mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2025-01-04 04:06:26 +00:00
ab8beb2047
571 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Joshua Hahn
|
05d4532b60 |
memcg/hugetlb: add hugeTLB counters to memcg
This patch introduces a new counter to memory.stat that tracks hugeTLB
usage, only if hugeTLB accounting is done to memory.current. This feature
is enabled the same way hugeTLB accounting is enabled, via the
memory_hugetlb_accounting mount flag for cgroupsv2.
1. Why is this patch necessary?
Currently, memcg hugeTLB accounting is an opt-in feature [1] that adds
hugeTLB usage to memory.current. However, the metric is not reported in
memory.stat. Given that users often interpret memory.stat as a breakdown
of the value reported in memory.current, the disparity between the two
reports can be confusing. This patch solves this problem by including the
metric in memory.stat as well, but only if it is also reported in
memory.current (it would also be confusing if the value was reported in
memory.stat, but not in memory.current)
Aside from the consistency between the two files, we also see benefits in
observability. Userspace might be interested in the hugeTLB footprint of
cgroups for many reasons. For instance, system admins might want to
verify that hugeTLB usage is distributed as expected across tasks: i.e.
memory-intensive tasks are using more hugeTLB pages than tasks that don't
consume a lot of memory, or are seen to fault frequently. Note that this
is separate from wanting to inspect the distribution for limiting purposes
(in which case, hugeTLB controller makes more sense).
2. We already have a hugeTLB controller. Why not use that?
It is true that hugeTLB tracks the exact value that we want. In fact, by
enabling the hugeTLB controller, we get all of the observability benefits
that I mentioned above, and users can check the total hugeTLB usage,
verify if it is distributed as expected, etc.
With this said, there are 2 problems:
(a) They are still not reported in memory.stat, which means the
disparity between the memcg reports are still there.
(b) We cannot reasonably expect users to enable the hugeTLB controller
just for the sake of hugeTLB usage reporting, especially since
they don't have any use for hugeTLB usage enforcing [2].
3. Implementation Details:
In the alloc / free hugetlb functions, we call lruvec_stat_mod_folio
regardless of whether memcg accounts hugetlb. mem_cgroup_commit_charge
which is called from alloc_hugetlb_folio will set memcg for the folio only
if the CGRP_ROOT_MEMORY_HUGETLB_ACCOUNTING cgroup mount option is used, so
lruvec_stat_mod_folio accounts per-memcg hugetlb counters only if the
feature is enabled. Regardless of whether memcg accounts for hugetlb, the
newly added global counter is updated and shown in /proc/vmstat.
The global counter is added because vmstats is the preferred framework for
cgroup stats. It makes stat items consistent between global and cgroups.
It also provides a per-node breakdown, which is useful. Because it does
not use cgroup-specific hooks, we also keep generic MM code separate from
memcg code.
[1] https://lore.kernel.org/all/20231006184629.155543-1-nphamcs@gmail.com/
[2] Of course, we can't make a new patch for every feature that can be
duplicated. However, since the existing solution of enabling the
hugeTLB controller is an imperfect solution that still leaves a
discrepancy between memory.stat and memory.curent, I think that it
is reasonable to isolate the feature in this case.
Link: https://lkml.kernel.org/r/20241101204402.1885383-1-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Suggested-by: Nhat Pham <nphamcs@gmail.com>
Suggested-by: Shakeel Butt <shakeel.butt@linux.dev>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Andrew Morton
|
2ec0859039 |
Merge branch 'mm-hotfixes-stable' into mm-stable
Pick up
|
||
|
Yu Zhao
|
c928807f6f |
mm/page_alloc: keep track of free highatomic
OOM kills due to vastly overestimated free highatomic reserves were observed: ... invoked oom-killer: gfp_mask=0x100cca(GFP_HIGHUSER_MOVABLE), order=0 ... Node 0 Normal free:1482936kB boost:0kB min:410416kB low:739404kB high:1068392kB reserved_highatomic:1073152KB ... Node 0 Normal: 1292*4kB (ME) 1920*8kB (E) 383*16kB (UE) 220*32kB (ME) 340*64kB (E) 2155*128kB (UE) 3243*256kB (UE) 615*512kB (U) 1*1024kB (M) 0*2048kB 0*4096kB = 1477408kB The second line above shows that the OOM kill was due to the following condition: free (1482936kB) - reserved_highatomic (1073152kB) = 409784KB < min (410416kB) And the third line shows there were no free pages in any MIGRATE_HIGHATOMIC pageblocks, which otherwise would show up as type 'H'. Therefore __zone_watermark_unusable_free() underestimated the usable free memory by over 1GB, which resulted in the unnecessary OOM kill above. The comments in __zone_watermark_unusable_free() warns about the potential risk, i.e., If the caller does not have rights to reserves below the min watermark then subtract the high-atomic reserves. This will over-estimate the size of the atomic reserve but it avoids a search. However, it is possible to keep track of free pages in reserved highatomic pageblocks with a new per-zone counter nr_free_highatomic protected by the zone lock, to avoid a search when calculating the usable free memory. And the cost would be minimal, i.e., simple arithmetics in the highatomic alloc/free/move paths. Note that since nr_free_highatomic can be relatively small, using a per-cpu counter might cause too much drift and defeat its purpose, in addition to the extra memory overhead. Dependson |
||
|
Wei Xu
|
f1001f3d3b |
mm/mglru: reset page lru tier bits when activating
When a folio is activated, lru_gen_add_folio() moves the folio to the
youngest generation. But unlike folio_update_gen()/folio_inc_gen(),
lru_gen_add_folio() doesn't reset the folio lru tier bits (LRU_REFS_MASK |
LRU_REFS_FLAGS). This inconsistency can affect how pages are aged via
folio_mark_accessed() (e.g. fd accesses), though no user visible impact
related to this has been detected yet.
Note that lru_gen_add_folio() cannot clear PG_workingset if the activation
is due to workingset refault, otherwise PSI accounting will be skipped.
So fix lru_gen_add_folio() to clear the lru tier bits other than
PG_workingset when activating a folio, and also clear all the lru tier
bits when a folio is activated via folio_activate() in
lru_gen_look_around().
Link: https://lkml.kernel.org/r/20241017181528.3358821-1-weixugc@google.com
Fixes:
|
||
|
Yu Zhao
|
1d4832becd |
mm: multi-gen LRU: use {ptep,pmdp}_clear_young_notify()
When the MM_WALK capability is enabled, memory that is mostly accessed by
a VM appears younger than it really is, therefore this memory will be less
likely to be evicted. Therefore, the presence of a running VM can
significantly increase swap-outs for non-VM memory, regressing the
performance for the rest of the system.
Fix this regression by always calling {ptep,pmdp}_clear_young_notify()
whenever we clear the young bits on PMDs/PTEs.
[jthoughton@google.com: fix link-time error]
Link: https://lkml.kernel.org/r/20241019012940.3656292-3-jthoughton@google.com
Fixes:
|
||
|
Yu Zhao
|
ddd6d8e975 |
mm: multi-gen LRU: remove MM_LEAF_OLD and MM_NONLEAF_TOTAL stats
Patch series "mm: multi-gen LRU: Have secondary MMUs participate in
MM_WALK".
Today, the MM_WALK capability causes MGLRU to clear the young bit from
PMDs and PTEs during the page table walk before eviction, but MGLRU does
not call the clear_young() MMU notifier in this case. By not calling this
notifier, the MM walk takes less time/CPU, but it causes pages that are
accessed mostly through KVM / secondary MMUs to appear younger than they
should be.
We do call the clear_young() notifier today, but only when attempting to
evict the page, so we end up clearing young/accessed information less
frequently for secondary MMUs than for mm PTEs, and therefore they appear
younger and are less likely to be evicted. Therefore, memory that is
*not* being accessed mostly by KVM will be evicted *more* frequently,
worsening performance.
ChromeOS observed a tab-open latency regression when enabling MGLRU with a
setup that involved running a VM:
Tab-open latency histogram (ms)
Version p50 mean p95 p99 max
base 1315 1198 2347 3454 10319
mglru 2559 1311 7399 12060 43758
fix 1119 926 2470 4211 6947
This series replaces the final non-selftest patchs from this series[1],
which introduced a similar change (and a new MMU notifier) with KVM
optimizations. I'll send a separate series (to Sean and Paolo) for the
KVM optimizations.
This series also makes proactive reclaim with MGLRU possible for KVM
memory. I have verified that this functions correctly with the selftest
from [1], but given that that test is a KVM selftest, I'll send it with
the rest of the KVM optimizations later. Andrew, let me know if you'd
like to take the test now anyway.
[1]: https://lore.kernel.org/linux-mm/20240926013506.860253-18-jthoughton@google.com/
This patch (of 2):
The removed stats, MM_LEAF_OLD and MM_NONLEAF_TOTAL, are not very helpful
and become more complicated to properly compute when adding
test/clear_young() notifiers in MGLRU's mm walk.
Link: https://lkml.kernel.org/r/20241019012940.3656292-1-jthoughton@google.com
Link: https://lkml.kernel.org/r/20241019012940.3656292-2-jthoughton@google.com
Fixes:
|
||
|
Andrew Morton
|
620943d7ee |
include/linux/mmzone.h: clean up watermark accessors
- we have a helper wmark_pages(). Teach min_wmark_pages(), low_wmark_pages(), high_wmark_pages() and promo_wmark_pages() to use it instead of open-coding its implementation. - there's no reason to implement all these things as macros. Redo them in C. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kaiyang Zhao
|
03790c51a4 |
mm: create promo_wmark_pages and clean up open-coded sites
Patch series "mm: print the promo watermark in zoneinfo", v2. This patch (of 2): Define promo_wmark_pages and convert current call sites of wmark_pages with fixed WMARK_PROMO to using it instead. Link: https://lkml.kernel.org/r/20240801232548.36604-1-kaiyang2@cs.cmu.edu Link: https://lkml.kernel.org/r/20240801232548.36604-2-kaiyang2@cs.cmu.edu Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Wei Yang
|
29943248af |
mm: improve code consistency with zonelist_* helper functions
Replace direct access to zoneref->zone, zoneref->zone_idx, or zone_to_nid(zoneref->zone) with the corresponding zonelist_* helper functions for consistency. No functional change. Link: https://lkml.kernel.org/r/20240729091717.464-1-shivankg@amd.com Co-developed-by: Shivank Garg <shivankg@amd.com> Signed-off-by: Shivank Garg <shivankg@amd.com> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Pasha Tatashin
|
9d85731110 |
mm: don't account memmap per-node
Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
Segmentation fault
dmesg:
Oops: general protection fault, probably for
non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN
PTI
KASAN: probably user-memory-access in range
[0x000000000002b280-0x000000000002b287]
CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1
Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS
2.20.1 09/13/2023
RIP: 0010:mod_node_page_state+0x2a/0x110
cxl-test users report a GPF when trying to unload the test module:
$ modrpobe -r cxl-test
dmesg
BUG: unable to handle page fault for address: 0000000000004200
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197
Tainted: [O]=OOT_MODULE, [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/15
RIP: 0010:mod_node_page_state+0x6/0x90
Currently, when memory is hot-plugged or hot-removed the accounting is
done based on the assumption that memmap is allocated from the same node
as the hot-plugged/hot-removed memory, which is not always the case.
In addition, there are challenges with keeping the node id of the memory
that is being remove to the time when memmap accounting is actually
performed: since this is done after remove_pfn_range_from_zone(), and
also after remove_memory_block_devices(). Meaning that we cannot use
pgdat nor walking though memblocks to get the nid.
Given all of that, account the memmap overhead system wide instead.
For this we are going to be using global atomic counters, but given that
memmap size is rarely modified, and normally is only modified either
during early boot when there is only one CPU, or under a hotplug global
mutex lock, therefore there is no need for per-cpu optimizations.
Also, while we are here rename nr_memmap to nr_memmap_pages, and
nr_memmap_boot to nr_memmap_boot_pages to be self explanatory that the
units are in page count.
[pasha.tatashin@soleen.com: address a few nits from David Hildenbrand]
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240808213437.682006-4-pasha.tatashin@soleen.com
Fixes:
|
||
|
Andrew Morton
|
8ef6fd0e9e |
Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm: fix
crashes from deferred split racing folio migration", needed by "mm: migrate: split folio_migrate_mapping()". |
||
|
Waiman Long
|
82f0b6f041 |
mm: prevent derefencing NULL ptr in pfn_section_valid()
Commit |
||
|
Sourav Panda
|
15995a3524 |
mm: report per-page metadata information
Today, we do not have any observability of per-page metadata and how much it takes away from the machine capacity. Thus, we want to describe the amount of memory that is going towards per-page metadata, which can vary depending on build configuration, machine architecture, and system use. This patch adds 2 fields to /proc/vmstat that can used as shown below: Accounting per-page metadata allocated by boot-allocator: /proc/vmstat:nr_memmap_boot * PAGE_SIZE Accounting per-page metadata allocated by buddy-allocator: /proc/vmstat:nr_memmap * PAGE_SIZE Accounting total Perpage metadata allocated on the machine: (/proc/vmstat:nr_memmap_boot + /proc/vmstat:nr_memmap) * PAGE_SIZE Utility for userspace: Observability: Describe the amount of memory overhead that is going to per-page metadata on the system at any given time since this overhead is not currently observable. Debugging: Tracking the changes or absolute value in struct pages can help detect anomalies as they can be correlated with other metrics in the machine (e.g., memtotal, number of huge pages, etc). page_ext overheads: Some kernel features such as page_owner page_table_check that use page_ext can be optionally enabled via kernel parameters. Having the total per-page metadata information helps users precisely measure impact. Furthermore, page-metadata metrics will reflect the amount of struct pages reliquished (or overhead reduced) when hugetlbfs pages are reserved which will vary depending on whether hugetlb vmemmap optimization is enabled or not. For background and results see: lore.kernel.org/all/20240220214558.3377482-1-souravpanda@google.com Link: https://lkml.kernel.org/r/20240605222751.1406125-1-souravpanda@google.com Signed-off-by: Sourav Panda <souravpanda@google.com> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Chen Linxuan <chenlinxuan@uniontech.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tomas Mudrunka <tomas.mudrunka@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Xu <weixugc@google.com> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
yangge
|
bf14ed81f5 |
mm/page_alloc: Separate THP PCP into movable and non-movable categories
Since commit |
||
|
Pasha Tatashin
|
212c5c078d |
iommu: account IOMMU allocated memory
In order to be able to limit the amount of memory that is allocated by IOMMU subsystem, the memory must be accounted. Account IOMMU as part of the secondary pagetables as it was discussed at LPC. The value of SecPageTables now contains mmeory allocation by IOMMU and KVM. There is a difference between GFP_ACCOUNT and what NR_IOMMU_PAGES shows. GFP_ACCOUNT is set only where it makes sense to charge to user processes, i.e. IOMMU Page Tables, but there more IOMMU shared data that should not really be charged to a specific process. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: David Rientjes <rientjes@google.com> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Link: https://lore.kernel.org/r/20240413002522.1101315-12-pasha.tatashin@soleen.com Signed-off-by: Joerg Roedel <jroedel@suse.de> |
||
|
Pasha Tatashin
|
bd3520a93a |
iommu: observability of the IOMMU allocations
Add NR_IOMMU_PAGES into node_stat_item that counts number of pages that are allocated by the IOMMU subsystem. The allocations can be view per-node via: /sys/devices/system/node/nodeN/vmstat. For example: $ grep iommu /sys/devices/system/node/node*/vmstat /sys/devices/system/node/node0/vmstat:nr_iommu_pages 106025 /sys/devices/system/node/node1/vmstat:nr_iommu_pages 3464 The value is in page-count, therefore, in the above example the iommu allocations amount to ~428M. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: David Rientjes <rientjes@google.com> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Link: https://lore.kernel.org/r/20240413002522.1101315-11-pasha.tatashin@soleen.com Signed-off-by: Joerg Roedel <jroedel@suse.de> |
||
|
Matthew Wilcox (Oracle)
|
fae7d834c4 |
mm: add __dump_folio()
Turn __dump_page() into a wrapper around __dump_folio(). Snapshot the page & folio into a stack variable so we don't hit BUG_ON() if an allocation is freed under us and what was a folio pointer becomes a pointer to a tail page. [willy@infradead.org: fix build issue] Link: https://lkml.kernel.org/r/ZeAKCyTn_xS3O9cE@casper.infradead.org [willy@infradead.org: fix __dump_folio] Link: https://lkml.kernel.org/r/ZeJJegP8zM7S9GTy@casper.infradead.org [willy@infradead.org: fix pointer confusion] Link: https://lkml.kernel.org/r/ZeYa00ixxC4k1ot-@casper.infradead.org [akpm@linux-foundation.org: s/printk/pr_warn/] Link: https://lkml.kernel.org/r/20240227192337.757313-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kinsey Ho
|
cc25bbe10a |
mm/mglru: improve struct lru_gen_mm_walk
Rename max_seq to seq in struct lru_gen_mm_walk to keep consistent with struct lru_gen_mm_state. Note that seq is not always up to date with max_seq from lru_gen_folio. No functional changes. Link: https://lkml.kernel.org/r/20240214060538.3524462-5-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Marco Elver
|
f6564fce25 |
mm, kmsan: fix infinite recursion due to RCU critical section
Alexander Potapenko writes in [1]: "For every memory access in the code
instrumented by KMSAN we call kmsan_get_metadata() to obtain the metadata
for the memory being accessed. For virtual memory the metadata pointers
are stored in the corresponding `struct page`, therefore we need to call
virt_to_page() to get them.
According to the comment in arch/x86/include/asm/page.h,
virt_to_page(kaddr) returns a valid pointer iff virt_addr_valid(kaddr) is
true, so KMSAN needs to call virt_addr_valid() as well.
To avoid recursion, kmsan_get_metadata() must not call instrumented code,
therefore ./arch/x86/include/asm/kmsan.h forks parts of
arch/x86/mm/physaddr.c to check whether a virtual address is valid or not.
But the introduction of rcu_read_lock() to pfn_valid() added instrumented
RCU API calls to virt_to_page_or_null(), which is called by
kmsan_get_metadata(), so there is an infinite recursion now. I do not
think it is correct to stop that recursion by doing
kmsan_enter_runtime()/kmsan_exit_runtime() in kmsan_get_metadata(): that
would prevent instrumented functions called from within the runtime from
tracking the shadow values, which might introduce false positives."
Fix the issue by switching pfn_valid() to the _sched() variant of
rcu_read_lock/unlock(), which does not require calling into RCU. Given
the critical section in pfn_valid() is very small, this is a reasonable
trade-off (with preemptible RCU).
KMSAN further needs to be careful to suppress calls into the scheduler,
which would be another source of recursion. This can be done by wrapping
the call to pfn_valid() into preempt_disable/enable_no_resched(). The
downside is that this sacrifices breaking scheduling guarantees; however,
a kernel compiled with KMSAN has already given up any performance
guarantees due to being heavily instrumented.
Note, KMSAN code already disables tracing via Makefile, and since mmzone.h
is included, it is not necessary to use the notrace variant, which is
generally preferred in all other cases.
Link: https://lkml.kernel.org/r/20240115184430.2710652-1-glider@google.com [1]
Link: https://lkml.kernel.org/r/20240118110022.2538350-1-elver@google.com
Fixes:
|
||
|
Kirill A. Shutemov
|
5e0a760b44 |
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
commit
|
||
|
Kirill A. Shutemov
|
fd37721803 |
mm, treewide: introduce NR_PAGE_ORDERS
NR_PAGE_ORDERS defines the number of page orders supported by the page allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total. NR_PAGE_ORDERS assists in defining arrays of page orders and allows for more natural iteration over them. [kirill.shutemov@linux.intel.com: fixup for kerneldoc warning] Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Li Zhijian
|
b805ab3c69 |
mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
Demotion can work well without CONFIG_NUMA_BALANCING. But the commit |
||
|
Kinsey Ho
|
745b13e647 |
mm/mglru: remove CONFIG_MEMCG
Remove CONFIG_MEMCG in a refactoring to improve code readability at the cost of a few bytes in struct lru_gen_folio per node when CONFIG_MEMCG=n. Link: https://lkml.kernel.org/r/20231227141205.2200125-4-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kinsey Ho
|
61dd3f246b |
mm/mglru: add CONFIG_LRU_GEN_WALKS_MMU
Add CONFIG_LRU_GEN_WALKS_MMU such that if disabled, the code that walks page tables to promote pages into the youngest generation will not be built. Also improves code readability by adding two helper functions get_mm_state() and get_next_mm(). Link: https://lkml.kernel.org/r/20231227141205.2200125-3-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Charan Teja Kalla
|
5ec8e8ea8b |
mm/sparsemem: fix race in accessing memory_section->usage
The below race is observed on a PFN which falls into the device memory
region with the system memory configuration where PFN's are such that
[ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL]. Since normal zone start and end
pfn contains the device memory PFN's as well, the compaction triggered
will try on the device memory PFN's too though they end up in NOP(because
pfn_to_online_page() returns NULL for ZONE_DEVICE memory sections). When
from other core, the section mappings are being removed for the
ZONE_DEVICE region, that the PFN in question belongs to, on which
compaction is currently being operated is resulting into the kernel crash
with CONFIG_SPASEMEM_VMEMAP enabled. The crash logs can be seen at [1].
compact_zone() memunmap_pages
------------- ---------------
__pageblock_pfn_to_page
......
(a)pfn_valid():
valid_section()//return true
(b)__remove_pages()->
sparse_remove_section()->
section_deactivate():
[Free the array ms->usage and set
ms->usage = NULL]
pfn_section_valid()
[Access ms->usage which
is NULL]
NOTE: From the above it can be said that the race is reduced to between
the pfn_valid()/pfn_section_valid() and the section deactivate with
SPASEMEM_VMEMAP enabled.
The commit b943f045a9af("mm/sparse: fix kernel crash with
pfn_section_valid check") tried to address the same problem by clearing
the SECTION_HAS_MEM_MAP with the expectation of valid_section() returns
false thus ms->usage is not accessed.
Fix this issue by the below steps:
a) Clear SECTION_HAS_MEM_MAP before freeing the ->usage.
b) RCU protected read side critical section will either return NULL
when SECTION_HAS_MEM_MAP is cleared or can successfully access ->usage.
c) Free the ->usage with kfree_rcu() and set ms->usage = NULL. No
attempt will be made to access ->usage after this as the
SECTION_HAS_MEM_MAP is cleared thus valid_section() return false.
Thanks to David/Pavan for their inputs on this patch.
[1] https://lore.kernel.org/linux-mm/994410bb-89aa-d987-1f50-f514903c55aa@quicinc.com/
On Snapdragon SoC, with the mentioned memory configuration of PFN's as
[ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL], we are able to see bunch of
issues daily while testing on a device farm.
For this particular issue below is the log. Though the below log is
not directly pointing to the pfn_section_valid(){ ms->usage;}, when we
loaded this dump on T32 lauterbach tool, it is pointing.
[ 540.578056] Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000
[ 540.578068] Mem abort info:
[ 540.578070] ESR = 0x0000000096000005
[ 540.578073] EC = 0x25: DABT (current EL), IL = 32 bits
[ 540.578077] SET = 0, FnV = 0
[ 540.578080] EA = 0, S1PTW = 0
[ 540.578082] FSC = 0x05: level 1 translation fault
[ 540.578085] Data abort info:
[ 540.578086] ISV = 0, ISS = 0x00000005
[ 540.578088] CM = 0, WnR = 0
[ 540.579431] pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBSBTYPE=--)
[ 540.579436] pc : __pageblock_pfn_to_page+0x6c/0x14c
[ 540.579454] lr : compact_zone+0x994/0x1058
[ 540.579460] sp : ffffffc03579b510
[ 540.579463] x29: ffffffc03579b510 x28: 0000000000235800 x27:000000000000000c
[ 540.579470] x26: 0000000000235c00 x25: 0000000000000068 x24:ffffffc03579b640
[ 540.579477] x23: 0000000000000001 x22: ffffffc03579b660 x21:0000000000000000
[ 540.579483] x20: 0000000000235bff x19: ffffffdebf7e3940 x18:ffffffdebf66d140
[ 540.579489] x17: 00000000739ba063 x16: 00000000739ba063 x15:00000000009f4bff
[ 540.579495] x14: 0000008000000000 x13: 0000000000000000 x12:0000000000000001
[ 540.579501] x11: 0000000000000000 x10: 0000000000000000 x9 :ffffff897d2cd440
[ 540.579507] x8 : 0000000000000000 x7 : 0000000000000000 x6 :ffffffc03579b5b4
[ 540.579512] x5 : 0000000000027f25 x4 : ffffffc03579b5b8 x3 :0000000000000001
[ 540.579518] x2 : ffffffdebf7e3940 x1 : 0000000000235c00 x0 :0000000000235800
[ 540.579524] Call trace:
[ 540.579527] __pageblock_pfn_to_page+0x6c/0x14c
[ 540.579533] compact_zone+0x994/0x1058
[ 540.579536] try_to_compact_pages+0x128/0x378
[ 540.579540] __alloc_pages_direct_compact+0x80/0x2b0
[ 540.579544] __alloc_pages_slowpath+0x5c0/0xe10
[ 540.579547] __alloc_pages+0x250/0x2d0
[ 540.579550] __iommu_dma_alloc_noncontiguous+0x13c/0x3fc
[ 540.579561] iommu_dma_alloc+0xa0/0x320
[ 540.579565] dma_alloc_attrs+0xd4/0x108
[quic_charante@quicinc.com: use kfree_rcu() in place of synchronize_rcu(), per David]
Link: https://lkml.kernel.org/r/1698403778-20938-1-git-send-email-quic_charante@quicinc.com
Link: https://lkml.kernel.org/r/1697202267-23600-1-git-send-email-quic_charante@quicinc.com
Fixes:
|
||
|
Andrew Morton
|
a721aeac8b | sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes | ||
|
Yu Zhao
|
4376807bf2 |
mm/mglru: reclaim offlined memcgs harder
In the effort to reduce zombie memcgs [1], it was discovered that the
memcg LRU doesn't apply enough pressure on offlined memcgs. Specifically,
instead of rotating them to the tail of the current generation
(MEMCG_LRU_TAIL) for a second attempt, it moves them to the next
generation (MEMCG_LRU_YOUNG) after the first attempt.
Not applying enough pressure on offlined memcgs can cause them to build
up, and this can be particularly harmful to memory-constrained systems.
On Pixel 8 Pro, launching apps for 50 cycles:
Before After Change
Zombie memcgs 45 35 -22%
[1] https://lore.kernel.org/CABdmKX2M6koq4Q0Cmp_-=wbP0Qa190HdEGGaHfxNS05gAkUtPA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-4-yuzhao@google.com
Fixes:
|
||
|
Yu Zhao
|
8aa4206179 |
mm/mglru: respect min_ttl_ms with memcgs
While investigating kswapd "consuming 100% CPU" [1] (also see "mm/mglru:
try to stop at high watermarks"), it was discovered that the memcg LRU can
breach the thrashing protection imposed by min_ttl_ms.
Before the memcg LRU:
kswapd()
shrink_node_memcgs()
mem_cgroup_iter()
inc_max_seq() // always hit a different memcg
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
After the memcg LRU:
kswapd()
shrink_many()
restart:
iterate the memcg LRU:
inc_max_seq() // occasionally hit the same memcg
if raced with lru_gen_rotate_memcg():
goto restart
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
Specifically, when the restart happens in shrink_many(), it needs to stick
with the (memcg LRU) generation it began with. In other words, it should
neither re-read memcg_lru->seq nor age an lruvec of a different
generation. Otherwise it can hit the same memcg multiple times without
giving lru_gen_age_node() a chance to check the timestamp of that memcg's
oldest generation (against min_ttl_ms).
[1] https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-3-yuzhao@google.com
Fixes:
|
||
|
Nhat Pham
|
b5ba474f3f |
zswap: shrink zswap pool based on memory pressure
Currently, we only shrink the zswap pool when the user-defined limit is hit. This means that if we set the limit too high, cold data that are unlikely to be used again will reside in the pool, wasting precious memory. It is hard to predict how much zswap space will be needed ahead of time, as this depends on the workload (specifically, on factors such as memory access patterns and compressibility of the memory pages). This patch implements a memcg- and NUMA-aware shrinker for zswap, that is initiated when there is memory pressure. The shrinker does not have any parameter that must be tuned by the user, and can be opted in or out on a per-memcg basis. Furthermore, to make it more robust for many workloads and prevent overshrinking (i.e evicting warm pages that might be refaulted into memory), we build in the following heuristics: * Estimate the number of warm pages residing in zswap, and attempt to protect this region of the zswap LRU. * Scale the number of freeable objects by an estimate of the memory saving factor. The better zswap compresses the data, the fewer pages we will evict to swap (as we will otherwise incur IO for relatively small memory saving). * During reclaim, if the shrinker encounters a page that is also being brought into memory, the shrinker will cautiously terminate its shrinking action, as this is a sign that it is touching the warmer region of the zswap LRU. As a proof of concept, we ran the following synthetic benchmark: build the linux kernel in a memory-limited cgroup, and allocate some cold data in tmpfs to see if the shrinker could write them out and improved the overall performance. Depending on the amount of cold data generated, we observe from 14% to 35% reduction in kernel CPU time used in the kernel builds. [nphamcs@gmail.com: check shrinker enablement early, use less costly stat flushing] Link: https://lkml.kernel.org/r/20231206194456.3234203-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20231130194023.4102148-7-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Chris Li <chrisl@kernel.org> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Li Zhijian
|
23e9f01389 |
mm/vmstat: move pgdemote_* to per-node stats
Demotion will migrate pages across nodes. Previously, only the global demotion statistics were accounted for. Changed them to per-node statistics, making it easier to observe where demotion occurs on each node. This will help to identify which nodes are under pressure. This patch also make pgdemote_* behind CONFIG_NUMA_BALANCING, since demotion is not available for !CONFIG_NUMA_BALANCING With this patch, here is a sample where node0 node1 are DRAM, node3 is PMEM: Global stats: $ grep demote /proc/vmstat pgdemote_kswapd 254288 pgdemote_direct 113497 pgdemote_khugepaged 0 Per-node stats: $ grep demote /sys/devices/system/node/node0/vmstat # demotion source pgdemote_kswapd 68454 pgdemote_direct 83431 pgdemote_khugepaged 0 $ grep demote /sys/devices/system/node/node1/vmstat # demotion source pgdemote_kswapd 185834 pgdemote_direct 30066 pgdemote_khugepaged 0 $ grep demote /sys/devices/system/node/node3/vmstat # demotion target pgdemote_kswapd 0 pgdemote_direct 0 pgdemote_khugepaged 0 Link: https://lkml.kernel.org/r/20231103031450.1456523-1-lizhijian@fujitsu.com Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> Acked-by: "Huang, Ying" <ying.huang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Huang Ying
|
6ccdcb6d3a |
mm, pcp: reduce detecting time of consecutive high order page freeing
In current PCP auto-tuning design, if the number of pages allocated is much more than that of pages freed on a CPU, the PCP high may become the maximal value even if the allocating/freeing depth is small, for example, in the sender of network workloads. If a CPU was used as sender originally, then it is used as receiver after context switching, we need to fill the whole PCP with maximal high before triggering PCP draining for consecutive high order freeing. This will hurt the performance of some network workloads. To solve the issue, in this patch, we will track the consecutive page freeing with a counter in stead of relying on PCP draining. So, we can detect consecutive page freeing much earlier. On a 2-socket Intel server with 128 logical CPU, we tested SCTP_STREAM_MANY test case of netperf test suite with 64-pair processes. With the patch, the network bandwidth improves 5.0%. This restores the performance drop caused by PCP auto-tuning. Link: https://lkml.kernel.org/r/20231016053002.756205-10-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Huang Ying
|
57c0419c5f |
mm, pcp: decrease PCP high if free pages < high watermark
One target of PCP is to minimize pages in PCP if the system free pages is too few. To reach that target, when page reclaiming is active for the zone (ZONE_RECLAIM_ACTIVE), we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. But this may be too late because the background page reclaiming may introduce latency for some workloads. So, in this patch, during page allocation we will detect whether the number of free pages of the zone is below high watermark. If so, we will stop increasing PCP high in allocating path, decrease PCP high and free some pages in freeing path. With this, we can reduce the possibility of the premature background page reclaiming caused by too large PCP. The high watermark checking is done in allocating path to reduce the overhead in hotter freeing path. Link: https://lkml.kernel.org/r/20231016053002.756205-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Huang Ying
|
90b41691b9 |
mm: add framework for PCP high auto-tuning
The page allocation performance requirements of different workloads are usually different. So, we need to tune PCP (per-CPU pageset) high to optimize the workload page allocation performance. Now, we have a system wide sysctl knob (percpu_pagelist_high_fraction) to tune PCP high by hand. But, it's hard to find out the best value by hand. And one global configuration may not work best for the different workloads that run on the same system. One solution to these issues is to tune PCP high of each CPU automatically. This patch adds the framework for PCP high auto-tuning. With it, pcp->high of each CPU will be changed automatically by tuning algorithm at runtime. The minimal high (pcp->high_min) is the original PCP high value calculated based on the low watermark pages. While the maximal high (pcp->high_max) is the PCP high value when percpu_pagelist_high_fraction sysctl knob is set to MIN_PERCPU_PAGELIST_HIGH_FRACTION. That is, the maximal pcp->high that can be set via sysctl knob by hand. It's possible that PCP high auto-tuning doesn't work well for some workloads. So, when PCP high is tuned by hand via the sysctl knob, the auto-tuning will be disabled. The PCP high set by hand will be used instead. This patch only adds the framework, so pcp->high will be set to pcp->high_min (original default) always. We will add actual auto-tuning algorithm in the following patches in the series. Link: https://lkml.kernel.org/r/20231016053002.756205-7-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Huang Ying
|
c0a242394c |
mm, page_alloc: scale the number of pages that are batch allocated
When a task is allocating a large number of order-0 pages, it may acquire the zone->lock multiple times allocating pages in batches. This may unnecessarily contend on the zone lock when allocating very large number of pages. This patch adapts the size of the batch based on the recent pattern to scale the batch size for subsequent allocations. On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances in parallel (each with `make -j 28`) in 8 cgroup. This simulates the kbuild server that is used by 0-Day kbuild service. With the patch, the cycles% of the spinlock contention (mostly for zone lock) decreases from 12.6% to 11.0% (with PCP size == 367). Link: https://lkml.kernel.org/r/20231016053002.756205-6-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Suggested-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Huang Ying
|
362d37a106 |
mm, pcp: reduce lock contention for draining high-order pages
In commit
|
||
|
Huang Ying
|
ca71fe1ad9 |
mm, pcp: avoid to drain PCP when process exit
Patch series "mm: PCP high auto-tuning", v3.
The page allocation performance requirements of different workloads are
often different. So, we need to tune the PCP (Per-CPU Pageset) high on
each CPU automatically to optimize the page allocation performance.
The list of patches in series is as follows,
[1/9] mm, pcp: avoid to drain PCP when process exit
[2/9] cacheinfo: calculate per-CPU data cache size
[3/9] mm, pcp: reduce lock contention for draining high-order pages
[4/9] mm: restrict the pcp batch scale factor to avoid too long latency
[5/9] mm, page_alloc: scale the number of pages that are batch allocated
[6/9] mm: add framework for PCP high auto-tuning
[7/9] mm: tune PCP high automatically
[8/9] mm, pcp: decrease PCP high if free pages < high watermark
[9/9] mm, pcp: reduce detecting time of consecutive high order page freeing
Patch [1/9], [2/9], [3/9] optimize the PCP draining for consecutive
high-order pages freeing.
Patch [4/9], [5/9] optimize batch freeing and allocating.
Patch [6/9], [7/9], [8/9] implement and optimize a PCP high
auto-tuning method.
Patch [9/9] optimize the PCP draining for consecutive high order page
freeing based on PCP high auto-tuning.
The test results for patches with performance impact are as follows,
kbuild
======
On a 2-socket Intel server with 224 logical CPU, we run 8 kbuild instances
in parallel (each with `make -j 28`) in 8 cgroup. This simulates the
kbuild server that is used by 0-Day kbuild service.
build time lock contend% free_high alloc_zone
---------- ---------- --------- ----------
base 100.0 14.0 100.0 100.0
patch1 99.5 12.8 19.5 95.6
patch3 99.4 12.6 7.1 95.6
patch5 98.6 11.0 8.1 97.1
patch7 95.1 0.5 2.8 15.6
patch9 95.0 1.0 8.8 20.0
The PCP draining optimization (patch [1/9], [3/9]) and PCP batch
allocation optimization (patch [5/9]) reduces zone lock contention a
little. The PCP high auto-tuning (patch [7/9], [9/9]) reduces build time
visibly. Where the tuning target: the number of pages allocated from zone
reduces greatly. So, the zone contention cycles% reduces greatly.
With PCP tuning patches (patch [7/9], [9/9]), the average used memory
during test increases up to 18.4% because more pages are cached in PCP.
But at the end of the test, the number of the used memory decreases to the
same level as that of the base patch. That is, the pages cached in PCP
will be released to zone after not being used actively.
netperf SCTP_STREAM_MANY
========================
On a 2-socket Intel server with 128 logical CPU, we tested
SCTP_STREAM_MANY test case of netperf test suite with 64-pair processes.
score lock contend% free_high alloc_zone cache miss rate%
----- ---------- --------- ---------- ----------------
base 100.0 2.1 100.0 100.0 1.3
patch1 99.4 2.1 99.4 99.4 1.3
patch3 106.4 1.3 13.3 106.3 1.3
patch5 106.0 1.2 13.2 105.9 1.3
patch7 103.4 1.9 6.7 90.3 7.6
patch9 108.6 1.3 13.7 108.6 1.3
The PCP draining optimization (patch [1/9]+[3/9]) improves performance.
The PCP high auto-tuning (patch [7/9]) reduces performance a little
because PCP draining cannot be triggered in time sometimes. So, the cache
miss rate% increases. The further PCP draining optimization (patch [9/9])
based on PCP tuning restore the performance.
lmbench3 UNIX (AF_UNIX)
=======================
On a 2-socket Intel server with 128 logical CPU, we tested UNIX
(AF_UNIX socket) test case of lmbench3 test suite with 16-pair
processes.
score lock contend% free_high alloc_zone cache miss rate%
----- ---------- --------- ---------- ----------------
base 100.0 51.4 100.0 100.0 0.2
patch1 116.8 46.1 69.5 104.3 0.2
patch3 199.1 21.3 7.0 104.9 0.2
patch5 200.0 20.8 7.1 106.9 0.3
patch7 191.6 19.9 6.8 103.8 2.8
patch9 193.4 21.7 7.0 104.7 2.1
The PCP draining optimization (patch [1/9], [3/9]) improves performance
much. The PCP tuning (patch [7/9]) reduces performance a little because
PCP draining cannot be triggered in time sometimes. The further PCP
draining optimization (patch [9/9]) based on PCP tuning restores the
performance partly.
The patchset adds several fields in struct per_cpu_pages. The struct
layout before/after the patchset is as follows,
base
====
struct per_cpu_pages {
spinlock_t lock; /* 0 4 */
int count; /* 4 4 */
int high; /* 8 4 */
int batch; /* 12 4 */
short int free_factor; /* 16 2 */
short int expire; /* 18 2 */
/* XXX 4 bytes hole, try to pack */
struct list_head lists[13]; /* 24 208 */
/* size: 256, cachelines: 4, members: 7 */
/* sum members: 228, holes: 1, sum holes: 4 */
/* padding: 24 */
} __attribute__((__aligned__(64)));
patched
=======
struct per_cpu_pages {
spinlock_t lock; /* 0 4 */
int count; /* 4 4 */
int high; /* 8 4 */
int high_min; /* 12 4 */
int high_max; /* 16 4 */
int batch; /* 20 4 */
u8 flags; /* 24 1 */
u8 alloc_factor; /* 25 1 */
u8 expire; /* 26 1 */
/* XXX 1 byte hole, try to pack */
short int free_count; /* 28 2 */
/* XXX 2 bytes hole, try to pack */
struct list_head lists[13]; /* 32 208 */
/* size: 256, cachelines: 4, members: 11 */
/* sum members: 237, holes: 2, sum holes: 3 */
/* padding: 16 */
} __attribute__((__aligned__(64)));
The size of the struct doesn't changed with the patchset.
This patch (of 9):
In commit
|
||
|
Vlastimil Babka
|
3dfbb555c9 |
mm, vmscan: remove ISOLATE_UNMAPPED
This isolate_mode_t flag is effectively unused since
|
||
|
Miaohe Lin
|
8f21912a4b |
mm: remove obsolete comment above struct per_cpu_pages
Since commit
|
||
|
Linus Torvalds
|
6e17c6de3d |
- Yosry Ahmed brought back some cgroup v1 stats in OOM logs.
- Yosry has also eliminated cgroup's atomic rstat flushing. - Nhat Pham adds the new cachestat() syscall. It provides userspace with the ability to query pagecache status - a similar concept to mincore() but more powerful and with improved usability. - Mel Gorman provides more optimizations for compaction, reducing the prevalence of page rescanning. - Lorenzo Stoakes has done some maintanance work on the get_user_pages() interface. - Liam Howlett continues with cleanups and maintenance work to the maple tree code. Peng Zhang also does some work on maple tree. - Johannes Weiner has done some cleanup work on the compaction code. - David Hildenbrand has contributed additional selftests for get_user_pages(). - Thomas Gleixner has contributed some maintenance and optimization work for the vmalloc code. - Baolin Wang has provided some compaction cleanups, - SeongJae Park continues maintenance work on the DAMON code. - Huang Ying has done some maintenance on the swap code's usage of device refcounting. - Christoph Hellwig has some cleanups for the filemap/directio code. - Ryan Roberts provides two patch series which yield some rationalization of the kernel's access to pte entries - use the provided APIs rather than open-coding accesses. - Lorenzo Stoakes has some fixes to the interaction between pagecache and directio access to file mappings. - John Hubbard has a series of fixes to the MM selftesting code. - ZhangPeng continues the folio conversion campaign. - Hugh Dickins has been working on the pagetable handling code, mainly with a view to reducing the load on the mmap_lock. - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from 128 to 8. - Domenico Cerasuolo has improved the zswap reclaim mechanism by reorganizing the LRU management. - Matthew Wilcox provides some fixups to make gfs2 work better with the buffer_head code. - Vishal Moola also has done some folio conversion work. - Matthew Wilcox has removed the remnants of the pagevec code - their functionality is migrated over to struct folio_batch. -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZJejewAKCRDdBJ7gKXxA joggAPwKMfT9lvDBEUnJagY7dbDPky1cSYZdJKxxM2cApGa42gEA6Cl8HRAWqSOh J0qXCzqaaN8+BuEyLGDVPaXur9KirwY= =B7yQ -----END PGP SIGNATURE----- Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull mm updates from Andrew Morton: - Yosry Ahmed brought back some cgroup v1 stats in OOM logs - Yosry has also eliminated cgroup's atomic rstat flushing - Nhat Pham adds the new cachestat() syscall. It provides userspace with the ability to query pagecache status - a similar concept to mincore() but more powerful and with improved usability - Mel Gorman provides more optimizations for compaction, reducing the prevalence of page rescanning - Lorenzo Stoakes has done some maintanance work on the get_user_pages() interface - Liam Howlett continues with cleanups and maintenance work to the maple tree code. Peng Zhang also does some work on maple tree - Johannes Weiner has done some cleanup work on the compaction code - David Hildenbrand has contributed additional selftests for get_user_pages() - Thomas Gleixner has contributed some maintenance and optimization work for the vmalloc code - Baolin Wang has provided some compaction cleanups, - SeongJae Park continues maintenance work on the DAMON code - Huang Ying has done some maintenance on the swap code's usage of device refcounting - Christoph Hellwig has some cleanups for the filemap/directio code - Ryan Roberts provides two patch series which yield some rationalization of the kernel's access to pte entries - use the provided APIs rather than open-coding accesses - Lorenzo Stoakes has some fixes to the interaction between pagecache and directio access to file mappings - John Hubbard has a series of fixes to the MM selftesting code - ZhangPeng continues the folio conversion campaign - Hugh Dickins has been working on the pagetable handling code, mainly with a view to reducing the load on the mmap_lock - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from 128 to 8 - Domenico Cerasuolo has improved the zswap reclaim mechanism by reorganizing the LRU management - Matthew Wilcox provides some fixups to make gfs2 work better with the buffer_head code - Vishal Moola also has done some folio conversion work - Matthew Wilcox has removed the remnants of the pagevec code - their functionality is migrated over to struct folio_batch * tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits) mm/hugetlb: remove hugetlb_set_page_subpool() mm: nommu: correct the range of mmap_sem_read_lock in task_mem() hugetlb: revert use of page_cache_next_miss() Revert "page cache: fix page_cache_next/prev_miss off by one" mm/vmscan: fix root proactive reclaim unthrottling unbalanced node mm: memcg: rename and document global_reclaim() mm: kill [add|del]_page_to_lru_list() mm: compaction: convert to use a folio in isolate_migratepages_block() mm: zswap: fix double invalidate with exclusive loads mm: remove unnecessary pagevec includes mm: remove references to pagevec mm: rename invalidate_mapping_pagevec to mapping_try_invalidate mm: remove struct pagevec net: convert sunrpc from pagevec to folio_batch i915: convert i915_gpu_error to use a folio_batch pagevec: rename fbatch_count() mm: remove check_move_unevictable_pages() drm: convert drm_gem_put_pages() to use a folio_batch i915: convert shmem_sg_free_table() to use a folio_batch scatterlist: add sg_set_folio() ... |
||
|
Yosry Ahmed
|
1bc545bff4 |
mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
When memory.reclaim was introduced, it became the first case where cgroup_reclaim() is true for the root cgroup. Johannes concluded [1] that for most cases this is okay, except for one case. Historically, kswapd would throttle reclaim on a node if a lot of pages marked for reclaim are under writeback (aka the node is congested). This occurred by setting LRUVEC_CONGESTED bit in lruvec->flags. The bit would be cleared when the node is balanced. Similarly, cgroup reclaim would set the same bit when an lruvec is congested, and clear it on the way out of reclaim (to throttle local reclaimers). Before the introduction of memory.reclaim, the root memcg was the only target of kswapd reclaim, and non-root memcgs were the only targets of cgroup reclaim, so they would never interfere. Using the same bit for both was fine. After memory.reclaim, it is possible for cgroup reclaim on the root cgroup to clear the bit set by kswapd. This would result in reclaim on the node to be unthrottled before the node is balanced. Fix this by introducing separate bits for cgroup-level and node-level congestion. kswapd can unthrottle an lruvec that is marked as congested by cgroup reclaim (as the entire node should no longer be congested), but not vice versa (to prevent premature unthrottling before the entire node is balanced). [1]https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/ Link: https://lkml.kernel.org/r/20230621023101.432780-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/ Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Vishal Moola (Oracle)
|
28fb54f6a2 |
mmzone: introduce folio_migratetype()
Introduce folio_migratetype() as a folio equivalent for get_pageblock_migratetype(). This function intends to return the migratetype the folio is located in, hence the name choice. Link: https://lkml.kernel.org/r/20230614021312.34085-3-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Vishal Moola (Oracle)
|
708ff4914d |
mmzone: introduce folio_is_zone_movable()
Patch series "Replace is_longterm_pinnable_page()", v2. This patchset introduces some more helper functions for the folio conversions, and converts all callers of is_longterm_pinnable_page() to use folios. This patch (of 5): Introduce folio_is_zone_movable() to act as a folio equivalent for is_zone_movable_page(). This is to assist in later folio conversions. Link: https://lkml.kernel.org/r/20230614021312.34085-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20230614021312.34085-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
T.J. Alumbaugh
|
5c7e7a0d79 |
mm: multi-gen LRU: cleanup lru_gen_soft_reclaim()
lru_gen_soft_reclaim() gets the lruvec from the memcg and node ID to keep a cleaner interface on the caller side. Link: https://lkml.kernel.org/r/20230522112058.2965866-2-talumbau@google.com Signed-off-by: T.J. Alumbaugh <talumbau@google.com> Reviewed-by: Yuanchu Xie <yuanchu@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
e95d372c4c |
mm: page_alloc: move sysctls into it own fils
This moves all page alloc related sysctls to its own file, as part of the kernel/sysctl.c spring cleaning, also move some functions declarations from mm.h into internal.h. Link: https://lkml.kernel.org/r/20230516063821.121844-13-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kirill A. Shutemov
|
dcdfdd40fa |
mm: Add support for unaccepted memory
UEFI Specification version 2.9 introduces the concept of memory
acceptance. Some Virtual Machine platforms, such as Intel TDX or AMD
SEV-SNP, require memory to be accepted before it can be used by the
guest. Accepting happens via a protocol specific to the Virtual Machine
platform.
There are several ways the kernel can deal with unaccepted memory:
1. Accept all the memory during boot. It is easy to implement and it
doesn't have runtime cost once the system is booted. The downside is
very long boot time.
Accept can be parallelized to multiple CPUs to keep it manageable
(i.e. via DEFERRED_STRUCT_PAGE_INIT), but it tends to saturate
memory bandwidth and does not scale beyond the point.
2. Accept a block of memory on the first use. It requires more
infrastructure and changes in page allocator to make it work, but
it provides good boot time.
On-demand memory accept means latency spikes every time kernel steps
onto a new memory block. The spikes will go away once workload data
set size gets stabilized or all memory gets accepted.
3. Accept all memory in background. Introduce a thread (or multiple)
that gets memory accepted proactively. It will minimize time the
system experience latency spikes on memory allocation while keeping
low boot time.
This approach cannot function on its own. It is an extension of #2:
background memory acceptance requires functional scheduler, but the
page allocator may need to tap into unaccepted memory before that.
The downside of the approach is that these threads also steal CPU
cycles and memory bandwidth from the user's workload and may hurt
user experience.
Implement #1 and #2 for now. #2 is the default. Some workloads may want
to use #1 with accept_memory=eager in kernel command line. #3 can be
implemented later based on user's demands.
Support of unaccepted memory requires a few changes in core-mm code:
- memblock accepts memory on allocation. It serves early boot memory
allocations and doesn't limit them to pre-accepted pool of memory.
- page allocator accepts memory on the first allocation of the page.
When kernel runs out of accepted memory, it accepts memory until the
high watermark is reached. It helps to minimize fragmentation.
EFI code will provide two helpers if the platform supports unaccepted
memory:
- accept_memory() makes a range of physical addresses accepted.
- range_contains_unaccepted_memory() checks anything within the range
of physical addresses requires acceptance.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mike Rapoport <rppt@linux.ibm.com> # memblock
Link: https://lore.kernel.org/r/20230606142637.5171-2-kirill.shutemov@linux.intel.com
|
||
|
Kalesh Singh
|
7f63cf2d9b |
mm: Multi-gen LRU: remove wait_event_killable()
Android 14 and later default to MGLRU [1] and field telemetry showed occasional long tail latency (>100ms) in the reclaim path. Tracing revealed priority inversion in the reclaim path. In try_to_inc_max_seq(), when high priority tasks were blocked on wait_event_killable(), the preemption of the low priority task to call wake_up_all() caused those high priority tasks to wait longer than necessary. In general, this problem is not different from others of its kind, e.g., one caused by mutex_lock(). However, it is specific to MGLRU because it introduced the new wait queue lruvec->mm_state.wait. The purpose of this new wait queue is to avoid the thundering herd problem. If many direct reclaimers rush into try_to_inc_max_seq(), only one can succeed, i.e., the one to wake up the rest, and the rest who failed might cause premature OOM kills if they do not wait. So far there is no evidence supporting this scenario, based on how often the wait has been hit. And this begs the question how useful the wait queue is in practice. Based on Minchan's recommendation, which is in line with his commit |
||
|
Mike Rapoport (IBM)
|
62f31bd4dc |
mm: move free_area_empty() to mm/internal.h
The free_area_empty() helper is only used inside mm/ so move it there to reduce noise in include/linux/mmzone.h Link: https://lkml.kernel.org/r/20230326160215.2674531-1-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kirill A. Shutemov
|
3f6dac0fd1 |
mm/page_alloc: make deferred page init free pages in MAX_ORDER blocks
Normal page init path frees pages during the boot in MAX_ORDER chunks, but deferred page init path does it in pageblock blocks. Change deferred page init path to work in MAX_ORDER blocks. For cases when MAX_ORDER is larger than pageblock, set migrate type to MIGRATE_MOVABLE for all pageblocks covered by the page. Link: https://lkml.kernel.org/r/20230321002415.20843-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Mike Rapoport (IBM)
|
5d671eb4ef |
mm: move get_page_from_free_area() to mm/page_alloc.c
The get_page_from_free_area() helper is only used in mm/page_alloc.c so move it there to reduce noise in include/linux/mmzone.h Link: https://lkml.kernel.org/r/20230319114214.2133332-1-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kirill A. Shutemov
|
23baf831a3 |
mm, treewide: redefine MAX_ORDER sanely
MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |