This test stresses the race between of madvise(DONTNEED), a page fault
and a parallel huge page mmap, which should fail due to lack of
available page available for mapping.
This test case must run on a system with one and only one huge page
available.
# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
During setup, the test allocates the only available page, and starts
three threads:
- thread 1:
* madvise(MADV_DONTNEED) on the allocated huge page
- thread 2:
* Write to the allocated huge page
- thread 3:
* Tries to allocated (steal) an extra huge page (which is not
available)
thread 3 should never succeed in the allocation, since the only huge
page was never unmapped, and should be reserved.
Touching the old page after thread3 allocation will raise a SIGBUS.
Link: https://lkml.kernel.org/r/20240105155419.1939484-2-leitao@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Similarly to what's been done in commit 85716a80c1 ("kmsan: allow using
__msan_instrument_asm_store() inside runtime"), it should be safe to call
kmsan_unpoison_memory() from within the runtime, as it does not allocate
memory or take locks. Remove the redundant runtime checks.
This should fix false positives seen with CONFIG_DEBUG_LIST=y when
the non-instrumented lib/stackdepot.c failed to unpoison the memory
chunks later checked by the instrumented lib/list_debug.c
Also replace the implementation of kmsan_unpoison_entry_regs() with
a call to kmsan_unpoison_memory().
Link: https://lkml.kernel.org/r/20240124173134.1165747-1-glider@google.com
Fixes: f80be4571b ("kmsan: add KMSAN runtime core")
Signed-off-by: Alexander Potapenko <glider@google.com>
Tested-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: zswap: simplify zswap_swapoff()", v2.
These patches aim to simplify zswap_swapoff() by removing the unnecessary
trees cleanup code. Patch 1 makes sure that the order of operations
during swapoff is enforced correctly, making sure the simplification in
patch 2 is correct in a future-proof manner.
This patch (of 2):
In swap_range_free(), we update inuse_pages then do some cleanups (arch
invalidation, zswap invalidation, swap cache cleanups, etc). During
swapoff, try_to_unuse() checks that inuse_pages is 0 to make sure all swap
entries are freed. Make sure we only update inuse_pages after we are done
with the cleanups in swap_range_free(), and use the proper memory barriers
to enforce it. This makes sure that code following try_to_unuse() can
safely assume that swap_range_free() ran for all entries in thr swapfile
(e.g. swap cache cleanup, zswap_swapoff()).
In practice, this currently isn't a problem because swap_range_free() is
called with the swap info lock held, and the swapoff code happens to spin
for that after try_to_unuse(). However, this seems fragile and
unintentional, so make it more relable and future-proof. This also
facilitates a following simplification of zswap_swapoff().
Link: https://lkml.kernel.org/r/20240124045113.415378-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20240124045113.415378-2-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Each swapfile has one rb-tree to search the mapping of swp_entry_t to
zswap_entry, that use a spinlock to protect, which can cause heavy lock
contention if multiple tasks zswap_store/load concurrently.
Optimize the scalability problem by splitting the zswap rb-tree into
multiple rb-trees, each corresponds to SWAP_ADDRESS_SPACE_PAGES (64M),
just like we did in the swap cache address_space splitting.
Although this method can't solve the spinlock contention completely, it
can mitigate much of that contention. Below is the results of kernel
build in tmpfs with zswap shrinker enabled:
linux-next zswap-lock-optimize
real 1m9.181s 1m3.820s
user 17m44.036s 17m40.100s
sys 7m37.297s 4m54.622s
So there are clearly improvements.
Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-2-b5cc55479090@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chriscli@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/zswap: optimize the scalability of zswap rb-tree", v2.
When testing the zswap performance by using kernel build -j32 in a tmpfs
directory, I found the scalability of zswap rb-tree is not good, which is
protected by the only spinlock. That would cause heavy lock contention if
multiple tasks zswap_store/load concurrently.
So a simple solution is to split the only one zswap rb-tree into multiple
rb-trees, each corresponds to SWAP_ADDRESS_SPACE_PAGES (64M). This idea
is from the commit 4b3ef9daa4 ("mm/swap: split swap cache into 64MB
trunks").
Although this method can't solve the spinlock contention completely, it
can mitigate much of that contention. Below is the results of kernel
build in tmpfs with zswap shrinker enabled:
linux-next zswap-lock-optimize
real 1m9.181s 1m3.820s
user 17m44.036s 17m40.100s
sys 7m37.297s 4m54.622s
So there are clearly improvements. And it's complementary with the
ongoing zswap xarray conversion by Chris. Anyway, I think we can also
merge this first, it's complementary IMHO. So I just refresh and resend
this for further discussion.
This patch (of 2):
Not all zswap interfaces can handle the absence of the zswap rb-tree,
actually only zswap_store() has handled it for now.
To make things simple, we make sure each swapfile always have the zswap
rb-tree prepared before being enabled and used. The preparation is
unlikely to fail in practice, this patch just make it explicit.
Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-0-b5cc55479090@bytedance.com
Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-1-b5cc55479090@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chriscli@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 2cafb58217 ("mempolicy: remove confusing MPOL_MF_LAZY dead code")
removes MPOL_MF_LAZY handling in queue_pages_test_walk(), and with that,
there is no effective use of the local variable endvma in that function
remaining.
Remove the local variable endvma and its dead code. No functional change.
This issue was identified with clang-analyzer's dead stores analysis.
Link: https://lkml.kernel.org/r/20240122092504.18377-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The local variables r_tmp and l_tmp in mast_spanning_rebalance() are
already initialized at its declaration; there is no need to assign the
value again.
Remove the duplicate initialization of {r,l}_tmp. No functional change.
Due to common compiler optimizations, also no change to object code.
This issue was identified with clang-analyzer's dead stores analysis.
Link: https://lkml.kernel.org/r/20240122102000.29558-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When running with CATEGORY= (thp | hugetlb) we see a large numbers of
tests failing. These failures are due to not being able to allocate a
hugepage and normally occur on memory contrainted systems or when using
large page sizes.
drop_cache and compact_memory before the tests for a higher chance at a
successful hugepage allocation.
Link: https://lkml.kernel.org/r/20240117180037.15734-1-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
One of our workloads (Postgres 14) has regressed when migrated from 5.10
to 6.1 upstream kernel. The regression can be reproduced by sysbench's
oltp_write_only benchmark. It seems like the always on rstat flush in
mem_cgroup_wb_stats() is causing the regression. So, rate limit that
specific rstat flush. One potential consequence would be the dirty
throttling might be decided on stale memcg stats. However from our
benchmarks and production traffic we have not observed any change in the
dirty throttling behavior of the application.
Link: https://lkml.kernel.org/r/20240118184235.618164-1-shakeelb@google.com
Fixes: 2d146aa3aa ("mm: memcontrol: switch to rstat")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The GFP flags from vma_thp_gfp_mask() according to user configuration only
used for large folio allocation but not for memory cgroup charge, and
GFP_KERNEL is used for both order-0 and large order folio when memory
cgroup charge at present. However, mem_cgroup_charge() uses the GFP flags
in a fairly sophisticated way. In addition to checking
gfpflags_allow_blocking(), it pays attention to __GFP_NORETRY and
__GFP_RETRY_MAYFAIL to ensure that processes within this memcg do not
exceed their quotas.
So we'd better to move mem_cgroup_charge() into alloc_anon_folio(),
1) it will make us to allocate as much as possible large order folio,
because we could try the next order if mem_cgroup_charge() fails,
although the memcg's memory usage is close to its limits.
2) using same GFP flags for allocation and charge is to be consistent
with PMD THP firstly, in addition, according to GFP flag returned from
vma_thp_gfp_mask(), GFP_TRANSHUGE_LIGHT could make us skip direct
reclaim, _GFP_NORETRY will make us skip mem_cgroup_oom() and won't
trigger memory cgroup oom from large order(order <= COSTLY_ORDER) folio
charging.
Link: https://lkml.kernel.org/r/20240122011612.501029-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240117103954.2756050-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With the proliferation of large folios for file-backed memory, and more
recently the introduction of multi-size THP for anonymous memory, it is
becoming useful to be able to see exactly how large folios are mapped into
processes. For some architectures (e.g. arm64), if most memory is mapped
using contpte-sized and -aligned blocks, TLB usage can be optimized so
it's useful to see where these requirements are and are not being met.
thpmaps is a Python utility that reads /proc/<pid>/smaps,
/proc/<pid>/pagemap and /proc/kpageflags to print information about how
transparent huge pages (both file and anon) are mapped to a specified
process or cgroup. It aims to help users debug and optimize their
workloads. In future we may wish to introduce stats directly into the
kernel (e.g. smaps or similar), but for now this provides a short term
solution without the need to introduce any new ABI.
Run with help option for a full listing of the arguments:
# ./thpmaps --help
--8<--
usage: thpmaps [-h] [--pid pid | --cgroup path] [--rollup]
[--cont size[KMG]] [--inc-smaps] [--inc-empty]
[--periodic sleep_ms]
Prints information about how transparent huge pages are mapped, either
system-wide, or for a specified process or cgroup.
When run with --pid, the user explicitly specifies the set of pids to
scan. e.g. "--pid 10 [--pid 134 ...]". When run with --cgroup, the user
passes either a v1 or v2 cgroup and all pids that belong to the cgroup
subtree are scanned. When run with neither --pid nor --cgroup, the full
set of pids on the system is gathered from /proc and scanned as if the
user had provided "--pid 1 --pid 2 ...".
A default set of statistics is always generated for THP mappings.
However, it is also possible to generate additional statistics for
"contiguous block mappings" where the block size is user-defined.
Statistics are maintained independently for anonymous and file-backed
(pagecache) memory and are shown both in kB and as a percentage of either
total anonymous or total file-backed memory as appropriate.
THP Statistics
--------------
Statistics are always generated for fully- and contiguously-mapped THPs
whose mapping address is aligned to their size, for each <size> supported
by the system. Separate counters describe THPs mapped by PTE vs those
mapped by PMD. (Although note a THP can only be mapped by PMD if it is
PMD-sized):
- anon-thp-pte-aligned-<size>kB
- file-thp-pte-aligned-<size>kB
- anon-thp-pmd-aligned-<size>kB
- file-thp-pmd-aligned-<size>kB
Similarly, statistics are always generated for fully- and contiguously-
mapped THPs whose mapping address is *not* aligned to their size, for each
<size> supported by the system. Due to the unaligned mapping, it is
impossible to map by PMD, so there are only PTE counters for this case:
- anon-thp-pte-unaligned-<size>kB
- file-thp-pte-unaligned-<size>kB
Statistics are also always generated for mapped pages that belong to a THP
but where the is THP is *not* fully- and contiguously- mapped. These
"partial" mappings are all counted in the same counter regardless of the
size of the THP that is partially mapped:
- anon-thp-pte-partial
- file-thp-pte-partial
Contiguous Block Statistics
---------------------------
An optional, additional set of statistics is generated for every
contiguous block size specified with `--cont <size>`. These statistics
show how much memory is mapped in contiguous blocks of <size> and also
aligned to <size>. A given contiguous block must all belong to the same
THP, but there is no requirement for it to be the *whole* THP. Separate
counters describe contiguous blocks mapped by PTE vs those mapped by PMD:
- anon-cont-pte-aligned-<size>kB
- file-cont-pte-aligned-<size>kB
- anon-cont-pmd-aligned-<size>kB
- file-cont-pmd-aligned-<size>kB
As an example, if monitoring 64K contiguous blocks (--cont 64K), there are
a number of sources that could provide such blocks: a fully- and
contiguously-mapped 64K THP that is aligned to a 64K boundary would
provide 1 block. A fully- and contiguously-mapped 128K THP that is
aligned to at least a 64K boundary would provide 2 blocks. Or a 128K THP
that maps its first 100K, but contiguously and starting at a 64K boundary
would provide 1 block. A fully- and contiguously-mapped 2M THP would
provide 32 blocks. There are many other possible permutations.
options:
-h, --help show this help message and exit
--pid pid Process id of the target process. Maybe issued
multiple times to scan multiple processes. --pid
and --cgroup are mutually exclusive. If neither
are provided, all processes are scanned to
provide system-wide information.
--cgroup path Path to the target cgroup in sysfs. Iterates
over every pid in the cgroup and its children.
--pid and --cgroup are mutually exclusive. If
neither are provided, all processes are scanned
to provide system-wide information.
--rollup Sum the per-vma statistics to provide a summary
over the whole system, process or cgroup.
--cont size[KMG] Adds stats for memory that is mapped in
contiguous blocks of <size> and also aligned to
<size>. May be issued multiple times to track
multiple sized blocks. Useful to infer e.g.
arm64 contpte and hpa mappings. Size must be a
power-of-2 number of pages.
--inc-smaps Include all numerical, additive
/proc/<pid>/smaps stats in the output.
--inc-empty Show all statistics including those whose value
is 0.
--periodic sleep_ms Run in a loop, polling every sleep_ms
milliseconds.
Requires root privilege to access pagemap and kpageflags.
--8<--
Example command to summarise fully and partially mapped THPs and 64K
contiguous blocks over all VMAs in all processes in the system
(--inc-empty forces printing stats that are 0):
# ./thpmaps --cont 64K --rollup --inc-empty
--8<--
anon-thp-pmd-aligned-2048kB: 139264 kB ( 6%)
file-thp-pmd-aligned-2048kB: 0 kB ( 0%)
anon-thp-pte-aligned-16kB: 0 kB ( 0%)
anon-thp-pte-aligned-32kB: 0 kB ( 0%)
anon-thp-pte-aligned-64kB: 72256 kB ( 3%)
anon-thp-pte-aligned-128kB: 0 kB ( 0%)
anon-thp-pte-aligned-256kB: 0 kB ( 0%)
anon-thp-pte-aligned-512kB: 0 kB ( 0%)
anon-thp-pte-aligned-1024kB: 0 kB ( 0%)
anon-thp-pte-aligned-2048kB: 0 kB ( 0%)
anon-thp-pte-unaligned-16kB: 0 kB ( 0%)
anon-thp-pte-unaligned-32kB: 0 kB ( 0%)
anon-thp-pte-unaligned-64kB: 0 kB ( 0%)
anon-thp-pte-unaligned-128kB: 0 kB ( 0%)
anon-thp-pte-unaligned-256kB: 0 kB ( 0%)
anon-thp-pte-unaligned-512kB: 0 kB ( 0%)
anon-thp-pte-unaligned-1024kB: 0 kB ( 0%)
anon-thp-pte-unaligned-2048kB: 0 kB ( 0%)
anon-thp-pte-partial: 63232 kB ( 3%)
file-thp-pte-aligned-16kB: 809024 kB (47%)
file-thp-pte-aligned-32kB: 43168 kB ( 3%)
file-thp-pte-aligned-64kB: 98496 kB ( 6%)
file-thp-pte-aligned-128kB: 17536 kB ( 1%)
file-thp-pte-aligned-256kB: 0 kB ( 0%)
file-thp-pte-aligned-512kB: 0 kB ( 0%)
file-thp-pte-aligned-1024kB: 0 kB ( 0%)
file-thp-pte-aligned-2048kB: 0 kB ( 0%)
file-thp-pte-unaligned-16kB: 21712 kB ( 1%)
file-thp-pte-unaligned-32kB: 704 kB ( 0%)
file-thp-pte-unaligned-64kB: 896 kB ( 0%)
file-thp-pte-unaligned-128kB: 44928 kB ( 3%)
file-thp-pte-unaligned-256kB: 0 kB ( 0%)
file-thp-pte-unaligned-512kB: 0 kB ( 0%)
file-thp-pte-unaligned-1024kB: 0 kB ( 0%)
file-thp-pte-unaligned-2048kB: 0 kB ( 0%)
file-thp-pte-partial: 9252 kB ( 1%)
anon-cont-pmd-aligned-64kB: 139264 kB ( 6%)
file-cont-pmd-aligned-64kB: 0 kB ( 0%)
anon-cont-pte-aligned-64kB: 100672 kB ( 4%)
file-cont-pte-aligned-64kB: 161856 kB ( 9%)
--8<--
Link: https://lkml.kernel.org/r/20240116141235.960842-1-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Barry Song <v-songbaohua@oppo.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zenghui Yu <yuzenghui@huawei.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The core-api create_workqueue is deprecated, this patch replaces the
create_workqueue with alloc_workqueue. The previous implementation
workqueue of zswap was a bounded workqueue, this patch uses
alloc_workqueue() to create an unbounded workqueue. The WQ_UNBOUND
attribute is desirable making the workqueue not localized to a specific
cpu so that the scheduler is free to exercise improvisations in any
demanding scenarios for offloading cpu time slices for workqueues. For
example if any other workqueues of the same primary cpu had to be served
which are WQ_HIGHPRI and WQ_CPU_INTENSIVE. Also Unbound workqueue happens
to be more efficient in a system during memory pressure scenarios in
comparison to a bounded workqueue.
shrink_wq = alloc_workqueue("zswap-shrink",
WQ_UNBOUND|WQ_MEM_RECLAIM, 1);
Overall the change suggested in this patch should be seamless and does not
alter the existing behavior, other than the improvisation to be an
unbounded workqueue.
Link: https://lkml.kernel.org/r/20240116133145.12454-1-debug.penguin32@gmail.com
Signed-off-by: Ronald Monthero <debug.penguin32@gmail.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A while loop is used to adjust the new_order to be lower than the
ra->size. ilog2 could be used to do the same instead of using a loop.
ilog2 typically resolves to a bit scan reverse instruction. This is
particularly useful when ra->size is smaller than the 2^new_order as it
resolves in one instruction instead of looping to find the new_order.
No functional changes.
Link: https://lkml.kernel.org/r/20240115102523.2336742-1-kernel@pankajraghav.com
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace some goto statements with return statements so that unmap() is not
called on an undefined address. This change is made so that unmap() can
only be reached after mmap() is called (and the address mentioned is
defined). Returning MAP_FAILED seems acceptable since client code checks
for this value.
Link: https://lkml.kernel.org/r/20240105202401.28851-1-inwardvessel@gmail.com
Fixes: 42096aa24b ("selftest/mm: ksm_functional_tests: test in mmap_and_merge_range() if anything got merged")
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
MEM_PREPARE_ONLINE memory notifier makes memory block physical
accessible via sclp assign command. The notifier ensures self-contained
memory maps are accessible and hence enabling the "memmap on memory" on
s390.
MEM_FINISH_OFFLINE memory notifier shifts the memory block to an
inaccessible state via sclp unassign command.
Implementation considerations:
* When MHP_MEMMAP_ON_MEMORY is disabled, the system retains the old
behavior. This means the memory map is allocated from default memory.
* If MACHINE_HAS_EDAT1 is unavailable, MHP_MEMMAP_ON_MEMORY is
automatically disabled. This ensures that vmemmap pagetables do not
consume additional memory from the default memory allocator.
* The MEM_GOING_ONLINE notifier has been modified to perform no
operation, as MEM_PREPARE_ONLINE already executes the sclp assign
command.
* The MEM_CANCEL_ONLINE/MEM_OFFLINE notifier now performs no operation, as
MEM_FINISH_OFFLINE already executes the sclp unassign command.
Link: https://lkml.kernel.org/r/20240108132747.3238763-5-sumanthk@linux.ibm.com
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.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>
