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Running my yearly branch profiler to see where likely/unlikely annotation
may be added or removed, I discovered this:
correct incorrect % Function File Line
------- --------- - -------- ---- ----
0 457918 100 page_try_dup_anon_rmap rmap.h 264
[..]
458021 0 0 page_try_dup_anon_rmap rmap.h 265
I thought it was interesting that line 264 of rmap.h had a 100% incorrect
annotation, but the line directly below it was 100% correct. Looking at the
code:
if (likely(!is_device_private_page(page) &&
unlikely(page_needs_cow_for_dma(vma, page))))
It didn't make sense. The "likely()" was around the entire if statement
(not just the "!is_device_private_page(page)"), which also included the
"unlikely()" portion of that if condition.
If the unlikely portion is unlikely to be true, that would make the entire
if condition unlikely to be true, so it made no sense at all to say the
entire if condition is true.
What is more likely to be likely is just the first part of the if statement
before the && operation. It's likely to be a misplaced parenthesis. And
after making the if condition broken into a likely() && unlikely(), both
now appear to be correct!
Link: https://lkml.kernel.org/r/20231201145936.5ddfdb50@gandalf.local.home
Fixes:fb3d824d1a46c ("mm/rmap: split page_dup_rmap() into page_dup_file_rmap() and page_try_dup_anon_rmap()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: cleanup and use more folio in page fault", v3.
Rename page_copy_prealloc() to folio_prealloc(), which is used by more
functions, also do more folio conversion in page fault.
This patch (of 5):
Since ksm only support normal page, no swapout/in for ksm large folio too,
add large folio check in ksm_might_need_to_copy(), also convert
page->index to folio->index as page->index is going away.
Then convert ksm_might_need_to_copy() to use more folio api to save nine
compound_head() calls, short 'address' to reduce max-line-length.
Link: https://lkml.kernel.org/r/20231118023232.1409103-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20231118023232.1409103-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/damon: let users feed and tame/auto-tune DAMOS".
Introduce Aim-oriented Feedback-driven DAMOS Aggressiveness Auto-tuning.
It makes DAMOS self-tuned with periodic simple user feedback.
Background: DAMOS Control Difficulty
====================================
DAMOS helps users easily implement access pattern aware system operations.
However, controlling DAMOS in the wild is not that easy.
The basic way for DAMOS control is specifying the target access pattern.
In this approach, the user is assumed to well understand the access
pattern and the characteristics of the system and the workloads. Though
there are useful tools for that, it takes time and effort depending on the
complexity and the dynamicity of the system and the workloads. After all,
the access pattern consists of three ranges, namely the size, the access
rate, and the age of the regions. It means users need to tune six
parameters, which is anyway not a simple task.
One of the worst cases would be DAMOS being too aggressive like a
berserker, and therefore consuming too much system resource and making
unwanted radical system operations. To let users avoid such cases, DAMOS
allows users to set the upper-limit of the schemes' aggressiveness, namely
DAMOS quota. DAMOS further provides its best-effort under the limit by
prioritizing regions based on the access pattern of the regions. For
example, users can ask DAMOS to page out up to 100 MiB of memory regions
per second. Then DAMOS pages out regions that are not accessed for a
longer time (colder) first under the limit. This allows users to set the
target access pattern a bit naive with wider ranges, and focus on tuning
only one parameter, the quota. In other words, the number of parameters
to tune can be reduced from six to one.
Still, however, the optimum value for the quota depends on the system and
the workloads' characteristics, so not that simple. The number of
parameters to tune can also increase again if the user needs to run
multiple schemes.
Aim-oriented Feedback-driven DAMOS Aggressiveness Auto Tuning
=============================================================
Users would use DAMOS since they want to achieve something with it. They
will likely have measurable metrics representing the achievement and the
target number of the metric like SLO, and continuously measure that
anyway. While the additional cost of getting the information is nearly
zero, it could be useful for DAMOS to understand how appropriate its
current aggressiveness is set, and adjust it on its own to make the metric
value more close to the target.
Based on this idea, we introduce a new way of tuning DAMOS with nearly
zero additional effort, namely Aim-oriented Feedback-driven DAMOS
Aggressiveness Auto Tuning. It asks users to provide feedback
representing how well DAMOS is doing relative to the users' aim. Then
DAMOS adjusts its aggressiveness, specifically the quota that provides
the best effort result under the limit, based on the current level of
the aggressiveness and the users' feedback.
Implementation
==============
The implementation asks users to represent the feedback with score
numbers. The scores could be anything including user-space specific
metrics including latency and throughput of special user-space workloads,
and system metrics including free memory ratio, memory pressure stall time
(PSI), and active to inactive LRU lists size ratio. The feedback scores
and the aggressiveness of the given DAMOS scheme are assumed to be
positively proportional, though. Selecting metrics of the assumption is
the users' responsibility.
The core logic uses the below simple feedback loop algorithm to calculate
the next aggressiveness level of the scheme from the current
aggressiveness level and the current feedback (target_score and
current_score). It calculates the compensation for next aggressiveness as
a proportion of current aggressiveness and distance to the target score.
As a result, it arrives at the near-goal state in a short time using big
steps when it's far from the goal, but avoids making unnecessarily radical
changes that could turn out to be a bad decision using small steps when
its near to the goal.
f(n) = max(1, f(n - 1) * ((target_score - current_score) / target_score + 1))
Note that the compensation value becomes negative when it's over
achieving the goal. That's why the feedback metric and the
aggressiveness of the scheme should be positively proportional. The
distance-adaptive speed manipulation is simply applied.
Example Use Cases
=================
If users want to reduce the memory footprint of the system as much as
possible as long as the time spent for handling the resulting memory
pressure is within a threshold, they could use DAMOS scheme that reclaims
cold memory regions aiming for a little level of memory pressure stall
time.
If users want the active/inactive LRU lists well balanced to reduce the
performance impact due to possible future memory pressure, they could use
two schemes. The first one would be set to locate hot pages in the active
LRU list, aiming for a specific active-to-inactive LRU list size ratio,
say, 70%. The second one would be to locate cold pages in the inactive
LRU list, aiming for a specific inactive-to-active LRU list size ratio,
say, 30%. Then, DAMOS will balance the two schemes based on the goal and
feedback.
This aim-oriented auto tuning could also be useful for general
balancing-required access aware system operations such as system memory
auto scaling[3] and tiered memory management[4]. These two example usages
are not what current DAMOS implementation is already supporting, but
require additional DAMOS action developments, though.
Evaluation: subtle memory pressure aiming proactive reclamation
===============================================================
To show if the implementation works as expected, we prepare four different
system configurations on AWS i3.metal instances. The first setup
(original) runs the workload without any DAMOS scheme. The second setup
(not-tuned) runs the workload with a virtual address space-based proactive
reclamation scheme that pages out memory regions that are not accessed for
five seconds or more. The third setup (offline-tuned) runs the same
proactive reclamation DAMOS scheme, but after making it tuned for each
workload offline, using our previous user-space driven automatic tuning
approach, namely DAMOOS[1]. The fourth and final setup (AFDAA) runs the
scheme that is the same as that of 'not-tuned' setup, but aims to keep
0.5% of 'some' memory pressure stall time (PSI) for the last 10 seconds
using the aiming-oriented auto tuning.
For each setup, we run realistic workloads from PARSEC3 and SPLASH-2X
benchmark suites. For each run, we measure RSS and runtime of the
workload, and 'some' memory pressure stall time (PSI) of the system. We
repeat the runs five times and use averaged measurements.
For simple comparison of the results, we normalize the measurements to
those of 'original'. In the case of the PSI, though, the measurement for
'original' was zero, so we normalize the value to that of 'not-tuned'
scheme's result. The normalized results are shown below.
Not-tuned Offline-tuned AFDAA
RSS 0.622688178226118 0.787950678944904 0.740093483278979
runtime 1.11767826657912 1.0564674983585 1.0910833880499
PSI 1 0.727521443794069 0.308498846350299
The 'not-tuned' scheme achieves about 38.7% memory saving but incur about
11.7% runtime slowdown. The 'offline-tuned' scheme achieves about 22.2%
memory saving with about 5.5% runtime slowdown. It also achieves about
28.2% memory pressure stall time saving. AFDAA achieves about 26% memory
saving with about 9.1% runtime slowdown. It also achieves about 69.1%
memory pressure stall time saving. We repeat this test multiple times,
and get consistent results. AFDAA is now integrated in our daily DAMON
performance test setup.
Apparently the aggressiveness of 'AFDAA' setup is somewhere between those
of 'not-tuned' and 'offline-tuned' setup, since its memory saving and
runtime overhead are between those of the other two setups. Actually we
set the memory pressure stall time goal aiming for this middle
aggressiveness. The difference in the two metrics are not significant,
though. However, it shows significant saving of the memory pressure stall
time, which was the goal of the auto-tuning, over the two variants.
Hence, we conclude the automatic tuning is working as expected.
Please note that the AFDAA setup is only for the evaluation, and
therefore intentionally set a bit aggressive. It might not be
appropriate for production environments.
The test code is also available[2], so you could reproduce it on your
system and workloads.
Patches Sequence
================
The first four patches implement the core logic and user interfaces for
the auto tuning. The first patch implements the core logic for the auto
tuning, and the API for DAMOS users in the kernel space. The second
patch implements basic file operations of DAMON sysfs directories and
files that will be used for setting the goals and providing the
feedback. The third patch connects the quota goals files inputs to the
DAMOS core logic. Finally the fourth patch implements a dedicated DAMOS
sysfs command for efficiently committing the quota goals feedback.
Two patches for simple tests of the logic and interfaces follow. The
fifth patch implements the core logic unit test. The sixth patch
implements a selftest for the DAMON Sysfs interface for the goals.
Finally, three patches for documentation follows. The seventh patch
documents the design of the feature. The eighth patch updates the API
doc for the new sysfs files. The final eighth patch updates the usage
document for the features.
References
==========
[1] DAOS paper:
https://www.amazon.science/publications/daos-data-access-aware-operating-system
[2] Evaluation code:
https://github.com/damonitor/damon-tests/commit/3f884e61193f0166b8724554b6d06b0c449a712d
[3] Memory auto scaling RFC idea:
https://lore.kernel.org/damon/20231112195114.61474-1-sj@kernel.org/
[4] DAMON-based tiered memory management RFC idea:
https://lore.kernel.org/damon/20231112195602.61525-1-sj@kernel.org/
This patch (of 9)
Users can effectively control the upper-limit aggressiveness of DAMOS
schemes using the quota feature. The quota provides best result under the
limit by prioritizing regions based on the access pattern. That said,
finding the best value, which could depend on dynamic characteristics of
the system and the workloads, is still challenging.
Implement a simple feedback-driven tuning mechanism and use it for
automatic tuning of DAMOS quota. The implementation allows users to
provide the feedback by setting a feedback score returning callback
function. Then DAMOS periodically calls the function back and adjusts the
quota based on the return value of the callback and current quota value.
Note that the absolute-value based time/size quotas still work as the
maximum hard limits of the scheme's aggressiveness. The feedback-driven
auto-tuned quota is applied only if it is not exceeding the manually set
maximum limits. Same for the scheme-target access pattern and filters
like other features.
[sj@kernel.org: document get_score_arg field of struct damos_quota]
Link: https://lkml.kernel.org/r/20231204170106.60992-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231130023652.50284-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231130023652.50284-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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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>
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Since zswap now writes back pages from memcg-specific LRUs, we now need a
new stat to show writebacks count for each memcg.
[nphamcs@gmail.com: rename ZSWP_WB to ZSWPWB]
Link: https://lkml.kernel.org/r/20231205193307.2432803-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-5-nphamcs@gmail.com
Suggested-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, we only have a single global LRU for zswap. This makes it
impossible to perform worload-specific shrinking - an memcg cannot
determine which pages in the pool it owns, and often ends up writing pages
from other memcgs. This issue has been previously observed in practice
and mitigated by simply disabling memcg-initiated shrinking:
https://lore.kernel.org/all/20230530232435.3097106-1-nphamcs@gmail.com/T/#u
This patch fully resolves the issue by replacing the global zswap LRU
with memcg- and NUMA-specific LRUs, and modify the reclaim logic:
a) When a store attempt hits an memcg limit, it now triggers a
synchronous reclaim attempt that, if successful, allows the new
hotter page to be accepted by zswap.
b) If the store attempt instead hits the global zswap limit, it will
trigger an asynchronous reclaim attempt, in which an memcg is
selected for reclaim in a round-robin-like fashion.
[nphamcs@gmail.com: use correct function for the onlineness check, use mem_cgroup_iter_break()]
Link: https://lkml.kernel.org/r/20231205195419.2563217-1-nphamcs@gmail.com
[nphamcs@gmail.com: drop the pool's reference at the end of the writeback step]
Link: https://lkml.kernel.org/r/20231206030627.4155634-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-4-nphamcs@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Co-developed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This patch implements a helper function that try to get a reference to an
memcg's css, as well as checking if it is online. This new function is
almost exactly the same as the existing mem_cgroup_tryget(), except for
the onlineness check. In the !CONFIG_MEMCG case, it always returns true,
analogous to mem_cgroup_tryget(). This is useful for e.g to the new zswap
writeback scheme, where we need to select the next online memcg as a
candidate for the global limit reclaim.
Link: https://lkml.kernel.org/r/20231130194023.4102148-3-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "workload-specific and memory pressure-driven zswap
writeback", v8.
There are currently several issues with zswap writeback:
1. There is only a single global LRU for zswap, making it impossible to
perform worload-specific shrinking - an memcg under memory pressure
cannot determine which pages in the pool it owns, and often ends up
writing pages from other memcgs. This issue has been previously
observed in practice and mitigated by simply disabling
memcg-initiated shrinking:
https://lore.kernel.org/all/20230530232435.3097106-1-nphamcs@gmail.com/T/#u
But this solution leaves a lot to be desired, as we still do not
have an avenue for an memcg to free up its own memory locked up in
the zswap pool.
2. 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 series solves these issues by separating the global zswap LRU
into per-memcg and per-NUMA LRUs, and performs workload-specific (i.e
memcg- and NUMA-aware) zswap writeback under memory pressure. The new
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.
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.
This patch (of 6):
The interface of list_lru is based on the assumption that the list node
and the data it represents belong to the same allocated on the correct
node/memcg. While this assumption is valid for existing slab objects LRU
such as dentries and inodes, it is undocumented, and rather inflexible for
certain potential list_lru users (such as the upcoming zswap shrinker and
the THP shrinker). It has caused us a lot of issues during our
development.
This patch changes list_lru interface so that the caller must explicitly
specify numa node and memcg when adding and removing objects. The old
list_lru_add() and list_lru_del() are renamed to list_lru_add_obj() and
list_lru_del_obj(), respectively.
It also extends the list_lru API with a new function, list_lru_putback,
which undoes a previous list_lru_isolate call. Unlike list_lru_add, it
does not increment the LRU node count (as list_lru_isolate does not
decrement the node count). list_lru_putback also allows for explicit
memcg and NUMA node selection.
Link: https://lkml.kernel.org/r/20231130194023.4102148-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-2-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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ma_wr_state was previously tracking the end of the node for writing.
Since the implementation of the ma_state end tracking, this is duplicated
work. This patch removes the maple write state tracking of the end of the
node and uses the maple state end instead.
Link: https://lkml.kernel.org/r/20231101171629.3612299-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The maple tree node is overloaded to keep status as well as the active
node. This, unfortunately, results in a re-walk on underflow or overflow.
Since the maple state has room, the status can be placed in its own enum
in the structure. Once an underflow/overflow is detected, certain modes
can restore the status to active and others may need to re-walk just that
one node to see the entry.
The status being an enum has the benefit of detecting unhandled status in
switch statements.
[Liam.Howlett@oracle.com: fix comments about MAS_*]
Link: https://lkml.kernel.org/r/20231106154124.614247-1-Liam.Howlett@oracle.com
[Liam.Howlett@oracle.com: update forking to separate maple state and node]
Link: https://lkml.kernel.org/r/20231106154551.615042-1-Liam.Howlett@oracle.com
[Liam.Howlett@oracle.com: fix mas_prev() state separation code]
Link: https://lkml.kernel.org/r/20231207193319.4025462-1-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20231101171629.3612299-9-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Analysis of the mas_for_each() iteration showed that there is a
significant time spent finding the end of a node. This time can be
greatly reduced if the end of the node is cached in the maple state. Care
must be taken to update & invalidate as necessary.
Link: https://lkml.kernel.org/r/20231101171629.3612299-5-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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__mas_set_range() was created to shortcut resetting the maple state and a
debug check was added to the caller (the vma iterator) to ensure the
internal maple state remains safe to use. Move the debug check from the
vma iterator into the maple tree itself so other users do not incorrectly
use the advanced maple state modification.
Fallout from this change include a large amount of debug setup needed to
be moved to earlier in the header, and the maple_tree.h radix-tree test
code needed to move the inclusion of the header to after the atomic
define. None of those changes have functional changes.
Link: https://lkml.kernel.org/r/20231101171629.3612299-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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kernel-doc is not happy about documentation in list_lru.h:
list_lru.h:90: warning: Function parameter or member 'lru' not described in 'list_lru_add'
list_lru.h:90: warning: Excess function parameter 'list_lru' description in 'list_lru_add'
list_lru.h:90: warning: No description found for return value of 'list_lru_add'
list_lru.h:103: warning: Function parameter or member 'lru' not described in 'list_lru_del'
list_lru.h:103: warning: Excess function parameter 'list_lru' description in 'list_lru_del'
list_lru.h:103: warning: No description found for return value of 'list_lru_del'
list_lru.h:116: warning: No description found for return value of 'list_lru_count_one'
list_lru.h:168: warning: No description found for return value of 'list_lru_walk_one'
list_lru.h:185: warning: No description found for return value of 'list_lru_walk_one_irq'
Fix the documentation accordingly.
While at it, fix the references to the parameters in functions
inside the long descriptions, on which the above script is not
complaining (yet?).
Link: https://lkml.kernel.org/r/20231123172320.2434780-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Rename ptdesc _refcount field to __page_refcount similar to the other
unused page fields.
Link: https://lkml.kernel.org/r/982bdc652ba79a606c3d01c905766e7e076b3315.1700594815.git.agordeev@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Suggested-by: Vishal Moola <vishal.moola@gmail.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "minor ptdesc updates", v3.
This patch (of 2):
Since commit d08d4e7cd6bf ("s390/mm: use full 4KB page for 2KB PTE") there
is no fragmented page tracking on s390. Fix the corresponding comments.
Link: https://lkml.kernel.org/r/cover.1700594815.git.agordeev@linux.ibm.com
Link: https://lkml.kernel.org/r/2eead241f3a45bed26c7911cf66bded1e35670b8.1700594815.git.agordeev@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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vmem_altmap_free() and vmem_altmap_offset() could be utlized without
CONFIG_ZONE_DEVICE enabled. For example,
mm/memory_hotplug.c:__add_pages() relies on that. The altmap is no longer
restricted to ZONE_DEVICE handling, but instead depends on
CONFIG_SPARSEMEM_VMEMMAP.
When CONFIG_SPARSEMEM_VMEMMAP is disabled, these functions are defined as
inline stubs, ensuring compatibility with configurations that do not use
sparsemem vmemmap. Without it, lkp reported the following:
ld: arch/x86/mm/init_64.o: in function `remove_pagetable':
init_64.c:(.meminit.text+0xfc7): undefined reference to
`vmem_altmap_free'
Link: https://lkml.kernel.org/r/20231120145354.308999-4-sumanthk@linux.ibm.com
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311180545.VeyRXEDq-lkp@intel.com/
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add stack_depot_put, a function that decrements the reference counter on a
stack record and removes it from the stack depot once the counter reaches
0.
Internally, when removing a stack record, the function unlinks it from the
hash table bucket and returns to the freelist.
With this change, the users of stack depot can call stack_depot_put when
keeping a stack trace in the stack depot is not needed anymore. This
allows avoiding polluting the stack depot with irrelevant stack traces and
thus have more space to store the relevant ones before the stack depot
reaches its capacity.
Link: https://lkml.kernel.org/r/1d1ad5692ee43d4fc2b3fd9d221331d30b36123f.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add a reference counter for how many times a stack records has been
added to stack depot.
Add a new STACK_DEPOT_FLAG_GET flag to stack_depot_save_flags that
instructs the stack depot to increment the refcount.
Do not yet decrement the refcount; this is implemented in one of the
following patches.
Do not yet enable any users to use the flag to avoid overflowing the
refcount.
This is preparatory patch for implementing the eviction of stack records
from the stack depot.
Link: https://lkml.kernel.org/r/a3fc14a2359d019d2a008d4ff8b46a665371ffee.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Change the bool can_alloc argument of __stack_depot_save to a u32
argument that accepts a set of flags.
The following patch will add another flag to stack_depot_save_flags
besides the existing STACK_DEPOT_FLAG_CAN_ALLOC.
Also rename the function to stack_depot_save_flags, as
__stack_depot_save is a cryptic name,
Link: https://lkml.kernel.org/r/645fa15239621eebbd3a10331e5864b718839512.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There were already assertions that we were not passing a tail page to
error_remove_page(), so make the compiler enforce that by converting
everything to pass and use a folio.
Link: https://lkml.kernel.org/r/20231117161447.2461643-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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GFP_NOWAIT callers are always prepared for their allocations to fail
because they fail so frequently. Forcing the callers to remember to add
__GFP_NOWARN is just annoying and leads to an endless stream of patches
for the places where we forgot to add it.
We can now remove __GFP_NOWARN from all the callers which specify
GFP_NOWAIT, but I'd rather wait a cycle and send patches to each
maintainer instead of creating a big pile of merge conflicts.
Link: https://lkml.kernel.org/r/20231109211507.2262419-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Nobody now checks the return value from any of these functions, so
add an assertion at the beginning of the function and return void.
Link: https://lkml.kernel.org/r/20231108204605.745109-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Make folio_start_writeback return void".
Most of the folio flag-setting functions return void.
folio_start_writeback is gratuitously different; the only two filesystems
that do anything with the return value emit debug messages if it's already
set, and we can (and should) do that internally without bothering the
filesystem to do it.
This patch (of 4):
There are no more callers of this wrapper.
Link: https://lkml.kernel.org/r/20231108204605.745109-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231108204605.745109-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The iomap code was limited to PAGE_SIZE bytes; generalise it to cover
an arbitrary-sized folio, and move it to be a common helper.
[akpm@linux-foundation.org: fix folio_fill_tail(), per Andreas Gruenbacher]
Link: https://lkml.kernel.org/r/20231107212643.3490372-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Add folio_zero_tail() and folio_fill_tail()".
I'm trying to make it easier for filesystems with tailpacking / stuffing /
inline data to use folios. The primary function here is
folio_fill_tail(). You give it a pointer to memory where the data
currently is, and it takes care of copying it into the folio at that
offset. That works for gfs2 & iomap. Then There's Ext4. Rather than gin
up some kind of specialist "Here's a two pointers to two blocks of memory"
routine, just let it do its current thing, and let it call
folio_zero_tail(), which is also called by folio_fill_tail().
Other filesystems can be converted later; these ones seemed like good
examples as they're already partly or completely converted to folios.
This patch (of 3):
Instead of unmapping the folio after copying the data to it, then mapping
it again to zero the tail, provide folio_zero_tail() to zero the tail of
an already-mapped folio.
[akpm@linux-foundation.org: fix kerneldoc argument ordering]
Link: https://lkml.kernel.org/r/20231107212643.3490372-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231107212643.3490372-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The PAGEMAP_SCAN ioctl returns information regarding page table entries.
It is more efficient compared to reading pagemap files. CRIU can start to
utilize this ioctl, but it needs info about soft-dirty bits to track
memory changes.
We are aware of a new method for tracking memory changes implemented in
the PAGEMAP_SCAN ioctl. For CRIU, the primary advantage of this method is
its usability by unprivileged users. However, it is not feasible to
transparently replace the soft-dirty tracker with the new one. The main
problem here is userfault descriptors that have to be preserved between
pre-dump iterations. It means criu continues supporting the soft-dirty
method to avoid breakage for current users. The new method will be
implemented as a separate feature.
[avagin@google.com: update tools/include/uapi/linux/fs.h]
Link: https://lkml.kernel.org/r/20231107164139.576046-1-avagin@google.com
Link: https://lkml.kernel.org/r/20231106220959.296568-1-avagin@google.com
Signed-off-by: Andrei Vagin <avagin@google.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Sanity check that makes sure the nodes cover all memory loops over
numa_meminfo to count the pages that have node id assigned by the
firmware, then loops again over memblock.memory to find the total amount
of memory and in the end checks that the difference between the total
memory and memory that covered by nodes is less than some threshold.
Worse, the loop over numa_meminfo calls __absent_pages_in_range() that
also partially traverses memblock.memory.
It's much simpler and more efficient to have a single traversal of
memblock.memory that verifies that amount of memory not covered by nodes
is less than a threshold.
Introduce memblock_validate_numa_coverage() that does exactly that and use
it instead of numa_meminfo_cover_memory().
Link: https://lkml.kernel.org/r/20231026020329.327329-1-zhiguangni01@gmail.com
Signed-off-by: Liam Ni <zhiguangni01@gmail.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Binbin Zhou <zhoubinbin@loongson.cn>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feiyang Chen <chenfeiyang@loongson.cn>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In dup_mmap(), using __mt_dup() to duplicate the old maple tree and then
directly replacing the entries of VMAs in the new maple tree can result in
better performance. __mt_dup() uses DFS pre-order to duplicate the maple
tree, so it is efficient.
The average time complexity of __mt_dup() is O(n), where n is the number
of VMAs. The proof of the time complexity is provided in the commit log
that introduces __mt_dup(). After duplicating the maple tree, each
element is traversed and replaced (ignoring the cases of deletion, which
are rare). Since it is only a replacement operation for each element,
this process is also O(n).
Analyzing the exact time complexity of the previous algorithm is
challenging because each insertion can involve appending to a node,
pushing data to adjacent nodes, or even splitting nodes. The frequency of
each action is difficult to calculate. The worst-case scenario for a
single insertion is when the tree undergoes splitting at every level. If
we consider each insertion as the worst-case scenario, we can determine
that the upper bound of the time complexity is O(n*log(n)), although this
is a loose upper bound. However, based on the test data, it appears that
the actual time complexity is likely to be O(n).
As the entire maple tree is duplicated using __mt_dup(), if dup_mmap()
fails, there will be a portion of VMAs that have not been duplicated in
the maple tree. To handle this, we mark the failure point with
XA_ZERO_ENTRY. In exit_mmap(), if this marker is encountered, stop
releasing VMAs that have not been duplicated after this point.
There is a "spawn" in byte-unixbench[1], which can be used to test the
performance of fork(). I modified it slightly to make it work with
different number of VMAs.
Below are the test results. The first row shows the number of VMAs. The
second and third rows show the number of fork() calls per ten seconds,
corresponding to next-20231006 and the this patchset, respectively. The
test results were obtained with CPU binding to avoid scheduler load
balancing that could cause unstable results. There are still some
fluctuations in the test results, but at least they are better than the
original performance.
21 121 221 421 821 1621 3221 6421 12821 25621 51221
112100 76261 54227 34035 20195 11112 6017 3161 1606 802 393
114558 83067 65008 45824 28751 16072 8922 4747 2436 1233 599
2.19% 8.92% 19.88% 34.64% 42.37% 44.64% 48.28% 50.17% 51.68% 53.74% 52.42%
[1] https://github.com/kdlucas/byte-unixbench/tree/master
Link: https://lkml.kernel.org/r/20231027033845.90608-11-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce interfaces __mt_dup() and mtree_dup(), which are used to
duplicate a maple tree. They duplicate a maple tree in Depth-First Search
(DFS) pre-order traversal. It uses memcopy() to copy nodes in the source
tree and allocate new child nodes in non-leaf nodes. The new node is
exactly the same as the source node except for all the addresses stored in
it. It will be faster than traversing all elements in the source tree and
inserting them one by one into the new tree. The time complexity of these
two functions is O(n).
The difference between __mt_dup() and mtree_dup() is that mtree_dup()
handles locks internally.
Analysis of the average time complexity of this algorithm:
For simplicity, let's assume that the maximum branching factor of all
non-leaf nodes is 16 (in allocation mode, it is 10), and the tree is a
full tree.
Under the given conditions, if there is a maple tree with n elements, the
number of its leaves is n/16. From bottom to top, the number of nodes in
each level is 1/16 of the number of nodes in the level below. So the
total number of nodes in the entire tree is given by the sum of n/16 +
n/16^2 + n/16^3 + ... + 1. This is a geometric series, and it has log(n)
terms with base 16. According to the formula for the sum of a geometric
series, the sum of this series can be calculated as (n-1)/15. Each node
has only one parent node pointer, which can be considered as an edge. In
total, there are (n-1)/15-1 edges.
This algorithm consists of two operations:
1. Traversing all nodes in DFS order.
2. For each node, making a copy and performing necessary modifications
to create a new node.
For the first part, DFS traversal will visit each edge twice. Let
T(ascend) represent the cost of taking one step downwards, and T(descend)
represent the cost of taking one step upwards. And both of them are
constants (although mas_ascend() may not be, as it contains a loop, but
here we ignore it and treat it as a constant). So the time spent on the
first part can be represented as ((n-1)/15-1) * (T(ascend) + T(descend)).
For the second part, each node will be copied, and the cost of copying a
node is denoted as T(copy_node). For each non-leaf node, it is necessary
to reallocate all child nodes, and the cost of this operation is denoted
as T(dup_alloc). The behavior behind memory allocation is complex and not
specific to the maple tree operation. Here, we assume that the time
required for a single allocation is constant. Since the size of a node is
fixed, both of these symbols are also constants. We can calculate that
the time spent on the second part is ((n-1)/15) * T(copy_node) + ((n-1)/15
- n/16) * T(dup_alloc).
Adding both parts together, the total time spent by the algorithm can be
represented as:
((n-1)/15) * (T(ascend) + T(descend) + T(copy_node) + T(dup_alloc)) -
n/16 * T(dup_alloc) - (T(ascend) + T(descend))
Let C1 = T(ascend) + T(descend) + T(copy_node) + T(dup_alloc)
Let C2 = T(dup_alloc)
Let C3 = T(ascend) + T(descend)
Finally, the expression can be simplified as:
((16 * C1 - 15 * C2) / (15 * 16)) * n - (C1 / 15 + C3).
This is a linear function, so the average time complexity is O(n).
Link: https://lkml.kernel.org/r/20231027033845.90608-4-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In some cases, nested locks may be needed, so {mtree,mas}_lock_nested is
introduced. For example, when duplicating maple tree, we need to hold the
locks of two trees, in which case nested locks are needed.
At the same time, add the definition of spin_lock_nested() in tools for
testing.
Link: https://lkml.kernel.org/r/20231027033845.90608-3-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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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>
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Clang static checker complains that value stored to 'from' is never read.
And memcpy_from_folio() only copy the last chunk memory from folio to
destination. Use 'to += chunk' to replace 'from += chunk' to fix this
typo problem.
Link: https://lkml.kernel.org/r/20231130034017.1210429-1-suhui@nfschina.com
Fixes: b23d03ef7af5 ("highmem: add memcpy_to_folio() and memcpy_from_folio()")
Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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BITS_PER_BYTE is defined in bits.h.
Link: https://lkml.kernel.org/r/20231128174404.393393-1-andriy.shevchenko@linux.intel.com
Fixes: e8eed5f7366f ("units: Add BYTES_PER_*BIT")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Damian Muszynski <damian.muszynski@intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The routine __vma_private_lock tests for the existence of a reserve map
associated with a private hugetlb mapping. A pointer to the reserve map
is in vma->vm_private_data. __vma_private_lock was checking the pointer
for NULL. However, it is possible that the low bits of the pointer could
be used as flags. In such instances, vm_private_data is not NULL and not
a valid pointer. This results in the null-ptr-deref reported by syzbot:
general protection fault, probably for non-canonical address 0xdffffc000000001d:
0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
CPU: 0 PID: 5048 Comm: syz-executor139 Not tainted 6.6.0-rc7-syzkaller-00142-g88
8cf78c29e2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 1
0/09/2023
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5004
...
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5753 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
down_write+0x93/0x200 kernel/locking/rwsem.c:1573
hugetlb_vma_lock_write mm/hugetlb.c:300 [inline]
hugetlb_vma_lock_write+0xae/0x100 mm/hugetlb.c:291
__hugetlb_zap_begin+0x1e9/0x2b0 mm/hugetlb.c:5447
hugetlb_zap_begin include/linux/hugetlb.h:258 [inline]
unmap_vmas+0x2f4/0x470 mm/memory.c:1733
exit_mmap+0x1ad/0xa60 mm/mmap.c:3230
__mmput+0x12a/0x4d0 kernel/fork.c:1349
mmput+0x62/0x70 kernel/fork.c:1371
exit_mm kernel/exit.c:567 [inline]
do_exit+0x9ad/0x2a20 kernel/exit.c:861
__do_sys_exit kernel/exit.c:991 [inline]
__se_sys_exit kernel/exit.c:989 [inline]
__x64_sys_exit+0x42/0x50 kernel/exit.c:989
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Mask off low bit flags before checking for NULL pointer. In addition, the
reserve map only 'belongs' to the OWNER (parent in parent/child
relationships) so also check for the OWNER flag.
Link: https://lkml.kernel.org/r/20231114012033.259600-1-mike.kravetz@oracle.com
Reported-by: syzbot+6ada951e7c0f7bc8a71e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/00000000000078d1e00608d7878b@google.com/
Fixes: bf4916922c60 ("hugetlbfs: extend hugetlb_vma_lock to private VMAs")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Cc: Edward Adam Davis <eadavis@qq.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Pull vfio fixes from Alex Williamson:
- Fix the lifecycle of a mutex in the pds variant driver such that a
reset prior to opening the device won't find it uninitialized.
Implement the release path to symmetrically destroy the mutex. Also
switch a different lock from spinlock to mutex as the code path has
the potential to sleep and doesn't need the spinlock context
otherwise (Brett Creeley)
- Fix an issue detected via randconfig where KVM tries to symbol_get an
undeclared function. The symbol is temporarily declared
unconditionally here, which resolves the problem and avoids churn
relative to a series pending for the next merge window which resolves
some of this symbol ugliness, but also fixes Kconfig dependencies
(Sean Christopherson)
* tag 'vfio-v6.7-rc4' of https://github.com/awilliam/linux-vfio:
vfio: Drop vfio_file_iommu_group() stub to fudge around a KVM wart
vfio/pds: Fix possible sleep while in atomic context
vfio/pds: Fix mutex lock->magic != lock warning
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes fixes from Masami Hiramatsu:
- objpool: Fix objpool overrun case on memory/cache access delay
especially on the big.LITTLE SoC. The objpool uses a copy of object
slot index internal loop, but the slot index can be changed on
another processor in parallel. In that case, the difference of 'head'
local copy and the 'slot->last' index will be bigger than local slot
size. In that case, we need to re-read the slot::head to update it.
- kretprobe: Fix to use appropriate rcu API for kretprobe holder. Since
kretprobe_holder::rp is RCU managed, it should use
rcu_assign_pointer() and rcu_dereference_check() correctly. Also
adding __rcu tag for finding wrong usage by sparse.
- rethook: Fix to use appropriate rcu API for rethook::handler. The
same as kretprobe, rethook::handler is RCU managed and it should use
rcu_assign_pointer() and rcu_dereference_check(). This also adds
__rcu tag for finding wrong usage by sparse.
* tag 'probes-fixes-v6.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
rethook: Use __rcu pointer for rethook::handler
kprobes: consistent rcu api usage for kretprobe holder
lib: objpool: fix head overrun on RK3588 SBC
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix issues in two cpufreq drivers, in the AMD P-state driver and
in the power-capping DTPM framework.
Specifics:
- Fix the AMD P-state driver's EPP sysfs interface in the cases when
the performance governor is in use (Ayush Jain)
- Make the ->fast_switch() callback in the AMD P-state driver return
the target frequency as expected (Gautham R. Shenoy)
- Allow user space to control the range of frequencies to use via
scaling_min_freq and scaling_max_freq when AMD P-state driver is in
use (Wyes Karny)
- Prevent power domains needed for wakeup signaling from being turned
off during system suspend on Qualcomm systems and prevent
performance states votes from runtime-suspended devices from being
lost across a system suspend-resume cycle in qcom-cpufreq-nvmem
(Stephan Gerhold)
- Fix disabling the 792 Mhz OPP in the imx6q cpufreq driver for the
i.MX6ULL types that can run at that frequency (Christoph
Niedermaier)
- Eliminate unnecessary and harmful conversions to uW from the DTPM
(dynamic thermal and power management) framework (Lukasz Luba)"
* tag 'pm-6.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq/amd-pstate: Only print supported EPP values for performance governor
cpufreq/amd-pstate: Fix scaling_min_freq and scaling_max_freq update
powercap: DTPM: Fix unneeded conversions to micro-Watts
cpufreq/amd-pstate: Fix the return value of amd_pstate_fast_switch()
pmdomain: qcom: rpmpd: Set GENPD_FLAG_ACTIVE_WAKEUP
cpufreq: qcom-nvmem: Preserve PM domain votes in system suspend
cpufreq: qcom-nvmem: Enable virtual power domain devices
cpufreq: imx6q: Don't disable 792 Mhz OPP unnecessarily
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI fixes from Rafael Wysocki:
"This fixes a recently introduced build issue on ARM32 and a NULL
pointer dereference in the ACPI backlight driver due to a design issue
exposed by a recent change in the ACPI bus type code.
Specifics:
- Fix a recently introduced build issue on ARM32 platforms caused by
an inadvertent header file breakage (Dave Jiang)
- Eliminate questionable usage of acpi_driver_data() in the ACPI
backlight cooling device code that leads to NULL pointer
dereferences after recent ACPI core changes (Hans de Goede)"
* tag 'acpi-6.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: video: Use acpi_video_device for cooling-dev driver data
ACPI: Fix ARM32 platforms compile issue introduced by fw_table changes
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu fixes from Joerg Roedel:
- Fix race conditions in device probe path
- Handle ERR_PTR() returns in __iommu_domain_alloc() path
- Update MAINTAINERS entry for Qualcom IOMMUs
- Printk argument fix in device tree specific code
- Several Intel VT-d fixes from Lu Baolu:
- Do not support enforcing cache coherency for non-empty domains
- Avoid devTLB invalidation if iommu is off
- Disable PCI ATS in legacy passthrough mode
- Support non-PCI devices when clearing context
- Fix incorrect cache invalidation for mm notification
- Add MTL to quirk list to skip TE disabling
- Set variable intel_dirty_ops to static
* tag 'iommu-fixes-v6.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu: Fix printk arg in of_iommu_get_resv_regions()
iommu/vt-d: Set variable intel_dirty_ops to static
iommu/vt-d: Fix incorrect cache invalidation for mm notification
iommu/vt-d: Add MTL to quirk list to skip TE disabling
iommu/vt-d: Make context clearing consistent with context mapping
iommu/vt-d: Disable PCI ATS in legacy passthrough mode
iommu/vt-d: Omit devTLB invalidation requests when TES=0
iommu/vt-d: Support enforce_cache_coherency only for empty domains
iommu: Avoid more races around device probe
MAINTAINERS: list all Qualcomm IOMMU drivers in the QUALCOMM IOMMU entry
iommu: Flow ERR_PTR out from __iommu_domain_alloc()
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"No surprise here, including only a collection of HD-audio
device-specific small fixes"
* tag 'sound-6.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda: Disable power-save on KONTRON SinglePC
ALSA: hda/realtek: Add supported ALC257 for ChromeOS
ALSA: hda/realtek: Headset Mic VREF to 100%
ALSA: hda: intel-nhlt: Ignore vbps when looking for DMIC 32 bps format
ALSA: hda: cs35l56: Enable low-power hibernation mode on SPI
ALSA: cs35l41: Fix for old systems which do not support command
ALSA: hda: cs35l41: Remove unnecessary boolean state variable firmware_running
ALSA: hda - Fix speaker and headset mic pin config for CHUWI CoreBook XPro
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Pull drm fixes from Dave Airlie:
"Weekly fixes, mostly amdgpu fixes with a scattering of nouveau, i915,
and a couple of reverts. Hopefully it will quieten down in coming
weeks.
drm:
- Revert unexport of prime helpers for fd/handle conversion
dma_resv:
- Do not double add fences in dma_resv_add_fence.
gpuvm:
- Fix GPUVM license identifier.
i915:
- Mark internal GSC engine with reserved uabi class
- Take VGA converters into account in eDP probe
- Fix intel_pre_plane_updates() call to ensure workarounds get applied
panel:
- Revert panel fixes as they require exporting device_is_dependent.
nouveau:
- fix oversized allocations in new vm path
- fix zero-length array
- remove a stray lock
nt36523:
- Fix error check for nt36523.
amdgpu:
- DMUB fix
- DCN 3.5 fixes
- XGMI fix
- DCN 3.2 fixes
- Vangogh suspend fix
- NBIO 7.9 fix
- GFX11 golden register fix
- Backlight fix
- NBIO 7.11 fix
- IB test overflow fix
- DCN 3.1.4 fixes
- fix a runtime pm ref count
- Retimer fix
- ABM fix
- DCN 3.1.5 fix
- Fix AGP addressing
- Fix possible memory leak in SMU error path
- Make sure PME is enabled in D3
- Fix possible NULL pointer dereference in debugfs
- EEPROM fix
- GC 9.4.3 fix
amdkfd:
- IP version check fix
- Fix memory leak in pqm_uninit()"
* tag 'drm-fixes-2023-12-01' of git://anongit.freedesktop.org/drm/drm: (53 commits)
Revert "drm/prime: Unexport helpers for fd/handle conversion"
drm/amdgpu: Use another offset for GC 9.4.3 remap
drm/amd/display: Fix some HostVM parameters in DML
drm/amdkfd: Free gang_ctx_bo and wptr_bo in pqm_uninit
drm/amdgpu: Update EEPROM I2C address for smu v13_0_0
drm/amd/display: Allow DTBCLK disable for DCN35
drm/amdgpu: Fix cat debugfs amdgpu_regs_didt causes kernel null pointer
drm/amd: Enable PCIe PME from D3
drm/amd/pm: fix a memleak in aldebaran_tables_init
drm/amdgpu: fix AGP addressing when GART is not at 0
drm/amd/display: update dcn315 lpddr pstate latency
drm/amd/display: fix ABM disablement
drm/amd/display: Fix black screen on video playback with embedded panel
drm/amd/display: Fix conversions between bytes and KB
drm/amdkfd: Use common function for IP version check
drm/amd/display: Remove config update
drm/amd/display: Update DCN35 clock table policy
drm/amd/display: force toggle rate wa for first link training for a retimer
drm/amdgpu: correct the amdgpu runtime dereference usage count
drm/amd/display: Update min Z8 residency time to 2100 for DCN314
...
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Pull io_uring fixes from Jens Axboe:
- Fix an issue with discontig page checking for IORING_SETUP_NO_MMAP
- Fix an issue with not allowing IORING_SETUP_NO_MMAP also disallowing
mmap'ed buffer rings
- Fix an issue with deferred release of memory mapped pages
- Fix a lockdep issue with IORING_SETUP_NO_MMAP
- Use fget/fput consistently, even from our sync system calls. No real
issue here, but if we were ever to allow closing io_uring descriptors
it would be required. Let's play it safe and just use the full ref
counted versions upfront. Most uses of io_uring are threaded anyway,
and hence already doing the full version underneath.
* tag 'io_uring-6.7-2023-11-30' of git://git.kernel.dk/linux:
io_uring: use fget/fput consistently
io_uring: free io_buffer_list entries via RCU
io_uring/kbuf: prune deferred locked cache when tearing down
io_uring/kbuf: recycle freed mapped buffer ring entries
io_uring/kbuf: defer release of mapped buffer rings
io_uring: enable io_mem_alloc/free to be used in other parts
io_uring: don't guard IORING_OFF_PBUF_RING with SETUP_NO_MMAP
io_uring: don't allow discontig pages for IORING_SETUP_NO_MMAP
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Pull block fixes from Jens Axboe:
- NVMe pull request via Keith:
- Invalid namespace identification error handling (Marizio Ewan,
Keith)
- Fabrics keep-alive tuning (Mark)
- Fix for a bad error check regression in bcache (Markus)
- Fix for a performance regression with O_DIRECT (Ming)
- Fix for a flush related deadlock (Ming)
- Make the read-only warn on per-partition (Yu)
* tag 'block-6.7-2023-12-01' of git://git.kernel.dk/linux:
nvme-core: check for too small lba shift
blk-mq: don't count completed flush data request as inflight in case of quiesce
block: Document the role of the two attribute groups
block: warn once for each partition in bio_check_ro()
block: move .bd_inode into 1st cacheline of block_device
nvme: check for valid nvme_identify_ns() before using it
nvme-core: fix a memory leak in nvme_ns_info_from_identify()
nvme: fine-tune sending of first keep-alive
bcache: revert replacing IS_ERR_OR_NULL with IS_ERR
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git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"Three small fixes, one in drivers.
The core changes are to the internal representation of flags in
scsi_devices which removes space wasting bools in favour of single bit
flags and to add a flag to force a runtime resume which is used by ATA
devices"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: sd: Fix system start for ATA devices
scsi: Change SCSI device boolean fields to single bit flags
scsi: ufs: core: Clear cmd if abort succeeds in MCQ mode
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Pull more bcachefs bugfixes from Kent Overstreet:
- bcache & bcachefs were broken with CFI enabled; patch for closures to
fix type punning
- mark erasure coding as extra-experimental; there are incompatible
disk space accounting changes coming for erasure coding, and I'm
still seeing checksum errors in some tests
- several fixes for durability-related issues (durability is a device
specific setting where we can tell bcachefs that data on a given
device should be counted as replicated x times)
- a fix for a rare livelock when a btree node merge then updates a
parent node that is almost full
- fix a race in the device removal path, where dropping a pointer in a
btree node to a device would be clobbered by an in flight btree write
updating the btree node key on completion
- fix one SRCU lock hold time warning in the btree gc code - ther's
still a bunch more of these to fix
- fix a rare race where we'd start copygc before initializing the "are
we rw" percpu refcount; copygc would think we were already ro and die
immediately
* tag 'bcachefs-2023-11-29' of https://evilpiepirate.org/git/bcachefs: (23 commits)
bcachefs: Extra kthread_should_stop() calls for copygc
bcachefs: Convert gc_alloc_start() to for_each_btree_key2()
bcachefs: Fix race between btree writes and metadata drop
bcachefs: move journal seq assertion
bcachefs: -EROFS doesn't count as move_extent_start_fail
bcachefs: trace_move_extent_start_fail() now includes errcode
bcachefs: Fix split_race livelock
bcachefs: Fix bucket data type for stripe buckets
bcachefs: Add missing validation for jset_entry_data_usage
bcachefs: Fix zstd compress workspace size
bcachefs: bpos is misaligned on big endian
bcachefs: Fix ec + durability calculation
bcachefs: Data update path won't accidentaly grow replicas
bcachefs: deallocate_extra_replicas()
bcachefs: Proper refcounting for journal_keys
bcachefs: preserve device path as device name
bcachefs: Fix an endianness conversion
bcachefs: Start gc, copygc, rebalance threads after initing writes ref
bcachefs: Don't stop copygc thread on device resize
bcachefs: Make sure bch2_move_ratelimit() also waits for move_ops
...
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Merge a fix for a recently introduced build issue on ARM32 platforms
caused by an inadvertent header file breakage (Dave Jiang).
* acpi-tables:
ACPI: Fix ARM32 platforms compile issue introduced by fw_table changes
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Since the rethook::handler is an RCU-maganged pointer so that it will
notice readers the rethook is stopped (unregistered) or not, it should
be an __rcu pointer and use appropriate functions to be accessed. This
will use appropriate memory barrier when accessing it. OTOH,
rethook::data is never changed, so we don't need to check it in
get_kretprobe().
NOTE: To avoid sparse warning, rethook::handler is defined by a raw
function pointer type with __rcu instead of rethook_handler_t.
Link: https://lore.kernel.org/all/170126066201.398836.837498688669005979.stgit@devnote2/
Fixes: 54ecbe6f1ed5 ("rethook: Add a generic return hook")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311241808.rv9ceuAh-lkp@intel.com/
Tested-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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It seems that the pointer-to-kretprobe "rp" within the kretprobe_holder is
RCU-managed, based on the (non-rethook) implementation of get_kretprobe().
The thought behind this patch is to make use of the RCU API where possible
when accessing this pointer so that the needed barriers are always in place
and to self-document the code.
The __rcu annotation to "rp" allows for sparse RCU checking. Plain writes
done to the "rp" pointer are changed to make use of the RCU macro for
assignment. For the single read, the implementation of get_kretprobe()
is simplified by making use of an RCU macro which accomplishes the same,
but note that the log warning text will be more generic.
I did find that there is a difference in assembly generated between the
usage of the RCU macros vs without. For example, on arm64, when using
rcu_assign_pointer(), the corresponding store instruction is a
store-release (STLR) which has an implicit barrier. When normal assignment
is done, a regular store (STR) is found. In the macro case, this seems to
be a result of rcu_assign_pointer() using smp_store_release() when the
value to write is not NULL.
Link: https://lore.kernel.org/all/20231122132058.3359-1-inwardvessel@gmail.com/
Fixes: d741bf41d7c7 ("kprobes: Remove kretprobe hash")
Cc: stable@vger.kernel.org
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening fixes from Kees Cook:
- struct_group: propagate attributes to top-level union (Dmitry
Antipov)
- gcc-plugins: randstruct: Update code comment in relayout_struct
(Gustavo A. R. Silva)
- MAINTAINERS: refresh LLVM support (Nick Desaulniers)
* tag 'hardening-v6.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: randstruct: Update code comment in relayout_struct()
uapi: propagate __struct_group() attributes to the container union
MAINTAINERS: refresh LLVM support
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