- The 6 patch series "panic: sys_info: Refactor and fix a potential
issue" from Andy Shevchenko fixes a build issue and does some cleanup in
ib/sys_info.c.
- The 9 patch series "Implement mul_u64_u64_div_u64_roundup()" from
David Laight enhances the 64-bit math code on behalf of a PWM driver and
beefs up the test module for these library functions.
- The 2 patch series "scripts/gdb/symbols: make BPF debug info available
to GDB" from Ilya Leoshkevich makes BPF symbol names, sizes, and line
numbers available to the GDB debugger.
- The 4 patch series "Enable hung_task and lockup cases to dump system
info on demand" from Feng Tang adds a sysctl which can be used to cause
additional info dumping when the hung-task and lockup detectors fire.
- The 6 patch series "lib/base64: add generic encoder/decoder, migrate
users" from Kuan-Wei Chiu adds a general base64 encoder/decoder to lib/
and migrates several users away from their private implementations.
- The 2 patch series "rbree: inline rb_first() and rb_last()" from Eric
Dumazet makes TCP a little faster.
- The 9 patch series "liveupdate: Rework KHO for in-kernel users" from
Pasha Tatashin reworks the KEXEC Handover interfaces in preparation for
Live Update Orchestrator (LUO), and possibly for other future clients.
- The 13 patch series "kho: simplify state machine and enable dynamic
updates" from Pasha Tatashin increases the flexibility of KEXEC
Handover. Also preparation for LUO.
- The 18 patch series "Live Update Orchestrator" from Pasha Tatashin is
a major new feature targeted at cloud environments. Quoting the [0/N]:
This series introduces the Live Update Orchestrator, a kernel subsystem
designed to facilitate live kernel updates using a kexec-based reboot.
This capability is critical for cloud environments, allowing hypervisors
to be updated with minimal downtime for running virtual machines. LUO
achieves this by preserving the state of selected resources, such as
memory, devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving memfd file
descriptors, which allows critical in-memory data, such as guest RAM or
any other large memory region, to be maintained in RAM across the kexec
reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- The 3 patch series "kexec: reorganize kexec and kdump sysfs" from
Sourabh Jain moves the kexec and kdump sysfs entries from /sys/kernel/
to /sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day.
- The 2 patch series "kho: fixes for vmalloc restoration" from Mike
Rapoport fixes a BUG which was being hit during KHO restoration of
vmalloc() regions.
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Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
fixes a build issue and does some cleanup in ib/sys_info.c
- "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
enhances the 64-bit math code on behalf of a PWM driver and beefs up
the test module for these library functions
- "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
makes BPF symbol names, sizes, and line numbers available to the GDB
debugger
- "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
adds a sysctl which can be used to cause additional info dumping when
the hung-task and lockup detectors fire
- "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
adds a general base64 encoder/decoder to lib/ and migrates several
users away from their private implementations
- "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
makes TCP a little faster
- "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
reworks the KEXEC Handover interfaces in preparation for Live Update
Orchestrator (LUO), and possibly for other future clients
- "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
increases the flexibility of KEXEC Handover. Also preparation for LUO
- "Live Update Orchestrator" (Pasha Tatashin)
is a major new feature targeted at cloud environments. Quoting the
cover letter:
This series introduces the Live Update Orchestrator, a kernel
subsystem designed to facilitate live kernel updates using a
kexec-based reboot. This capability is critical for cloud
environments, allowing hypervisors to be updated with minimal
downtime for running virtual machines. LUO achieves this by
preserving the state of selected resources, such as memory,
devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving
memfd file descriptors, which allows critical in-memory data, such
as guest RAM or any other large memory region, to be maintained in
RAM across the kexec reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
moves the kexec and kdump sysfs entries from /sys/kernel/ to
/sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day
- "kho: fixes for vmalloc restoration" (Mike Rapoport)
fixes a BUG which was being hit during KHO restoration of vmalloc()
regions
* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
calibrate: update header inclusion
Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
vmcoreinfo: track and log recoverable hardware errors
kho: fix restoring of contiguous ranges of order-0 pages
kho: kho_restore_vmalloc: fix initialization of pages array
MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
init: replace simple_strtoul with kstrtoul to improve lpj_setup
KHO: fix boot failure due to kmemleak access to non-PRESENT pages
Documentation/ABI: new kexec and kdump sysfs interface
Documentation/ABI: mark old kexec sysfs deprecated
kexec: move sysfs entries to /sys/kernel/kexec
test_kho: always print restore status
kho: free chunks using free_page() instead of kfree()
selftests/liveupdate: add kexec test for multiple and empty sessions
selftests/liveupdate: add simple kexec-based selftest for LUO
selftests/liveupdate: add userspace API selftests
docs: add documentation for memfd preservation via LUO
mm: memfd_luo: allow preserving memfd
liveupdate: luo_file: add private argument to store runtime state
mm: shmem: export some functions to internal.h
...
If there is an error half way through KHO memory preservation, we should
rollback and unpreserve everything that is partially preserved.
[akpm@linux-foundation.org: s/err_no_fdt_page/err_report/ in prepare_kho_fdt(), per Mike]
Link: https://lkml.kernel.org/r/20251101142325.1326536-5-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Suggested-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The KHO framework uses a notifier chain as the mechanism for clients to
participate in the finalization process. While this works for a single,
central state machine, it is too restrictive for kernel-internal
components like pstore/reserve_mem or IMA. These components need a
simpler, direct way to register their state for preservation (e.g., during
their initcall) without being part of a complex, shutdown-time notifier
sequence. The notifier model forces all participants into a single
finalization flow and makes direct preservation from an arbitrary context
difficult. This patch refactors the client participation model by
removing the notifier chain and introducing a direct API for managing FDT
subtrees.
The core kho_finalize() and kho_abort() state machine remains, but clients
now register their data with KHO beforehand.
Link: https://lkml.kernel.org/r/20251101142325.1326536-3-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
memblock_estimated_nr_free_pages() returns the difference between the total
size of the "memory" memblock type and the "reserved" memblock type.
The "soft-reserved" memory regions are added to the "reserved" memblock
type, but not to the "memory" memblock type. Therefore,
memblock_estimated_nr_free_pages() may return a smaller value than
expected, or if it underflows, an extremely large value.
/proc/sys/kernel/threads-max is determined by the value of
memblock_estimated_nr_free_pages(). This issue was discovered on machines
with CXL memory because kernel.threads-max was either smaller than expected
or extremely large for the installed DRAM size.
This fixes the issue by replacing memblock_reserved_size() with
memblock_reserved_kern_size() that tells how much memory was
reserved from the actual RAM.
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Link: https://patch.msgid.link/20251111010010.7800-1-akinobu.mita@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
to make it clear that KHO operates on pages rather than on a random
physical address.
The kho_preserve_pages() will be also used in upcoming support for vmalloc
preservation.
Link: https://lkml.kernel.org/r/20250921054458.4043761-3-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
for_each_free_mem_pfn_range_in_zone_from() and its "backend" implementation
__next_mem_pfn_range_in_zone() were only used by deferred initialization of
the memory map.
Remove them as they are not used anymore.
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
The kernel-doc description of MEMBLOCK_RSRV_NOINIT and
memblock_reserved_mark_noinit() do not accurately describe their
functionality.
Expand their kernel doc to make it clear that the user of
MEMBLOCK_RSRV_NOINIT is responsible to properly initialize the struct pages
for such regions and add more details about effects of using this flag.
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/f8140a17-c4ec-489b-b314-d45abe48bf36@redhat.com
Link: https://lore.kernel.org/r/20250826071947.1949725-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Replace the manual bitwise conversion of bytes to MB with
SZ_1M macro, a standard macro used within the mm subsystem,
to improve readability.
Signed-off-by: Pratyush Brahma <pratyush.brahma@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250820-numa-memblks-refac-v2-1-43bf1af02acd@oss.qualcomm.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Linux has recently gained support for "reserve_mem": A mechanism to
allocate a region of memory early enough in boot that we can cross our
fingers and hope it stays at the same location during most boots, so we
can store for example ftrace buffers into it.
Thanks to KASLR, we can never be really sure that "reserve_mem"
allocations are static across kexec. Let's teach it KHO awareness so that
it serializes its reservations on kexec exit and deserializes them again
on boot, preserving the exact same mapping across kexec.
This is an example user for KHO in the KHO patch set to ensure we have at
least one (not very controversial) user in the tree before extending KHO's
use to more subsystems.
Link: https://lkml.kernel.org/r/20250509074635.3187114-16-changyuanl@google.com
Signed-off-by: Alexander Graf <graf@amazon.com>
Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Co-developed-by: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When we have a KHO kexec, we get an FDT blob and scratch region to
populate the state of the system. Provide helper functions that allow
architecture code to easily handle memory reservations based on them and
give device drivers visibility into the KHO FDT and memory reservations so
they can recover their own state.
Include a fix from Arnd Bergmann <arnd@arndb.de>
https://lore.kernel.org/lkml/20250424093302.3894961-1-arnd@kernel.org/.
Link: https://lkml.kernel.org/r/20250509074635.3187114-6-changyuanl@google.com
Signed-off-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Co-developed-by: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With deferred initialization of struct page it will be necessary to
initialize memory map for KHO scratch regions early.
Add memmap_init_kho_scratch() method that will allow such initialization
in upcoming patches.
Link: https://lkml.kernel.org/r/20250509074635.3187114-4-changyuanl@google.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With KHO (Kexec HandOver), we need a way to ensure that the new kernel
does not allocate memory on top of any memory regions that the previous
kernel was handing over. But to know where those are, we need to include
them in the memblock.reserved array which may not be big enough to hold
all ranges that need to be persisted across kexec. To resize the array,
we need to allocate memory. That brings us into a catch 22 situation.
The solution to that is limit memblock allocations to the scratch regions:
safe regions to operate in the case when there is memory that should
remain intact across kexec.
KHO provides several "scratch regions" as part of its metadata. These
scratch regions are contiguous memory blocks that known not to contain any
memory that should be persisted across kexec. These regions should be
large enough to accommodate all memblock allocations done by the kexeced
kernel.
We introduce a new memblock_set_scratch_only() function that allows KHO to
indicate that any memblock allocation must happen from the scratch
regions.
Later, we may want to perform another KHO kexec. For that, we reuse the
same scratch regions. To ensure that no eventually handed over data gets
allocated inside a scratch region, we flip the semantics of the scratch
region with memblock_clear_scratch_only(): After that call, no allocations
may happen from scratch memblock regions. We will lift that restriction
in the next patch.
Link: https://lkml.kernel.org/r/20250509074635.3187114-3-changyuanl@google.com
Signed-off-by: Alexander Graf <graf@amazon.com>
Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "kexec: introduce Kexec HandOver (KHO)", v8.
Kexec today considers itself purely a boot loader: When we enter the new
kernel, any state the previous kernel left behind is irrelevant and the
new kernel reinitializes the system.
However, there are use cases where this mode of operation is not what we
actually want. In virtualization hosts for example, we want to use kexec
to update the host kernel while virtual machine memory stays untouched.
When we add device assignment to the mix, we also need to ensure that
IOMMU and VFIO states are untouched. If we add PCIe peer to peer DMA, we
need to do the same for the PCI subsystem. If we want to kexec while an
SEV-SNP enabled virtual machine is running, we need to preserve the VM
context pages and physical memory. See "pkernfs: Persisting guest memory
and kernel/device state safely across kexec" Linux Plumbers Conference
2023 presentation for details:
https://lpc.events/event/17/contributions/1485/
To start us on the journey to support all the use cases above, this patch
implements basic infrastructure to allow hand over of kernel state across
kexec (Kexec HandOver, aka KHO). As a really simple example target, we
use memblock's reserve_mem.
With this patchset applied, memory that was reserved using "reserve_mem"
command line options remains intact after kexec and it is guaranteed to
reside at the same physical address.
== Alternatives ==
There are alternative approaches to (parts of) the problems above:
* Memory Pools [1] - preallocated persistent memory region + allocator
* PRMEM [2] - resizable persistent memory regions with fixed metadata
pointer on the kernel command line + allocator
* Pkernfs [3] - preallocated file system for in-kernel data with fixed
address location on the kernel command line
* PKRAM [4] - handover of user space pages using a fixed metadata page
specified via command line
All of the approaches above fundamentally have the same problem: They
require the administrator to explicitly carve out a physical memory
location because they have no mechanism outside of the kernel command line
to pass data (including memory reservations) between kexec'ing kernels.
KHO provides that base foundation. We will determine later whether we
still need any of the approaches above for fast bulk memory handover of
for example IOMMU page tables. But IMHO they would all be users of KHO,
with KHO providing the foundational primitive to pass metadata and bulk
memory reservations as well as provide easy versioning for data.
== Overview ==
We introduce a metadata file that the kernels pass between each other.
How they pass it is architecture specific. The file's format is a
Flattened Device Tree (fdt) which has a generator and parser already
included in Linux. KHO is enabled in the kernel command line by `kho=on`.
When the root user enables KHO through
/sys/kernel/debug/kho/out/finalize, the kernel invokes callbacks to every
KHO users to register preserved memory regions, which contain drivers'
states.
When the actual kexec happens, the fdt is part of the image set that we
boot into. In addition, we keep "scratch regions" available for kexec:
physically contiguous memory regions that are guaranteed to not have any
memory that KHO would preserve. The new kernel bootstraps itself using
the scratch regions and sets all handed over memory as in use. When
drivers initialize that support KHO, they introspect the fdt, restore
preserved memory regions, and retrieve their states stored in the
preserved memory.
== Limitations ==
Currently KHO is only implemented for file based kexec. The kernel
interfaces in the patch set are already in place to support user space
kexec as well, but it is still not implemented it yet inside kexec tools.
== How to Use ==
To use the code, please boot the kernel with the "kho=on" command line
parameter. KHO will automatically create scratch regions. If you want to
set the scratch size explicitly you can use "kho_scratch=" command line
parameter. For instance, "kho_scratch=16M,512M,256M" will reserve a 16
MiB low memory scratch area, a 512 MiB global scratch region, and 256 MiB
per NUMA node scratch regions on boot.
Make sure to have a reserved memory range requested with reserv_mem
command line option, for example, "reserve_mem=64m:4k:n1".
Then before you invoke file based "kexec -l", finalize KHO FDT:
# echo 1 > /sys/kernel/debug/kho/out/finalize
You can preview the generated FDT using `dtc`,
# dtc /sys/kernel/debug/kho/out/fdt
# dtc /sys/kernel/debug/kho/out/sub_fdts/memblock
`dtc` is available on ubuntu by `sudo apt-get install device-tree-compiler`.
Now kexec into the new kernel,
# kexec -l Image --initrd=initrd -s
# kexec -e
(The order of KHO finalization and "kexec -l" does not matter.)
The new kernel will boot up and contain the previous kernel's reserve_mem
contents at the same physical address as the first kernel.
You can also review the FDT passed from the old kernel,
# dtc /sys/kernel/debug/kho/in/fdt
# dtc /sys/kernel/debug/kho/in/sub_fdts/memblock
This patch (of 17):
To denote areas that were reserved for kernel use either directly with
memblock_reserve_kern() or via memblock allocations.
Link: https://lore.kernel.org/lkml/20250424083258.2228122-1-changyuanl@google.com/
Link: https://lore.kernel.org/lkml/aAeaJ2iqkrv_ffhT@kernel.org/
Link: https://lore.kernel.org/lkml/35c58191-f774-40cf-8d66-d1e2aaf11a62@intel.com/
Link: https://lore.kernel.org/lkml/20250424093302.3894961-1-arnd@kernel.org/
Link: https://lkml.kernel.org/r/20250509074635.3187114-1-changyuanl@google.com
Link: https://lkml.kernel.org/r/20250509074635.3187114-2-changyuanl@google.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Co-developed-by: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Will Deacon <will@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When increasing the array size in memblock_double_array() and the slab
is not yet available, a call to memblock_find_in_range() is used to
reserve/allocate memory. However, the range returned may not have been
accepted, which can result in a crash when booting an SNP guest:
RIP: 0010:memcpy_orig+0x68/0x130
Code: ...
RSP: 0000:ffffffff9cc03ce8 EFLAGS: 00010006
RAX: ff11001ff83e5000 RBX: 0000000000000000 RCX: fffffffffffff000
RDX: 0000000000000bc0 RSI: ffffffff9dba8860 RDI: ff11001ff83e5c00
RBP: 0000000000002000 R08: 0000000000000000 R09: 0000000000002000
R10: 000000207fffe000 R11: 0000040000000000 R12: ffffffff9d06ef78
R13: ff11001ff83e5000 R14: ffffffff9dba7c60 R15: 0000000000000c00
memblock_double_array+0xff/0x310
memblock_add_range+0x1fb/0x2f0
memblock_reserve+0x4f/0xa0
memblock_alloc_range_nid+0xac/0x130
memblock_alloc_internal+0x53/0xc0
memblock_alloc_try_nid+0x3d/0xa0
swiotlb_init_remap+0x149/0x2f0
mem_init+0xb/0xb0
mm_core_init+0x8f/0x350
start_kernel+0x17e/0x5d0
x86_64_start_reservations+0x14/0x30
x86_64_start_kernel+0x92/0xa0
secondary_startup_64_no_verify+0x194/0x19b
Mitigate this by calling accept_memory() on the memory range returned
before the slab is available.
Prior to v6.12, the accept_memory() interface used a 'start' and 'end'
parameter instead of 'start' and 'size', therefore the accept_memory()
call must be adjusted to specify 'start + size' for 'end' when applying
to kernels prior to v6.12.
Cc: stable@vger.kernel.org # see patch description, needs adjustments for <= 6.11
Fixes: dcdfdd40fa ("mm: Add support for unaccepted memory")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/da1ac73bf4ded761e21b4e4bb5178382a580cd73.1746725050.git.thomas.lendacky@amd.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Commit 61167ad5fe ("mm: pass nid to reserve_bootmem_region()") introduce
a way to set nid to all reserved region.
But there is a corner case it will leave some region with invalid nid.
When memblock_set_node() doubles the array of memblock.reserved, it may
lead to a new reserved region before current position. The new region
will be left with an invalid node id.
Repeat the process when detecting it.
Fixes: 61167ad5fe ("mm: pass nid to reserve_bootmem_region()")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Mike Rapoport <rppt@kernel.org>
CC: Yajun Deng <yajun.deng@linux.dev>
CC: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250318071948.23854-3-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
The second parameter of memblock_set_node() is size instead of end.
Since it iterates from lower address to higher address, finally the node
id is correct. But during the process, some of them are wrong.
Pass size instead of end.
Fixes: 61167ad5fe ("mm: pass nid to reserve_bootmem_region()")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Mike Rapoport <rppt@kernel.org>
CC: Yajun Deng <yajun.deng@linux.dev>
CC: stable@vger.kernel.org
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20250318071948.23854-2-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Uros Bizjak uses x86 named address space qualifiers to provide
compile-time checking of percpu area accesses.
This has caused a small amount of fallout - two or three issues were
reported. In all cases the calling code was founf to be incorrect.
- The 4 patch series "Some cleanup for memcg" from Chen Ridong
implements some relatively monir cleanups for the memcontrol code.
- The 17 patch series "mm: fixes for device-exclusive entries (hmm)"
from David Hildenbrand fixes a boatload of issues which David found then
using device-exclusive PTE entries when THP is enabled. More work is
needed, but this makes thins better - our own HMM selftests now succeed.
- The 2 patch series "mm: zswap: remove z3fold and zbud" from Yosry
Ahmed remove the z3fold and zbud implementations. They have been
deprecated for half a year and nobody has complained.
- The 5 patch series "mm: further simplify VMA merge operation" from
Lorenzo Stoakes implements numerous simplifications in this area. No
runtime effects are anticipated.
- The 4 patch series "mm/madvise: remove redundant mmap_lock operations
from process_madvise()" from SeongJae Park rationalizes the locking in
the madvise() implementation. Performance gains of 20-25% were observed
in one MADV_DONTNEED microbenchmark.
- The 12 patch series "Tiny cleanup and improvements about SWAP code"
from Baoquan He contains a number of touchups to issues which Baoquan
noticed when working on the swap code.
- The 2 patch series "mm: kmemleak: Usability improvements" from Catalin
Marinas implements a couple of improvements to the kmemleak user-visible
output.
- The 2 patch series "mm/damon/paddr: fix large folios access and
schemes handling" from Usama Arif provides a couple of fixes for DAMON's
handling of large folios.
- The 3 patch series "mm/damon/core: fix wrong and/or useless
damos_walk() behaviors" from SeongJae Park fixes a few issues with the
accuracy of kdamond's walking of DAMON regions.
- The 3 patch series "expose mapping wrprotect, fix fb_defio use" from
Lorenzo Stoakes changes the interaction between framebuffer deferred-io
and core MM. No functional changes are anticipated - this is
preparatory work for the future removal of page structure fields.
- The 4 patch series "mm/damon: add support for hugepage_size DAMOS
filter" from Usama Arif adds a DAMOS filter which permits the filtering
by huge page sizes.
- The 4 patch series "mm: permit guard regions for file-backed/shmem
mappings" from Lorenzo Stoakes extends the guard region feature from its
present "anon mappings only" state. The feature now covers shmem and
file-backed mappings.
- The 4 patch series "mm: batched unmap lazyfree large folios during
reclamation" from Barry Song cleans up and speeds up the unmapping for
pte-mapped large folios.
- The 18 patch series "reimplement per-vma lock as a refcount" from
Suren Baghdasaryan puts the vm_lock back into the vma. Our reasons for
pulling it out were largely bogus and that change made the code more
messy. This patchset provides small (0-10%) improvements on one
microbenchmark.
- The 5 patch series "Docs/mm/damon: misc DAMOS filters documentation
fixes and improves" from SeongJae Park does some maintenance work on the
DAMON docs.
- The 27 patch series "hugetlb/CMA improvements for large systems" from
Frank van der Linden addresses a pile of issues which have been observed
when using CMA on large machines.
- The 2 patch series "mm/damon: introduce DAMOS filter type for unmapped
pages" from SeongJae Park enables users of DMAON/DAMOS to filter my the
page's mapped/unmapped status.
- The 19 patch series "zsmalloc/zram: there be preemption" from Sergey
Senozhatsky teaches zram to run its compression and decompression
operations preemptibly.
- The 12 patch series "selftests/mm: Some cleanups from trying to run
them" from Brendan Jackman fixes a pile of unrelated issues which
Brendan encountered while runnimg our selftests.
- The 2 patch series "fs/proc/task_mmu: add guard region bit to pagemap"
from Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
determine whether a particular page is a guard page.
- The 7 patch series "mm, swap: remove swap slot cache" from Kairui Song
removes the swap slot cache from the allocation path - it simply wasn't
being effective.
- The 5 patch series "mm: cleanups for device-exclusive entries (hmm)"
from David Hildenbrand implements a number of unrelated cleanups in this
code.
- The 5 patch series "mm: Rework generic PTDUMP configs" from Anshuman
Khandual implements a number of preparatoty cleanups to the
GENERIC_PTDUMP Kconfig logic.
- The 8 patch series "mm/damon: auto-tune aggregation interval" from
SeongJae Park implements a feedback-driven automatic tuning feature for
DAMON's aggregation interval tuning.
- The 5 patch series "Fix lazy mmu mode" from Ryan Roberts fixes some
issues in powerpc, sparc and x86 lazy MMU implementations. Ryan did
this in preparation for implementing lazy mmu mode for arm64 to optimize
vmalloc.
- The 2 patch series "mm/page_alloc: Some clarifications for migratetype
fallback" from Brendan Jackman reworks some commentary to make the code
easier to follow.
- The 3 patch series "page_counter cleanup and size reduction" from
Shakeel Butt cleans up the page_counter code and fixes a size increase
which we accidentally added late last year.
- The 3 patch series "Add a command line option that enables control of
how many threads should be used to allocate huge pages" from Thomas
Prescher does that. It allows the careful operator to significantly
reduce boot time by tuning the parallalization of huge page
initialization.
- The 3 patch series "Fix calculations in trace_balance_dirty_pages()
for cgwb" from Tang Yizhou fixes the tracing output from the dirty page
balancing code.
- The 9 patch series "mm/damon: make allow filters after reject filters
useful and intuitive" from SeongJae Park improves the handling of allow
and reject filters. Behaviour is made more consistent and the
documention is updated accordingly.
- The 5 patch series "Switch zswap to object read/write APIs" from Yosry
Ahmed updates zswap to the new object read/write APIs and thus permits
the removal of some legacy code from zpool and zsmalloc.
- The 6 patch series "Some trivial cleanups for shmem" from Baolin Wang
does as it claims.
- The 20 patch series "fs/dax: Fix ZONE_DEVICE page reference counts"
from Alistair Popple regularizes the weird ZONE_DEVICE page refcount
handling in DAX, permittig the removal of a number of special-case
checks.
- The 4 patch series "refactor mremap and fix bug" from Lorenzo Stoakes
is a preparatoty refactoring and cleanup of the mremap() code.
- The 20 patch series "mm: MM owner tracking for large folios (!hugetlb)
+ CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
which we determine whether a large folio is known to be mapped
exclusively into a single MM.
- The 8 patch series "mm/damon: add sysfs dirs for managing DAMOS
filters based on handling layers" from SeongJae Park adds a couple of
new sysfs directories to ease the management of DAMON/DAMOS filters.
- The 13 patch series "arch, mm: reduce code duplication in mem_init()"
from Mike Rapoport consolidates many per-arch implementations of
mem_init() into code generic code, where that is practical.
- The 13 patch series "mm/damon/sysfs: commit parameters online via
damon_call()" from SeongJae Park continues the cleaning up of sysfs
access to DAMON internal data.
- The 3 patch series "mm: page_ext: Introduce new iteration API" from
Luiz Capitulino reworks the page_ext initialization to fix a boot-time
crash which was observed with an unusual combination of compile and
cmdline options.
- The 8 patch series "Buddy allocator like (or non-uniform) folio split"
from Zi Yan reworks the code to split a folio into smaller folios. The
main benefit is lessened memory consumption: fewer post-split folios are
generated.
- The 2 patch series "Minimize xa_node allocation during xarry split"
from Zi Yan reduces the number of xarray xa_nodes which are generated
during an xarray split.
- The 2 patch series "drivers/base/memory: Two cleanups" from Gavin Shan
performs some maintenance work on the drivers/base/memory code.
- The 3 patch series "Add tracepoints for lowmem reserves, watermarks
and totalreserve_pages" from Martin Liu adds some more tracepoints to
the page allocator code.
- The 4 patch series "mm/madvise: cleanup requests validations and
classifications" from SeongJae Park cleans up some warts which SeongJae
observed during his earlier madvise work.
- The 3 patch series "mm/hwpoison: Fix regressions in memory failure
handling" from Shuai Xue addresses two quite serious regressions which
Shuai has observed in the memory-failure implementation.
- The 5 patch series "mm: reliable huge page allocator" from Johannes
Weiner makes huge page allocations cheaper and more reliable by reducing
fragmentation.
- The 5 patch series "Minor memcg cleanups & prep for memdescs" from
Matthew Wilcox is preparatory work for the future implementation of
memdescs.
- The 4 patch series "track memory used by balloon drivers" from Nico
Pache introduces a way to track memory used by our various balloon
drivers.
- The 2 patch series "mm/damon: introduce DAMOS filter type for active
pages" from Nhat Pham permits users to filter for active/inactive pages,
separately for file and anon pages.
- The 2 patch series "Adding Proactive Memory Reclaim Statistics" from
Hao Jia separates the proactive reclaim statistics from the direct
reclaim statistics.
- The 2 patch series "mm/vmscan: don't try to reclaim hwpoison folio"
from Jinjiang Tu fixes our handling of hwpoisoned pages within the
reclaim code.
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Merge tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- The series "Enable strict percpu address space checks" from Uros
Bizjak uses x86 named address space qualifiers to provide
compile-time checking of percpu area accesses.
This has caused a small amount of fallout - two or three issues were
reported. In all cases the calling code was found to be incorrect.
- The series "Some cleanup for memcg" from Chen Ridong implements some
relatively monir cleanups for the memcontrol code.
- The series "mm: fixes for device-exclusive entries (hmm)" from David
Hildenbrand fixes a boatload of issues which David found then using
device-exclusive PTE entries when THP is enabled. More work is
needed, but this makes thins better - our own HMM selftests now
succeed.
- The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
remove the z3fold and zbud implementations. They have been deprecated
for half a year and nobody has complained.
- The series "mm: further simplify VMA merge operation" from Lorenzo
Stoakes implements numerous simplifications in this area. No runtime
effects are anticipated.
- The series "mm/madvise: remove redundant mmap_lock operations from
process_madvise()" from SeongJae Park rationalizes the locking in the
madvise() implementation. Performance gains of 20-25% were observed
in one MADV_DONTNEED microbenchmark.
- The series "Tiny cleanup and improvements about SWAP code" from
Baoquan He contains a number of touchups to issues which Baoquan
noticed when working on the swap code.
- The series "mm: kmemleak: Usability improvements" from Catalin
Marinas implements a couple of improvements to the kmemleak
user-visible output.
- The series "mm/damon/paddr: fix large folios access and schemes
handling" from Usama Arif provides a couple of fixes for DAMON's
handling of large folios.
- The series "mm/damon/core: fix wrong and/or useless damos_walk()
behaviors" from SeongJae Park fixes a few issues with the accuracy of
kdamond's walking of DAMON regions.
- The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
Stoakes changes the interaction between framebuffer deferred-io and
core MM. No functional changes are anticipated - this is preparatory
work for the future removal of page structure fields.
- The series "mm/damon: add support for hugepage_size DAMOS filter"
from Usama Arif adds a DAMOS filter which permits the filtering by
huge page sizes.
- The series "mm: permit guard regions for file-backed/shmem mappings"
from Lorenzo Stoakes extends the guard region feature from its
present "anon mappings only" state. The feature now covers shmem and
file-backed mappings.
- The series "mm: batched unmap lazyfree large folios during
reclamation" from Barry Song cleans up and speeds up the unmapping
for pte-mapped large folios.
- The series "reimplement per-vma lock as a refcount" from Suren
Baghdasaryan puts the vm_lock back into the vma. Our reasons for
pulling it out were largely bogus and that change made the code more
messy. This patchset provides small (0-10%) improvements on one
microbenchmark.
- The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
improves" from SeongJae Park does some maintenance work on the DAMON
docs.
- The series "hugetlb/CMA improvements for large systems" from Frank
van der Linden addresses a pile of issues which have been observed
when using CMA on large machines.
- The series "mm/damon: introduce DAMOS filter type for unmapped pages"
from SeongJae Park enables users of DMAON/DAMOS to filter my the
page's mapped/unmapped status.
- The series "zsmalloc/zram: there be preemption" from Sergey
Senozhatsky teaches zram to run its compression and decompression
operations preemptibly.
- The series "selftests/mm: Some cleanups from trying to run them" from
Brendan Jackman fixes a pile of unrelated issues which Brendan
encountered while runnimg our selftests.
- The series "fs/proc/task_mmu: add guard region bit to pagemap" from
Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
determine whether a particular page is a guard page.
- The series "mm, swap: remove swap slot cache" from Kairui Song
removes the swap slot cache from the allocation path - it simply
wasn't being effective.
- The series "mm: cleanups for device-exclusive entries (hmm)" from
David Hildenbrand implements a number of unrelated cleanups in this
code.
- The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
implements a number of preparatoty cleanups to the GENERIC_PTDUMP
Kconfig logic.
- The series "mm/damon: auto-tune aggregation interval" from SeongJae
Park implements a feedback-driven automatic tuning feature for
DAMON's aggregation interval tuning.
- The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
preparation for implementing lazy mmu mode for arm64 to optimize
vmalloc.
- The series "mm/page_alloc: Some clarifications for migratetype
fallback" from Brendan Jackman reworks some commentary to make the
code easier to follow.
- The series "page_counter cleanup and size reduction" from Shakeel
Butt cleans up the page_counter code and fixes a size increase which
we accidentally added late last year.
- The series "Add a command line option that enables control of how
many threads should be used to allocate huge pages" from Thomas
Prescher does that. It allows the careful operator to significantly
reduce boot time by tuning the parallalization of huge page
initialization.
- The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
from Tang Yizhou fixes the tracing output from the dirty page
balancing code.
- The series "mm/damon: make allow filters after reject filters useful
and intuitive" from SeongJae Park improves the handling of allow and
reject filters. Behaviour is made more consistent and the documention
is updated accordingly.
- The series "Switch zswap to object read/write APIs" from Yosry Ahmed
updates zswap to the new object read/write APIs and thus permits the
removal of some legacy code from zpool and zsmalloc.
- The series "Some trivial cleanups for shmem" from Baolin Wang does as
it claims.
- The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
Alistair Popple regularizes the weird ZONE_DEVICE page refcount
handling in DAX, permittig the removal of a number of special-case
checks.
- The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
preparatoty refactoring and cleanup of the mremap() code.
- The series "mm: MM owner tracking for large folios (!hugetlb) +
CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
which we determine whether a large folio is known to be mapped
exclusively into a single MM.
- The series "mm/damon: add sysfs dirs for managing DAMOS filters based
on handling layers" from SeongJae Park adds a couple of new sysfs
directories to ease the management of DAMON/DAMOS filters.
- The series "arch, mm: reduce code duplication in mem_init()" from
Mike Rapoport consolidates many per-arch implementations of
mem_init() into code generic code, where that is practical.
- The series "mm/damon/sysfs: commit parameters online via
damon_call()" from SeongJae Park continues the cleaning up of sysfs
access to DAMON internal data.
- The series "mm: page_ext: Introduce new iteration API" from Luiz
Capitulino reworks the page_ext initialization to fix a boot-time
crash which was observed with an unusual combination of compile and
cmdline options.
- The series "Buddy allocator like (or non-uniform) folio split" from
Zi Yan reworks the code to split a folio into smaller folios. The
main benefit is lessened memory consumption: fewer post-split folios
are generated.
- The series "Minimize xa_node allocation during xarry split" from Zi
Yan reduces the number of xarray xa_nodes which are generated during
an xarray split.
- The series "drivers/base/memory: Two cleanups" from Gavin Shan
performs some maintenance work on the drivers/base/memory code.
- The series "Add tracepoints for lowmem reserves, watermarks and
totalreserve_pages" from Martin Liu adds some more tracepoints to the
page allocator code.
- The series "mm/madvise: cleanup requests validations and
classifications" from SeongJae Park cleans up some warts which
SeongJae observed during his earlier madvise work.
- The series "mm/hwpoison: Fix regressions in memory failure handling"
from Shuai Xue addresses two quite serious regressions which Shuai
has observed in the memory-failure implementation.
- The series "mm: reliable huge page allocator" from Johannes Weiner
makes huge page allocations cheaper and more reliable by reducing
fragmentation.
- The series "Minor memcg cleanups & prep for memdescs" from Matthew
Wilcox is preparatory work for the future implementation of memdescs.
- The series "track memory used by balloon drivers" from Nico Pache
introduces a way to track memory used by our various balloon drivers.
- The series "mm/damon: introduce DAMOS filter type for active pages"
from Nhat Pham permits users to filter for active/inactive pages,
separately for file and anon pages.
- The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
separates the proactive reclaim statistics from the direct reclaim
statistics.
- The series "mm/vmscan: don't try to reclaim hwpoison folio" from
Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
code.
* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
x86/mm: restore early initialization of high_memory for 32-bits
mm/vmscan: don't try to reclaim hwpoison folio
mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
selftests/mm: speed up split_huge_page_test
selftests/mm: uffd-unit-tests support for hugepages > 2M
docs/mm/damon/design: document active DAMOS filter type
mm/damon: implement a new DAMOS filter type for active pages
fs/dax: don't disassociate zero page entries
MM documentation: add "Unaccepted" meminfo entry
selftests/mm: add commentary about 9pfs bugs
fork: use __vmalloc_node() for stack allocation
docs/mm: Physical Memory: Populate the "Zones" section
xen: balloon: update the NR_BALLOON_PAGES state
hv_balloon: update the NR_BALLOON_PAGES state
balloon_compaction: update the NR_BALLOON_PAGES state
meminfo: add a per node counter for balloon drivers
mm: remove references to folio in __memcg_kmem_uncharge_page()
...
Add reserve_mem_release_by_name() to release a reserved memory region
with a given name. This allows us to release reserved memory which is
defined by kernel cmdline, after boot.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/173989133862.230693.14094993331347437600.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
All architectures that support HIGHMEM have their code that frees high
memory pages to the buddy allocator while __free_memory_core() is limited
to freeing only low memory.
There is no actual reason for that. The memory map is completely ready by
the time memblock_free_all() is called and high pages can be released to
the buddy allocator along with low memory.
Remove low memory limit from __free_memory_core() and drop per-architecture
code that frees high memory pages.
Link: https://lkml.kernel.org/r/20250313135003.836600-12-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> [x86]
Tested-by: Mark Brown <broonie@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren (csky) <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory. In most cases, when memory allocation fails, an
immediate panic is required. To simplify this behavior and reduce
repetitive checks, introduce `memblock_alloc_or_panic`. This function
ensures that memory allocation failures result in a panic automatically,
improving code readability and consistency across subsystems that require
this behavior.
[guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic]
Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com
Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/
Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390]
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently memblock validate_numa_converage() returns false negative when
threshold set to zero.
Make the check if the memory size with invalid node ID is greater than
the threshold exclusive to fix that.
Link: https://lore.kernel.org/all/Z0mIDBD4KLyxyOCm@kernel.org/
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
* new memblock_estimated_nr_free_pages() helper to replace totalram_pages()
which is less accurate when CONFIG_DEFERRED_STRUCT_PAGE_INIT is set
* fixes for memblock tests
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Merge tag 'memblock-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock updates from Mike Rapoport:
- new memblock_estimated_nr_free_pages() helper to replace
totalram_pages() which is less accurate when
CONFIG_DEFERRED_STRUCT_PAGE_INIT is set
- fixes for memblock tests
* tag 'memblock-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
s390/mm: get estimated free pages by memblock api
kernel/fork.c: get estimated free pages by memblock api
mm/memblock: introduce a new helper memblock_estimated_nr_free_pages()
memblock test: fix implicit declaration of function 'strscpy'
memblock test: fix implicit declaration of function 'isspace'
memblock test: fix implicit declaration of function 'memparse'
memblock test: add the definition of __setup()
memblock test: fix implicit declaration of function 'virt_to_phys'
tools/testing: abstract two init.h into common include directory
memblock tests: include export.h in linkage.h as kernel dose
memblock tests: include memory_hotplug.h in mmzone.h as kernel dose
Make accept_memory() and range_contains_unaccepted_memory() take 'start'
and 'size' arguments instead of 'start' and 'end'.
Remove accept_page(), replacing it with direct calls to accept_memory().
The accept_page() name is going to be used for a different function.
Link: https://lkml.kernel.org/r/20240809114854.3745464-6-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During bootup, system may need the number of free pages in the whole system
to do some calculation before all pages are freed to buddy system. Usually
this number is get from totalram_pages(). Since we plan to move the free
pages accounting in __free_pages_core(), this value may not represent
total free pages at the early stage, especially when
CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled.
Instead of using raw memblock api, let's introduce a new helper for user
to get the estimated number of free pages from memblock point of view.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20240808001415.6298-1-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
* reserve_mem command line parameter to allow creation of named memory
reservation at boot time.
The driving use-case is to improve the ability of pstore to retain
ramoops data across reboots.
* cleaunps and small improvements in memblock and mm_init
* new tests cases in memblock test suite
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Merge tag 'memblock-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock updates from Mike Rapoport:
- 'reserve_mem' command line parameter to allow creation of named
memory reservation at boot time.
The driving use-case is to improve the ability of pstore to retain
ramoops data across reboots.
- cleanups and small improvements in memblock and mm_init
- new tests cases in memblock test suite
* tag 'memblock-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock tests: fix implicit declaration of function 'numa_valid_node'
memblock: Move late alloc warning down to phys alloc
pstore/ramoops: Add ramoops.mem_name= command line option
mm/memblock: Add "reserve_mem" to reserved named memory at boot up
mm/mm_init.c: don't initialize page->lru again
mm/mm_init.c: not always search next deferred_init_pfn from very beginning
mm/mm_init.c: use deferred_init_mem_pfn_range_in_zone() to decide loop condition
mm/mm_init.c: get the highest zone directly
mm/mm_init.c: move nr_initialised reset down a bit
mm/memblock: fix a typo in description of for_each_mem_region()
mm/mm_init.c: use memblock_region_memory_base_pfn() to get startpfn
mm/memblock: use PAGE_ALIGN_DOWN to get pgend in free_memmap
mm/memblock: return true directly on finding overlap region
memblock tests: add memblock_overlaps_region_checks
mm/memblock: fix comment for memblock_isolate_range()
memblock tests: add memblock_reserve_many_may_conflict_check()
memblock tests: add memblock_reserve_all_locations_check()
mm/memblock: remove empty dummy entry
If a driver/subsystem tries to do an allocation after the memblock
allocations have been freed and the memory handed to the buddy
allocator, it will not actually be legal to use that allocation: the
buddy allocator owns the memory. Currently this mis-use is handled by
the memblock function which does allocations and returns virtual
addresses by printing a warning and doing a kmalloc instead. However
the physical allocation function does not to do this check - callers of
the physical alloc function are unprotected against mis-use.
Improve the error catching here by moving the check into the physical
allocation function which is used by the virtual addr allocation
function.
Signed-off-by: James Gowans <jgowans@amazon.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Graf <graf@amazon.de>
Link: https://lore.kernel.org/r/20240619095555.85980-1-jgowans@amazon.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
In order to allow for requesting a memory region that can be used for
things like pstore on multiple machines where the memory layout is not the
same, add a new option to the kernel command line called "reserve_mem".
The format is: reserve_mem=nn:align:name
Where it will find nn amount of memory at the given alignment of align.
The name field is to allow another subsystem to retrieve where the memory
was found. For example:
reserve_mem=12M:4096:oops ramoops.mem_name=oops
Where ramoops.mem_name will tell ramoops that memory was reserved for it
via the reserve_mem option and it can find it by calling:
if (reserve_mem_find_by_name("oops", &start, &size)) {
// start holds the start address and size holds the size given
This is typically used for systems that do not wipe the RAM, and this
command line will try to reserve the same physical memory on soft reboots.
Note, it is not guaranteed to be the same location. For example, if KASLR
places the kernel at the location of where the RAM reservation was from a
previous boot, the new reservation will be at a different location. Any
subsystem using this feature must add a way to verify that the contents of
the physical memory is from a previous boot, as there may be cases where
the memory will not be located at the same location.
Not all systems may work either. There could be bit flips if the reboot
goes through the BIOS. Using kexec to reboot the machine is likely to
have better results in such cases.
Link: https://lore.kernel.org/all/ZjJVnZUX3NZiGW6q@kernel.org/
Suggested-by: Mike Rapoport <rppt@kernel.org>
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20240613155527.437020271@goodmis.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Introduce numa_valid_node(nid) that verifies that nid is a valid node ID
and use that instead of comparing nid parameter with either NUMA_NO_NODE
or MAX_NUMNODES.
This makes the checks for valid node IDs consistent and more robust and
allows to get rid of multiple WARNings.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
The isolated range is [*@start_rgn, *@end_rgn - 1], while the comment says
"the end region inside the range" is *@end_rgn.
Let's correct it.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-4-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
The dummy entry is introduced in the initial implementation of lmb in
commit 7c8c6b9776 ("powerpc: Merge lmb.c and make MM initialization
use it.").
As the comment says the empty dummy entry is to simplify the code.
/* Create a dummy zero size LMB which will get coalesced away later.
* This simplifies the lmb_add() code below...
*/
While current code is reimplemented by Tejun in commit 784656f9c6
("memblock: Reimplement memblock_add_region()"). This empty dummy entry
seems not benefit the code any more.
Let's remove it.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Paul Mackerras <paulus@ozlabs.org>
CC: Tejun Heo <tj@kernel.org>
CC: Mike Rapoport <rppt@kernel.org>
Link: https://lore.kernel.org/r/20240405015821.13411-1-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
On an (old) x86 system with SRAT just covering space above 4Gb:
ACPI: SRAT: Node 0 PXM 0 [mem 0x100000000-0xfffffffff] hotplug
the commit referenced below leads to this NUMA configuration no longer
being refused by a CONFIG_NUMA=y kernel (previously
NUMA: nodes only cover 6144MB of your 8185MB e820 RAM. Not used.
No NUMA configuration found
Faking a node at [mem 0x0000000000000000-0x000000027fffffff]
was seen in the log directly after the message quoted above), because of
memblock_validate_numa_coverage() checking for NUMA_NO_NODE (only). This
in turn led to memblock_alloc_range_nid()'s warning about MAX_NUMNODES
triggering, followed by a NULL deref in memmap_init() when trying to
access node 64's (NODE_SHIFT=6) node data.
To compensate said change, make memblock_set_node() warn on and adjust
a passed in value of MAX_NUMNODES, just like various other functions
already do.
Fixes: ff6c3d81f2 ("NUMA: optimize detection of memory with no node id assigned by firmware")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1c8a058c-5365-4f27-a9f1-3aeb7fb3e7b2@suse.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
- Fix NUMA initialization from ACPI CEDT.CFMWS
- Fix region assembly failures due to async init order
- Fix / simplify export of qos_class information
- Fix cxl_acpi initialization vs single-window-init failures
- Fix handling of repeated 'pci_channel_io_frozen' notifications
- Workaround platforms that violate host-physical-address ==
system-physical address assumptions
- Defer CXL CPER notification handling to v6.9
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Merge tag 'cxl-fixes-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl
Pull cxl fixes from Dan Williams:
"A collection of significant fixes for the CXL subsystem.
The largest change in this set, that bordered on "new development", is
the fix for the fact that the location of the new qos_class attribute
did not match the Documentation. The fix ends up deleting more code
than it added, and it has a new unit test to backstop basic errors in
this interface going forward. So the "red-diff" and unit test saved
the "rip it out and try again" response.
In contrast, the new notification path for firmware reported CXL
errors (CXL CPER notifications) has a locking context bug that can not
be fixed with a red-diff. Given where the release cycle stands, it is
not comfortable to squeeze in that fix in these waning days. So, that
receives the "back it out and try again later" treatment.
There is a regression fix in the code that establishes memory NUMA
nodes for platform CXL regions. That has an ack from x86 folks. There
are a couple more fixups for Linux to understand (reassemble) CXL
regions instantiated by platform firmware. The policy around platforms
that do not match host-physical-address with system-physical-address
(i.e. systems that have an address translation mechanism between the
address range reported in the ACPI CEDT.CFMWS and endpoint decoders)
has been softened to abort driver load rather than teardown the memory
range (can cause system hangs). Lastly, there is a robustness /
regression fix for cases where the driver would previously continue in
the face of error, and a fixup for PCI error notification handling.
Summary:
- Fix NUMA initialization from ACPI CEDT.CFMWS
- Fix region assembly failures due to async init order
- Fix / simplify export of qos_class information
- Fix cxl_acpi initialization vs single-window-init failures
- Fix handling of repeated 'pci_channel_io_frozen' notifications
- Workaround platforms that violate host-physical-address ==
system-physical address assumptions
- Defer CXL CPER notification handling to v6.9"
* tag 'cxl-fixes-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
cxl/acpi: Fix load failures due to single window creation failure
acpi/ghes: Remove CXL CPER notifications
cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS window
cxl/test: Add support for qos_class checking
cxl: Fix sysfs export of qos_class for memdev
cxl: Remove unnecessary type cast in cxl_qos_class_verify()
cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'
cxl/region: Allow out of order assembly of autodiscovered regions
cxl/region: Handle endpoint decoders in cxl_region_find_decoder()
x86/numa: Fix the sort compare func used in numa_fill_memblks()
x86/numa: Fix the address overlap check in numa_fill_memblks()
cxl/pci: Skip to handle RAS errors if CXL.mem device is detached
numa_fill_memblks() fills in the gaps in numa_meminfo memblks over a
physical address range. To do so, it first creates a list of existing
memblks that overlap that address range. The issue is that it is off
by one when comparing to the end of the address range, so memblks
that do not overlap are selected.
The impact of selecting a memblk that does not actually overlap is
that an existing memblk may be filled when the expected action is to
do nothing and return NUMA_NO_MEMBLK to the caller. The caller can
then add a new NUMA node and memblk.
Replace the broken open-coded search for address overlap with the
memblock helper memblock_addrs_overlap(). Update the kernel doc
and in code comments.
Suggested by: "Huang, Ying" <ying.huang@intel.com>
Fixes: 8f012db27c ("x86/numa: Introduce numa_fill_memblks()")
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/10a3e6109c34c21a8dd4c513cf63df63481a2b07.1705085543.git.alison.schofield@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, the initialization of
reserved pages may cause access of NODE_DATA() with invalid nid and crash.
Add a fall back to early_pfn_to_nid() in memmap_init_reserved_pages() to
ensure a valid node id is always passed to init_reserved_page().
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Merge tag 'fixes-2024-01-28' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock fix from Mike Rapoport:
"Fix crash when reserved memory is not added to memory.
When CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, the initialization
of reserved pages may cause access of NODE_DATA() with invalid nid and
crash.
Add a fall back to early_pfn_to_nid() in memmap_init_reserved_pages()
to ensure a valid node id is always passed to init_reserved_page()"
* tag 'fixes-2024-01-28' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock: fix crash when reserved memory is not added to memory
After commit 61167ad5fe ("mm: pass nid to reserve_bootmem_region()")
nid of a reserved region is used by init_reserved_page() (with
CONFIG_DEFERRED_STRUCT_PAGE_INIT=y) to access node strucure.
In many cases the nid of the reserved memory is not set and this causes
a crash.
When the nid of a reserved region is not set, fall back to
early_pfn_to_nid(), so that nid of the first_online_node will be passed
to init_reserved_page().
Fixes: 61167ad5fe ("mm: pass nid to reserve_bootmem_region()")
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Link: https://lore.kernel.org/r/20240118061853.2652295-1-yajun.deng@linux.dev
[rppt: massaged the commit message]
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Use NUMA_NO_NODE instead of -1 as return value of memblock_search_pfn_nid()
to improve code readability and consistency with the callers of that
function.
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Merge tag 'memblock-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock update from Mike Rapoport:
"Code readability improvement.
Use NUMA_NO_NODE instead of -1 as return value of
memblock_search_pfn_nid() to improve code readability
and consistency with the callers of that function"
* tag 'memblock-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock: Return NUMA_NO_NODE instead of -1 to improve code readability
commit 23baf831a3 ("mm, treewide: redefine MAX_ORDER sanely") has
changed the definition of MAX_ORDER to be inclusive. This has caused
issues with code that was not yet upstream and depended on the previous
definition.
To draw attention to the altered meaning of the define, rename MAX_ORDER
to MAX_PAGE_ORDER.
Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
When no corresponding memory region is found for the given pfn, return
NUMA_NO_NODE instead of -1. This improves code readability and aligns with
the existing logic of the memblock_search_pfn_nid() function's user.
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Link: https://lore.kernel.org/r/20231207131001.224914-1-ytcoode@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Numerous memblock reservations at early boot may exhaust static
memblock.reserved array and it is unnoticed because most of the callers don't
check memblock_reserve() return value.
In this case the system will crash later, but the reason is hard to identify.
Replace return of an error with panic() when memblock.reserved is exhausted
before it can be resized.
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Merge tag 'memblock-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock update from Mike Rapoport:
"Report failures when memblock_can_resize is not set.
Numerous memblock reservations at early boot may exhaust static
memblock.reserved array and it is unnoticed because most of the
callers don't check memblock_reserve() return value.
In this case the system will crash later, but the reason is hard to
identify.
Replace return of an error with panic() when memblock.reserved is
exhausted before it can be resized"
* tag 'memblock-v6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock: report failures when memblock_can_resize is not set
For reserved memory regions marked with this flag, reserve_bootmem_region
is not called during memmap_init_reserved_pages. This can be used to
avoid struct page initialization for regions which won't need them, for
e.g. hugepages with Hugepage Vmemmap Optimization enabled.
Link: https://lkml.kernel.org/r/20230913105401.519709-4-usama.arif@bytedance.com
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This allows setting flags to both memblock types and is in preparation for
setting flags (for e.g. to not initialize struct pages) on reserved
memory region.
[usama.arif@bytedance.com: add missing argument definition]
Link: https://lkml.kernel.org/r/20230918090657.220463-1-usama.arif@bytedance.com
Link: https://lkml.kernel.org/r/20230913105401.519709-3-usama.arif@bytedance.com
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The callers of memblock_reserve() do not check the return value
presuming that memblock_reserve() always succeeds, but there are
cases where it may fail.
Having numerous memblock reservations at early boot where
memblock_can_resize is unset may exhaust the INIT_MEMBLOCK_REGIONS sized
memblock.reserved regions array and an attempt to double this array via
memblock_double_array() will fail and will return -1 to the caller.
When this happens the system crashes anyway, but it's hard to identify
the reason for the crash.
Add a panic message to memblock_double_array() to aid debugging of the
cases when too many regions are reserved before memblock can resize
memblock.reserved array.
Link: https://lore.kernel.org/linux-kernel/20230614131746.3670303-1-songshuaishuai@tinylab.org/
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Link: https://lore.kernel.org/r/20230624032607.921173-1-songshuaishuai@tinylab.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
For system with kernelcore=mirror enabled while no mirrored memory is
reported by efi. This could lead to kernel OOM during startup since all
memory beside zone DMA are in the movable zone and this prevents the
kernel to use it.
Zone DMA/DMA32 initialization is independent of mirrored memory and their
max pfn is set in zone_sizes_init(). Since kernel can fallback to zone
DMA/DMA32 if there is no memory in zone Normal, these zones are seen as
mirrored memory no mather their memory attributes are.
To solve this problem, disable kernelcore=mirror when there is no real
mirrored memory exists.
Link: https://lkml.kernel.org/r/20230802072328.2107981-1-mawupeng1@huawei.com
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Suggested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Levi Yun <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 9e46e4dcd9.
kbuild reports a warning in memblock_remove_region() because of a false
positive caused by partial reset of the memblock state.
Doing the full reset will remove the false positives, but will allow
late use of memblock_free() to go unnoticed, so it is better to revert
the offending commit.
WARNING: CPU: 0 PID: 1 at mm/memblock.c:352 memblock_remove_region (kbuild/src/x86_64/mm/memblock.c:352 (discriminator 1))
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.5.0-rc3-00001-g9e46e4dcd9d6 #2
RIP: 0010:memblock_remove_region (kbuild/src/x86_64/mm/memblock.c:352 (discriminator 1))
Call Trace:
memblock_discard (kbuild/src/x86_64/mm/memblock.c:383)
page_alloc_init_late (kbuild/src/x86_64/include/linux/find.h:208 kbuild/src/x86_64/include/linux/nodemask.h:266 kbuild/src/x86_64/mm/mm_init.c:2405)
kernel_init_freeable (kbuild/src/x86_64/init/main.c:1325 kbuild/src/x86_64/init/main.c:1546)
kernel_init (kbuild/src/x86_64/init/main.c:1439)
ret_from_fork (kbuild/src/x86_64/arch/x86/kernel/process.c:145)
ret_from_fork_asm (kbuild/src/x86_64/arch/x86/entry/entry_64.S:298)
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202307271656.447aa17e-oliver.sang@intel.com
Signed-off-by: "Mike Rapoport (IBM)" <rppt@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memblock_discard function frees the memblock.reserved.regions
array, which is good.
However, if a subsequent memblock_free (or memblock_phys_free) comes
in later, from for example ima_free_kexec_buffer, that will result in
a use after free bug in memblock_isolate_range.
When running a kernel with CONFIG_KASAN enabled, this will cause a
kernel panic very early in boot. Without CONFIG_KASAN, there is
a chance that memblock_isolate_range might scribble on memory
that is now in use by somebody else.
Avoid those issues by making sure that memblock_discard points
memblock.reserved.regions back at the static buffer.
If memblock_free is called after memblock memory is discarded, that will
print a warning in memblock_remove_region.
Signed-off-by: Rik van Riel <riel@surriel.com>
Link: https://lore.kernel.org/r/20230719154137.732d8525@imladris.surriel.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Linus Torvalds