Commit 7efc3b7261 ("mm/compaction: fix set skip in
fast_find_migrateblock") address an issue where a pageblock selected by
fast_find_migrateblock() was ignored. Unfortunately, the same fix
resulted in numerous reports of khugepaged or kcompactd stalling for long
periods of time or consuming 100% of CPU.
Tracing showed that there was a lot of rescanning between a small subset
of pageblocks because the conditions for marking the block skip are not
met. The scan is not reaching the end of the pageblock because enough
pages were isolated but none were migrated successfully. Eventually it
circles back to the same block.
Pageblock skip tracking tries to minimise both latency and excessive
scanning but tracking exactly when a block is fully scanned requires an
excessive amount of state. This patch forcibly rescans a pageblock when
all isolated pages fail to migrate even though it could be for transient
reasons such as page writeback or page dirty. This will sometimes migrate
too many pages but pageblocks will be marked skip and forward progress
will be made.
"Usemen" from the mmtests configuration
workload-usemem-stress-numa-compact was used to stress compaction. The
compaction trace events were recorded using a 6.2-rc5 kernel that includes
commit 7efc3b7261 and count of unique ranges were measured. The top 5
ranges were
3076 range=(0x10ca00-0x10cc00)
3076 range=(0x110a00-0x110c00)
3098 range=(0x13b600-0x13b800)
3104 range=(0x141c00-0x141e00)
11424 range=(0x11b600-0x11b800)
While this workload is very different than what the bugs reported, the
pattern of the same subset of blocks being repeatedly scanned is observed.
At one point, *only* the range range=(0x11b600 ~ 0x11b800) was scanned
for 2 seconds. 14 seconds passed between the first migration-related
event and the last.
With the series applied including this patch, the top 5 ranges were
1 range=(0x11607e-0x116200)
1 range=(0x116200-0x116278)
1 range=(0x116278-0x116400)
1 range=(0x116400-0x116424)
1 range=(0x116424-0x116600)
Only unique ranges were scanned and the time between the first
migration-related event was 0.11 milliseconds.
Link: https://lkml.kernel.org/r/20230125134434.18017-5-mgorman@techsingularity.net
Fixes: 7efc3b7261 ("mm/compaction: fix set skip in fast_find_migrateblock")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cc->finish_pageblock is set when the current pageblock should be rescanned
but fast_find_migrateblock can select an alternative block. Disable
fast_find_migrateblock when the current pageblock scan should be
completed.
Link: https://lkml.kernel.org/r/20230125134434.18017-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If a page has been captured then draining is unnecssary so check first for
a captured page.
Link: https://lkml.kernel.org/r/20230125134434.18017-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fix excessive CPU usage during compaction".
Commit 7efc3b7261 ("mm/compaction: fix set skip in fast_find_migrateblock")
fixed a problem where pageblocks found by fast_find_migrateblock() were
ignored. Unfortunately there were numerous bug reports complaining about high
CPU usage and massive stalls once 6.1 was released. Due to the severity,
the patch was reverted by Vlastimil as a short-term fix[1] to -stable.
The underlying problem for each of the bugs is suspected to be the
repeated scanning of the same pageblocks. This series should guarantee
forward progress even with commit 7efc3b7261. More information is in
the changelog for patch 4.
[1] http://lore.kernel.org/r/20230113173345.9692-1-vbabka@suse.cz
This patch (of 4):
The rescan field was not well named albeit accurate at the time. Rename
the field to finish_pageblock to indicate that the remainder of the
pageblock should be scanned regardless of COMPACT_CLUSTER_MAX. The intent
is that pageblocks with transient failures get marked for skipping to
avoid revisiting the same pageblock.
Link: https://lkml.kernel.org/r/20230125134434.18017-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The implementation of page_alloc poisoning sampling assumed that
tag_clear_highpage resets page tags for __GFP_ZEROTAGS allocations.
However, this is no longer the case since commit 70c248aca9 ("mm: kasan:
Skip unpoisoning of user pages").
This leads to kernel crashes when MTE-enabled userspace mappings are used
with Hardware Tag-Based KASAN enabled.
Reset page tags for __GFP_ZEROTAGS allocations in post_alloc_hook().
Also clarify and fix related comments.
[andreyknvl@google.com: update comment]
Link: https://lkml.kernel.org/r/5dbd866714b4839069e2d8469ac45b60953db290.1674592780.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/24ea20c1b19c2b4b56cf9f5b354915f8dbccfc77.1674592496.git.andreyknvl@google.com
Fixes: 44383cef54 ("kasan: allow sampling page_alloc allocations for HW_TAGS")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Peter Collingbourne <pcc@google.com>
Tested-by: Peter Collingbourne <pcc@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
W=1 build with clangs complains:
mm/sparse.c:347:27: warning: unused function 'pgdat_to_phys' [-Wunused-function]
static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat)
^
1 warning generated.
pgdat_to_phys() is only used by functions defined when
CONFIG_MEMORY_HOTREMOVE=y.
Move pgdat_to_phys() under #ifdef CONFIG_MEMORY_HOTREMOVE
to make clang happy.
Link: https://lkml.kernel.org/r/20230121101151.1703292-1-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202301210155.1E5zABb5-lkp@intel.com
Cc: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When allocating a high-order page, separate allocation timestamp is
recorded for each sub-page resulting in different timestamp values between
them.
This behavior is not consistent with the behavior when recording free
timestamp and caused confusion when analyzing memory dumps. Record single
timestamp for the entire allocation, aligning with the behavior for free
timestamps.
Link: https://lkml.kernel.org/r/20230121165054.520507-1-42.hyeyoo@gmail.com
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add documentation for memory_failure's per NUMA node sysfs entries
Link: https://lkml.kernel.org/r/20230120034622.2698268-4-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Right before memory_failure finishes its handling, accumulate poisoned
page's resolution counters to pglist_data's memory_failure_stats, so as to
update the corresponding sysfs entries.
Tested:
1) Start an application to allocate memory buffer chunks
2) Convert random memory buffer addresses to physical addresses
3) Inject memory errors using EINJ at chosen physical addresses
4) Access poisoned memory buffer and recover from SIGBUS
5) Check counter values under
/sys/devices/system/node/node*/memory_failure/*
Link: https://lkml.kernel.org/r/20230120034622.2698268-3-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Introduce per NUMA node memory error statistics", v2.
Background
==========
In the RFC for Kernel Support of Memory Error Detection [1], one advantage
of software-based scanning over hardware patrol scrubber is the ability to
make statistics visible to system administrators. The statistics include
2 categories:
* Memory error statistics, for example, how many memory error are
encountered, how many of them are recovered by the kernel. Note these
memory errors are non-fatal to kernel: during the machine check
exception (MCE) handling kernel already classified MCE's severity to be
unnecessary to panic (but either action required or optional).
* Scanner statistics, for example how many times the scanner have fully
scanned a NUMA node, how many errors are first detected by the scanner.
The memory error statistics are useful to userspace and actually not
specific to scanner detected memory errors, and are the focus of this
patchset.
Motivation
==========
Memory error stats are important to userspace but insufficient in kernel
today. Datacenter administrators can better monitor a machine's memory
health with the visible stats. For example, while memory errors are
inevitable on servers with 10+ TB memory, starting server maintenance when
there are only 1~2 recovered memory errors could be overreacting; in cloud
production environment maintenance usually means live migrate all the
workload running on the server and this usually causes nontrivial
disruption to the customer. Providing insight into the scope of memory
errors on a system helps to determine the appropriate follow-up action.
In addition, the kernel's existing memory error stats need to be
standardized so that userspace can reliably count on their usefulness.
Today kernel provides following memory error info to userspace, but they
are not sufficient or have disadvantages:
* HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total,
not per NUMA node stats though
* ras:memory_failure_event: only available after explicitly enabled
* /dev/mcelog provides many useful info about the MCEs, but doesn't
capture how memory_failure recovered memory MCEs
* kernel logs: userspace needs to process log text
Exposing memory error stats is also a good start for the in-kernel memory
error detector. Today the data source of memory error stats are either
direct memory error consumption, or hardware patrol scrubber detection
(either signaled as UCNA or SRAO). Once in-kernel memory scanner is
implemented, it will be the main source as it is usually configured to
scan memory DIMMs constantly and faster than hardware patrol scrubber.
How Implemented
===============
As Naoya pointed out [2], exposing memory error statistics to userspace is
useful independent of software or hardware scanner. Therefore we
implement the memory error statistics independent of the in-kernel memory
error detector. It exposes the following per NUMA node memory error
counters:
/sys/devices/system/node/node${X}/memory_failure/total
/sys/devices/system/node/node${X}/memory_failure/recovered
/sys/devices/system/node/node${X}/memory_failure/ignored
/sys/devices/system/node/node${X}/memory_failure/failed
/sys/devices/system/node/node${X}/memory_failure/delayed
These counters describe how many raw pages are poisoned and after the
attempted recoveries by the kernel, their resolutions: how many are
recovered, ignored, failed, or delayed respectively. This approach can be
easier to extend for future use cases than /proc/meminfo, trace event, and
log. The following math holds for the statistics:
* total = recovered + ignored + failed + delayed
These memory error stats are reset during machine boot.
The 1st commit introduces these sysfs entries. The 2nd commit populates
memory error stats every time memory_failure attempts memory error
recovery. The 3rd commit adds documentations for introduced stats.
[1] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#mc22959244f5388891c523882e61163c6e4d703af
[2] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#m52d8d7a333d8536bd7ce74253298858b1c0c0ac6
This patch (of 3):
Today kernel provides following memory error info to userspace, but each
has its own disadvantage
* HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total,
not per NUMA node stats though
* ras:memory_failure_event: only available after explicitly enabled
* /dev/mcelog provides many useful info about the MCEs, but
doesn't capture how memory_failure recovered memory MCEs
* kernel logs: userspace needs to process log text
Exposes per NUMA node memory error stats as sysfs entries:
/sys/devices/system/node/node${X}/memory_failure/total
/sys/devices/system/node/node${X}/memory_failure/recovered
/sys/devices/system/node/node${X}/memory_failure/ignored
/sys/devices/system/node/node${X}/memory_failure/failed
/sys/devices/system/node/node${X}/memory_failure/delayed
These counters describe how many raw pages are poisoned and after the
attempted recoveries by the kernel, their resolutions: how many are
recovered, ignored, failed, or delayed respectively. The following math
holds for the statistics:
* total = recovered + ignored + failed + delayed
Link: https://lkml.kernel.org/r/20230120034622.2698268-1-jiaqiyan@google.com
Link: https://lkml.kernel.org/r/20230120034622.2698268-2-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Update the folio generation in place with or without
current->reclaim_state->mm_walk. The LRU lock is held for longer, if
mm_walk is NULL and the number of folios to update is more than
PAGEVEC_SIZE.
This causes a measurable regression from the LRU lock contention during a
microbencmark. But a tiny regression is not worth the complexity.
Link: https://lkml.kernel.org/r/20230118001827.1040870-8-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Improve readability of walk_pmd_range() and walk_pmd_range_locked().
Link: https://lkml.kernel.org/r/20230118001827.1040870-7-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move memcg LRU code into a dedicated section. Improve the design doc to
outline its architecture.
Link: https://lkml.kernel.org/r/20230118001827.1040870-5-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move Bloom filters code into a dedicated section. Improve the design doc
to explain Bloom filter usage and connection between aging and eviction in
their use.
Link: https://lkml.kernel.org/r/20230118001827.1040870-4-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a section for lru_gen_look_around() in the code and the design doc.
Link: https://lkml.kernel.org/r/20230118001827.1040870-3-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: multi-gen LRU: improve".
This patch series improves a few MGLRU functions, collects related
functions, and adds additional documentation.
This patch (of 7):
Add a section for working set protection in the code and the design doc.
The admin doc already contains its usage.
Link: https://lkml.kernel.org/r/20230118001827.1040870-1-talumbau@google.com
Link: https://lkml.kernel.org/r/20230118001827.1040870-2-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a simple unit test for damon_update_monitoring_results() function.
Link: https://lkml.kernel.org/r/20230119013831.1911-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
region->nr_accesses is the number of sampling intervals in the last
aggregation interval that access to the region has found, and region->age
is the number of aggregation intervals that its access pattern has
maintained. Hence, the real meaning of the two fields' values is
depending on current sampling and aggregation intervals.
This means the values need to be updated for every sampling and/or
aggregation intervals updates. As DAMON core doesn't, it is a duty of
in-kernel DAMON framework applications like DAMON sysfs interface, or the
userspace users.
Handling it in userspace or in-kernel DAMON application is complicated,
inefficient, and repetitive compared to doing the update in DAMON core.
Do the update in DAMON core.
Link: https://lkml.kernel.org/r/20230119013831.1911-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: misc fixes".
This patchset contains three miscellaneous simple fixes for DAMON online
tuning.
This patch (of 3):
Commit cbeaa77b04 ("mm/damon/core: use a dedicated struct for monitoring
attributes") moved monitoring intervals from damon_ctx to a new struct,
damon_attrs, but a comment in the header file has not updated for the
change. Update it.
Link: https://lkml.kernel.org/r/20230119013831.1911-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230119013831.1911-2-sj@kernel.org
Fixes: cbeaa77b04 ("mm/damon/core: use a dedicated struct for monitoring attributes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 6edda04ccc ("mm/kmemleak: prevent soft lockup in first object
iteration loop of kmemleak_scan()") fixes soft lockup problem in
kmemleak_scan() by periodically doing a cond_resched(). It does take a
reference of the current object before doing it. Unfortunately, if the
object has been deleted from the object_list, the next object pointed to
by its next pointer may no longer be valid after coming back from
cond_resched(). This can result in use-after-free and other nasty
problem.
Fix this problem by adding a del_state flag into kmemleak_object structure
to synchronize the object deletion process between kmemleak_cond_resched()
and __remove_object() to make sure that the object remained in the
object_list in the duration of the cond_resched() call.
Link: https://lkml.kernel.org/r/20230119040111.350923-3-longman@redhat.com
Fixes: 6edda04ccc ("mm/kmemleak: prevent soft lockup in first object iteration loop of kmemleak_scan()")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF", v2.
It was found that a KASAN use-after-free error was reported in the
kmemleak_scan() function. After further examination, it is believe that
even though a reference is taken from the current object, it does not
prevent the object pointed to by the next pointer from going away after a
cond_resched().
To fix that, additional flags are added to make sure that the current
object won't be removed from the object_list during the duration of the
cond_resched() to ensure the validity of the next pointer.
While making the change, I also simplify the current usage of
kmemleak_cond_resched() to make it easier to understand.
This patch (of 2):
The presence of a pinned argument and the 64k loop count make
kmemleak_cond_resched() a bit more complex to read. The pinned argument
is used only by first kmemleak_scan() loop.
Simplify the usage of kmemleak_cond_resched() by removing the pinned
argument and always do a get_object()/put_object() sequence. In addition,
the 64k loop is removed by using need_resched() to decide if
kmemleak_cond_resched() should be called.
Link: https://lkml.kernel.org/r/20230119040111.350923-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20230119040111.350923-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: In-kernel support for memory-deny-write-execute (MDWE)",
v2.
The background to this is that systemd has a configuration option called
MemoryDenyWriteExecute [2], implemented as a SECCOMP BPF filter. Its aim
is to prevent a user task from inadvertently creating an executable
mapping that is (or was) writeable. Since such BPF filter is stateless,
it cannot detect mappings that were previously writeable but subsequently
changed to read-only. Therefore the filter simply rejects any
mprotect(PROT_EXEC). The side-effect is that on arm64 with BTI support
(Branch Target Identification), the dynamic loader cannot change an ELF
section from PROT_EXEC to PROT_EXEC|PROT_BTI using mprotect(). For
libraries, it can resort to unmapping and re-mapping but for the main
executable it does not have a file descriptor. The original bug report in
the Red Hat bugzilla - [3] - and subsequent glibc workaround for libraries
- [4].
This series adds in-kernel support for this feature as a prctl
PR_SET_MDWE, that is inherited on fork(). The prctl denies PROT_WRITE |
PROT_EXEC mappings. Like the systemd BPF filter it also denies adding
PROT_EXEC to mappings. However unlike the BPF filter it only denies it if
the mapping didn't previous have PROT_EXEC. This allows to PROT_EXEC ->
PROT_EXEC | PROT_BTI with mprotect(), which is a problem with the BPF
filter.
This patch (of 2):
The aim of such policy is to prevent a user task from creating an
executable mapping that is also writeable.
An example of mmap() returning -EACCESS if the policy is enabled:
mmap(0, size, PROT_READ | PROT_WRITE | PROT_EXEC, flags, 0, 0);
Similarly, mprotect() would return -EACCESS below:
addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0);
mprotect(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC);
The BPF filter that systemd MDWE uses is stateless, and disallows
mprotect() with PROT_EXEC completely. This new prctl allows PROT_EXEC to
be enabled if it was already PROT_EXEC, which allows the following case:
addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0);
mprotect(addr, size, PROT_READ | PROT_EXEC | PROT_BTI);
where PROT_BTI enables branch tracking identification on arm64.
Link: https://lkml.kernel.org/r/20230119160344.54358-1-joey.gouly@arm.com
Link: https://lkml.kernel.org/r/20230119160344.54358-2-joey.gouly@arm.com
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: nd <nd@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Topi Miettinen <toiwoton@gmail.com>
Cc: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Right now there is no way to provide additional cflags/ldflags when
building tools/vm binaries. And using eg. make CFLAGS=<options> will
override the CFLAGS being set in the Makefile, making the build fail since
it requires the include of the ../lib dir (for libapi).
This change then allows you to specify:
CFLAGS=<options> LDFLAGS=<options> make V=1 -C tools/vm
And the options will be correctly appended as can be seen from the
make output.
Link: https://lkml.kernel.org/r/20230116224921.4106324-1-herton@redhat.com
Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Justin Forbes <jforbes@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Scott Weaver <scweaver@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We should use highmem replace higmem.
Link: https://lkml.kernel.org/r/20230118025403.1531-1-wangdeming@inspur.com
Signed-off-by: Deming Wang <wangdeming@inspur.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suppose memblock_alloc_range_nid() with highmem_start succeeds when
cma_declare_contiguous_nid is called with !fixed on a 32-bit system with
PHYS_ADDR_T_64BIT enabled with memblock.bottom_up == false.
But the next trial to memblock_alloc_range_nid() to allocate in [SIZE_4G,
limits) nullifies former successfully allocated addr and it retries
memblock_alloc_ragne_nid().
In this situation, the first successfully allocated address area is lost.
Change the order of allocation (SIZE_4G, high_memory and base) and check
whether the allocated succeeded to prevent potential memory loss.
Link: https://lkml.kernel.org/r/20230118080523.44522-1-ppbuk5246@gmail.com
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shadow_nodes is for shadow nodes reclaiming of workingset handling, it is
updated when page cache add or delete since long time ago workingset only
supported page cache. But when workingset supports anonymous page
detection, we missied updating shadow nodes for it. This caused that
shadow nodes of anonymous page will never be reclaimd by
scan_shadow_nodes() even they use much memory and system memory is tense.
So update shadow_nodes of anonymous page when swap cache is add or delete
by calling xas_set_update(..workingset_update_node).
Link: https://lkml.kernel.org/r/202301182013032211005@zte.com.cn
Fixes: aae466b005 ("mm/swap: implement workingset detection for anonymous LRU")
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Straightforward conversion of get_hwpoison_huge_page() to
get_hwpoison_hugetlb_folio(). Reduces two references to a head page in
memory-failure.c
[arnd@arndb.de: fix get_hwpoison_hugetlb_folio() stub]
Link: https://lkml.kernel.org/r/20230119111920.635260-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20230118174039.14247-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This changes key characteristics (pages per-zspage and objects per-zspage)
of a number of size classes which in results in different pool
configuration. With zspage chain size of 8 we have more size clases
clusters (123) and higher huge size class watermark (3632 bytes).
Please read zsmalloc documentation for more details.
Link: https://lkml.kernel.org/r/20230118005210.2814763-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove hard coded limit on the maximum number of physical pages
per-zspage.
This will allow tuning of zsmalloc pool as zspage chain size changes
`pages per-zspage` and `objects per-zspage` characteristics of size
classes which also affects size classes clustering (the way size classes
are merged).
Link: https://lkml.kernel.org/r/20230118005210.2814763-4-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If a class size is power of 2 then it wastes no memory and the best
configuration is 1 physical page per-zspage.
Link: https://lkml.kernel.org/r/20230118005210.2814763-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "zsmalloc: make zspage chain size configurable".
Computers are bad at division. We currently decide the best zspage chain
size (max number of physical pages per-zspage) by looking at a `used
percentage` value. This is not enough as we lose precision during usage
percentage calculations For example, let's look at size class 208:
pages per zspage wasted bytes used%
1 144 96
2 80 99
3 16 99
4 160 99
Current algorithm will select 2 page per zspage configuration, as it's the
first one to reach 99%. However, 3 pages per zspage waste less memory.
Change algorithm and select zspage configuration that has lowest wasted
value.
Link: https://lkml.kernel.org/r/20230118005210.2814763-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20230118005210.2814763-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Instead of directly accessing static deferred_pages, replace such
instances with the helper deferred_pages_enabled(). No functional change
is intended.
Link: https://lkml.kernel.org/r/20230105082506.241529-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
page_ext must be initialized after all struct pages are initialized.
Therefore, page_ext is initialized after page_alloc_init_late(), and can
optionally be initialized earlier via early_page_ext kernel parameter
which as a side effect also disables deferred struct pages.
Allow to automatically init page_ext early when there are no deferred
struct pages in order to be able to use page_ext during kernel boot and
track for example page allocations early.
[pasha.tatashin@soleen.com: fix build with CONFIG_PAGE_EXTENSION=n]
Link: https://lkml.kernel.org/r/20230118155251.2522985-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20230117204617.1553748-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sometimes there is no scheme in damon's context, for example just use damo
record to monitor workload's data access pattern.
If current damon context doesn't have any scheme in the list, kdamond has
no need to iterate over list of all targets and regions but do nothing.
So, skip apply schemes when ctx->schemes is empty.
Link: https://lkml.kernel.org/r/20230116062347.1148553-1-huaisheng.ye@intel.com
Signed-off-by: Huaisheng Ye <huaisheng.ye@intel.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The pointer file is being initialized with a value that is never read, it
is being re-assigned later on. Clean up code by removing the redundant
initialization.
Link: https://lkml.kernel.org/r/20230116164332.79500-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foudation.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace the uses of page with a folio. Also add a missing test for
workingset in the leading edge expansion.
Link: https://lkml.kernel.org/r/20230116193941.2148487-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The folio isn't returned from this function, so this is an entirely
internal change.
Link: https://lkml.kernel.org/r/20230116193941.2148487-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Some more filemap folio conversions".
Three more places which could easily be converted to folios. The third
one fixes a minor bug in readahead_expand(), but it's only a performance
bug and there are few users of readahead_expand(), so I don't think it's
worth backporting.
This patch (of 3):
Save a few calls to compound_head(). We specify exactly which page from
the folio to use by passing in start_pgoff, which means this will work for
a folio which is larger than PMD size. The rest of the VM isn't prepared
for that yet, but now this function is.
Link: https://lkml.kernel.org/r/20230116193941.2148487-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230116193941.2148487-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Avoid the compound_head() call in PageAnon() by passing in the folio that
all callers have. Also save me from wondering whether page->mapping can
ever be overwritten on a tail page (I don't think it can, but I'm not 100%
sure).
Link: https://lkml.kernel.org/r/20230116192959.2147032-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All callers now have a folio and can call munlock_vma_folio(). Update the
documentation to refer to munlock_vma_folio().
Link: https://lkml.kernel.org/r/20230116192827.2146732-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All callers now have a folio and can call mlock_vma_folio(). Update the
documentation to refer to mlock_vma_folio().
Link: https://lkml.kernel.org/r/20230116192827.2146732-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Only one caller doesn't have a folio, so move the page_folio() call to
that one caller from mem_cgroup_css_from_folio().
Link: https://lkml.kernel.org/r/20230116192507.2146150-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We still have to keep the page around because we need to know which page
in the folio we're copying, but we can replace five implict calls to
compound_head() with one.
Link: https://lkml.kernel.org/r/20230116191813.2145215-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
