of DAMON (refer to :doc:`design` for the detail) make it - *scalable* (the upper-bound of the overhead is in constant range regardless of the size of target workloads). -Using this framework, therefore, the kernel's memory management mechanisms can -make advanced decisions. Experimental memory management optimization works -that incurring high data accesses monitoring overhead could implemented again. -In user space, meanwhile, users who have some special workloads can write -personalized applications for better understanding and optimizations of their -workloads and systems. +Using this framework, therefore, the kernel can operate system in an +access-aware fashion. Because the features are also exposed to the user space, +users who have special information about their workloads can write personalized +applications for better understanding and optimizations of their workloads and +systems. + +For easier development of such systems, DAMON provides a feature called DAMOS +(DAMon-based Operation Schemes) in addition to the monitoring. Using the +feature, DAMON users in both kernel and user spaces can do access-aware system +operations with no code but simple configurations. .. toctree:: :maxdepth: 2 @@ -27,3 +32,4 @@ workloads and systems. faq design api + maintainer-profile diff --git a/Documentation/mm/damon/maintainer-profile.rst b/Documentation/mm/damon/maintainer-profile.rst new file mode 100644 index 000000000000..24a202f03de8 --- /dev/null +++ b/Documentation/mm/damon/maintainer-profile.rst @@ -0,0 +1,62 @@ +.. SPDX-License-Identifier: GPL-2.0 + +DAMON Maintainer Entry Profile +============================== + +The DAMON subsystem covers the files that listed in 'DATA ACCESS MONITOR' +section of 'MAINTAINERS' file. + +The mailing lists for the subsystem are damon@lists.linux.dev and +linux-mm@kvack.org. Patches should be made against the mm-unstable tree [1]_ +whenever possible and posted to the mailing lists. + +SCM Trees +--------- + +There are multiple Linux trees for DAMON development. Patches under +development or testing are queued in damon/next [2]_ by the DAMON maintainer. +Suffieicntly reviewed patches will be queued in mm-unstable [1]_ by the memory +management subsystem maintainer. After more sufficient tests, the patches will +be queued in mm-stable [3]_ , and finally pull-requested to the mainline by the +memory management subsystem maintainer. + +Note again the patches for review should be made against the mm-unstable +tree[1] whenever possible. damon/next is only for preview of others' works in +progress. + +Submit checklist addendum +------------------------- + +When making DAMON changes, you should do below. + +- Build changes related outpu |
