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Alexander Graf
f992307802 memblock: add KHO support for reserve_mem 
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>
 2025-05-12 23:50:42 -07:00
Alexander Graf
c609c144b0 kexec: add KHO parsing support 
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>
 2025-05-12 23:50:39 -07:00
Mike Rapoport (Microsoft)
b8a8f96a6d memblock: introduce memmap_init_kho_scratch() 
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>
 2025-05-12 23:50:39 -07:00
Alexander Graf
d59f43b574 memblock: add support for scratch memory 
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>
 2025-05-12 23:50:39 -07:00
Mike Rapoport (Microsoft)
4c78cc596b memblock: add MEMBLOCK_RSRV_KERN flag 
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>
 2025-05-12 23:50:38 -07:00
Tom Lendacky
da8bf5daa5 memblock: Accept allocated memory before use in memblock_double_array() 
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>
 2025-05-09 08:53:12 +03:00
Wei Yang
eac8ea8736 mm/memblock: repeat setting reserved region nid if array is doubled 
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>
 2025-04-07 09:28:01 +03:00
Wei Yang
06eaa824fd mm/memblock: pass size instead of end to memblock_set_node() 
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>
 2025-04-07 09:28:01 +03:00
Mike Rapoport (Microsoft)
7790c9c926 memblock: don't release high memory to page allocator when HIGHMEM is off 
Nathan Chancellor reports the following crash on a MIPS system with
CONFIG_HIGHMEM=n:

  Linux version 6.14.0-rc6-00359-g6faea3422e3b (nathan@ax162) (mips-linux-gcc (GCC) 14.2.0, GNU ld (GNU Binutils) 2.42) #1 SMP Fri Mar 21 08:12:02 MST 2025
  earlycon: uart8250 at I/O port 0x3f8 (options '38400n8')
  printk: legacy bootconsole [uart8250] enabled
  Config serial console: console=ttyS0,38400n8r
  CPU0 revision is: 00019300 (MIPS 24Kc)
  FPU revision is: 00739300
  MIPS: machine is mti,malta
  Software DMA cache coherency enabled
  Initial ramdisk at: 0x8fad0000 (5360128 bytes)
  OF: reserved mem: Reserved memory: No reserved-memory node in the DT
  Primary instruction cache 2kB, VIPT, 2-way, linesize 16 bytes.
  Primary data cache 2kB, 2-way, VIPT, no aliases, linesize 16 bytes
  Zone ranges:
    DMA      [mem 0x0000000000000000-0x0000000000ffffff]
    Normal   [mem 0x0000000001000000-0x000000001fffffff]
  Movable zone start for each node
  Early memory node ranges
    node   0: [mem 0x0000000000000000-0x000000000fffffff]
    node   0: [mem 0x0000000090000000-0x000000009fffffff]
  Initmem setup node 0 [mem 0x0000000000000000-0x000000009fffffff]
  On node 0, zone Normal: 16384 pages in unavailable ranges
  random: crng init done
  percpu: Embedded 3 pages/cpu s18832 r8192 d22128 u49152
  Kernel command line: rd_start=0xffffffff8fad0000 rd_size=5360128  console=ttyS0,38400n8r
  printk: log buffer data + meta data: 32768 + 102400 = 135168 bytes
  Dentry cache hash table entries: 65536 (order: 4, 262144 bytes, linear)
  Inode-cache hash table entries: 32768 (order: 3, 131072 bytes, linear)
  Writing ErrCtl register=00000000
  Readback ErrCtl register=00000000
  Built 1 zonelists, mobility grouping on.  Total pages: 16384
  mem auto-init: stack:all(zero), heap alloc:off, heap free:off
  Unhandled kernel unaligned access[#1]:
  CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.14.0-rc6-00359-g6faea3422e3b #1
  Hardware name: mti,malta
  $ 0   : 00000000 00000001 81cb0880 00129027
  $ 4   : 00000001 0000000a 00000002 00129026
  $ 8   : ffffdfff 80101e00 00000002 00000000
  $12   : 81c9c224 81c63e68 00000002 00000000
  $16   : 805b1e00 00025800 81cb0880 00000002
  $20   : 00000000 81c63e64 0000000a 81f10000
  $24   : 81c63e64 81c63e60
  $28   : 81c60000 81c63de0 00000001 81cc9d20
  Hi    : 00000000
  Lo    : 00000000
  epc   : 814a227c __free_pages_ok+0x144/0x3c0
  ra    : 81cc9d20 memblock_free_all+0x1d4/0x27c
  Status: 10000002        KERNEL EXL
  Cause : 00800410 (ExcCode 04)
  BadVA : 00129026
  PrId  : 00019300 (MIPS 24Kc)
  Modules linked in:
  Process swapper (pid: 0, threadinfo=(ptrval), task=(ptrval), tls=00000000)
  Stack : 81f10000 805a9e00 81c80000 00000000 00000002 814aa240 000003ff 00000400
          00000000 81f10000 81c9c224 00003b1f 81c80000 81c63e60 81ca0000 81c63e64
          81f10000 0000000a 0000001f 81cc9d20 81f10000 81cc96d8 00000000 81c80000
          81c9c224 81c63e60 81c63e64 00000000 81f10000 00024000 00028000 00025c00
          90000000 a0000000 00000002 00000017 00000000 00000000 81f10000 81f10000
          ...
  Call Trace:
  [<814a227c>] __free_pages_ok+0x144/0x3c0
  [<81cc9d20>] memblock_free_all+0x1d4/0x27c
  [<81cc6764>] mm_core_init+0x100/0x138
  [<81cb4ba4>] start_kernel+0x4a0/0x6e4

  Code: 1080ffd5  02003825  2467ffff <8ce30000> 7c630500  1060ffd4  00000000  8ce30000  7c630180

The crash happens because commit 6faea3422e ("arch, mm: streamline
HIGHMEM freeing") too eagerly frees high memory to the page allocator even
when HIGHMEM is disabled.

Make sure that when CONFIG_HIGHMEM=n the high memory is not released to the
page allocator.

Link: https://lore.kernel.org/all/20250323190647.GA1009914@ax162
Link: https://lkml.kernel.org/r/20250325114928.1791109-3-rppt@kernel.org
Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: 6faea3422e ("arch, mm: streamline HIGHMEM freeing")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-04-01 15:17:11 -07:00
Linus Torvalds
eb0ece1602 - The 6 patch 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 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()
  ...
 2025-04-01 09:29:18 -07:00
Masami Hiramatsu (Google)
74e2498ccf mm/memblock: Add reserved memory release function 
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>
 2025-03-28 08:39:28 -04:00
Mike Rapoport (Microsoft)
6faea3422e arch, mm: streamline HIGHMEM freeing 
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>
 2025-03-17 22:06:53 -07:00
Guo Weikang
c6f239796b mm/memblock: add memblock_alloc_or_panic interface 
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>
 2025-01-25 20:22:38 -08:00
Mike Rapoport (Microsoft)
9cdc6423ac memblock: allow zero threshold in validate_numa_converage() 
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>
 2024-12-01 21:08:56 +02:00
Linus Torvalds
aa486552a1 memblock: updates for 6.12-rc1 
* 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
 2024-09-25 11:35:19 -07:00
Kirill A. Shutemov
5adfeaecc4 mm: rework accept memory helpers 
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>
 2024-09-01 20:26:07 -07:00
Wei Yang
d0f8a8973f mm/memblock: introduce a new helper memblock_estimated_nr_free_pages() 
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>
 2024-08-11 19:18:52 +03:00
Linus Torvalds
b2fc97c186 memblock: updates for 6.11-rc1 
* 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
 2024-07-18 14:48:11 -07:00
James Gowans
94ff46de4a memblock: Move late alloc warning down to phys alloc 
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>
 2024-06-19 18:05:25 +03:00
Steven Rostedt (Google)
1e4c64b71c mm/memblock: Add "reserve_mem" to reserved named memory at boot up 
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>
 2024-06-19 10:59:49 +03:00
Mike Rapoport (IBM)
8043832e2a memblock: use numa_valid_node() helper to check for invalid node ID 
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>
 2024-06-16 10:17:57 +03:00
Wei Yang
b73f6b98bb mm/memblock: use PAGE_ALIGN_DOWN to get pgend in free_memmap 
Leverage the macro PAGE_ALIGN_DOWN to get pgend.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-7-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2024-06-05 10:22:22 +03:00
Wei Yang
1eb0a28d03 mm/memblock: return true directly on finding overlap region 
Not necessary to break and check i against type->cnt again.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-6-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2024-06-05 10:22:22 +03:00
Wei Yang
3aca2cea90 mm/memblock: fix comment for memblock_isolate_range() 
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>
 2024-06-05 10:22:22 +03:00
Wei Yang
721f4a6526 mm/memblock: remove empty dummy entry 
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>
 2024-06-05 10:21:47 +03:00
Jan Beulich
e0eec24e2e memblock: make memblock_set_node() also warn about use of MAX_NUMNODES 
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>
 2024-05-31 12:36:28 +03:00
Linus Torvalds
ac389bc0ca cxl fixes for 6.8-rc6 
- 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
 2024-02-24 15:53:40 -08:00
Anshuman Khandual
4f155af0ae mm/memblock: add MEMBLOCK_RSRV_NOINIT into flagname[] array 
The commit 77e6c43e13 ("memblock: introduce MEMBLOCK_RSRV_NOINIT flag")
skipped adding this newly introduced memblock flag into flagname[] array,
thus preventing a correct memblock flags output for applicable memblock
regions.

Link: https://lkml.kernel.org/r/20240209030912.1382251-1-anshuman.khandual@arm.com
Fixes: 77e6c43e13 ("memblock: introduce MEMBLOCK_RSRV_NOINIT flag")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Rapoport <rppt@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-02-20 14:20:49 -08:00
Alison Schofield
9b99c17f75 x86/numa: Fix the address overlap check in numa_fill_memblks() 
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>
 2024-02-16 23:20:34 -08:00
Linus Torvalds
a08ebda97e memblock: 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().
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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
 2024-01-28 09:41:39 -08:00
Yajun Deng
6a9531c3a8 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>
 2024-01-19 10:53:59 +02:00
Linus Torvalds
77c9622d87 memblock: 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.
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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
 2024-01-18 16:46:18 -08:00
Kirill A. Shutemov
5e0a760b44 mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 
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>
 2024-01-08 15:27:15 -08:00
Liam Ni
ff6c3d81f2 NUMA: optimize detection of memory with no node id assigned by firmware 
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>
 2023-12-10 16:51:34 -08:00
Yuntao Wang
2159bd4e90 memblock: Return NUMA_NO_NODE instead of -1 to improve code readability 
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>
 2023-12-08 10:31:00 +02:00
Linus Torvalds
447cec034b memblock: 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.
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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
 2023-11-08 09:40:13 -08:00
Usama Arif
77e6c43e13 memblock: introduce MEMBLOCK_RSRV_NOINIT flag 
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>
 2023-10-04 10:32:30 -07:00
Usama Arif
ee8d2071ef memblock: pass memblock_type to memblock_setclr_flag 
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>
 2023-10-04 10:32:30 -07:00
Song Shuai
e96c6b8f21 memblock: report failures when memblock_can_resize is not set 
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>
 2023-09-28 09:04:33 +03:00
Ma Wupeng
0db31d63f2 mm: disable kernelcore=mirror when no mirror memory 
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>
 2023-08-21 13:37:43 -07:00
Mike Rapoport (IBM)
c442a957b2 Revert "mm,memblock: reset memblock.reserved to system init state to prevent UAF" 
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>
 2023-07-28 09:47:06 -07:00
Rik van Riel
9e46e4dcd9 mm,memblock: reset memblock.reserved to system init state to prevent UAF 
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>
 2023-07-24 08:52:56 +03:00
Linus Torvalds
075e333591 memblock: small updates for 6.5-rc1 
* add test for memblock_alloc_node()
 * minor coding style fixes
 * add flags and nid info in memblock debugfs
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Merge tag 'memblock-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

Pull memblock updates from Mike Rapoport:

 - add test for memblock_alloc_node()

 - minor coding style fixes

 - add flags and nid info in memblock debugfs

* tag 'memblock-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  memblock: Update nid info in memblock debugfs
  memblock: Add flags and nid info in memblock debugfs
  Fix some coding style errors in memblock.c
  Add tests for memblock_alloc_node()
 2023-06-29 23:21:20 -07:00
Linus Torvalds
6e17c6de3d - Yosry Ahmed brought back some cgroup v1 stats in OOM logs. 
- Yosry has also eliminated cgroup's atomic rstat flushing.
 
 - Nhat Pham adds the new cachestat() syscall.  It provides userspace
   with the ability to query pagecache status - a similar concept to
   mincore() but more powerful and with improved usability.
 
 - Mel Gorman provides more optimizations for compaction, reducing the
   prevalence of page rescanning.
 
 - Lorenzo Stoakes has done some maintanance work on the get_user_pages()
   interface.
 
 - Liam Howlett continues with cleanups and maintenance work to the maple
   tree code.  Peng Zhang also does some work on maple tree.
 
 - Johannes Weiner has done some cleanup work on the compaction code.
 
 - David Hildenbrand has contributed additional selftests for
   get_user_pages().
 
 - Thomas Gleixner has contributed some maintenance and optimization work
   for the vmalloc code.
 
 - Baolin Wang has provided some compaction cleanups,
 
 - SeongJae Park continues maintenance work on the DAMON code.
 
 - Huang Ying has done some maintenance on the swap code's usage of
   device refcounting.
 
 - Christoph Hellwig has some cleanups for the filemap/directio code.
 
 - Ryan Roberts provides two patch series which yield some
   rationalization of the kernel's access to pte entries - use the provided
   APIs rather than open-coding accesses.
 
 - Lorenzo Stoakes has some fixes to the interaction between pagecache
   and directio access to file mappings.
 
 - John Hubbard has a series of fixes to the MM selftesting code.
 
 - ZhangPeng continues the folio conversion campaign.
 
 - Hugh Dickins has been working on the pagetable handling code, mainly
   with a view to reducing the load on the mmap_lock.
 
 - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment from
   128 to 8.
 
 - Domenico Cerasuolo has improved the zswap reclaim mechanism by
   reorganizing the LRU management.
 
 - Matthew Wilcox provides some fixups to make gfs2 work better with the
   buffer_head code.
 
 - Vishal Moola also has done some folio conversion work.
 
 - Matthew Wilcox has removed the remnants of the pagevec code - their
   functionality is migrated over to struct folio_batch.
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Merge tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull mm updates from Andrew Morton:

 - Yosry Ahmed brought back some cgroup v1 stats in OOM logs

 - Yosry has also eliminated cgroup's atomic rstat flushing

 - Nhat Pham adds the new cachestat() syscall. It provides userspace
   with the ability to query pagecache status - a similar concept to
   mincore() but more powerful and with improved usability

 - Mel Gorman provides more optimizations for compaction, reducing the
   prevalence of page rescanning

 - Lorenzo Stoakes has done some maintanance work on the
   get_user_pages() interface

 - Liam Howlett continues with cleanups and maintenance work to the
   maple tree code. Peng Zhang also does some work on maple tree

 - Johannes Weiner has done some cleanup work on the compaction code

 - David Hildenbrand has contributed additional selftests for
   get_user_pages()

 - Thomas Gleixner has contributed some maintenance and optimization
   work for the vmalloc code

 - Baolin Wang has provided some compaction cleanups,

 - SeongJae Park continues maintenance work on the DAMON code

 - Huang Ying has done some maintenance on the swap code's usage of
   device refcounting

 - Christoph Hellwig has some cleanups for the filemap/directio code

 - Ryan Roberts provides two patch series which yield some
   rationalization of the kernel's access to pte entries - use the
   provided APIs rather than open-coding accesses

 - Lorenzo Stoakes has some fixes to the interaction between pagecache
   and directio access to file mappings

 - John Hubbard has a series of fixes to the MM selftesting code

 - ZhangPeng continues the folio conversion campaign

 - Hugh Dickins has been working on the pagetable handling code, mainly
   with a view to reducing the load on the mmap_lock

 - Catalin Marinas has reduced the arm64 kmalloc() minimum alignment
   from 128 to 8

 - Domenico Cerasuolo has improved the zswap reclaim mechanism by
   reorganizing the LRU management

 - Matthew Wilcox provides some fixups to make gfs2 work better with the
   buffer_head code

 - Vishal Moola also has done some folio conversion work

 - Matthew Wilcox has removed the remnants of the pagevec code - their
   functionality is migrated over to struct folio_batch

* tag 'mm-stable-2023-06-24-19-15' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (380 commits)
  mm/hugetlb: remove hugetlb_set_page_subpool()
  mm: nommu: correct the range of mmap_sem_read_lock in task_mem()
  hugetlb: revert use of page_cache_next_miss()
  Revert "page cache: fix page_cache_next/prev_miss off by one"
  mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
  mm: memcg: rename and document global_reclaim()
  mm: kill [add|del]_page_to_lru_list()
  mm: compaction: convert to use a folio in isolate_migratepages_block()
  mm: zswap: fix double invalidate with exclusive loads
  mm: remove unnecessary pagevec includes
  mm: remove references to pagevec
  mm: rename invalidate_mapping_pagevec to mapping_try_invalidate
  mm: remove struct pagevec
  net: convert sunrpc from pagevec to folio_batch
  i915: convert i915_gpu_error to use a folio_batch
  pagevec: rename fbatch_count()
  mm: remove check_move_unevictable_pages()
  drm: convert drm_gem_put_pages() to use a folio_batch
  i915: convert shmem_sg_free_table() to use a folio_batch
  scatterlist: add sg_set_folio()
  ...
 2023-06-28 10:28:11 -07:00
Yajun Deng
61167ad5fe mm: pass nid to reserve_bootmem_region() 
early_pfn_to_nid() is called frequently in init_reserved_page(), it
returns the node id of the PFN.  These PFN are probably from the same
memory region, they have the same node id.  It's not necessary to call
early_pfn_to_nid() for each PFN.

Pass nid to reserve_bootmem_region() and drop the call to
early_pfn_to_nid() in init_reserved_page().  Also, set nid on all reserved
pages before doing this, as some reserved memory regions may not be set
nid.

The most beneficial function is memmap_init_reserved_pages() if
CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled.

The following data was tested on an x86 machine with 190GB of RAM.

before:
memmap_init_reserved_pages()  67ms

after:
memmap_init_reserved_pages()  20ms

Link: https://lkml.kernel.org/r/20230619023406.424298-1-yajun.deng@linux.dev
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-06-23 16:59:27 -07:00
Haifeng Xu
a668968f84 mm/memory_hotplug: remove reset_node_managed_pages() in hotadd_init_pgdat() 
managed pages has already been set to 0 in free_area_init_core_hotplug(),
via zone_init_internals() on each zone.  It's pointless to reset again.

Furthermore, reset_node_managed_pages() no longer needs to be exposed
outside of mm/memblock.c.  Remove declaration in include/linux/memblock.h
and define it as static.

In addtion to this, the only caller of reset_node_managed_pages() is
reset_all_zones_managed_pages(), which is annotated with __init, so it
should be safe to also mark reset_node_managed_pages() as __init.

Link: https://lkml.kernel.org/r/20230607024548.1240-1-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-06-19 16:19:05 -07:00
Kirill A. Shutemov
dcdfdd40fa mm: Add support for unaccepted memory 
UEFI Specification version 2.9 introduces the concept of memory
acceptance. Some Virtual Machine platforms, such as Intel TDX or AMD
SEV-SNP, require memory to be accepted before it can be used by the
guest. Accepting happens via a protocol specific to the Virtual Machine
platform.

There are several ways the kernel can deal with unaccepted memory:

 1. Accept all the memory during boot. It is easy to implement and it
    doesn't have runtime cost once the system is booted. The downside is
    very long boot time.

    Accept can be parallelized to multiple CPUs to keep it manageable
    (i.e. via DEFERRED_STRUCT_PAGE_INIT), but it tends to saturate
    memory bandwidth and does not scale beyond the point.

 2. Accept a block of memory on the first use. It requires more
    infrastructure and changes in page allocator to make it work, but
    it provides good boot time.

    On-demand memory accept means latency spikes every time kernel steps
    onto a new memory block. The spikes will go away once workload data
    set size gets stabilized or all memory gets accepted.

 3. Accept all memory in background. Introduce a thread (or multiple)
    that gets memory accepted proactively. It will minimize time the
    system experience latency spikes on memory allocation while keeping
    low boot time.

    This approach cannot function on its own. It is an extension of #2:
    background memory acceptance requires functional scheduler, but the
    page allocator may need to tap into unaccepted memory before that.

    The downside of the approach is that these threads also steal CPU
    cycles and memory bandwidth from the user's workload and may hurt
    user experience.

Implement #1 and #2 for now. #2 is the default. Some workloads may want
to use #1 with accept_memory=eager in kernel command line. #3 can be
implemented later based on user's demands.

Support of unaccepted memory requires a few changes in core-mm code:

  - memblock accepts memory on allocation. It serves early boot memory
    allocations and doesn't limit them to pre-accepted pool of memory.

  - page allocator accepts memory on the first allocation of the page.
    When kernel runs out of accepted memory, it accepts memory until the
    high watermark is reached. It helps to minimize fragmentation.

EFI code will provide two helpers if the platform supports unaccepted
memory:

 - accept_memory() makes a range of physical addresses accepted.

 - range_contains_unaccepted_memory() checks anything within the range
   of physical addresses requires acceptance.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>	# memblock
Link: https://lore.kernel.org/r/20230606142637.5171-2-kirill.shutemov@linux.intel.com
 2023-06-06 16:38:22 +02:00
Yuwei Guan
de649e7f5e memblock: Update nid info in memblock debugfs 
The node id for memblock reserved regions will be wrong,
so let's show 'x' for reg->nid == MAX_NUMNODES in debugfs to keep it align.

Suggested-by: Mike Rapoport (IBM) <rppt@kernel.org>
Co-developed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Yuwei Guan <ssawgyw@gmail.com>
Link: https://lore.kernel.org/r/20230601133149.37160-1-ssawgyw@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2023-06-02 08:23:41 +03:00
Yuwei Guan
493f349e38 memblock: Add flags and nid info in memblock debugfs 
Currently, the memblock debugfs can display the count of memblock_type and
the base and end of the reg. However, when memblock_mark_*() or
memblock_set_node() is executed on some range, the information in the
existing debugfs cannot make it clear why the address is not consecutive.

For example,
cat /sys/kernel/debug/memblock/memory
   0: 0x0000000080000000..0x00000000901fffff
   1: 0x0000000090200000..0x00000000905fffff
   2: 0x0000000090600000..0x0000000092ffffff
   3: 0x0000000093000000..0x00000000973fffff
   4: 0x0000000097400000..0x00000000b71fffff
   5: 0x00000000c0000000..0x00000000dfffffff
   6: 0x00000000e2500000..0x00000000f87fffff
   7: 0x00000000f8800000..0x00000000fa7fffff
   8: 0x00000000fa800000..0x00000000fd3effff
   9: 0x00000000fd3f0000..0x00000000fd3fefff
  10: 0x00000000fd3ff000..0x00000000fd7fffff
  11: 0x00000000fd800000..0x00000000fd901fff
  12: 0x00000000fd902000..0x00000000fd909fff
  13: 0x00000000fd90a000..0x00000000fd90bfff
  14: 0x00000000fd90c000..0x00000000ffffffff
  15: 0x0000000880000000..0x0000000affffffff

So we can add flags and nid to this debugfs.

For example,
cat /sys/kernel/debug/memblock/memory
   0: 0x0000000080000000..0x00000000901fffff    0 NONE
   1: 0x0000000090200000..0x00000000905fffff    0 NOMAP
   2: 0x0000000090600000..0x0000000092ffffff    0 NONE
   3: 0x0000000093000000..0x00000000973fffff    0 NOMAP
   4: 0x0000000097400000..0x00000000b71fffff    0 NONE
   5: 0x00000000c0000000..0x00000000dfffffff    0 NONE
   6: 0x00000000e2500000..0x00000000f87fffff    0 NONE
   7: 0x00000000f8800000..0x00000000fa7fffff    0 NOMAP
   8: 0x00000000fa800000..0x00000000fd3effff    0 NONE
   9: 0x00000000fd3f0000..0x00000000fd3fefff    0 NOMAP
  10: 0x00000000fd3ff000..0x00000000fd7fffff    0 NONE
  11: 0x00000000fd800000..0x00000000fd901fff    0 NOMAP
  12: 0x00000000fd902000..0x00000000fd909fff    0 NONE
  13: 0x00000000fd90a000..0x00000000fd90bfff    0 NOMAP
  14: 0x00000000fd90c000..0x00000000ffffffff    0 NONE
  15: 0x0000000880000000..0x0000000affffffff    0 NONE

Signed-off-by: Yuwei Guan <ssawgyw@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Link: https://lore.kernel.org/r/20230519105321.333-1-ssawgyw@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2023-05-24 11:56:30 +03:00
Claudio Migliorelli
fc493f83a2 Fix some coding style errors in memblock.c 
This patch removes the initialization of some static variables to 0 and
`false` in the memblock source file, according to the coding style
guidelines.

Signed-off-by: Claudio Migliorelli <claudio.migliorelli@mail.polimi.it>
Link: https://lore.kernel.org/r/87r0sa7mm8.fsf@mail.polimi.it
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2023-05-24 11:56:30 +03:00