diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-02 19:38:47 -1000 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-02 19:38:47 -1000 |
commit | ecae0bd5173b1014f95a14a8dfbe40ec10367dcf (patch) | |
tree | f571213ef1a35354ea79f0240a180fdb4111b290 /Documentation | |
parent | bc3012f4e3a9765de81f454cb8f9bb16aafc6ff5 (diff) | |
parent | 9732336006764e2ee61225387e3c70eae9139035 (diff) |
Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
- Kemeng Shi has contributed some compation maintenance work in the
series 'Fixes and cleanups to compaction'
- Joel Fernandes has a patchset ('Optimize mremap during mutual
alignment within PMD') which fixes an obscure issue with mremap()'s
pagetable handling during a subsequent exec(), based upon an
implementation which Linus suggested
- More DAMON/DAMOS maintenance and feature work from SeongJae Park i
the following patch series:
mm/damon: misc fixups for documents, comments and its tracepoint
mm/damon: add a tracepoint for damos apply target regions
mm/damon: provide pseudo-moving sum based access rate
mm/damon: implement DAMOS apply intervals
mm/damon/core-test: Fix memory leaks in core-test
mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval
- In the series 'Do not try to access unaccepted memory' Adrian
Hunter provides some fixups for the recently-added 'unaccepted
memory' feature. To increase the feature's checking coverage. 'Plug
a few gaps where RAM is exposed without checking if it is
unaccepted memory'
- In the series 'cleanups for lockless slab shrink' Qi Zheng has done
some maintenance work which is preparation for the lockless slab
shrinking code
- Qi Zheng has redone the earlier (and reverted) attempt to make slab
shrinking lockless in the series 'use refcount+RCU method to
implement lockless slab shrink'
- David Hildenbrand contributes some maintenance work for the rmap
code in the series 'Anon rmap cleanups'
- Kefeng Wang does more folio conversions and some maintenance work
in the migration code. Series 'mm: migrate: more folio conversion
and unification'
- Matthew Wilcox has fixed an issue in the buffer_head code which was
causing long stalls under some heavy memory/IO loads. Some cleanups
were added on the way. Series 'Add and use bdev_getblk()'
- In the series 'Use nth_page() in place of direct struct page
manipulation' Zi Yan has fixed a potential issue with the direct
manipulation of hugetlb page frames
- In the series 'mm: hugetlb: Skip initialization of gigantic tail
struct pages if freed by HVO' has improved our handling of gigantic
pages in the hugetlb vmmemmep optimizaton code. This provides
significant boot time improvements when significant amounts of
gigantic pages are in use
- Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
rationalization and folio conversions in the hugetlb code
- Yin Fengwei has improved mlock()'s handling of large folios in the
series 'support large folio for mlock'
- In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
added statistics for memcg v1 users which are available (and
useful) under memcg v2
- Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
prctl so that userspace may direct the kernel to not automatically
propagate the denial to child processes. The series is named 'MDWE
without inheritance'
- Kefeng Wang has provided the series 'mm: convert numa balancing
functions to use a folio' which does what it says
- In the series 'mm/ksm: add fork-exec support for prctl' Stefan
Roesch makes is possible for a process to propagate KSM treatment
across exec()
- Huang Ying has enhanced memory tiering's calculation of memory
distances. This is used to permit the dax/kmem driver to use 'high
bandwidth memory' in addition to Optane Data Center Persistent
Memory Modules (DCPMM). The series is named 'memory tiering:
calculate abstract distance based on ACPI HMAT'
- In the series 'Smart scanning mode for KSM' Stefan Roesch has
optimized KSM by teaching it to retain and use some historical
information from previous scans
- Yosry Ahmed has fixed some inconsistencies in memcg statistics in
the series 'mm: memcg: fix tracking of pending stats updates
values'
- In the series 'Implement IOCTL to get and optionally clear info
about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
which permits us to atomically read-then-clear page softdirty
state. This is mainly used by CRIU
- Hugh Dickins contributed the series 'shmem,tmpfs: general
maintenance', a bunch of relatively minor maintenance tweaks to
this code
- Matthew Wilcox has increased the use of the VMA lock over
file-backed page faults in the series 'Handle more faults under the
VMA lock'. Some rationalizations of the fault path became possible
as a result
- In the series 'mm/rmap: convert page_move_anon_rmap() to
folio_move_anon_rmap()' David Hildenbrand has implemented some
cleanups and folio conversions
- In the series 'various improvements to the GUP interface' Lorenzo
Stoakes has simplified and improved the GUP interface with an eye
to providing groundwork for future improvements
- Andrey Konovalov has sent along the series 'kasan: assorted fixes
and improvements' which does those things
- Some page allocator maintenance work from Kemeng Shi in the series
'Two minor cleanups to break_down_buddy_pages'
- In thes series 'New selftest for mm' Breno Leitao has developed
another MM self test which tickles a race we had between madvise()
and page faults
- In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
and an optimization to the core pagecache code
- Nhat Pham has added memcg accounting for hugetlb memory in the
series 'hugetlb memcg accounting'
- Cleanups and rationalizations to the pagemap code from Lorenzo
Stoakes, in the series 'Abstract vma_merge() and split_vma()'
- Audra Mitchell has fixed issues in the procfs page_owner code's new
timestamping feature which was causing some misbehaviours. In the
series 'Fix page_owner's use of free timestamps'
- Lorenzo Stoakes has fixed the handling of new mappings of sealed
files in the series 'permit write-sealed memfd read-only shared
mappings'
- Mike Kravetz has optimized the hugetlb vmemmap optimization in the
series 'Batch hugetlb vmemmap modification operations'
- Some buffer_head folio conversions and cleanups from Matthew Wilcox
in the series 'Finish the create_empty_buffers() transition'
- As a page allocator performance optimization Huang Ying has added
automatic tuning to the allocator's per-cpu-pages feature, in the
series 'mm: PCP high auto-tuning'
- Roman Gushchin has contributed the patchset 'mm: improve
performance of accounted kernel memory allocations' which improves
their performance by ~30% as measured by a micro-benchmark
- folio conversions from Kefeng Wang in the series 'mm: convert page
cpupid functions to folios'
- Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
kmemleak'
- Qi Zheng has improved our handling of memoryless nodes by keeping
them off the allocation fallback list. This is done in the series
'handle memoryless nodes more appropriately'
- khugepaged conversions from Vishal Moola in the series 'Some
khugepaged folio conversions'"
[ bcachefs conflicts with the dynamically allocated shrinkers have been
resolved as per Stephen Rothwell in
https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/
with help from Qi Zheng.
The clone3 test filtering conflict was half-arsed by yours truly ]
* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
mm/damon/sysfs: update monitoring target regions for online input commit
mm/damon/sysfs: remove requested targets when online-commit inputs
selftests: add a sanity check for zswap
Documentation: maple_tree: fix word spelling error
mm/vmalloc: fix the unchecked dereference warning in vread_iter()
zswap: export compression failure stats
Documentation: ubsan: drop "the" from article title
mempolicy: migration attempt to match interleave nodes
mempolicy: mmap_lock is not needed while migrating folios
mempolicy: alloc_pages_mpol() for NUMA policy without vma
mm: add page_rmappable_folio() wrapper
mempolicy: remove confusing MPOL_MF_LAZY dead code
mempolicy: mpol_shared_policy_init() without pseudo-vma
mempolicy trivia: use pgoff_t in shared mempolicy tree
mempolicy trivia: slightly more consistent naming
mempolicy trivia: delete those ancient pr_debug()s
mempolicy: fix migrate_pages(2) syscall return nr_failed
kernfs: drop shared NUMA mempolicy hooks
hugetlbfs: drop shared NUMA mempolicy pretence
mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-mm-damon | 7 | ||||
-rw-r--r-- | Documentation/admin-guide/cgroup-v1/memory.rst | 1 | ||||
-rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 38 | ||||
-rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 124 | ||||
-rw-r--r-- | Documentation/admin-guide/mm/ksm.rst | 11 | ||||
-rw-r--r-- | Documentation/admin-guide/mm/pagemap.rst | 89 | ||||
-rw-r--r-- | Documentation/admin-guide/mm/userfaultfd.rst | 35 | ||||
-rw-r--r-- | Documentation/core-api/maple_tree.rst | 2 | ||||
-rw-r--r-- | Documentation/dev-tools/kasan.rst | 7 | ||||
-rw-r--r-- | Documentation/dev-tools/kcsan.rst | 4 | ||||
-rw-r--r-- | Documentation/dev-tools/kmsan.rst | 6 | ||||
-rw-r--r-- | Documentation/dev-tools/ubsan.rst | 6 | ||||
-rw-r--r-- | Documentation/mm/damon/design.rst | 26 | ||||
-rw-r--r-- | Documentation/trace/postprocess/trace-vmscan-postprocess.pl | 42 |
14 files changed, 317 insertions, 81 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon index 420b30f09cf0..b35649a46a2f 100644 --- a/Documentation/ABI/testing/sysfs-kernel-mm-damon +++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon @@ -151,6 +151,13 @@ Contact: SeongJae Park <sj@kernel.org> Description: Writing to and reading from this file sets and gets the action of the scheme. +What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/apply_interval_us +Date: Sep 2023 +Contact: SeongJae Park <sj@kernel.org> +Description: Writing a value to this file sets the action apply interval of + the scheme in microseconds. Reading this file returns the + value. + What: /sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/sz/min 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 ff456871bf4b..ca7d9402f6be 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -551,6 +551,7 @@ memory.stat file includes following statistics: event happens each time a page is unaccounted from the cgroup. swap # of bytes of swap usage + swapcached # of bytes of swap cached in memory dirty # of bytes that are waiting to get written back to the disk. writeback # of bytes of file/anon cache that are queued for syncing to disk. diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 3f081459a5be..3f85254f3cef 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -210,6 +210,35 @@ cgroup v2 currently supports the following mount options. relying on the original semantics (e.g. specifying bogusly high 'bypass' protection values at higher tree levels). + memory_hugetlb_accounting + Count HugeTLB memory usage towards the cgroup's overall + memory usage for the memory controller (for the purpose of + statistics reporting and memory protetion). This is a new + behavior that could regress existing setups, so it must be + explicitly opted in with this mount option. + + A few caveats to keep in mind: + + * There is no HugeTLB pool management involved in the memory + controller. The pre-allocated pool does not belong to anyone. + Specifically, when a new HugeTLB folio is allocated to + the pool, it is not accounted for from the perspective of the + memory controller. It is only charged to a cgroup when it is + actually used (for e.g at page fault time). Host memory + overcommit management has to consider this when configuring + hard limits. In general, HugeTLB pool management should be + done via other mechanisms (such as the HugeTLB controller). + * Failure to charge a HugeTLB folio to the memory controller + results in SIGBUS. This could happen even if the HugeTLB pool + still has pages available (but the cgroup limit is hit and + reclaim attempt fails). + * Charging HugeTLB memory towards the memory controller affects + memory protection and reclaim dynamics. Any userspace tuning + (of low, min limits for e.g) needs to take this into account. + * HugeTLB pages utilized while this option is not selected + will not be tracked by the memory controller (even if cgroup + v2 is remounted later on). + Organizing Processes and Threads -------------------------------- @@ -1539,6 +1568,15 @@ PAGE_SIZE multiple when read back. collapsing an existing range of pages. This counter is not present when CONFIG_TRANSPARENT_HUGEPAGE is not set. + thp_swpout (npn) + Number of transparent hugepages which are swapout in one piece + without splitting. + + thp_swpout_fallback (npn) + Number of transparent hugepages which were split before swapout. + Usually because failed to allocate some continuous swap space + for the huge page. + memory.numa_stat A read-only nested-keyed file which exists on non-root cgroups. diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index 8da1b7281827..da94feb97ed1 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -20,18 +20,18 @@ DAMON provides below interfaces for different users. you can write and use your personalized DAMON sysfs wrapper programs that reads/writes the sysfs files instead of you. The `DAMON user space tool <https://github.com/awslabs/damo>`_ is one example of such programs. -- *debugfs interface. (DEPRECATED!)* - :ref:`This <debugfs_interface>` is almost identical to :ref:`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 writing kernel space DAMON application programs for you. You can even extend DAMON for various address spaces. For detail, please refer to the interface :doc:`document </mm/damon/api>`. +- *debugfs interface. (DEPRECATED!)* + :ref:`This <debugfs_interface>` is almost identical to :ref:`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. .. _sysfs_interface: @@ -76,7 +76,7 @@ comma (","). :: │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr_schemes - │ │ │ │ │ │ 0/action + │ │ │ │ │ │ 0/action,apply_interval_us │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max @@ -105,14 +105,12 @@ having the root permission could use this directory. kdamonds/ --------- -The monitoring-related information including request specifications and results -are called DAMON context. DAMON executes each context with a kernel thread -called kdamond, and multiple kdamonds could run in parallel. - Under the ``admin`` directory, one directory, ``kdamonds``, which has files for -controlling the kdamonds exist. In the beginning, this directory has only one -file, ``nr_kdamonds``. Writing a number (``N``) to the file creates the number -of child directories named ``0`` to ``N-1``. Each directory represents each +controlling the kdamonds (refer to +:ref:`design <damon_design_execution_model_and_data_structures>` for more +details) exists. In the beginning, this directory has only one file, +``nr_kdamonds``. Writing a number (``N``) to the file creates the number of +child directories named ``0`` to ``N-1``. Each directory represents each kdamond. kdamonds/<N>/ @@ -150,9 +148,10 @@ kdamonds/<N>/contexts/ In the beginning, this directory has only one file, ``nr_contexts``. Writing a number (``N``) to the file creates the number of child directories named as -``0`` to ``N-1``. Each directory represents each monitoring context. At the -moment, only one context per kdamond is supported, so only ``0`` or ``1`` can -be written to the file. +``0`` to ``N-1``. Each directory represents each monitoring context (refer to +:ref:`design <damon_design_execution_model_and_data_structures>` for more +details). At the moment, only one context per kdamond is supported, so only +``0`` or ``1`` can be written to the file. .. _sysfs_contexts: @@ -270,8 +269,8 @@ schemes/<N>/ ------------ In each scheme directory, five directories (``access_pattern``, ``quotas``, -``watermarks``, ``filters``, ``stats``, and ``tried_regions``) and one file -(``action``) exist. +``watermarks``, ``filters``, ``stats``, and ``tried_regions``) and two files +(``action`` and ``apply_interval``) exist. 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 @@ -297,6 +296,9 @@ Note that support of each action depends on the running DAMON operations set - ``stat``: Do nothing but count the statistics. Supported by all operations sets. +The ``apply_interval_us`` file is for setting and getting the scheme's +:ref:`apply_interval <damon_design_damos>` in microseconds. + schemes/<N>/access_pattern/ --------------------------- @@ -392,7 +394,7 @@ pages of all memory cgroups except ``/having_care_already``.:: echo N > 1/matching Note that ``anon`` and ``memcg`` filters are currently supported only when -``paddr`` `implementation <sysfs_contexts>` is being used. +``paddr`` :ref:`implementation <sysfs_contexts>` is being used. Also, memory regions that are filtered out by ``addr`` or ``target`` filters are not counted as the scheme has tried to those, while regions that filtered @@ -430,9 +432,9 @@ that reading it returns the total size of the scheme tried regions, and creates directories named integer starting from ``0`` under this directory. Each directory contains files exposing detailed information about each of the memory region that the corresponding scheme's ``action`` has tried to be applied under -this directory, during next :ref:`aggregation interval -<sysfs_monitoring_attrs>`. The information includes address range, -``nr_accesses``, and ``age`` of the region. +this directory, during next :ref:`apply interval <damon_design_damos>` of the +corresponding scheme. The information includes address range, ``nr_accesses``, +and ``age`` of the region. Writing ``update_schemes_tried_bytes`` to the relevant ``kdamonds/<N>/state`` file will only update the ``total_bytes`` file, and will not create the @@ -495,6 +497,62 @@ Please note that it's highly recommended to use user space tools like `damo <https://github.com/awslabs/damo>`_ rather than manually reading and writing the files as above. Above is only for an example. +.. _tracepoint: + +Tracepoints for Monitoring Results +================================== + +Users can get the monitoring results via the :ref:`tried_regions +<sysfs_schemes_tried_regions>`. The interface is useful for getting a +snapshot, but it could be inefficient for fully recording all the monitoring +results. For the purpose, two trace points, namely ``damon:damon_aggregated`` +and ``damon:damos_before_apply``, are provided. ``damon:damon_aggregated`` +provides the whole monitoring results, while ``damon:damos_before_apply`` +provides the monitoring results for regions that each DAMON-based Operation +Scheme (:ref:`DAMOS <damon_design_damos>`) is gonna be applied. Hence, +``damon:damos_before_apply`` is more useful for recording internal behavior of +DAMOS, or DAMOS target access +:ref:`pattern <damon_design_damos_access_pattern>` based query-like efficient +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 + # perf record -e damon:damon_aggregated & + # sleep 5 + # kill 9 $(pidof perf) + # echo off > monitor_on + # perf script + kdamond.0 46568 [027] 79357.842179: damon:damon_aggregated: target_id=0 nr_regions=11 122509119488-135708762112: 0 864 + [...] + +Each line of the perf script output represents each monitoring region. The +first five fields are as usual other tracepoint outputs. The sixth field +(``target_id=X``) shows the ide of the monitoring target of the region. The +seventh field (``nr_regions=X``) shows the total number of monitoring regions +for the target. The eighth field (``X-Y:``) shows the start (``X``) and end +(``Y``) addresses of the region in bytes. The ninth field (``X``) shows the +``nr_accesses`` of the region (refer to +:ref:`design <damon_design_region_based_sampling>` for more details of the +counter). Finally the tenth field (``X``) shows the ``age`` of the region +(refer to :ref:`design <damon_design_age_tracking>` for more details of the +counter). + +If the event was ``damon:damos_beofre_apply``, the ``perf script`` output would +be somewhat like below:: + + kdamond.0 47293 [000] 80801.060214: damon:damos_before_apply: ctx_idx=0 scheme_idx=0 target_idx=0 nr_regions=11 121932607488-135128711168: 0 136 + [...] + +Each line of the output represents each monitoring region that each DAMON-based +Operation Scheme was about to be applied at the traced time. The first five +fields are as usual. It shows the index of the DAMON context (``ctx_idx=X``) +of the scheme in the list of the contexts of the context's kdamond, the index +of the scheme (``scheme_idx=X``) in the list of the schemes of the context, in +addition to the output of ``damon_aggregated`` tracepoint. + + .. _debugfs_interface: debugfs Interface (DEPRECATED!) @@ -790,23 +848,3 @@ directory by putting the name of the context to the ``rm_contexts`` file. :: Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on`` files are in the root directory only. - - -.. _tracepoint: - -Tracepoint for Monitoring Results -================================= - -Users can get the monitoring results via the :ref:`tried_regions -<sysfs_schemes_tried_regions>` or a tracepoint, ``damon:damon_aggregated``. -While the tried regions directory is useful for getting a snapshot, the -tracepoint is useful for getting a full record of the results. 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 - # perf record -e damon:damon_aggregated & - # sleep 5 - # kill 9 $(pidof perf) - # echo off > monitor_on - # perf script diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 776f244bdae4..e59231ac6bb7 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -155,6 +155,15 @@ stable_node_chains_prune_millisecs scan. It's a noop if not a single KSM page hit the ``max_page_sharing`` yet. +smart_scan + Historically KSM checked every candidate page for each scan. It did + not take into account historic information. When smart scan is + enabled, pages that have previously not been de-duplicated get + skipped. How often these pages are skipped depends on how often + de-duplication has already been tried and failed. By default this + optimization is enabled. The ``pages_skipped`` metric shows how + effective the setting is. + The effectiveness of KSM and MADV_MERGEABLE is shown in ``/sys/kernel/mm/ksm/``: general_profit @@ -169,6 +178,8 @@ pages_unshared how many pages unique but repeatedly checked for merging pages_volatile how many pages changing too fast to be placed in a tree +pages_skipped + how many pages did the "smart" page scanning algorithm skip full_scans how many times all mergeable areas have been scanned stable_node_chains diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index c8f380271cad..fe17cf210426 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -227,3 +227,92 @@ Before Linux 3.11 pagemap bits 55-60 were used for "page-shift" (which is always 12 at most architectures). Since Linux 3.11 their meaning changes after first clear of soft-dirty bits. Since Linux 4.2 they are used for flags unconditionally. + +Pagemap Scan IOCTL +================== + +The ``PAGEMAP_SCAN`` IOCTL on the pagemap file can be used to get or optionally +clear the info about page table entries. The following operations are supported +in this IOCTL: + +- Scan the address range and get the memory ranges matching the provided criteria. + This is performed when the output buffer is specified. +- Write-protect the pages. The ``PM_SCAN_WP_MATCHING`` is used to write-protect + the pages of interest. The ``PM_SCAN_CHECK_WPASYNC`` aborts the operation if + non-Async Write Protected pages are found. The ``PM_SCAN_WP_MATCHING`` can be + used with or without ``PM_SCAN_CHECK_WPASYNC``. +- Both of those operations can be combined into one atomic operation where we can + get and write protect the pages as well. + +Following flags about pages are currently supported: + +- ``PAGE_IS_WPALLOWED`` - Page has async-write-protection enabled +- ``PAGE_IS_WRITTEN`` - Page has been written to from the time it was write protected +- ``PAGE_IS_FILE`` - Page is file backed +- ``PAGE_IS_PRESENT`` - Page is present in the memory +- ``PAGE_IS_SWAPPED`` - Page is in swapped +- ``PAGE_IS_PFNZERO`` - Page has zero PFN +- ``PAGE_IS_HUGE`` - Page is THP or Hugetlb backed + +The ``struct pm_scan_arg`` is used as the argument of the IOCTL. + + 1. The size of the ``struct pm_scan_arg`` must be specified in the ``size`` + field. This field will be helpful in recognizing the structure if extensions + are done later. + 2. The flags can be specified in the ``flags`` field. The ``PM_SCAN_WP_MATCHING`` + and ``PM_SCAN_CHECK_WPASYNC`` are the only added flags at this time. The get + operation is optionally performed depending upon if the output buffer is + provided or not. + 3. The range is specified through ``start`` and ``end``. + 4. The walk can abort before visiting the complete range such as the user buffer + can get full etc. The walk ending address is specified in``end_walk``. + 5. The output buffer of ``struct page_region`` array and size is specified in + ``vec`` and ``vec_len``. + 6. The optional maximum requested pages are specified in the ``max_pages``. + 7. The masks are specified in ``category_mask``, ``category_anyof_mask``, + ``category_inverted`` and ``return_mask``. + +Find pages which have been written and WP them as well:: + + struct pm_scan_arg arg = { + .size = sizeof(arg), + .flags = PM_SCAN_CHECK_WPASYNC | PM_SCAN_CHECK_WPASYNC, + .. + .category_mask = PAGE_IS_WRITTEN, + .return_mask = PAGE_IS_WRITTEN, + }; + +Find pages which have been written, are file backed, not swapped and either +present or huge:: + + struct pm_scan_arg arg = { + .size = sizeof(arg), + .flags = 0, + .. + .category_mask = PAGE_IS_WRITTEN | PAGE_IS_SWAPPED, + .category_inverted = PAGE_IS_SWAPPED, + .category_anyof_mask = PAGE_IS_PRESENT | PAGE_IS_HUGE, + .return_mask = PAGE_IS_WRITTEN | PAGE_IS_SWAPPED | + PAGE_IS_PRESENT | PAGE_IS_HUGE, + }; + +The ``PAGE_IS_WRITTEN`` flag can be considered as a better-performing alternative +of soft-dirty flag. It doesn't get affected by VMA merging of the kernel and hence +the user can find the true soft-dirty pages in case of normal pages. (There may +still be extra dirty pages reported for THP or Hugetlb pages.) + +"PAGE_IS_WRITTEN" category is used with uffd write protect-enabled ranges to +implement memory dirty tracking in userspace: + + 1. The userfaultfd file descriptor is created with ``userfaultfd`` syscall. + 2. The ``UFFD_FEATURE_WP_UNPOPULATED`` and ``UFFD_FEATURE_WP_ASYNC`` features + are set by ``UFFDIO_API`` IOCTL. + 3. The memory range is registered with ``UFFDIO_REGISTER_MODE_WP`` mode + through ``UFFDIO_REGISTER`` IOCTL. + 4. Then any part of the registered memory or the whole memory region must + be write protected using ``PAGEMAP_SCAN`` IOCTL with flag ``PM_SCAN_WP_MATCHING`` + or the ``UFFDIO_WRITEPROTECT`` IOCTL can be used. Both of these perform the + same operation. The former is better in terms of performance. + 5. Now the ``PAGEMAP_SCAN`` IOCTL can be used to either just find pages which + have been written to since they were last marked and/or optionally write protect + the pages as well. diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst index 4349a8c2b978..203e26da5f92 100644 --- a/Documentation/admin-guide/mm/userfaultfd.rst +++ b/Documentation/admin-guide/mm/userfaultfd.rst @@ -244,6 +244,41 @@ write-protected (so future writes will also result in a WP fault). These ioctls support a mode flag (``UFFDIO_COPY_MODE_WP`` or ``UFFDIO_CONTINUE_MODE_WP`` respectively) to configure the mapping this way. +If the userfaultfd context has ``UFFD_FEATURE_WP_ASYNC`` feature bit set, +any vma registered with write-protection will work in async mode rather +than the default sync mode. + +In async mode, there will be no message generated when a write operation +happens, meanwhile the write-protection will be resolved automatically by +the kernel. It can be seen as a more accurate version of soft-dirty +tracking and it can be different in a few ways: + + - The dirty result will not be affected by vma changes (e.g. vma + merging) because the dirty is only tracked by the pte. + + - It supports range operations by default, so one can enable tracking on + any range of memory as long as page aligned. + + - Dirty information will not get lost if the pte was zapped due to + various reasons (e.g. during split of a shmem transparent huge page). + + - Due to a reverted meaning of soft-dirty (page clean when uffd-wp bit + set; dirty when uffd-wp bit cleared), it has different semantics on + some of the memory operations. For example: ``MADV_DONTNEED`` on + anonymous (or ``MADV_REMOVE`` on a file mapping) will be treated as + dirtying of memory by dropping uffd-wp bit during the procedure. + +The user app can collect the "written/dirty" status by looking up the +uffd-wp bit for the pages being interested in /proc/pagemap. + +The page will not be under track of uffd-wp async mode until the page is +explicitly write-protected by ``ioctl(UFFDIO_WRITEPROTECT)`` with the mode +flag ``UFFDIO_WRITEPROTECT_MODE_WP`` set. Trying to resolve a page fault +that was tracked by async mode userfaultfd-wp is invalid. + +When userfaultfd-wp async mode is used alone, it can be applied to all +kinds of memory. + Memory Poisioning Emulation --------------------------- diff --git a/Documentation/core-api/maple_tree.rst b/Documentation/core-api/maple_tree.rst index 45defcf15da7..96f3d5f076b5 100644 --- a/Documentation/core-api/maple_tree.rst +++ b/Documentation/core-api/maple_tree.rst @@ -175,7 +175,7 @@ will return the previous entry which occurs before the entry at index. mas_find() will find the first entry which exists at or above index on the first call, and the next entry from every subsequent calls. -mas_find_rev() will find the fist entry which exists at or below the last on +mas_find_rev() will find the first entry which exists at or below the last on the first call, and the previous entry from every subsequent calls. If the user needs to yield the lock during an operation, then the maple state diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 382818a7197a..858c77fe7dc4 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -1,5 +1,8 @@ -The Kernel Address Sanitizer (KASAN) -==================================== +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2023, Google LLC. + +Kernel Address Sanitizer (KASAN) +================================ Overview -------- diff --git a/Documentation/dev-tools/kcsan.rst b/Documentation/dev-tools/kcsan.rst index 3ae866dcc924..94b6802ab0ab 100644 --- a/Documentation/dev-tools/kcsan.rst +++ b/Documentation/dev-tools/kcsan.rst @@ -1,8 +1,8 @@ .. SPDX-License-Identifier: GPL-2.0 .. Copyright (C) 2019, Google LLC. -The Kernel Concurrency Sanitizer (KCSAN) -======================================== +Kernel Concurrency Sanitizer (KCSAN) +==================================== The Kernel Concurrency Sanitizer (KCSAN) is a dynamic race detector, which relies on compile-time instrumentation, and uses a watchpoint-based sampling diff --git a/Documentation/dev-tools/kmsan.rst b/Documentation/dev-tools/kmsan.rst index 55fa82212eb2..323eedad53cd 100644 --- a/Documentation/dev-tools/kmsan.rst +++ b/Documentation/dev-tools/kmsan.rst @@ -1,9 +1,9 @@ .. SPDX-License-Identifier: GPL-2.0 .. Copyright (C) 2022, Google LLC. -=================================== -The Kernel Memory Sanitizer (KMSAN) -=================================== +=============================== +Kernel Memory Sanitizer (KMSAN) +=============================== KMSAN is a dynamic error detector aimed at finding uses of uninitialized values. It is based on compiler instrumentation, and is quite similar to the diff --git a/Documentation/dev-tools/ubsan.rst b/Documentation/dev-tools/ubsan.rst index 1be6618e232d..2de7c63415da 100644 --- a/Documentation/dev-tools/ubsan.rst +++ b/Documentation/dev-tools/ubsan.rst @@ -1,5 +1,7 @@ -The Undefined Behavior Sanitizer - UBSAN -======================================== +.. SPDX-License-Identifier: GPL-2.0 + +Undefined Behavior Sanitizer - UBSAN +==================================== UBSAN is a runtime undefined behaviour checker. diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index a20383d01a95..1f7e0586b5fa 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -154,6 +154,8 @@ The monitoring overhead of this mechanism will arbitrarily increase as the size of the target workload grows. +.. _damon_design_region_based_sampling: + Region Based Sampling ~~~~~~~~~~~~~~~~~~~~~ @@ -163,9 +165,10 @@ assumption (pages in a region have the same access frequencies) is kept, only one page in the region is required to be checked. Thus, for each ``sampling interval``, DAMON randomly picks one page in each region, waits for one ``sampling interval``, checks whether the page is accessed meanwhile, and -increases the access frequency of the region if so. Therefore, the monitoring -overhead is controllable by setting the number of regions. DAMON allows users -to set the minimum and the maximum number of regions for the trade-off. +increases the access frequency counter of the region if so. The counter is +called ``nr_regions`` of the region. Therefore, the monitoring overhead is +controllable by setting the number of regions. DAMON allows users to set the +minimum and the maximum number of regions for the trade-off. This scheme, however, cannot preserve the quality of the output if the assumption is not guaranteed. @@ -190,6 +193,8 @@ In this way, DAMON provides its best-effort quality and minimal overhead while keeping the bounds users set for their trade-off. +.. _damon_design_age_tracking: + Age Tracking ~~~~~~~~~~~~ @@ -254,7 +259,8 @@ works, DAMON provides a feature called Data Access Monitoring-based Operation Schemes (DAMOS). It lets users specify their desired schemes at a high level. For such specifications, DAMON starts monitoring, finds regions having the access pattern of interest, and applies the user-desired operation actions -to the regions as soon as found. +to the regions, for every user-specified time interval called +``apply_interval``. .. _damon_design_damos_action: @@ -471,3 +477,15 @@ modules for proactive reclamation and LRU lists manipulation are provided. For more detail, please read the usage documents for those (:doc:`/admin-guide/mm/damon/reclaim` and :doc:`/admin-guide/mm/damon/lru_sort`). + + +.. _damon_design_execution_model_and_data_structures: + +Execution Model and Data Structures +=================================== + +The monitoring-related information including the monitoring request +specification and DAMON-based operation schemes are stored in a data structure +called DAMON ``context``. DAMON executes each context with a kernel thread +called ``kdamond``. Multiple kdamonds could run in parallel, for different +types of monitoring. diff --git a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl index e24c009789a0..048dc0dbce64 100644 --- a/Documentation/trace/postprocess/trace-vmscan-postprocess.pl +++ b/Documentation/trace/postprocess/trace-vmscan-postprocess.pl @@ -107,14 +107,14 @@ GetOptions( ); # Defaults for dynamically discovered regex's -my $regex_direct_begin_default = 'order=([0-9]*) may_writepage=([0-9]*) gfp_flags=([A-Z_|]*)'; +my $regex_direct_begin_default = 'order=([0-9]*) gfp_flags=([A-Z_|]*)'; my $regex_direct_end_default = 'nr_reclaimed=([0-9]*)'; my $regex_kswapd_wake_default = 'nid=([0-9]*) order=([0-9]*)'; my $regex_kswapd_sleep_default = 'nid=([0-9]*)'; -my $regex_wakeup_kswapd_default = 'nid=([0-9]*) zid=([0-9]*) order=([0-9]*) gfp_flags=([A-Z_|]*)'; -my $regex_lru_isolate_default = 'isolate_mode=([0-9]*) classzone_idx=([0-9]*) order=([0-9]*) nr_requested=([0-9]*) nr_scanned=([0-9]*) nr_skipped=([0-9]*) nr_taken=([0-9]*) lru=([a-z_]*)'; +my $regex_wakeup_kswapd_default = 'nid=([0-9]*) order=([0-9]*) gfp_flags=([A-Z_|]*)'; +my $regex_lru_isolate_default = 'classzone=([0-9]*) order=([0-9]*) nr_requested=([0-9]*) nr_scanned=([0-9]*) nr_skipped=([0-9]*) nr_taken=([0-9]*) lru=([a-z_]*)'; my $regex_lru_shrink_inactive_default = 'nid=([0-9]*) nr_scanned=([0-9]*) nr_reclaimed=([0-9]*) nr_dirty=([0-9]*) nr_writeback=([0-9]*) nr_congested=([0-9]*) nr_immediate=([0-9]*) nr_activate_anon=([0-9]*) nr_activate_file=([0-9]*) nr_ref_keep=([0-9]*) nr_unmap_fail=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)'; -my $regex_lru_shrink_active_default = 'lru=([A-Z_]*) nr_scanned=([0-9]*) nr_rotated=([0-9]*) priority=([0-9]*)'; +my $regex_lru_shrink_active_default = 'lru=([A-Z_]*) nr_taken=([0-9]*) nr_active=([0-9]*) nr_deactivated=([0-9]*) nr_referenced=([0-9]*) priority=([0-9]*) flags=([A-Z_|]*)' ; my $regex_writepage_default = 'page=([0-9a-f]*) pfn=([0-9]*) flags=([A-Z_|]*)'; # Dyanically discovered regex @@ -184,8 +184,7 @@ sub generate_traceevent_regex { $regex_direct_begin = generate_traceevent_regex( "vmscan/mm_vmscan_direct_reclaim_begin", $regex_direct_begin_default, - "order", "may_writepage", - "gfp_flags"); + "order", "gfp_flags"); $regex_direct_end = generate_traceevent_regex( "vmscan/mm_vmscan_direct_reclaim_end", $regex_direct_end_default, @@ -201,11 +200,11 @@ $regex_kswapd_sleep = generate_traceevent_regex( $regex_wakeup_kswapd = generate_traceevent_regex( "vmscan/mm_vmscan_wakeup_kswapd", $regex_wakeup_kswapd_default, - "nid", "zid", "order", "gfp_flags"); + "nid", "order", "gfp_flags"); $regex_lru_isolate = generate_traceevent_regex( "vmscan/mm_vmscan_lru_isolate", $regex_lru_isolate_default, - "isolate_mode", "classzone_idx", "order", + "classzone", "order", "nr_requested", "nr_scanned", "nr_skipped", "nr_taken", "lru"); $regex_lru_shrink_inactive = generate_traceevent_regex( @@ -218,11 +217,10 @@ $regex_lru_shrink_inactive = generate_traceevent_regex( $regex_lru_shrink_active = generate_traceevent_regex( "vmscan/mm_vmscan_lru_shrink_active", $regex_lru_shrink_active_default, - "nid", "zid", - "lru", - "nr_scanned", "nr_rotated", "priority"); + "nid", "nr_taken", "nr_active", "nr_deactivated", "nr_referenced", + "priority", "flags"); $regex_writepage = generate_traceevent_regex( - "vmscan/mm_vmscan_writepage", + "vmscan/mm_vmscan_write_folio", $regex_writepage_default, "page", "pfn", "flags"); @@ -371,7 +369,7 @@ EVENT_PROCESS: print " $regex_wakeup_kswapd\n"; next; } - my $order = $3; + my $order = $2; $perprocesspid{$process_pid}->{MM_VMSCAN_WAKEUP_KSWAPD_PERORDER}[$order]++; } elsif ($tracepoint eq "mm_vmscan_lru_isolate") { $details = $6; @@ -381,18 +379,14 @@ EVENT_PROCESS: print " $regex_lru_isolate/o\n"; next; } - my $isolate_mode = $1; - my $nr_scanned = $5; - my $file = $8; - - # To closer match vmstat scanning statistics, only count isolate_both - # and isolate_inactive as scanning. isolate_active is rotation - # isolate_inactive == 1 - # isolate_active == 2 - # isolate_both == 3 - if ($isolate_mode != 2) { + my $nr_scanned = $4; + my $lru = $7; + + # To closer match vmstat scanning statistics, only count + # inactive lru as scanning + if ($lru =~ /inactive_/) { $perprocesspid{$process_pid}->{HIGH_NR_SCANNED} += $nr_scanned; - if ($file =~ /_file/) { + if ($lru =~ /_file/) { $perprocesspid{$process_pid}->{HIGH_NR_FILE_SCANNED} += $nr_scanned; } else { $perprocesspid{$process_pid}->{HIGH_NR_ANON_SCANNED} += $nr_scanned; |