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Patch series "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and
vmemmap_check_pmd()", v3.
The weak vmemmap_set_pmd() and vmemmap_check_pmd() hooks are currently
no-ops in the generic code, which leaves architectures that need PMD-level
handling to open-code the same logic locally.
This series provides generic implementations for both helpers in
mm/sparse-vmemmap.c. vmemmap_set_pmd() installs a huge PMD with
PAGE_KERNEL protection, and vmemmap_check_pmd() verifies a present leaf
PMD before reusing the existing vmemmap_verify() helper.
With those generic helpers in place, patches 2-5 remove the now redundant
arch-specific implementations from arm64, riscv, loongarch, and sparc.
This patch (of 5):
The two weak functions are currently no-ops on every architecture, forcing
each platform that needs them to duplicate the same handful of lines.
Provide a generic implementation:
- vmemmap_set_pmd() simply sets a huge PMD with PAGE_KERNEL protection.
- vmemmap_check_pmd() verifies that the PMD is present and leaf,
then calls the existing vmemmap_verify() helper.
Architectures that need special handling can continue to override the weak
symbols; everyone else gets the standard version for free.
Link: https://lore.kernel.org/20260601084845.3792171-1-songmuchun@bytedance.com
Link: https://lore.kernel.org/20260601084845.3792171-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Oscar Salvador (SUSE) <osalvador@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When vmemmap optimization is enabled for DAX, the nr_memmap_pages counter
in /proc/vmstat is incorrect. The current code always accounts for the
full, non-optimized vmemmap size, but vmemmap optimization reduces the
actual number of vmemmap pages by reusing tail pages. This causes the
system to overcount vmemmap usage, leading to inaccurate page statistics
in /proc/vmstat.
Fix this by introducing section_nr_vmemmap_pages(), which returns the
exact vmemmap page count for a given pfn range based on whether
optimization is in effect.
Link: https://lore.kernel.org/20260428081855.1249045-5-songmuchun@bytedance.com
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Liam R. Howlett <liam@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, the memory hot-remove call chain -- arch_remove_memory(),
__remove_pages(), sparse_remove_section() and section_deactivate() -- does
not carry the struct dev_pagemap pointer. This prevents the lower levels
from knowing whether the section was originally populated with vmemmap
optimizations (e.g., DAX with vmemmap optimization enabled).
Without this information, we cannot call vmemmap_can_optimize() to
determine if the vmemmap pages were optimized. As a result, the vmemmap
page accounting during teardown will mistakenly assume a non-optimized
allocation, leading to incorrect memmap statistics.
To lay the groundwork for fixing the vmemmap page accounting, we need to
pass the @pgmap pointer down to the deactivation location. Plumb the
@pgmap argument through the APIs of arch_remove_memory(), __remove_pages()
and sparse_remove_section(), mirroring the corresponding *_activate()
paths.
Link: https://lore.kernel.org/20260428081855.1249045-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Liam R. Howlett <liam@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: Fix vmemmap optimization accounting and initialization",
v8.
The series fixes several bugs in vmemmap optimization, mainly around
incorrect page accounting and memmap initialization in DAX and memory
hotplug paths. It also fixes pageblock migratetype initialization and
struct page initialization for ZONE_DEVICE compound pages.
Patches 1-4 fix vmemmap accounting issues. Patch 1 fixes an accounting
underflow in the section activation failure path by moving vmemmap page
accounting into the lower-level allocation and freeing helpers. Patch 2
fixes incorrect altmap passing in the memory hotplug error path. Patch 3
passes pgmap through memory deactivation paths so the teardown side can
determine whether vmemmap optimization was in effect. Patch 4 uses that
information to account the optimized DAX vmemmap size correctly.
Patches 5-6 fix initialization issues in mm/mm_init. One makes sure all
pageblocks in ZONE_DEVICE compound pages get their migratetype
initialized. The other fixes a case where DAX memory hotplug reuses an
unoptimized early-section memmap while compound_nr_pages() still assumes
vmemmap optimization, leaving tail struct pages uninitialized.
This patch (of 6):
In section_activate(), if populate_section_memmap() fails, the error
handling path calls section_deactivate() to roll back the state. This
causes a vmemmap accounting imbalance.
Since commit c3576889d87b ("mm: fix accounting of memmap pages"), memmap
pages are accounted for only after populate_section_memmap() succeeds.
However, the failure path unconditionally calls section_deactivate(),
which decreases the vmemmap count. Consequently, a failure in
populate_section_memmap() leads to an accounting underflow, incorrectly
reducing the system's tracked vmemmap usage.
Fix this more thoroughly by moving all accounting calls into the lower
level functions that actually perform the vmemmap allocation and freeing:
- populate_section_memmap() accounts for newly allocated vmemmap pages -
depopulate_section_memmap() unaccounts when vmemmap is freed
This ensures proper accounting in all code paths, including error handling
and early section cases.
Link: https://lore.kernel.org/20260428081855.1249045-1-songmuchun@bytedance.com
Link: https://lore.kernel.org/20260428081855.1249045-2-songmuchun@bytedance.com
Fixes: c3576889d87b ("mm: fix accounting of memmap pages")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Liam R. Howlett <liam@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit 9bdac9142407 ("sparsemem: Put mem map for one node together.")
introduced a mechanism to pre-allocate a large memory block to hold all
memmaps for a NUMA node upfront.
However, the original commit message did not clearly state the actual
benefits or the necessity of explicitly pre-allocating a single chunk for
all memmap areas of a given node.
One of the concerns about removing this pre-allocation is that the
subsequent per-section memmap allocations could become scattered around,
and might turn too many memory blocks/sections into an "un-offlinable"
state. However, tests show that even without the explicit node-wide
pre-allocation, memblock still allocates memory closely and back-to-back.
When tracing vmemmap_set_pmd allocations, the physical chunks allocated by
memblock are strictly adjacent to each other in a single contiguous
physical range (mapped top-down). Because they are packed tightly
together naturally, they will at most consume or pollute the exact same
number of memory blocks as the explicit pre-allocation did.
Another concern is the boot performance impact of calling memmap_alloc()
multiple times compared to one large node-wide allocation. Tests on a
256GB VM showed that memmap allocation time increased from 199,555 ns to
741,292 ns. Even though it is 3.7x slower, on a 1TB machine, the entire
memory allocation time would only take a few milliseconds. This boot
performance difference is completely negligible.
Since no negative impact on memory offlining behavior or noticeable boot
performance regression was found, this patch proposes removing the
explicit node-wide memmap pre-allocation mechanism to reduce the
maintenance burden.
Link: https://lore.kernel.org/20260410092419.2446420-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since the vmemmap_p?d_populate functions are unused outside the mm
subsystem, we can remove their external declarations and convert them to
static functions.
Link: https://lore.kernel.org/20260423101441.7089-1-kaitao.cheng@linux.dev
Signed-off-by: Chengkaitao <chengkaitao@kylinos.cn>
Acked-by: David Hildenbrand (arm) <david@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Static variables defined inside __meminit functions should also be marked
with __meminitdata, so that their storage is placed in the .init.data
section and reclaimed with free_initmem(), thereby reducing permanent .bss
memory usage when CONFIG_MEMORY_HOTPLUG is disabled.
Link: https://lkml.kernel.org/r/20260321120847.8159-1-pilgrimtao@gmail.com
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Let's move all memory hoptplug related code to sparse-vmemmap.c.
We only have to expose sparse_index_init(). While at it, drop the
definition of sparse_index_init() for !CONFIG_SPARSEMEM, which is unused,
and place the declaration in internal.h.
Link: https://lkml.kernel.org/r/20260320-sparsemem_cleanups-v2-15-096addc8800d@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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HugeTLB Vmemmap Optimization (HVO) reduces memory usage by freeing most
vmemmap pages for huge pages and remapping the freed range to a single
page containing the struct page metadata.
With the new mask-based compound_info encoding (for power-of-2 struct page
sizes), all tail pages of the same order are now identical regardless of
which compound page they belong to. This means the tail pages can be
truly shared without fake heads.
Allocate a single page of initialized tail struct pages per zone per order
in the vmemmap_tails[] array in struct zone. All huge pages of that order
in the zone share this tail page, mapped read-only into their vmemmap.
The head page remains unique per huge page.
Redefine MAX_FOLIO_ORDER using ilog2(). The define has to produce a
compile-constant as it is used to specify vmemmap_tail array size. For
some reason, compiler is not able to solve get_order() at compile-time,
but ilog2() works.
Avoid PUD_ORDER to define MAX_FOLIO_ORDER as it adds dependency to
<linux/pgtable.h> which generates hard-to-break include loop.
This eliminates fake heads while maintaining the same memory savings, and
simplifies compound_head() by removing fake head detection.
Link: https://lkml.kernel.org/r/20260227194302.274384-13-kas@kernel.org
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, the vmemmap for bootmem-allocated gigantic pages is populated
early in hugetlb_vmemmap_init_early(). However, the zone information is
only available after zones are initialized. If it is later discovered
that a page spans multiple zones, the HVO mapping must be undone and
replaced with a normal mapping using vmemmap_undo_hvo().
Defer the actual vmemmap population to hugetlb_vmemmap_init_late(). At
this stage, zones are already initialized, so it can be checked if the
page is valid for HVO before deciding how to populate the vmemmap.
This allows us to remove vmemmap_undo_hvo() and the complex logic required
to rollback HVO mappings.
In hugetlb_vmemmap_init_late(), if HVO population fails or if the zones
are invalid, fall back to a normal vmemmap population.
Postponing population until hugetlb_vmemmap_init_late() also makes zone
information available from within vmemmap_populate_hvo().
Link: https://lkml.kernel.org/r/20260227194302.274384-10-kas@kernel.org
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Replace all READ_ONCE() with a standard page table accessors i.e
pxdp_get() that defaults into READ_ONCE() in cases where platform does not
override.
Link: https://lkml.kernel.org/r/20251007063100.2396936-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce and use {pgd,p4d}_populate_kernel() in core MM code when
populating PGD and P4D entries for the kernel address space. These
helpers ensure proper synchronization of page tables when updating the
kernel portion of top-level page tables.
Until now, the kernel has relied on each architecture to handle
synchronization of top-level page tables in an ad-hoc manner. For
example, see commit 9b861528a801 ("x86-64, mem: Update all PGDs for direct
mapping and vmemmap mapping changes").
However, this approach has proven fragile for following reasons:
1) It is easy to forget to perform the necessary page table
synchronization when introducing new changes.
For instance, commit 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory
savings for compound devmaps") overlooked the need to synchronize
page tables for the vmemmap area.
2) It is also easy to overlook that the vmemmap and direct mapping areas
must not be accessed before explicit page table synchronization.
For example, commit 8d400913c231 ("x86/vmemmap: handle unpopulated
sub-pmd ranges")) caused crashes by accessing the vmemmap area
before calling sync_global_pgds().
To address this, as suggested by Dave Hansen, introduce _kernel() variants
of the page table population helpers, which invoke architecture-specific
hooks to properly synchronize page tables. These are introduced in a new
header file, include/linux/pgalloc.h, so they can be called from common
code.
They reuse existing infrastructure for vmalloc and ioremap.
Synchronization requirements are determined by ARCH_PAGE_TABLE_SYNC_MASK,
and the actual synchronization is performed by
arch_sync_kernel_mappings().
This change currently targets only x86_64, so only PGD and P4D level
helpers are introduced. Currently, these helpers are no-ops since no
architecture sets PGTBL_{PGD,P4D}_MODIFIED in ARCH_PAGE_TABLE_SYNC_MASK.
In theory, PUD and PMD level helpers can be added later if needed by other
architectures. For now, 32-bit architectures (x86-32 and arm) only handle
PGTBL_PMD_MODIFIED, so p*d_populate_kernel() will never affect them unless
we introduce a PMD level helper.
[harry.yoo@oracle.com: fix KASAN build error due to p*d_populate_kernel()]
Link: https://lkml.kernel.org/r/20250822020727.202749-1-harry.yoo@oracle.com
Link: https://lkml.kernel.org/r/20250818020206.4517-3-harry.yoo@oracle.com
Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Kiryl Shutsemau <kas@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: bibo mao <maobibo@loongson.cn>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Christoph Lameter (Ampere) <cl@gentwo.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For !CONFIG_SPARSEMEM_VMEMMAP, memmap page accounting is currently done
upfront in sparse_buffer_init(). However, sparse_buffer_alloc() may
return NULL in failure scenario.
Also, memmap pages may be allocated either from the memblock allocator
during early boot or from the buddy allocator. When removed via
arch_remove_memory(), accounting of memmap pages must reflect the original
allocation source.
To ensure correctness:
* Account memmap pages after successful allocation in sparse_init_nid()
and section_activate().
* Account memmap pages in section_deactivate() based on allocation
source.
Link: https://lkml.kernel.org/r/20250807183545.1424509-1-sumanthk@linux.ibm.com
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
For large systems, the overhead of vmemmap pages for hugetlb is
substantial. It's about 1.5% of memory, which is about 45G for a 3T
system. If you want to configure most of that system for hugetlb (e.g.
to use as backing memory for VMs), there is a chance of running out of
memory on boot, even though you know that the 45G will become available
later.
To avoid this scenario, and since it's a waste to first allocate and then
free that 45G during boot, do pre-HVO for hugetlb bootmem allocated pages
('gigantic' pages).
pre-HVO is done by adding functions that are called from
sparse_init_nid_early and sparse_init_nid_late. The first is called
before memmap allocation, so it takes care of allocating memmap HVO-style.
The second verifies that all bootmem pages look good, specifically it
checks that they do not intersect with multiple zones. This can only be
done from sparse_init_nid_late path, when zones have been initialized.
The hugetlb page size must be aligned to the section size, and aligned to
the size of memory described by the number of page structures contained in
one PMD (since pre-HVO is not prepared to split PMDs). This should be
true for most 'gigantic' pages, it is for 1G pages on x86, where both of
these alignment requirements are 128M.
This will only have an effect if hugetlb_bootmem_alloc was called early in
boot. If not, it won't do anything, and HVO for bootmem hugetlb pages
works as before.
Link: https://lkml.kernel.org/r/20250228182928.2645936-20-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add a few functions to enable early HVO:
vmemmap_populate_hvo
vmemmap_undo_hvo
vmemmap_wrprotect_hvo
The populate and undo functions are expected to be used in early init,
from the sparse_init_nid_early() function. The wrprotect function is to
be used, potentially, later.
To implement these functions, mostly re-use the existing compound pages
vmemmap logic used by DAX. vmemmap_populate_address has its argument
changed a bit in this commit: the page structure passed in to be reused in
the mapping is replaced by a PFN and a flag. The flag indicates whether
an extra ref should be taken on the vmemmap page containing the head page
structure. Taking the ref is appropriate to for DAX / ZONE_DEVICE, but
not for HugeTLB HVO.
The HugeTLB vmemmap optimization maps tail page structure pages read-only.
The vmemmap_wrprotect_hvo function that does this is implemented
separately, because it cannot be guaranteed that reserved page structures
will not be write accessed during memory initialization. Even with
CONFIG_DEFERRED_STRUCT_PAGE_INIT, they might still be written to (if they
are at the bottom of a zone). So, vmemmap_populate_hvo leaves the tail
page structure pages RW initially, and then later during initialization,
after memmap init is fully done, vmemmap_wrprotect_hvo must be called to
finish the job.
Subsequent commits will use these functions for early HugeTLB HVO.
Link: https://lkml.kernel.org/r/20250228182928.2645936-15-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add functions that are called just before the per-section memmap is
initialized and just before the memmap page structures are initialized.
They are called sparse_vmemmap_init_nid_early and
sparse_vmemmap_init_nid_late, respectively.
This allows for mm subsystems to add calls to initialize memmap and page
structures in a specific way, if using SPARSEMEM_VMEMMAP. Specifically,
hugetlb can pre-HVO bootmem allocated pages that way, so that no time and
resources are wasted on allocating vmemmap pages, only to free them later
(and possibly unnecessarily running the system out of memory in the
process).
Refactor some code and export a few convenience functions for external
use.
In sparse_init_nid, skip any sections that are already initialized, e.g.
they have been initialized by sparse_vmemmap_init_nid_early already.
The hugetlb code to use these functions will be added in a later commit.
Export section_map_size, as any alternate memmap init code will want to
use it.
The internal config option to enable this is SPARSEMEM_VMEMMAP_PREINIT,
which is selected if an architecture-specific option,
ARCH_WANT_HUGETLB_VMEMMAP_PREINIT, is set. In the future, if other
subsystems want to do preinit too, they can do it in a similar fashion.
The internal config option is there because a section flag is used, and
the number of flags available is architecture-dependent (see mmzone.h).
Architecures can decide if there is room for the flag when enabling
options that select SPARSEMEM_VMEMMAP_PREINIT.
Fortunately, as of right now, all sparse vmemmap using architectures do
have room.
Link: https://lkml.kernel.org/r/20250228182928.2645936-11-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
kmemleak explicitly scans the mem_map through the valid struct page
objects. However, memmap_alloc() was also adding this memory to the gray
object list, causing it to be scanned twice. Remove memmap_alloc() from
the scan list and add a comment to clarify the behavior.
Link: https://lore.kernel.org/lkml/CAOm6qn=FVeTpH54wGDFMHuCOeYtvoTx30ktnv9-w3Nh8RMofEA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20250106021126.1678334-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
pud_init(), pmd_init() and kernel_pte_init() are duplicated defined in
file kasan.c and sparse-vmemmap.c as weak functions. Move them to generic
header file pgtable.h, architecture can redefine them.
Link: https://lkml.kernel.org/r/20241104070712.52902-1-maobibo@loongson.cn
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There are two pages in one TLB entry on LoongArch system. For kernel
space, it requires both two pte entries (buddies) with PAGE_GLOBAL bit
set, otherwise HW treats it as non-global tlb, there will be potential
problems if tlb entry for kernel space is not global. Such as fail to
flush kernel tlb with the function local_flush_tlb_kernel_range() which
supposed only flush tlb with global bit.
Kernel address space areas include percpu, vmalloc, vmemmap, fixmap and
kasan areas. For these areas both two consecutive page table entries
should be enabled with PAGE_GLOBAL bit. So with function set_pte() and
pte_clear(), pte buddy entry is checked and set besides its own pte
entry. However it is not atomic operation to set both two pte entries,
there is problem with test_vmalloc test case.
So function kernel_pte_init() is added to init a pte table when it is
created for kernel address space, and the default initial pte value is
PAGE_GLOBAL rather than zero at beginning. Then only its own pte entry
need update with function set_pte() and pte_clear(), nothing to do with
the pte buddy entry.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
|
|
Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
Segmentation fault
dmesg:
Oops: general protection fault, probably for
non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN
PTI
KASAN: probably user-memory-access in range
[0x000000000002b280-0x000000000002b287]
CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1
Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS
2.20.1 09/13/2023
RIP: 0010:mod_node_page_state+0x2a/0x110
cxl-test users report a GPF when trying to unload the test module:
$ modrpobe -r cxl-test
dmesg
BUG: unable to handle page fault for address: 0000000000004200
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197
Tainted: [O]=OOT_MODULE, [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/15
RIP: 0010:mod_node_page_state+0x6/0x90
Currently, when memory is hot-plugged or hot-removed the accounting is
done based on the assumption that memmap is allocated from the same node
as the hot-plugged/hot-removed memory, which is not always the case.
In addition, there are challenges with keeping the node id of the memory
that is being remove to the time when memmap accounting is actually
performed: since this is done after remove_pfn_range_from_zone(), and
also after remove_memory_block_devices(). Meaning that we cannot use
pgdat nor walking though memblocks to get the nid.
Given all of that, account the memmap overhead system wide instead.
For this we are going to be using global atomic counters, but given that
memmap size is rarely modified, and normally is only modified either
during early boot when there is only one CPU, or under a hotplug global
mutex lock, therefore there is no need for per-cpu optimizations.
Also, while we are here rename nr_memmap to nr_memmap_pages, and
nr_memmap_boot to nr_memmap_boot_pages to be self explanatory that the
units are in page count.
[pasha.tatashin@soleen.com: address a few nits from David Hildenbrand]
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240809191020.1142142-4-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240808213437.682006-4-pasha.tatashin@soleen.com
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com
Reported-by: Alison Schofield <alison.schofield@intel.com>
Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Today, we do not have any observability of per-page metadata and how much
it takes away from the machine capacity. Thus, we want to describe the
amount of memory that is going towards per-page metadata, which can vary
depending on build configuration, machine architecture, and system use.
This patch adds 2 fields to /proc/vmstat that can used as shown below:
Accounting per-page metadata allocated by boot-allocator:
/proc/vmstat:nr_memmap_boot * PAGE_SIZE
Accounting per-page metadata allocated by buddy-allocator:
/proc/vmstat:nr_memmap * PAGE_SIZE
Accounting total Perpage metadata allocated on the machine:
(/proc/vmstat:nr_memmap_boot +
/proc/vmstat:nr_memmap) * PAGE_SIZE
Utility for userspace:
Observability: Describe the amount of memory overhead that is going to
per-page metadata on the system at any given time since this overhead is
not currently observable.
Debugging: Tracking the changes or absolute value in struct pages can help
detect anomalies as they can be correlated with other metrics in the
machine (e.g., memtotal, number of huge pages, etc).
page_ext overheads: Some kernel features such as page_owner
page_table_check that use page_ext can be optionally enabled via kernel
parameters. Having the total per-page metadata information helps users
precisely measure impact. Furthermore, page-metadata metrics will reflect
the amount of struct pages reliquished (or overhead reduced) when
hugetlbfs pages are reserved which will vary depending on whether hugetlb
vmemmap optimization is enabled or not.
For background and results see:
lore.kernel.org/all/20240220214558.3377482-1-souravpanda@google.com
Link: https://lkml.kernel.org/r/20240605222751.1406125-1-souravpanda@google.com
Signed-off-by: Sourav Panda <souravpanda@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chen Linxuan <chenlinxuan@uniontech.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tomas Mudrunka <tomas.mudrunka@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Architectures like powerpc will like to use different page table
allocators and mapping mechanisms to implement vmemmap optimization.
Similar to vmemmap_populate allow architectures to implement
vmemap_populate_compound_pages
Link: https://lkml.kernel.org/r/20230724190759.483013-5-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Convert all instances of direct pte_t* dereferencing to instead use
ptep_get() helper. This means that by default, the accesses change from a
C dereference to a READ_ONCE(). This is technically the correct thing to
do since where pgtables are modified by HW (for access/dirty) they are
volatile and therefore we should always ensure READ_ONCE() semantics.
But more importantly, by always using the helper, it can be overridden by
the architecture to fully encapsulate the contents of the pte. Arch code
is deliberately not converted, as the arch code knows best. It is
intended that arch code (arm64) will override the default with its own
implementation that can (e.g.) hide certain bits from the core code, or
determine young/dirty status by mixing in state from another source.
Conversion was done using Coccinelle:
----
// $ make coccicheck \
// COCCI=ptepget.cocci \
// SPFLAGS="--include-headers" \
// MODE=patch
virtual patch
@ depends on patch @
pte_t *v;
@@
- *v
+ ptep_get(v)
----
Then reviewed and hand-edited to avoid multiple unnecessary calls to
ptep_get(), instead opting to store the result of a single call in a
variable, where it is correct to do so. This aims to negate any cost of
READ_ONCE() and will benefit arch-overrides that may be more complex.
Included is a fix for an issue in an earlier version of this patch that
was pointed out by kernel test robot. The issue arose because config
MMU=n elides definition of the ptep helper functions, including
ptep_get(). HUGETLB_PAGE=n configs still define a simple
huge_ptep_clear_flush() for linking purposes, which dereferences the ptep.
So when both configs are disabled, this caused a build error because
ptep_get() is not defined. Fix by continuing to do a direct dereference
when MMU=n. This is safe because for this config the arch code cannot be
trying to virtualize the ptes because none of the ptep helpers are
defined.
Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
commit 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for
compound devmaps") added support for using optimized vmmemap for devdax
devices. But how vmemmap mappings are created are architecture specific.
For example, powerpc with hash translation doesn't have vmemmap mappings
in init_mm page table instead they are bolted table entries in the
hardware page table
vmemmap_populate_compound_pages() used by vmemmap optimization code is not
aware of these architecture-specific mapping. Hence allow architecture to
opt for this feature. I selected architectures supporting
HUGETLB_PAGE_OPTIMIZE_VMEMMAP option as also supporting this feature.
This patch fixes the below crash on ppc64.
BUG: Unable to handle kernel data access on write at 0xc00c000100400038
Faulting instruction address: 0xc000000001269d90
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc5-150500.34-default+ #2 5c90a668b6bbd142599890245c2fb5de19d7d28a
Hardware name: IBM,9009-42G POWER9 (raw) 0x4e0202 0xf000005 of:IBM,FW950.40 (VL950_099) hv:phyp pSeries
NIP: c000000001269d90 LR: c0000000004c57d4 CTR: 0000000000000000
REGS: c000000003632c30 TRAP: 0300 Not tainted (6.3.0-rc5-150500.34-default+)
MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24842228 XER: 00000000
CFAR: c0000000004c57d0 DAR: c00c000100400038 DSISR: 42000000 IRQMASK: 0
....
NIP [c000000001269d90] __init_single_page.isra.74+0x14/0x4c
LR [c0000000004c57d4] __init_zone_device_page+0x44/0xd0
Call Trace:
[c000000003632ed0] [c000000003632f60] 0xc000000003632f60 (unreliable)
[c000000003632f10] [c0000000004c5ca0] memmap_init_zone_device+0x170/0x250
[c000000003632fe0] [c0000000005575f8] memremap_pages+0x2c8/0x7f0
[c0000000036330c0] [c000000000557b5c] devm_memremap_pages+0x3c/0xa0
[c000000003633100] [c000000000d458a8] dev_dax_probe+0x108/0x3e0
[c0000000036331a0] [c000000000d41430] dax_bus_probe+0xb0/0x140
[c0000000036331d0] [c000000000cef27c] really_probe+0x19c/0x520
[c000000003633260] [c000000000cef6b4] __driver_probe_device+0xb4/0x230
[c0000000036332e0] [c000000000cef888] driver_probe_device+0x58/0x120
[c000000003633320] [c000000000cefa6c] __device_attach_driver+0x11c/0x1e0
[c0000000036333a0] [c000000000cebc58] bus_for_each_drv+0xa8/0x130
[c000000003633400] [c000000000ceefcc] __device_attach+0x15c/0x250
[c0000000036334a0] [c000000000ced458] bus_probe_device+0x108/0x110
[c0000000036334f0] [c000000000ce92dc] device_add+0x7fc/0xa10
[c0000000036335b0] [c000000000d447c8] devm_create_dev_dax+0x1d8/0x530
[c000000003633640] [c000000000d46b60] __dax_pmem_probe+0x200/0x270
[c0000000036337b0] [c000000000d46bf0] dax_pmem_probe+0x20/0x70
[c0000000036337d0] [c000000000d2279c] nvdimm_bus_probe+0xac/0x2b0
[c000000003633860] [c000000000cef27c] really_probe+0x19c/0x520
[c0000000036338f0] [c000000000cef6b4] __driver_probe_device+0xb4/0x230
[c000000003633970] [c000000000cef888] driver_probe_device+0x58/0x120
[c0000000036339b0] [c000000000cefd08] __driver_attach+0x1d8/0x240
[c000000003633a30] [c000000000cebb04] bus_for_each_dev+0xb4/0x130
[c000000003633a90] [c000000000cee564] driver_attach+0x34/0x50
[c000000003633ab0] [c000000000ced878] bus_add_driver+0x218/0x300
[c000000003633b40] [c000000000cf1144] driver_register+0xa4/0x1b0
[c000000003633bb0] [c000000000d21a0c] __nd_driver_register+0x5c/0x100
[c000000003633c10] [c00000000206a2e8] dax_pmem_init+0x34/0x48
[c000000003633c30] [c0000000000132d0] do_one_initcall+0x60/0x320
[c000000003633d00] [c0000000020051b0] kernel_init_freeable+0x360/0x400
[c000000003633de0] [c000000000013764] kernel_init+0x34/0x1d0
[c000000003633e50] [c00000000000de14] ret_from_kernel_thread+0x5c/0x64
Link: https://lkml.kernel.org/r/20230411142214.64464-1-aneesh.kumar@linux.ibm.com
Fixes: 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for compound devmaps")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Generalise vmemmap_populate_hugepages() so ARM64 & X86 & LoongArch can
share its implementation.
Link: https://lkml.kernel.org/r/20221027125253.3458989-4-chenhuacai@loongson.cn
Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Min Zhou <zhoumin@loongson.cn>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Cc: Xuerui Wang <kernel@xen0n.name>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Add sparse memory vmemmap support for LoongArch. SPARSEMEM_VMEMMAP uses a
virtually mapped memmap to optimise pfn_to_page and page_to_pfn
operations. This is the most efficient option when sufficient kernel
resources are available.
Link: https://lkml.kernel.org/r/20221027125253.3458989-3-chenhuacai@loongson.cn
Signed-off-by: Min Zhou <zhoumin@loongson.cn>
Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Will Deacon <will@kernel.org>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Cc: Xuerui Wang <kernel@xen0n.name>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When I first introduced vmemmap manipulation functions related to HugeTLB,
I thought those functions may be reused by other modules (e.g. using
similar approach to optimize vmemmap pages, unfortunately, the DAX used
the same approach but does not use those functions). After two years, we
didn't see any other users. So move those functions to hugetlb_vmemmap.c.
Code movement without any functional change.
Link: https://lkml.kernel.org/r/20220628092235.91270-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
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git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
- Enable mirrored memory for arm64
- Fix up several abuses of the efivar API
- Refactor the efivar API in preparation for moving the 'business
logic' part of it into efivarfs
- Enable ACPI PRM on arm64
* tag 'efi-next-for-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (24 commits)
ACPI: Move PRM config option under the main ACPI config
ACPI: Enable Platform Runtime Mechanism(PRM) support on ARM64
ACPI: PRM: Change handler_addr type to void pointer
efi: Simplify arch_efi_call_virt() macro
drivers: fix typo in firmware/efi/memmap.c
efi: vars: Drop __efivar_entry_iter() helper which is no longer used
efi: vars: Use locking version to iterate over efivars linked lists
efi: pstore: Omit efivars caching EFI varstore access layer
efi: vars: Add thin wrapper around EFI get/set variable interface
efi: vars: Don't drop lock in the middle of efivar_init()
pstore: Add priv field to pstore_record for backend specific use
Input: applespi - avoid efivars API and invoke EFI services directly
selftests/kexec: remove broken EFI_VARS secure boot fallback check
brcmfmac: Switch to appropriate helper to load EFI variable contents
iwlwifi: Switch to proper EFI variable store interface
media: atomisp_gmin_platform: stop abusing efivar API
efi: efibc: avoid efivar API for setting variables
efi: avoid efivars layer when loading SSDTs from variables
efi: Correct comment on efi_memmap_alloc
memblock: Disable mirror feature if kernelcore is not specified
...
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there is an unexpected word 'a' in the comments that need to be dropped
Link: https://lkml.kernel.org/r/24fbdae3.c86.1819a0f31b9.Coremail.chenxuebing@jari.cn
Signed-off-by: XueBing Chen <chenxuebing@jari.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Higher order allocations for vmemmap pages from buddy allocator must be
able to be treated as indepdenent small pages as they can be freed
individually by the caller. There is no problem for higher order vmemmap
pages allocated at boot time since each individual small page will be
initialized at boot time. However, it will be an issue for memory hotplug
case since those higher order vmemmap pages are allocated from buddy
allocator without initializing each individual small page's refcount. The
system will panic in put_page_testzero() when CONFIG_DEBUG_VM is enabled
if the vmemmap page is freed.
Link: https://lkml.kernel.org/r/20220620023019.94257-1-songmuchun@bytedance.com
Fixes: d8d55f5616cf ("mm: sparsemem: use page table lock to protect kernel pmd operations")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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so it will be consistent with code mm directory and with
Documentation/admin-guide/mm and won't be confused with virtual machines.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Wu XiangCheng <bobwxc@email.cn>
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vmemmap_populate_compound_pages()
Remove unnecessary initialization for the variable 'next'. This fixes
the clang scan warning: Value stored to 'next' during its
initialization is never read [deadcode.DeadStores]
Link: https://lkml.kernel.org/r/20220612182320.160651-1-gautammenghani201@gmail.com
Signed-off-by: Gautam Menghani <gautammenghani201@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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<linux/mm.h> already provides the PAGE_ALIGNED macro. Let's use this
macro instead of IS_ALIGNED and passing PAGE_SIZE directly.
Link: https://lkml.kernel.org/r/20220526140257.1568744-1-bh1scw@gmail.com
Signed-off-by: Fanjun Kong <bh1scw@gmail.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For a system only have limited mirrored memory or some numa node without
mirrored memory, the per node vmemmap page_structs prefer to allocate
memory from mirrored region, which will lead to vmemmap_verify() in
vmemmap_populate_basepages() report lots of warning message.
This patch change the frequency of "potential offnode page_structs" warning
messages to only once to avoid a very long print during bootup.
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220614092156.1972846-4-mawupeng1@huawei.com
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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A compound devmap is a dev_pagemap with @vmemmap_shift > 0 and it means
that pages are mapped at a given huge page alignment and utilize uses
compound pages as opposed to order-0 pages.
Take advantage of the fact that most tail pages look the same (except the
first two) to minimize struct page overhead. Allocate a separate page for
the vmemmap area which contains the head page and separate for the next 64
pages. The rest of the subsections then reuse this tail vmemmap page to
initialize the rest of the tail pages.
Sections are arch-dependent (e.g. on x86 it's 64M, 128M or 512M) and when
initializing compound devmap with big enough @vmemmap_shift (e.g. 1G PUD)
it may cross multiple sections. The vmemmap code needs to consult @pgmap
so that multiple sections that all map the same tail data can refer back
to the first copy of that data for a given gigantic page.
On compound devmaps with 2M align, this mechanism lets 6 pages be saved
out of the 8 necessary PFNs necessary to set the subsection's 512 struct
pages being mapped. On a 1G compound devmap it saves 4094 pages.
Altmap isn't supported yet, given various restrictions in altmap pfn
allocator, thus fallback to the already in use vmemmap_populate(). It is
worth noting that altmap for devmap mappings was there to relieve the
pressure of inordinate amounts of memmap space to map terabytes of pmem.
With compound pages the motivation for altmaps for pmem gets reduced.
Link: https://lkml.kernel.org/r/20220420155310.9712-5-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In preparation for describing a memmap with compound pages, move the
actual pte population logic into a separate function
vmemmap_populate_address() and have a new helper vmemmap_populate_range()
walk through all base pages it needs to populate.
While doing that, change the helper to use a pte_t* as return value,
rather than an hardcoded errno of 0 or -ENOMEM.
Link: https://lkml.kernel.org/r/20220420155310.9712-3-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Patch series "sparse-vmemmap: memory savings for compound devmaps (device-dax)", v9.
This series minimizes 'struct page' overhead by pursuing a similar
approach as Muchun Song series "Free some vmemmap pages of hugetlb page"
(now merged since v5.14), but applied to devmap with @vmemmap_shift
(device-dax).
The vmemmap dedpulication original idea (already used in HugeTLB) is to
reuse/deduplicate tail page vmemmap areas, particular the area which only
describes tail pages. So a vmemmap page describes 64 struct pages, and
the first page for a given ZONE_DEVICE vmemmap would contain the head page
and 63 tail pages. The second vmemmap page would contain only tail pages,
and that's what gets reused across the rest of the subsection/section.
The bigger the page size, the bigger the savings (2M hpage -> save 6
vmemmap pages; 1G hpage -> save 4094 vmemmap pages).
This is done for PMEM /specifically only/ on device-dax configured
namespaces, not fsdax. In other words, a devmap with a @vmemmap_shift.
In terms of savings, per 1Tb of memory, the struct page cost would go down
with compound devmap:
* with 2M pages we lose 4G instead of 16G (0.39% instead of 1.5% of
total memory)
* with 1G pages we lose 40MB instead of 16G (0.0014% instead of 1.5% of
total memory)
The series is mostly summed up by patch 4, and to summarize what the
series does:
Patches 1 - 3: Minor cleanups in preparation for patch 4. Move the very
nice docs of hugetlb_vmemmap.c into a Documentation/vm/ entry.
Patch 4: Patch 4 is the one that takes care of the struct page savings
(also referred to here as tail-page/vmemmap deduplication). Much like
Muchun series, we reuse the second PTE tail page vmemmap areas across a
given @vmemmap_shift On important difference though, is that contrary to
the hugetlbfs series, there's no vmemmap for the area because we are
late-populating it as opposed to remapping a system-ram range. IOW no
freeing of pages of already initialized vmemmap like the case for
hugetlbfs, which greatly simplifies the logic (besides not being
arch-specific). altmap case unchanged and still goes via the
vmemmap_populate(). Also adjust the newly added docs to the device-dax
case.
[Note that device-dax is still a little behind HugeTLB in terms of
savings. I have an additional simple patch that reuses the head vmemmap
page too, as a follow-up. That will double the savings and namespaces
initialization.]
Patch 5: Initialize fewer struct pages depending on the page size with
DRAM backed struct pages -- because fewer pages are unique and most tail
pages (with bigger vmemmap_shift).
NVDIMM namespace bootstrap improves from ~268-358 ms to
~80-110/<1ms on 128G NVDIMMs with 2M and 1G respectivally. And struct
page needed capacity will be 3.8x / 1071x smaller for 2M and 1G
respectivelly. Tested on x86 with 1.5Tb of pmem (including pinning,
and RDMA registration/deregistration scalability with 2M MRs)
This patch (of 5):
In support of using compound pages for devmap mappings, plumb the pgmap
down to the vmemmap_populate implementation. Note that while altmap is
retrievable from pgmap the memory hotplug code passes altmap without
pgmap[*], so both need to be independently plumbed.
So in addition to @altmap, pass @pgmap to sparse section populate
functions namely:
sparse_add_section
section_activate
populate_section_memmap
__populate_section_memmap
Passing @pgmap allows __populate_section_memmap() to both fetch the
vmemmap_shift in which memmap metadata is created for and also to let
sparse-vmemmap fetch pgmap ranges to co-relate to a given section and pick
whether to just reuse tail pages from past onlined sections.
While at it, fix the kdoc for @altmap for sparse_add_section().
[*] https://lore.kernel.org/linux-mm/20210319092635.6214-1-osalvador@suse.de/
Link: https://lkml.kernel.org/r/20220420155310.9712-1-joao.m.martins@oracle.com
Link: https://lkml.kernel.org/r/20220420155310.9712-2-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The word of "free" is not expressive enough to express the feature of
optimizing vmemmap pages associated with each HugeTLB, rename this keywork
to "optimize". In this patch , cheanup configs to make code more
expressive.
Link: https://lkml.kernel.org/r/20220404074652.68024-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
The vmemmap_remap_free/alloc are relevant to HugeTLB, so move those
functiongs to the scope of CONFIG_HUGETLB_PAGE_FREE_VMEMMAP.
Link: https://lkml.kernel.org/r/20211101031651.75851-6-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The init_mm.page_table_lock is used to protect kernel page tables, we
can use it to serialize splitting vmemmap PMD mappings instead of mmap
write lock, which can increase the concurrency of vmemmap_remap_free().
Actually, It increase the concurrency between allocations of HugeTLB
pages. But it is not the only benefit. There are a lot of users of
mmap read lock of init_mm. The mmap write lock is holding through
vmemmap_remap_free(), removing mmap write lock usage to make it does not
affect other users of mmap read lock. It is not making anything worse
and always a win to move.
Now the kernel page table walker does not hold the page_table_lock when
walking pmd entries. There may be consistency issue of a pmd entry,
because pmd entry might change from a huge pmd entry to a PTE page
table. There is only one user of kernel page table walker, namely
ptdump. The ptdump already considers the consistency, which use a local
variable to cache the value of pmd entry. But we also need to update
->action to ACTION_CONTINUE to make sure the walker does not walk every
pte entry again when concurrent thread has split the huge pmd.
Link: https://lkml.kernel.org/r/20211101031651.75851-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Free the 2nd vmemmap page associated with each HugeTLB
page", v7.
This series can minimize the overhead of struct page for 2MB HugeTLB
pages significantly. It further reduces the overhead of struct page by
12.5% for a 2MB HugeTLB compared to the previous approach, which means
2GB per 1TB HugeTLB. It is a nice gain. Comments and reviews are
welcome. Thanks.
The main implementation and details can refer to the commit log of patch
1. In this series, I have changed the following four helpers, the
following table shows the impact of the overhead of those helpers.
+------------------+-----------------------+
| APIs | head page | tail page |
+------------------+-----------+-----------+
| PageHead() | Y | N |
+------------------+-----------+-----------+
| PageTail() | Y | N |
+------------------+-----------+-----------+
| PageCompound() | N | N |
+------------------+-----------+-----------+
| compound_head() | Y | N |
+------------------+-----------+-----------+
Y: Overhead is increased.
N: Overhead is _NOT_ increased.
It shows that the overhead of those helpers on a tail page don't change
between "hugetlb_free_vmemmap=on" and "hugetlb_free_vmemmap=off". But the
overhead on a head page will be increased when "hugetlb_free_vmemmap=on"
(except PageCompound()). So I believe that Matthew Wilcox's folio series
will help with this.
The users of PageHead() and PageTail() are much less than compound_head()
and most users of PageTail() are VM_BUG_ON(), so I have done some tests
about the overhead of compound_head() on head pages.
I have tested the overhead of calling compound_head() on a head page,
which is 2.11ns (Measure the call time of 10 million times
compound_head(), and then average).
For a head page whose address is not aligned with PAGE_SIZE or a
non-compound page, the overhead of compound_head() is 2.54ns which is
increased by 20%. For a head page whose address is aligned with
PAGE_SIZE, the overhead of compound_head() is 2.97ns which is increased by
40%. Most pages are the former. I do not think the overhead is
significant since the overhead of compound_head() itself is low.
This patch (of 5):
This patch minimizes the overhead of struct page for 2MB HugeTLB pages
significantly. It further reduces the overhead of struct page by 12.5%
for a 2MB HugeTLB compared to the previous approach, which means 2GB per
1TB HugeTLB (2MB type).
After the feature of "Free sonme vmemmap pages of HugeTLB page" is
enabled, the mapping of the vmemmap addresses associated with a 2MB
HugeTLB page becomes the figure below.
HugeTLB struct pages(8 pages) page frame(8 pages)
+-----------+ ---virt_to_page---> +-----------+ mapping to +-----------+---> PG_head
| | | 0 | -------------> | 0 |
| | +-----------+ +-----------+
| | | 1 | -------------> | 1 |
| | +-----------+ +-----------+
| | | 2 | ----------------^ ^ ^ ^ ^ ^
| | +-----------+ | | | | |
| | | 3 | ------------------+ | | | |
| | +-----------+ | | | |
| | | 4 | --------------------+ | | |
| 2MB | +-----------+ | | |
| | | 5 | ----------------------+ | |
| | +-----------+ | |
| | | 6 | ------------------------+ |
| | +-----------+ |
| | | 7 | --------------------------+
| | +-----------+
| |
| |
| |
+-----------+
As we can see, the 2nd vmemmap page frame (indexed by 1) is reused and
remaped. However, the 2nd vmemmap page frame is also can be freed to
the buddy allocator, then we can change the mapping from the figure
above to the figure below.
HugeTLB struct pages(8 pages) page frame(8 pages)
+-----------+ ---virt_to_page---> +-----------+ mapping to +-----------+---> PG_head
| | | 0 | -------------> | 0 |
| | +-----------+ +-----------+
| | | 1 | ---------------^ ^ ^ ^ ^ ^ ^
| | +-----------+ | | | | | |
| | | 2 | -----------------+ | | | | |
| | +-----------+ | | | | |
| | | 3 | -------------------+ | | | |
| | +-----------+ | | | |
| | | 4 | ---------------------+ | | |
| 2MB | +-----------+ | | |
| | | 5 | -----------------------+ | |
| | +-----------+ | |
| | | 6 | -------------------------+ |
| | +-----------+ |
| | | 7 | ---------------------------+
| | +-----------+
| |
| |
| |
+-----------+
After we do this, all tail vmemmap pages (1-7) are mapped to the head
vmemmap page frame (0). In other words, there are more than one page
struct with PG_head associated with each HugeTLB page. We __know__ that
there is only one head page struct, the tail page structs with PG_head are
fake head page structs. We need an approach to distinguish between those
two different types of page structs so that compound_head(), PageHead()
and PageTail() can work properly if the parameter is the tail page struct
but with PG_head.
The following code snippet describes how to distinguish between real and
fake head page struct.
if (test_bit(PG_head, &page->flags)) {
unsigned long head = READ_ONCE(page[1].compound_head);
if (head & 1) {
if (head == (unsigned long)page + 1)
==> head page struct
else
==> tail page struct
} else
==> head page struct
}
We can safely access the field of the @page[1] with PG_head because the
@page is a compound page composed with at least two contiguous pages.
[songmuchun@bytedance.com: restore lost comment changes]
Link: https://lkml.kernel.org/r/20211101031651.75851-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20211101031651.75851-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The smp_wmb() which is in the __pte_alloc() is used to ensure all ptes
setup is visible before the pte is made visible to other CPUs by being
put into page tables. We only need this when the pte is actually
populated, so move it to pmd_install(). __pte_alloc_kernel(),
__p4d_alloc(), __pud_alloc() and __pmd_alloc() are similar to this case.
We can also defer smp_wmb() to the place where the pmd entry is really
populated by preallocated pte. There are two kinds of user of
preallocated pte, one is filemap & finish_fault(), another is THP. The
former does not need another smp_wmb() because the smp_wmb() has been
done by pmd_install(). Fortunately, the latter also does not need
another smp_wmb() because there is already a smp_wmb() before populating
the new pte when the THP uses a preallocated pte to split a huge pmd.
Link: https://lkml.kernel.org/r/20210901102722.47686-3-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mika Penttila <mika.penttila@nextfour.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Split huge PMD mapping of vmemmap pages", v4.
In order to reduce the difficulty of code review in series[1]. We disable
huge PMD mapping of vmemmap pages when that feature is enabled. In this
series, we do not disable huge PMD mapping of vmemmap pages anymore. We
will split huge PMD mapping when needed. When HugeTLB pages are freed
from the pool we do not attempt coalasce and move back to a PMD mapping
because it is much more complex.
[1] https://lore.kernel.org/linux-doc/20210510030027.56044-1-songmuchun@bytedance.com/
This patch (of 3):
In [1], PMD mappings of vmemmap pages were disabled if the the feature
hugetlb_free_vmemmap was enabled. This was done to simplify the initial
implementation of vmmemap freeing for hugetlb pages. Now, remove this
simplification by allowing PMD mapping and switching to PTE mappings as
needed for allocated hugetlb pages.
When a hugetlb page is allocated, the vmemmap page tables are walked to
free vmemmap pages. During this walk, split huge PMD mappings to PTE
mappings as required. In the unlikely case PTE pages can not be
allocated, return error(ENOMEM) and do not optimize vmemmap of the hugetlb
page.
When HugeTLB pages are freed from the pool, we do not attempt to
coalesce and move back to a PMD mapping because it is much more complex.
[1] https://lkml.kernel.org/r/20210510030027.56044-8-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210616094915.34432-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210616094915.34432-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When we free a HugeTLB page to the buddy allocator, we need to allocate
the vmemmap pages associated with it. However, we may not be able to
allocate the vmemmap pages when the system is under memory pressure. In
this case, we just refuse to free the HugeTLB page. This changes behavior
in some corner cases as listed below:
1) Failing to free a huge page triggered by the user (decrease nr_pages).
User needs to try again later.
2) Failing to free a surplus huge page when freed by the application.
Try again later when freeing a huge page next time.
3) Failing to dissolve a free huge page on ZONE_MOVABLE via
offline_pages().
This can happen when we have plenty of ZONE_MOVABLE memory, but
not enough kernel memory to allocate vmemmmap pages. We may even
be able to migrate huge page contents, but will not be able to
dissolve the source huge page. This will prevent an offline
operation and is unfortunate as memory offlining is expected to
succeed on movable zones. Users that depend on memory hotplug
to succeed for movable zones should carefully consider whether the
memory savings gained from this feature are worth the risk of
possibly not being able to offline memory in certain situations.
4) Failing to dissolve a huge page on CMA/ZONE_MOVABLE via
alloc_contig_range() - once we have that handling in place. Mainly
affects CMA and virtio-mem.
Similar to 3). virito-mem will handle migration errors gracefully.
CMA might be able to fallback on other free areas within the CMA
region.
Vmemmap pages are allocated from the page freeing context. In order for
those allocations to be not disruptive (e.g. trigger oom killer)
__GFP_NORETRY is used. hugetlb_lock is dropped for the allocation because
a non sleeping allocation would be too fragile and it could fail too
easily under memory pressure. GFP_ATOMIC or other modes to access memory
reserves is not used because we want to prevent consuming reserves under
heavy hugetlb freeing.
[mike.kravetz@oracle.com: fix dissolve_free_huge_page use of tail/head page]
Link: https://lkml.kernel.org/r/20210527231225.226987-1-mike.kravetz@oracle.com
[willy@infradead.org: fix alloc_vmemmap_page_list documentation warning]
Link: https://lkml.kernel.org/r/20210615200242.1716568-6-willy@infradead.org
Link: https://lkml.kernel.org/r/20210510030027.56044-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Every HugeTLB has more than one struct page structure. We __know__ that
we only use the first 4 (__NR_USED_SUBPAGE) struct page structures to
store metadata associated with each HugeTLB.
There are a lot of struct page structures associated with each HugeTLB
page. For tail pages, the value of compound_head is the same. So we can
reuse first page of tail page structures. We map the virtual addresses of
the remaining pages of tail page structures to the first tail page struct,
and then free these page frames. Therefore, we need to reserve two pages
as vmemmap areas.
When we allocate a HugeTLB page from the buddy, we can free some vmemmap
pages associated with each HugeTLB page. It is more appropriate to do it
in the prep_new_huge_page().
The free_vmemmap_pages_per_hpage(), which indicates how many vmemmap pages
associated with a HugeTLB page can be freed, returns zero for now, which
means the feature is disabled. We will enable it once all the
infrastructure is there.
[willy@infradead.org: fix documentation warning]
Link: https://lkml.kernel.org/r/20210615200242.1716568-5-willy@infradead.org
Link: https://lkml.kernel.org/r/20210510030027.56044-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Chen Huang <chenhuang5@huawei.com>
Tested-by: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There are two code path which invoke __populate_section_memmap()
* sparse_init_nid()
* sparse_add_section()
For both case, we are sure the memory range is sub-section aligned.
* we pass PAGES_PER_SECTION to sparse_init_nid()
* we check range by check_pfn_span() before calling
sparse_add_section()
Also, the counterpart of __populate_section_memmap(), we don't do such
calculation and check since the range is checked by check_pfn_span() in
__remove_pages().
Clear the calculation and check to keep it simple and comply with its
counterpart.
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Link: http://lkml.kernel.org/r/20200703031828.14645-1-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There are many instances where vmemap allocation is often switched between
regular memory and device memory just based on whether altmap is available
or not. vmemmap_alloc_block_buf() is used in various platforms to
allocate vmemmap mappings. Lets also enable it to handle altmap based
device memory allocation along with existing regular memory allocations.
This will help in avoiding the altmap based allocation switch in many
places. To summarize there are two different methods to call
vmemmap_alloc_block_buf().
vmemmap_alloc_block_buf(size, node, NULL) /* Allocate from system RAM */
vmemmap_alloc_block_buf(size, node, altmap) /* Allocate from altmap */
This converts altmap_alloc_block_buf() into a static function, drops it's
entry from the header and updates Documentation/vm/memory-model.rst.
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jia He <justin.he@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Link: http://lkml.kernel.org/r/1594004178-8861-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "arm64: Enable vmemmap mapping from device memory", v4.
This series enables vmemmap backing memory allocation from device memory
ranges on arm64. But before that, it enables vmemmap_populate_basepages()
and vmemmap_alloc_block_buf() to accommodate struct vmem_altmap based
alocation requests.
This patch (of 3):
vmemmap_populate_basepages() is used across platforms to allocate backing
memory for vmemmap mapping. This is used as a standard default choice or
as a fallback when intended huge pages allocation fails. This just
creates entire vmemmap mapping with base pages (PAGE_SIZE).
On arm64 platforms, vmemmap_populate_basepages() is called instead of the
platform specific vmemmap_populate() when ARM64_SWAPPER_USES_SECTION_MAPS
is not enabled as in case for ARM64_16K_PAGES and ARM64_64K_PAGES configs.
At present vmemmap_populate_basepages() does not support allocating from
driver defined struct vmem_altmap while trying to create vmemmap mapping
for a device memory range. It prevents ARM64_16K_PAGES and
ARM64_64K_PAGES configs on arm64 from supporting device memory with
vmemap_altmap request.
This enables vmem_altmap support in vmemmap_populate_basepages() unlocking
device memory allocation for vmemap mapping on arm64 platforms with 16K or
64K base page configs.
Each architecture should evaluate and decide on subscribing device memory
based base page allocation through vmemmap_populate_basepages(). Hence
lets keep it disabled on all archs in order to preserve the existing
semantics. A subsequent patch enables it on arm64.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jia He <justin.he@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Link: http://lkml.kernel.org/r/1594004178-8861-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1594004178-8861-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "mm: consolidate definitions of page table accessors", v2.
The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once. For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.
Most of these definitions are actually identical and typically it boils
down to, e.g.
static inline unsigned long pmd_index(unsigned long address)
{
return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}
These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.
For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.
These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.
This patch (of 12):
The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g. pte_alloc() and
pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.
The include statements in such cases are remove with a simple loop:
for f in $(git grep -l "include <linux/mm.h>") ; do
sed -i -e '/include <asm\/pgtable.h>/ d' $f
done
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
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: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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