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Document {core,ops}_filters directories on usage document.
Link: https://lkml.kernel.org/r/20250305222733.59089-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
PM_MMAP_EXCLUSIVE will now be set if folio_likely_mapped_shared() is true
-- when the folio is considered "mapped shared", including when it once
was "mapped shared" but no longer is, as documented.
This might result in and under-indication of "exclusively mapped", which
is considered better than over-indicating it: under-estimating the USS
(Unique Set Size) is better than over-estimating it.
As an alternative, we could simply remove that flag with
CONFIG_NO_PAGE_MAPCOUNT completely, but there might be value to it. So,
let's keep it like that and document the behavior.
Link: https://lkml.kernel.org/r/20250303163014.1128035-18-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(CONFIG_NO_PAGE_MAPCOUNT)
Let's implement an alternative when per-page mapcounts in large folios are
no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT.
For large folios, we'll return the per-page average mapcount within the
folio, whereby we round to the closest integer when calculating the
average: however, we'll always return at least 1 if the folio is mapped.
So assuming a folio with 512 pages, the average would be:
* 0 if not pages are mapped
* 1 if there are 1 .. 767 per-page mappings
* 2 if there are 767 .. 1279 per-page mappings
...
For hugetlb folios and for large folios that are fully mapped into all
address spaces, there is no change.
We'll make use of this helper in other context next.
As an alternative, we could simply return 0 for non-hugetlb large folios,
or disable this legacy interface with CONFIG_NO_PAGE_MAPCOUNT.
But the information exposed by this interface can still be valuable, and
frequently we deal with fully-mapped large folios where the average
corresponds to the actual page mapcount. So we'll leave it like this for
now and document the new behavior.
Note: this interface is likely not very relevant for performance. If ever
required, we could try doing a rather expensive rmap walk to collect
precisely how often this folio page is mapped.
Link: https://lkml.kernel.org/r/20250303163014.1128035-17-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add a command line option that enables control of how many threads should
be used to allocate huge pages.
[akpm@linux-foundation.org: tidy up a comment]
Link: https://lkml.kernel.org/r/20250227-hugepage-parameter-v2-2-7db8c6dc0453@cyberus-technology.de
Signed-off-by: Thomas Prescher <thomas.prescher@cyberus-technology.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Document DAMON sysfs interface usage for DAMON sampling and aggregation
intervals auto-tuning.
Link: https://lkml.kernel.org/r/20250303221726.484227-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "fs/proc/task_mmu: add guard region bit to pagemap".
Currently there is no means of determining whether a given page in a
mapping range is designated a guard region (as installed via madvise()
using the MADV_GUARD_INSTALL flag).
This is generally not an issue, but in some instances users may wish to
determine whether this is the case.
This series adds this ability via /proc/$pid/pagemap, updates the
documentation and adds a self test to assert that this functions
correctly.
This patch (of 2):
Currently there is no means by which users can determine whether a given
page in memory is in fact a guard region, that is having had the
MADV_GUARD_INSTALL madvise() flag applied to it.
This is intentional, as to provide this information in VMA metadata would
contradict the intent of the feature (providing a means to change fault
behaviour at a page table level rather than a VMA level), and would
require VMA metadata operations to scan page tables, which is
unacceptable.
In many cases, users have no need to reflect and determine what regions
have been designated guard regions, as it is the user who has established
them in the first place.
But in some instances, such as monitoring software, or software that
relies upon being able to ascertain the nature of mappings within a remote
process for instance, it becomes useful to be able to determine which
pages have the guard region marker applied.
This patch makes use of an unused pagemap bit (58) to provide this
information.
This patch updates the documentation at the same time as making the change
such that the implementation of the feature and the documentation of it
are tied together.
Link: https://lkml.kernel.org/r/cover.1740139449.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/521d99c08b975fb06a1e7201e971cc24d68196d1.1740139449.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, CMA manages one range of physically contiguous memory.
Creation of larger CMA areas with hugetlb_cma may run in to gaps in
physical memory, so that they are not able to allocate that contiguous
physical range from memblock when creating the CMA area.
This can happen, for example, on an AMD system with > 1TB of memory, where
there will be a gap just below the 1TB (40bit DMA) line. If you have set
aside most of memory for potential hugetlb CMA allocation,
cma_declare_contiguous_nid will fail.
hugetlb_cma doesn't need the entire area to be one physically contiguous
range. It just cares about being able to get physically contiguous chunks
of a certain size (e.g. 1G), and it is fine to have the CMA area backed
by multiple physical ranges, as long as it gets 1G contiguous allocations.
Multi-range support is implemented by introducing an array of ranges,
instead of just one big one. Each range has its own bitmap. Effectively,
the allocate and release operations work as before, just per-range. So,
instead of going through one large bitmap, they now go through a number of
smaller ones.
The maximum number of supported ranges is 8, as defined in CMA_MAX_RANGES.
Since some current users of CMA expect a CMA area to just use one
physically contiguous range, only allow for multiple ranges if a new
interface, cma_declare_contiguous_nid_multi, is used. The other
interfaces will work like before, creating only CMA areas with 1 range.
cma_declare_contiguous_nid_multi works as follows, mimicking the
default "bottom-up, above 4G" reservation approach:
0) Try cma_declare_contiguous_nid, which will use only one
region. If this succeeds, return. This makes sure that for
all the cases that currently work, the behavior remains
unchanged even if the caller switches from
cma_declare_contiguous_nid to cma_declare_contiguous_nid_multi.
1) Select the largest free memblock ranges above 4G, with
a maximum number of CMA_MAX_RANGES.
2) If we did not find at most CMA_MAX_RANGES that add
up to the total size requested, return -ENOMEM.
3) Sort the selected ranges by base address.
4) Reserve them bottom-up until we get what we wanted.
Link: https://lkml.kernel.org/r/20250228182928.2645936-3-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMON sysfs usage doc is describing DAMOS filter type names and their
meanings in short. The design doc is providing the short meaning and
detailed descriptions, too. This is unnecessary duplicates and confuses
where to document new DAMOS filter types and features. Move the details
from usage to design doc.
Link: https://lkml.kernel.org/r/20250218223708.53437-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This includes both the 'hugepage_size' filter type and the min/max files
used to decide range of sizes to filter on.
Link: https://lkml.kernel.org/r/20250211124437.278873-5-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The zbud compressed pages allocator is rarely used, most users use
zsmalloc. zbud consumes much more memory (only stores 1 or 2 compressed
pages per physical page). The only advantage of zbud is a marginal
performance improvement that by no means justify the memory overhead.
Historically, zsmalloc had significantly worse latency than zbud and
z3fold but offered better memory savings. This is no longer the case as
shown by a simple recent analysis [1]. In a kernel build test on tmpfs in
a limited cgroup, zbud 2-3% less time than zsmalloc, but at the cost of
using ~32% more memory (1.5G vs 1.13G). The tradeoff does not make sense
for zbud in any practical scenario.
The only alleged advantage of zbud is not having the dependency on
CONFIG_MMU, but CONFIG_SWAP already depends on CONFIG_MMU anyway, and zbud
is only used by zswap.
Remove zbud after z3fold's removal, leaving zsmalloc as the one and only
zpool allocator. Leave the removal of the zpool API (and its associated
config options) to a followup cleanup after no more allocators show up.
Deprecating zbud for a few cycles before removing it was initially
proposed [2], like z3fold was marked as deprecated for 2 cycles [3].
However, Johannes rightfully pointed out that the 2 cycles is too short
for most downstream consumers, and z3fold was deprecated first only as a
courtesy anyway.
[1]https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@mail.gmail.com/
[2]https://lore.kernel.org/lkml/Z5gdnSX5Lv-nfjQL@google.com/
[3]https://lore.kernel.org/lkml/20240904233343.933462-1-yosryahmed@google.com/
Link: https://lkml.kernel.org/r/20250129180633.3501650-3-yosry.ahmed@linux.dev
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Two of DAMON user-space tool (damo) commands that are used for examples on
DAMON getting started document, namely 'damo show' and 'damo report heats'
are deprecated[1,2], and replaced by new commands that provides same
functions with unified and simplified user interfaces. Also the example
output of 'damo show' is outdated. 'damo schemes' command is not
deprecated, but users are recommended to use 'damo start' or 'damo tune'
instead.
Update the examples to use the replacements, recommendations, and
up-to-date output formats.
[1] https://git.kernel.org/sj/damo/c/3272e0ac94ecc5e1
[2] https://git.kernel.org/sj/damo/c/da3ec66bbdd9e87d
Link: https://lkml.kernel.org/r/20250110185232.54907-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yunjeong Mun <yunjeong.mun@sk.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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files on files hierarchy
DAMOS filter directory part of DAMON sysfs files hierarchy on the usage
document is wrong. 'memcg_path' file under the directory is wrongly
written as 'memcg_id'. Also the directory has 'addr_start', 'addr_end',
and 'target_idx' files, but the list is missing those. Fix the wrong name
and add missing files.
Link: https://lkml.kernel.org/r/20250110185232.54907-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yunjeong Mun <yunjeong.mun@sk.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update DAMON usage document for the newly added 'allow' sysfs file for
DAMOS filters.
Link: https://lkml.kernel.org/r/20250109175126.57878-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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design doc
DAMON usage document is describing some details about DAMOS filters, which
are also documented on the design doc. Deduplicate the details in favor
of the design doc.
Link: https://lkml.kernel.org/r/20250109175126.57878-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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It's time to remove DAMON debugfs interface, which has deprecated long
before in February 2023. Read the cover letter of this patch series for
more details.
Remove DAMON debugfs interface usage documentation, to avoid confusing
users with documents for an already removed thing.
Link: https://lkml.kernel.org/r/20250106191941.107070-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Rae Moar <rmoar@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <si.yanteng@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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region directories
Document the newly added DAMON sysfs interface file for per-scheme-tried
region's bytes that passed the operations set handling DAMOS filters.
Link: https://lkml.kernel.org/r/20250106193401.109161-16-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Document the new per-scheme operations set layer-handled DAMOS filters
passed bytes statistic file on DAMON sysfs interface usage document.
Link: https://lkml.kernel.org/r/20250106193401.109161-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMON sysfs usage document focuses on usage, rather than the detail of the
stat metric itself. Add a link to the design document on DAMOS stat usage
section.
Link: https://lkml.kernel.org/r/20250106193401.109161-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Memory hotplug presently auto-onlines memory into a zone the kernel deems
appropriate if CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y.
The memhp_default_state boot param enables runtime config, but it's not
possible to do this at build-time.
Remove CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE, and replace it with
CONFIG_MHP_DEFAULT_ONLINE_TYPE_* choices that sync with the boot param.
Selections:
CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE
=> mhp_default_online_type = "offline"
Memory will not be onlined automatically.
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO
=> mhp_default_online_type = "online"
Memory will be onlined automatically in a zone deemed.
appropriate by the kernel.
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL
=> mhp_default_online_type = "online_kernel"
Memory will be onlined automatically.
The zone may allow kernel data (e.g. ZONE_NORMAL).
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE
=> mhp_default_online_type = "online_movable"
Memory will be onlined automatically.
The zone will be ZONE_MOVABLE.
Default to CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE to match the existing
default CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n behavior.
Existing users of CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y should use
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO.
[gourry@gourry.net: update KConfig comments]
Link: https://lkml.kernel.org/r/20241226182918.648799-1-gourry@gourry.net
Link: https://lkml.kernel.org/r/20241220210709.300066-1-gourry@gourry.net
Signed-off-by: Gregory Price <gourry@gourry.net>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, large folio swap-in is supported, but we lack a method to
analyze their success ratio. Similar to anon_fault_fallback, we introduce
per-order mTHP swpin_fallback and swpin_fallback_charge counters for
calculating their success ratio. The new counters are located at:
/sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats/
swpin_fallback
swpin_fallback_charge
Link: https://lkml.kernel.org/r/20241202124730.2407037-1-haowenchao22@gmail.com
Signed-off-by: Wenchao Hao <haowenchao22@gmail.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Drop 'fadvise()' from the doc, since fadvise() has no HUGEPAGE advise
currently.
Link: https://lkml.kernel.org/r/3a10bb49832f6d9827dc2c76aec0bf43a892876b.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update the large folios policy for tmpfs and shmem.
Link: https://lkml.kernel.org/r/9b7418af30e300d1eb05721b81d79074d0bb0ec9.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now the tmpfs can allow to allocate any sized large folios, and the default
huge policy is still preferred to be 'never'. Due to tmpfs not behaving like
other file systems in some cases as previously explained by David[1]:
: I think I raised this in the past, but tmpfs/shmem is just like any
: other file system .. except it sometimes really isn't and behaves much
: more like (swappable) anonymous memory. (or mlocked files)
:
: There are many systems out there that run without swap enabled, or with
: extremely minimal swap (IIRC until recently kubernetes was completely
: incompatible with swapping). Swap can even be disabled today for shmem
: using a mount option.
:
: That's a big difference to all other file systems where you are
: guaranteed to have backend storage where you can simply evict under
: memory pressure (might temporarily fail, of course).
:
: I *think* that's the reason why we have the "huge=" parameter that also
: controls the THP allocations during page faults (IOW possible memory
: over-allocation). Maybe also because it was a new feature, and we only
: had a single THP size.
Thus adding a new command line to change the default huge policy will be
helpful to use the large folios for tmpfs, which is similar to the
'transparent_hugepage_shmem' cmdline for shmem.
[1] https://lore.kernel.org/all/cbadd5fe-69d5-4c21-8eb8-3344ed36c721@redhat.com/
Link: https://lkml.kernel.org/r/ff390b2656f0d39649547f8f2cbb30fcb7e7be2d.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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The '/proc/PID/smaps' does not have the 'FileHugeMapped' field to count
the file transparent huge pages, instead, the 'FilePmdMapped' field should
be used. Fix it.
Link: https://lkml.kernel.org/r/d520ce3aba2b03b088be30bece732426a939049a.1734425264.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Add the ``thp_shmem=`` kernel command line to allow specifying the default
policy of each supported shmem hugepage size. The kernel parameter
accepts the following format:
thp_shmem=<size>[KMG],<size>[KMG]:<policy>;<size>[KMG]-<size>[KMG]:<policy>
For example,
thp_shmem=16K-64K:always;128K,512K:inherit;256K:advise;1M-2M:never;4M-8M:within_size
Some GPUs may benefit from using huge pages. Since DRM GEM uses shmem to
allocate anonymous pageable memory, it's essential to control the huge
page allocation policy for the internal shmem mount. This control can be
achieved through the ``transparent_hugepage_shmem=`` parameter.
Beyond just setting the allocation policy, it's crucial to have granular
control over the size of huge pages that can be allocated. The GPU may
support only specific huge page sizes, and allocating pages larger/smaller
than those sizes would be ineffective.
Link: https://lkml.kernel.org/r/20241101165719.1074234-6-mcanal@igalia.com
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: add more kernel parameters to control mTHP", v5.
This series introduces four patches related to the kernel parameters
controlling mTHP and a fifth patch replacing `strcpy()` for `strscpy()` in
the file `mm/huge_memory.c`.
The first patch is a straightforward documentation update, correcting the
format of the kernel parameter ``thp_anon=``.
The second, third, and fourth patches focus on controlling THP support for
shmem via the kernel command line. The second patch introduces a
parameter to control the global default huge page allocation policy for
the internal shmem mount. The third patch moves a piece of code to a
shared header to ease the implementation of the fourth patch. Finally,
the fourth patch implements a parameter similar to ``thp_anon=``, but for
shmem.
The goal of these changes is to simplify the configuration of systems that
rely on mTHP support for shmem. For instance, a platform with a GPU that
benefits from huge pages may want to enable huge pages for shmem. Having
these kernel parameters streamlines the configuration process and ensures
consistency across setups.
This patch (of 4):
Add a new kernel command line to control the hugepage allocation policy
for the internal shmem mount, ``transparent_hugepage_shmem``. The
parameter is similar to ``transparent_hugepage`` and has the following
format:
transparent_hugepage_shmem=<policy>
where ``<policy>`` is one of the seven valid policies available for
shmem.
Configuring the default huge page allocation policy for the internal
shmem mount can be beneficial for DRM GPU drivers. Just as CPU
architectures, GPUs can also take advantage of huge pages, but this is
possible only if DRM GEM objects are backed by huge pages.
Since GEM uses shmem to allocate anonymous pageable memory, having control
over the default huge page allocation policy allows for the exploration of
huge pages use on GPUs that rely on GEM objects backed by shmem.
Link: https://lkml.kernel.org/r/20241101165719.1074234-2-mcanal@igalia.com
Link: https://lkml.kernel.org/r/20241101165719.1074234-4-mcanal@igalia.com
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kernel-dev@igalia.com
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This helps profile the sizes of folios being swapped in. Currently,
only mTHP swap-out is being counted.
The new interface can be found at:
/sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats
swpin
For example,
cat /sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpin
12809
cat /sys/kernel/mm/transparent_hugepage/hugepages-32kB/stats/swpin
4763
[v-songbaohua@oppo.com: add a blank line in doc]
Link: https://lkml.kernel.org/r/20241030233423.80759-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20241026082423.26298-1-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Added a new MTHP_STAT_ZSWPOUT entry to the sysfs transparent_hugepage
stats so that successful large folio zswap stores can be accounted under
the per-order sysfs "zswpout" stats:
/sys/kernel/mm/transparent_hugepage/hugepages-*kB/stats/zswpout
Other non-zswap swap device swap-out events will be counted under
the existing sysfs "swpout" stats:
/sys/kernel/mm/transparent_hugepage/hugepages-*kB/stats/swpout
Also, added documentation for the newly added sysfs per-order hugepage
"zswpout" stats. The documentation clarifies that only non-zswap swapouts
will be accounted in the existing "swpout" stats.
Link: https://lkml.kernel.org/r/20241001053222.6944-8-kanchana.p.sridhar@intel.com
Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Wajdi Feghali <wajdi.k.feghali@intel.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: "Zou, Nanhai" <nanhai.zou@intel.com>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
If we add ``thp_anon=32,64K:always`` to the kernel command line, we
will see the following error:
[ 0.000000] huge_memory: thp_anon=32,64K:always: error parsing string, ignoring setting
This happens because the correct format isn't ``thp_anon=<size>,<size>[KMG]:<state>```,
as [KMG] must follow each number to especify its unit. So, the correct
format is ``thp_anon=<size>[KMG],<size>[KMG]:<state>```.
Therefore, adjust the documentation to reflect the correct format of the
parameter ``thp_anon=``.
Link: https://lkml.kernel.org/r/20241101165719.1074234-3-mcanal@igalia.com
Fixes: dd4d30d1cdbe ("mm: override mTHP "enabled" defaults at kernel cmdline")
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Acked-by: Barry Song <baohua@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
"Many singleton patches - please see the various changelogs for
details.
Quite a lot of nilfs2 work this time around.
Notable patch series in this pull request are:
- "mul_u64_u64_div_u64: new implementation" by Nicolas Pitre, with
assistance from Uwe Kleine-König. Reimplement mul_u64_u64_div_u64()
to provide (much) more accurate results. The current implementation
was causing Uwe some issues in the PWM drivers.
- "xz: Updates to license, filters, and compression options" from
Lasse Collin. Miscellaneous maintenance and kinor feature work to
the xz decompressor.
- "Fix some GDB command error and add some GDB commands" from
Kuan-Ying Lee. Fixes and enhancements to the gdb scripts.
- "treewide: add missing MODULE_DESCRIPTION() macros" from Jeff
Johnson. Adds lots of MODULE_DESCRIPTIONs, thus fixing lots of
warnings about this.
- "nilfs2: add support for some common ioctls" from Ryusuke Konishi.
Adds various commonly-available ioctls to nilfs2.
- "This series fixes a number of formatting issues in kernel doc
comments" from Ryusuke Konishi does that.
- "nilfs2: prevent unexpected ENOENT propagation" from Ryusuke
Konishi. Fix issues where -ENOENT was being unintentionally and
inappropriately returned to userspace.
- "nilfs2: assorted cleanups" from Huang Xiaojia.
- "nilfs2: fix potential issues with empty b-tree nodes" from Ryusuke
Konishi fixes some issues which can occur on corrupted nilfs2
filesystems.
- "scripts/decode_stacktrace.sh: improve error reporting and
usability" from Luca Ceresoli does those things"
* tag 'mm-nonmm-stable-2024-09-21-07-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (103 commits)
list: test: increase coverage of list_test_list_replace*()
list: test: fix tests for list_cut_position()
proc: use __auto_type more
treewide: correct the typo 'retun'
ocfs2: cleanup return value and mlog in ocfs2_global_read_info()
nilfs2: remove duplicate 'unlikely()' usage
nilfs2: fix potential oob read in nilfs_btree_check_delete()
nilfs2: determine empty node blocks as corrupted
nilfs2: fix potential null-ptr-deref in nilfs_btree_insert()
user_namespace: use kmemdup_array() instead of kmemdup() for multiple allocation
tools/mm: rm thp_swap_allocator_test when make clean
squashfs: fix percpu address space issues in decompressor_multi_percpu.c
lib: glob.c: added null check for character class
nilfs2: refactor nilfs_segctor_thread()
nilfs2: use kthread_create and kthread_stop for the log writer thread
nilfs2: remove sc_timer_task
nilfs2: do not repair reserved inode bitmap in nilfs_new_inode()
nilfs2: eliminate the shared counter and spinlock for i_generation
nilfs2: separate inode type information from i_state field
nilfs2: use the BITS_PER_LONG macro
...
|
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If disabled, THPs faulted in or collapsed will not be added to
_deferred_list, and therefore won't be considered for splitting under
memory pressure if underused.
Link: https://lkml.kernel.org/r/20240830100438.3623486-7-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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This is an attempt to mitigate the issue of running out of memory when THP
is always enabled. During runtime whenever a THP is being faulted in
(__do_huge_pmd_anonymous_page) or collapsed by khugepaged
(collapse_huge_page), the THP is added to _deferred_list. Whenever memory
reclaim happens in linux, the kernel runs the deferred_split shrinker
which goes through the _deferred_list.
If the folio was partially mapped, the shrinker attempts to split it. If
the folio is not partially mapped, the shrinker checks if the THP was
underused, i.e. how many of the base 4K pages of the entire THP were
zero-filled. If this number goes above a certain threshold (decided by
/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none), the
shrinker will attempt to split that THP. Then at remap time, the pages
that were zero-filled are mapped to the shared zeropage, hence saving
memory.
Link: https://lkml.kernel.org/r/20240830100438.3623486-6-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Suggested-by: Rik van Riel <riel@surriel.com>
Co-authored-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexander Zhu <alexlzhu@fb.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuang Zhai <zhais@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Shuang Zhai <szhai2@cs.rochester.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Patch series "Docs/damon: update GitHub repo URLs and maintainer-profile".
Replace GitHub URLS on DAMON documents for none-kernel parts DAMON repos
with new ones[1] via the first patch. With following two patches,
wordsmith maitnainer-profile for better readability, and document the
Google clendsar for bi-weekly meetups, respectively.
[1] https://lore.kernel.org/20240813232158.83903-1-sj@kernel.org
This patch (of 3):
GitHub repos for non-kernel parts of DAMON project including 'damo',
'damon-tests' and 'damoos' will be moved[1] from 'awslabs' org to
'damonitor', by 2024-09-05. Update related URLs in kernel tree.
[1] https://lore.kernel.org/20240813232158.83903-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240826015741.80707-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240826015741.80707-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When a THP is added to the deferred_list due to partially mapped, its
partial pages are unused, leading to wasted memory and potentially
increasing memory reclamation pressure.
Detailing the specifics of how unmapping occurs is quite difficult and not
that useful, so we adopt a simple approach: each time a THP enters the
deferred_list, we increment the count by 1; whenever it leaves for any
reason, we decrement the count by 1.
Link: https://lkml.kernel.org/r/20240824010441.21308-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuai Yuan <yuanshuai@oppo.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: count the number of anonymous THPs per size", v4.
Knowing the number of transparent anon THPs in the system is crucial
for performance analysis. It helps in understanding the ratio and
distribution of THPs versus small folios throughout the system.
Additionally, partial unmapping by userspace can lead to significant waste
of THPs over time and increase memory reclamation pressure. We need this
information for comprehensive system tuning.
This patch (of 2):
Let's track for each anonymous THP size, how many of them are currently
allocated. We'll track the complete lifespan of an anon THP, starting
when it becomes an anon THP ("large anon folio") (->mapping gets set),
until it gets freed (->mapping gets cleared).
Introduce a new "nr_anon" counter per THP size and adjust the
corresponding counter in the following cases:
* We allocate a new THP and call folio_add_new_anon_rmap() to map
it the first time and turn it into an anon THP.
* We split an anon THP into multiple smaller ones.
* We migrate an anon THP, when we prepare the destination.
* We free an anon THP back to the buddy.
Note that AnonPages in /proc/meminfo currently tracks the total number of
*mapped* anonymous *pages*, and therefore has slightly different
semantics. In the future, we might also want to track "nr_anon_mapped"
for each THP size, which might be helpful when comparing it to the number
of allocated anon THPs (long-term pinning, stuck in swapcache, memory
leaks, ...).
Further note that for now, we only track anon THPs after they got their
->mapping set, for example via folio_add_new_anon_rmap(). If we would
allocate some in the swapcache, they will only show up in the statistics
for now after they have been mapped to user space the first time, where we
call folio_add_new_anon_rmap().
[akpm@linux-foundation.org: documentation fixups, per David]
Link: https://lkml.kernel.org/r/3e8add35-e26b-443b-8a04-1078f4bc78f6@redhat.com
Link: https://lkml.kernel.org/r/20240824010441.21308-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240824010441.21308-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
C |
