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Linus Torvalds
51d90a15fe Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 
Pull KVM updates from Paolo Bonzini:
 "ARM:

   - Support for userspace handling of synchronous external aborts
     (SEAs), allowing the VMM to potentially handle the abort in a
     non-fatal manner

   - Large rework of the VGIC's list register handling with the goal of
     supporting more active/pending IRQs than available list registers
     in hardware. In addition, the VGIC now supports EOImode==1 style
     deactivations for IRQs which may occur on a separate vCPU than the
     one that acked the IRQ

   - Support for FEAT_XNX (user / privileged execute permissions) and
     FEAT_HAF (hardware update to the Access Flag) in the software page
     table walkers and shadow MMU

   - Allow page table destruction to reschedule, fixing long
     need_resched latencies observed when destroying a large VM

   - Minor fixes to KVM and selftests

  Loongarch:

   - Get VM PMU capability from HW GCFG register

   - Add AVEC basic support

   - Use 64-bit register definition for EIOINTC

   - Add KVM timer test cases for tools/selftests

  RISC/V:

   - SBI message passing (MPXY) support for KVM guest

   - Give a new, more specific error subcode for the case when in-kernel
     AIA virtualization fails to allocate IMSIC VS-file

   - Support KVM_DIRTY_LOG_INITIALLY_SET, enabling dirty log gradually
     in small chunks

   - Fix guest page fault within HLV* instructions

   - Flush VS-stage TLB after VCPU migration for Andes cores

  s390:

   - Always allocate ESCA (Extended System Control Area), instead of
     starting with the basic SCA and converting to ESCA with the
     addition of the 65th vCPU. The price is increased number of exits
     (and worse performance) on z10 and earlier processor; ESCA was
     introduced by z114/z196 in 2010

   - VIRT_XFER_TO_GUEST_WORK support

   - Operation exception forwarding support

   - Cleanups

  x86:

   - Skip the costly "zap all SPTEs" on an MMIO generation wrap if MMIO
     SPTE caching is disabled, as there can't be any relevant SPTEs to
     zap

   - Relocate a misplaced export

   - Fix an async #PF bug where KVM would clear the completion queue
     when the guest transitioned in and out of paging mode, e.g. when
     handling an SMI and then returning to paged mode via RSM

   - Leave KVM's user-return notifier registered even when disabling
     virtualization, as long as kvm.ko is loaded. On reboot/shutdown,
     keeping the notifier registered is ok; the kernel does not use the
     MSRs and the callback will run cleanly and restore host MSRs if the
     CPU manages to return to userspace before the system goes down

   - Use the checked version of {get,put}_user()

   - Fix a long-lurking bug where KVM's lack of catch-up logic for
     periodic APIC timers can result in a hard lockup in the host

   - Revert the periodic kvmclock sync logic now that KVM doesn't use a
     clocksource that's subject to NTP corrections

   - Clean up KVM's handling of MMIO Stale Data and L1TF, and bury the
     latter behind CONFIG_CPU_MITIGATIONS

   - Context switch XCR0, XSS, and PKRU outside of the entry/exit fast
     path; the only reason they were handled in the fast path was to
     paper of a bug in the core #MC code, and that has long since been
     fixed

   - Add emulator support for AVX MOV instructions, to play nice with
     emulated devices whose guest drivers like to access PCI BARs with
     large multi-byte instructions

  x86 (AMD):

   - Fix a few missing "VMCB dirty" bugs

   - Fix the worst of KVM's lack of EFER.LMSLE emulation

   - Add AVIC support for addressing 4k vCPUs in x2AVIC mode

   - Fix incorrect handling of selective CR0 writes when checking
     intercepts during emulation of L2 instructions

   - Fix a currently-benign bug where KVM would clobber SPEC_CTRL[63:32]
     on VMRUN and #VMEXIT

   - Fix a bug where KVM corrupt the guest code stream when re-injecting
     a soft interrupt if the guest patched the underlying code after the
     VM-Exit, e.g. when Linux patches code with a temporary INT3

   - Add KVM_X86_SNP_POLICY_BITS to advertise supported SNP policy bits
     to userspace, and extend KVM "support" to all policy bits that
     don't require any actual support from KVM

  x86 (Intel):

   - Use the root role from kvm_mmu_page to construct EPTPs instead of
     the current vCPU state, partly as worthwhile cleanup, but mostly to
     pave the way for tracking per-root TLB flushes, and elide EPT
     flushes on pCPU migration if the root is clean from a previous
     flush

   - Add a few missing nested consistency checks

   - Rip out support for doing "early" consistency checks via hardware
     as the functionality hasn't been used in years and is no longer
     useful in general; replace it with an off-by-default module param
     to WARN if hardware fails a check that KVM does not perform

   - Fix a currently-benign bug where KVM would drop the guest's
     SPEC_CTRL[63:32] on VM-Enter

   - Misc cleanups

   - Overhaul the TDX code to address systemic races where KVM (acting
     on behalf of userspace) could inadvertantly trigger lock contention
     in the TDX-Module; KVM was either working around these in weird,
     ugly ways, or was simply oblivious to them (though even Yan's
     devilish selftests could only break individual VMs, not the host
     kernel)

   - Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a
     TDX vCPU, if creating said vCPU failed partway through

   - Fix a few sparse warnings (bad annotation, 0 != NULL)

   - Use struct_size() to simplify copying TDX capabilities to userspace

   - Fix a bug where TDX would effectively corrupt user-return MSR
     values if the TDX Module rejects VP.ENTER and thus doesn't clobber
     host MSRs as expected

  Selftests:

   - Fix a math goof in mmu_stress_test when running on a single-CPU
     system/VM

   - Forcefully override ARCH from x86_64 to x86 to play nice with
     specifying ARCH=x86_64 on the command line

   - Extend a bunch of nested VMX to validate nested SVM as well

   - Add support for LA57 in the core VM_MODE_xxx macro, and add a test
     to verify KVM can save/restore nested VMX state when L1 is using
     5-level paging, but L2 is not

   - Clean up the guest paging code in anticipation of sharing the core
     logic for nested EPT and nested NPT

  guest_memfd:

   - Add NUMA mempolicy support for guest_memfd, and clean up a variety
     of rough edges in guest_memfd along the way

   - Define a CLASS to automatically handle get+put when grabbing a
     guest_memfd from a memslot to make it harder to leak references

   - Enhance KVM selftests to make it easer to develop and debug
     selftests like those added for guest_memfd NUMA support, e.g. where
     test and/or KVM bugs often result in hard-to-debug SIGBUS errors

   - Misc cleanups

  Generic:

   - Use the recently-added WQ_PERCPU when creating the per-CPU
     workqueue for irqfd cleanup

   - Fix a goof in the dirty ring documentation

   - Fix choice of target for directed yield across different calls to
     kvm_vcpu_on_spin(); the function was always starting from the first
     vCPU instead of continuing the round-robin search"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (260 commits)
  KVM: arm64: at: Update AF on software walk only if VM has FEAT_HAFDBS
  KVM: arm64: at: Use correct HA bit in TCR_EL2 when regime is EL2
  KVM: arm64: Document KVM_PGTABLE_PROT_{UX,PX}
  KVM: arm64: Fix spelling mistake "Unexpeced" -> "Unexpected"
  KVM: arm64: Add break to default case in kvm_pgtable_stage2_pte_prot()
  KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()
  KVM: arm64: Fix compilation when CONFIG_ARM64_USE_LSE_ATOMICS=n
  KVM: arm64: selftests: Add test for AT emulation
  KVM: arm64: nv: Expose hardware access flag management to NV guests
  KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW
  KVM: arm64: Implement HW access flag management in stage-1 SW PTW
  KVM: arm64: Propagate PTW errors up to AT emulation
  KVM: arm64: Add helper for swapping guest descriptor
  KVM: arm64: nv: Use pgtable definitions in stage-2 walk
  KVM: arm64: Handle endianness in read helper for emulated PTW
  KVM: arm64: nv: Stop passing vCPU through void ptr in S2 PTW
  KVM: arm64: Call helper for reading descriptors directly
  KVM: arm64: nv: Advertise support for FEAT_XNX
  KVM: arm64: Teach ptdump about FEAT_XNX permissions
  KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions
  ...
 2025-12-05 17:01:20 -08:00
Lorenzo Stoakes
93976a2034 mm: eliminate further swapops predicates 
Having converted so much of the code base to software leaf entries, we can
mop up some remaining cases.

We replace is_pfn_swap_entry(), pfn_swap_entry_to_page(),
is_writable_device_private_entry(), is_device_exclusive_entry(),
is_migration_entry(), is_writable_migration_entry(),
is_readable_migration_entry(), swp_offset_pfn() and pfn_swap_entry_folio()
with softleaf equivalents.

No functional change intended.

Link: https://lkml.kernel.org/r/956bc9c031604811c0070d2f4bf2f1373f230213.1762812360.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-11-24 15:08:52 -08:00
Lorenzo Stoakes
03bfbc3ad6 mm: remove is_hugetlb_entry_[migration, hwpoisoned]() 
We do not need to have explicit helper functions for these, it adds a
level of confusion and indirection when we can simply use software leaf
entry logic here instead and spell out the special huge_pte_none() case we
must consider.

No functional change intended.

Link: https://lkml.kernel.org/r/0e92d6924d3de88cd014ce1c53e20edc08fc152e.1762812360.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-11-24 15:08:51 -08:00
Lorenzo Stoakes
0ac881efe1 mm: replace pmd_to_swp_entry() with softleaf_from_pmd() 
Introduce softleaf_from_pmd() to do the equivalent operation for PMDs that
softleaf_from_pte() fulfils, and cascade changes through code base
accordingly, introducing helpers as necessary.

We are then able to eliminate pmd_to_swp_entry(),
is_pmd_migration_entry(), is_pmd_device_private_entry() and
is_pmd_non_present_folio_entry().

This further establishes the use of leaf operations throughout the code
base and further establishes the foundations for eliminating
is_swap_pmd().

No functional change intended.

[lorenzo.stoakes@oracle.com: check writable, not readable/writable, per Vlastimil]
  Link: https://lkml.kernel.org/r/cd97b6ec-00f9-45a4-9ae0-8f009c212a94@lucifer.local
Link: https://lkml.kernel.org/r/3fb431699639ded8fdc63d2210aa77a38c8891f1.1762812360.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: SeongJae Park <sj@kernel.org>\
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-11-24 15:08:51 -08:00
Kefeng Wang
ca43034cdb mm: mprotect: convert to folio_can_map_prot_numa() 
The prot_numa_skip() naming is not good since it updates the folio access
time except checking whether to skip prot NUMA, so rename it to
folio_can_map_prot_numa(), and cleanup it a bit, remove ret by directly
return value instead of goto style.

Adding a new helper vma_is_single_threaded_private() to check whether it's
a single threaded private VMA, and make folio_can_map_prot_numa() a
non-static function so that they could be reused in change_huge_pmd(),
since folio_can_map_prot_numa() will be shared in different paths, let's
move it near change_prot_numa() in mempolicy.c.

Link: https://lkml.kernel.org/r/20251023113737.3572790-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-11-16 17:28:03 -08:00
Shivank Garg
f634f10809 mm/mempolicy: Export memory policy symbols 
KVM guest_memfd wants to implement support for NUMA policies just like
shmem already does using the shared policy infrastructure. As
guest_memfd currently resides in KVM module code, we have to export the
relevant symbols.

In the future, guest_memfd might be moved to core-mm, at which point the
symbols no longer would have to be exported. When/if that happens is
still unclear.

Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Tested-by: Ashish Kalra <ashish.kalra@amd.com>
Link: https://lore.kernel.org/r/20250827175247.83322-6-shivankg@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
 2025-10-20 06:30:26 -07:00
David Hildenbrand
dd80cfd487 mm: split folio_pte_batch() into folio_pte_batch() and folio_pte_batch_flags() 
Many users (including upcoming ones) don't really need the flags etc, and
can live with the possible overhead of a function call.

So let's provide a basic, non-inlined folio_pte_batch(), to avoid code
bloat while still providing a variant that optimizes out all flag checks
at runtime.  folio_pte_batch_flags() will get inlined into
folio_pte_batch(), optimizing out any conditionals that depend on input
flags.

folio_pte_batch() will behave like folio_pte_batch_flags() when no flags
are specified.  It's okay to add new users of folio_pte_batch_flags(), but
using folio_pte_batch() if applicable is preferred.

So, before this change, folio_pte_batch() was inlined into the C file
optimized by propagating constants within the resulting object file.

With this change, we now also have a folio_pte_batch() that is optimized
by propagating all constants.  But instead of having one instance per
object file, we have a single shared one.

In zap_present_ptes(), where we care about performance, the compiler
already seem to generate a call to a common inlined folio_pte_batch()
variant, shared with fork() code.  So calling the new non-inlined variant
should not make a difference.

While at it, drop the "addr" parameter that is unused.

Link: https://lkml.kernel.org/r/20250702104926.212243-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/linux-mm/20250503182858.5a02729fcffd6d4723afcfc2@linux-foundation.org/
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 18:59:45 -07:00
David Hildenbrand
e66d7a4f55 mm: convert FPB_IGNORE_* into FPB_RESPECT_* 
Patch series "mm: folio_pte_batch() improvements", v2.

Ever since we added folio_pte_batch() for fork() + munmap() purposes, a
lot more users appeared (and more are being proposed), and more
functionality was added.

Most of the users only need basic functionality, and could benefit from a
non-inlined version.

So let's clean up folio_pte_batch() and split it into a basic
folio_pte_batch() (no flags) and a more advanced folio_pte_batch_ext(). 
Using either variant will now look much cleaner.

This series will likely conflict with some changes in some (old+new)
folio_pte_batch() users, but conflicts should be trivial to resolve.


This patch (of 4):

Respecting these PTE bits is the exception, so let's invert the meaning.

With this change, most callers don't have to pass any flags.  This is a
preparation for splitting folio_pte_batch() into a non-inlined variant
that doesn't consume any flags.

Long-term, we want folio_pte_batch() to probably ignore most common PTE
bits (e.g., write/dirty/young/soft-dirty) that are not relevant for most
page table walkers: uffd-wp and protnone might be bits to consider in the
future.  Only walkers that care about them can opt-in to respect them.

No functional change intended.

Link: https://lkml.kernel.org/r/20250702104926.212243-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-19 18:59:45 -07:00
Oscar Salvador
cf0b61adf2 mm,mempolicy: use node-notifier instead of memory-notifier 
mempolicy is only concerned when a numa node changes its memory state,
because it needs to take this node into account for the auto-weighted
memory policy system.  So stop using the memory notifier and use the new
numa node notifer instead.

Link: https://lkml.kernel.org/r/20250616135158.450136-10-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Rakie Kim <rakie.kim@sk.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-13 16:38:16 -07:00
Joshua Hahn
1ec8a6e30e mm/mempolicy: skip unnecessary synchronize_rcu() 
By unconditionally setting wi_state to NULL and conditionally calling
synchronize_rcu(), we can save an unncessary call when there is no
old_wi_state.

Link: https://lkml.kernel.org/r/20250602162345.2595696-2-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-07-09 22:42:02 -07:00
Joshua Hahn
41ffaa0ea7 mm/mempolicy: fix incorrect freeing of wi_kobj 
We should not free wi_group->wi_kobj here.  In the error path of
add_weighted_interleave_group() where this snippet is called from,
kobj_{del, put} is immediately called right after this section.  Thus, it
is not only unnecessary but also incorrect to free it here.

Link: https://lkml.kernel.org/r/20250602162345.2595696-1-joshua.hahnjy@gmail.com
Fixes: e341f9c3c8 ("mm/mempolicy: Weighted Interleave Auto-tuning")
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506011545.Fduxqxqj-lkp@intel.com/
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-06-05 22:02:23 -07:00
Joshua Hahn
e341f9c3c8 mm/mempolicy: Weighted Interleave Auto-tuning 
On machines with multiple memory nodes, interleaving page allocations
across nodes allows for better utilization of each node's bandwidth. 
Previous work by Gregory Price [1] introduced weighted interleave, which
allowed for pages to be allocated across nodes according to user-set
ratios.

Ideally, these weights should be proportional to their bandwidth, so that
under bandwidth pressure, each node uses its maximal efficient bandwidth
and prevents latency from increasing exponentially.

Previously, weighted interleave's default weights were just 1s -- which
would be equivalent to the (unweighted) interleave mempolicy, which goes
through the nodes in a round-robin fashion, ignoring bandwidth
information.

This patch has two main goals: First, it makes weighted interleave easier
to use for users who wish to relieve bandwidth pressure when using nodes
with varying bandwidth (CXL).  By providing a set of "real" default
weights that just work out of the box, users who might not have the
capability (or wish to) perform experimentation to find the most optimal
weights for their system can still take advantage of bandwidth-informed
weighted interleave.

Second, it allows for weighted interleave to dynamically adjust to
hotplugged memory with new bandwidth information.  Instead of manually
updating node weights every time new bandwidth information is reported or
taken off, weighted interleave adjusts and provides a new set of default
weights for weighted interleave to use when there is a change in bandwidth
information.

To meet these goals, this patch introduces an auto-configuration mode for
the interleave weights that provides a reasonable set of default weights,
calculated using bandwidth data reported by the system.  In auto mode,
weights are dynamically adjusted based on whatever the current bandwidth
information reports (and responds to hotplug events).

This patch still supports users manually writing weights into the nodeN
sysfs interface by entering into manual mode.  When a user enters manual
mode, the system stops dynamically updating any of the node weights, even
during hotplug events that shift the optimal weight distribution.

A new sysfs interface "auto" is introduced, which allows users to switch
between the auto (writing 1 or Y) and manual (writing 0 or N) modes.  The
system also automatically enters manual mode when a nodeN interface is
manually written to.

There is one functional change that this patch makes to the existing
weighted_interleave ABI: previously, writing 0 directly to a nodeN
interface was said to reset the weight to the system default.  Before this
patch, the default for all weights were 1, which meant that writing 0 and
1 were functionally equivalent.  With this patch, writing 0 is invalid.

Link: https://lkml.kernel.org/r/20250520141236.2987309-1-joshua.hahnjy@gmail.com
[joshua.hahnjy@gmail.com: wordsmithing changes, simplification, fixes]
  Link: https://lkml.kernel.org/r/20250511025840.2410154-1-joshua.hahnjy@gmail.com
[joshua.hahnjy@gmail.com: remove auto_kobj_attr field from struct sysfs_wi_group]
  Link: https://lkml.kernel.org/r/20250512142511.3959833-1-joshua.hahnjy@gmail.com
https://lore.kernel.org/linux-mm/20240202170238.90004-1-gregory.price@memverge.com/ [1]
Link: https://lkml.kernel.org/r/20250505182328.4148265-1-joshua.hahnjy@gmail.com
Co-developed-by: Gregory Price <gourry@gourry.net>
Signed-off-by: Gregory Price <gourry@gourry.net>
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Suggested-by: Yunjeong Mun <yunjeong.mun@sk.com>
Suggested-by: Oscar Salvador <osalvador@suse.de>
Suggested-by: Ying Huang <ying.huang@linux.alibaba.com>
Suggested-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Reviewed-by: Honggyu Kim <honggyu.kim@sk.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-05-21 09:55:15 -07:00
Rakie Kim
dec92bf95f mm/mempolicy: support memory hotplug in weighted interleave 
The weighted interleave policy distributes page allocations across
multiple NUMA nodes based on their performance weight, thereby improving
memory bandwidth utilization.  The weight values for each node are
configured through sysfs.

Previously, sysfs entries for configuring weighted interleave were created
for all possible nodes (N_POSSIBLE) at initialization, including nodes
that might not have memory.  However, not all nodes in N_POSSIBLE are
usable at runtime, as some may remain memoryless or offline.  This led to
sysfs entries being created for unusable nodes, causing potential
misconfiguration issues.

To address this issue, this patch modifies the sysfs creation logic to:
1) Limit sysfs entries to nodes that are online and have memory, avoiding
   the creation of sysfs entries for nodes that cannot be used.
2) Support memory hotplug by dynamically adding and removing sysfs entries
   based on whether a node transitions into or out of the N_MEMORY state.

Additionally, the patch ensures that sysfs attributes are properly managed
when nodes go offline, preventing stale or redundant entries from
persisting in the system.

By making these changes, the weighted interleave policy now manages its
sysfs entries more efficiently, ensuring that only relevant nodes are
considered for interleaving, and dynamically adapting to memory hotplug
events.

[dan.carpenter@linaro.org: fix error code in sysfs_wi_node_add()]
  Link: https://lkml.kernel.org/r/aBjL7Bwc0QBzgajK@stanley.mountain
Link: https://lkml.kernel.org/r/20250417072839.711-4-rakie.kim@sk.com
Co-developed-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Co-developed-by: Yunjeong Mun <yunjeong.mun@sk.com>
Signed-off-by: Yunjeong Mun <yunjeong.mun@sk.com>
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-05-11 17:48:35 -07:00
Rakie Kim
cf8cecf2bc mm/mempolicy: prepare weighted interleave sysfs for memory hotplug 
Previously, the weighted interleave sysfs structure was statically managed
during initialization.  This prevented new nodes from being recognized
when memory hotplug events occurred, limiting the ability to update or
extend sysfs entries dynamically at runtime.

To address this, this patch refactors the sysfs infrastructure and
encapsulates it within a new structure, `sysfs_wi_group`, which holds both
the kobject and an array of node attribute pointers.

By allocating this group structure globally, the per-node sysfs attributes
can be managed beyond initialization time, enabling external modules to
insert or remove node entries in response to events such as memory hotplug
or node online/offline transitions.

Instead of allocating all per-node sysfs attributes at once, the
initialization path now uses the existing sysfs_wi_node_add() and
sysfs_wi_node_delete() helpers.  This refactoring makes it possible to
modularly manage per-node sysfs entries and ensures the infrastructure is
ready for runtime extension.

Link: https://lkml.kernel.org/r/20250417072839.711-3-rakie.kim@sk.com
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yunjeong Mun <yunjeong.mun@sk.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-05-11 17:48:35 -07:00
Rakie Kim
bb52e89d8b mm/mempolicy: fix memory leaks in weighted interleave sysfs 
Patch series "Enhance sysfs handling for memory hotplug in weighted
interleave", v9.

The following patch series enhances the weighted interleave policy in the
memory management subsystem by improving sysfs handling, fixing memory
leaks, and introducing dynamic sysfs updates for memory hotplug support.


This patch (of 3):

Memory leaks occurred when removing sysfs attributes for weighted
interleave.  Improper kobject deallocation led to unreleased memory when
initialization failed or when nodes were removed.

The risk of leak is low because it only appears to trigger if setup
fails.  Setup only fails due to -ENOMEM which is unlikely to happen
from a late_initcall() when memory pressure is low.

This patch resolves the issue by replacing unnecessary `kfree()` calls
with proper `kobject_del()` and `kobject_put()` sequences, ensuring
correct teardown and preventing memory leaks.

By explicitly calling `kobject_del()` before `kobject_put()`, the release
function is now invoked safely, and internal sysfs state is correctly
cleaned up.  This guarantees that the memory associated with the kobject
is fully released and avoids resource leaks, thereby improving system
stability.

Additionally, sysfs_remove_file() is no longer called from the release
function to avoid accessing invalid sysfs state after kobject_del().  All
attribute removals are now done before kobject_del(), preventing WARN_ON()
in kernfs and ensuring safe and consistent cleanup of sysfs entries.

Link: https://lkml.kernel.org/r/20250417072839.711-1-rakie.kim@sk.com
Link: https://lkml.kernel.org/r/20250417072839.711-2-rakie.kim@sk.com
Fixes: dce41f5ae2 ("mm/mempolicy: implement the sysfs-based weighted_interleave interface")
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yunjeong Mun <yunjeong.mun@sk.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-05-11 17:48:35 -07:00
Dev Jain
4a34c584d8 mempolicy: optimize queue_folios_pte_range by PTE batching 
After the check for queue_folio_required(), the code only cares about the
folio in the for loop, i.e the PTEs are redundant.  Therefore, optimize
this loop by skipping over a PTE batch mapping the same folio.

With a test program migrating pages of the calling process, which includes
a mapped VMA of size 4GB with pte-mapped large folios of order-9, and
migrating once back and forth node-0 and node-1, the average execution
time reduces from 7.5 to 4 seconds, giving an approx 47% speedup.

Link: https://lkml.kernel.org/r/20250416053048.96479-1-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-05-11 17:48:33 -07:00
Linus Torvalds
eb0ece1602 Merge tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 
Pull MM updates from Andrew Morton:

 - The series "Enable strict percpu address space checks" from Uros
   Bizjak uses x86 named address space qualifiers to provide
   compile-time checking of percpu area accesses.

   This has caused a small amount of fallout - two or three issues were
   reported. In all cases the calling code was found to be incorrect.

 - The series "Some cleanup for memcg" from Chen Ridong implements some
   relatively monir cleanups for the memcontrol code.

 - The series "mm: fixes for device-exclusive entries (hmm)" from David
   Hildenbrand fixes a boatload of issues which David found then using
   device-exclusive PTE entries when THP is enabled. More work is
   needed, but this makes thins better - our own HMM selftests now
   succeed.

 - The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
   remove the z3fold and zbud implementations. They have been deprecated
   for half a year and nobody has complained.

 - The series "mm: further simplify VMA merge operation" from Lorenzo
   Stoakes implements numerous simplifications in this area. No runtime
   effects are anticipated.

 - The series "mm/madvise: remove redundant mmap_lock operations from
   process_madvise()" from SeongJae Park rationalizes the locking in the
   madvise() implementation. Performance gains of 20-25% were observed
   in one MADV_DONTNEED microbenchmark.

 - The series "Tiny cleanup and improvements about SWAP code" from
   Baoquan He contains a number of touchups to issues which Baoquan
   noticed when working on the swap code.

 - The series "mm: kmemleak: Usability improvements" from Catalin
   Marinas implements a couple of improvements to the kmemleak
   user-visible output.

 - The series "mm/damon/paddr: fix large folios access and schemes
   handling" from Usama Arif provides a couple of fixes for DAMON's
   handling of large folios.

 - The series "mm/damon/core: fix wrong and/or useless damos_walk()
   behaviors" from SeongJae Park fixes a few issues with the accuracy of
   kdamond's walking of DAMON regions.

 - The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
   Stoakes changes the interaction between framebuffer deferred-io and
   core MM. No functional changes are anticipated - this is preparatory
   work for the future removal of page structure fields.

 - The series "mm/damon: add support for hugepage_size DAMOS filter"
   from Usama Arif adds a DAMOS filter which permits the filtering by
   huge page sizes.

 - The series "mm: permit guard regions for file-backed/shmem mappings"
   from Lorenzo Stoakes extends the guard region feature from its
   present "anon mappings only" state. The feature now covers shmem and
   file-backed mappings.

 - The series "mm: batched unmap lazyfree large folios during
   reclamation" from Barry Song cleans up and speeds up the unmapping
   for pte-mapped large folios.

 - The series "reimplement per-vma lock as a refcount" from Suren
   Baghdasaryan puts the vm_lock back into the vma. Our reasons for
   pulling it out were largely bogus and that change made the code more
   messy. This patchset provides small (0-10%) improvements on one
   microbenchmark.

 - The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
   improves" from SeongJae Park does some maintenance work on the DAMON
   docs.

 - The series "hugetlb/CMA improvements for large systems" from Frank
   van der Linden addresses a pile of issues which have been observed
   when using CMA on large machines.

 - The series "mm/damon: introduce DAMOS filter type for unmapped pages"
   from SeongJae Park enables users of DMAON/DAMOS to filter my the
   page's mapped/unmapped status.

 - The series "zsmalloc/zram: there be preemption" from Sergey
   Senozhatsky teaches zram to run its compression and decompression
   operations preemptibly.

 - The series "selftests/mm: Some cleanups from trying to run them" from
   Brendan Jackman fixes a pile of unrelated issues which Brendan
   encountered while runnimg our selftests.

 - The series "fs/proc/task_mmu: add guard region bit to pagemap" from
   Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
   determine whether a particular page is a guard page.

 - The series "mm, swap: remove swap slot cache" from Kairui Song
   removes the swap slot cache from the allocation path - it simply
   wasn't being effective.

 - The series "mm: cleanups for device-exclusive entries (hmm)" from
   David Hildenbrand implements a number of unrelated cleanups in this
   code.

 - The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
   implements a number of preparatoty cleanups to the GENERIC_PTDUMP
   Kconfig logic.

 - The series "mm/damon: auto-tune aggregation interval" from SeongJae
   Park implements a feedback-driven automatic tuning feature for
   DAMON's aggregation interval tuning.

 - The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
   powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
   preparation for implementing lazy mmu mode for arm64 to optimize
   vmalloc.

 - The series "mm/page_alloc: Some clarifications for migratetype
   fallback" from Brendan Jackman reworks some commentary to make the
   code easier to follow.

 - The series "page_counter cleanup and size reduction" from Shakeel
   Butt cleans up the page_counter code and fixes a size increase which
   we accidentally added late last year.

 - The series "Add a command line option that enables control of how
   many threads should be used to allocate huge pages" from Thomas
   Prescher does that. It allows the careful operator to significantly
   reduce boot time by tuning the parallalization of huge page
   initialization.

 - The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
   from Tang Yizhou fixes the tracing output from the dirty page
   balancing code.

 - The series "mm/damon: make allow filters after reject filters useful
   and intuitive" from SeongJae Park improves the handling of allow and
   reject filters. Behaviour is made more consistent and the documention
   is updated accordingly.

 - The series "Switch zswap to object read/write APIs" from Yosry Ahmed
   updates zswap to the new object read/write APIs and thus permits the
   removal of some legacy code from zpool and zsmalloc.

 - The series "Some trivial cleanups for shmem" from Baolin Wang does as
   it claims.

 - The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
   Alistair Popple regularizes the weird ZONE_DEVICE page refcount
   handling in DAX, permittig the removal of a number of special-case
   checks.

 - The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
   preparatoty refactoring and cleanup of the mremap() code.

 - The series "mm: MM owner tracking for large folios (!hugetlb) +
   CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
   which we determine whether a large folio is known to be mapped
   exclusively into a single MM.

 - The series "mm/damon: add sysfs dirs for managing DAMOS filters based
   on handling layers" from SeongJae Park adds a couple of new sysfs
   directories to ease the management of DAMON/DAMOS filters.

 - The series "arch, mm: reduce code duplication in mem_init()" from
   Mike Rapoport consolidates many per-arch implementations of
   mem_init() into code generic code, where that is practical.

 - The series "mm/damon/sysfs: commit parameters online via
   damon_call()" from SeongJae Park continues the cleaning up of sysfs
   access to DAMON internal data.

 - The series "mm: page_ext: Introduce new iteration API" from Luiz
   Capitulino reworks the page_ext initialization to fix a boot-time
   crash which was observed with an unusual combination of compile and
   cmdline options.

 - The series "Buddy allocator like (or non-uniform) folio split" from
   Zi Yan reworks the code to split a folio into smaller folios. The
   main benefit is lessened memory consumption: fewer post-split folios
   are generated.

 - The series "Minimize xa_node allocation during xarry split" from Zi
   Yan reduces the number of xarray xa_nodes which are generated during
   an xarray split.

 - The series "drivers/base/memory: Two cleanups" from Gavin Shan
   performs some maintenance work on the drivers/base/memory code.

 - The series "Add tracepoints for lowmem reserves, watermarks and
   totalreserve_pages" from Martin Liu adds some more tracepoints to the
   page allocator code.

 - The series "mm/madvise: cleanup requests validations and
   classifications" from SeongJae Park cleans up some warts which
   SeongJae observed during his earlier madvise work.

 - The series "mm/hwpoison: Fix regressions in memory failure handling"
   from Shuai Xue addresses two quite serious regressions which Shuai
   has observed in the memory-failure implementation.

 - The series "mm: reliable huge page allocator" from Johannes Weiner
   makes huge page allocations cheaper and more reliable by reducing
   fragmentation.

 - The series "Minor memcg cleanups & prep for memdescs" from Matthew
   Wilcox is preparatory work for the future implementation of memdescs.

 - The series "track memory used by balloon drivers" from Nico Pache
   introduces a way to track memory used by our various balloon drivers.

 - The series "mm/damon: introduce DAMOS filter type for active pages"
   from Nhat Pham permits users to filter for active/inactive pages,
   separately for file and anon pages.

 - The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
   separates the proactive reclaim statistics from the direct reclaim
   statistics.

 - The series "mm/vmscan: don't try to reclaim hwpoison folio" from
   Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
   code.

* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
  mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
  x86/mm: restore early initialization of high_memory for 32-bits
  mm/vmscan: don't try to reclaim hwpoison folio
  mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
  cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
  mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
  selftests/mm: speed up split_huge_page_test
  selftests/mm: uffd-unit-tests support for hugepages > 2M
  docs/mm/damon/design: document active DAMOS filter type
  mm/damon: implement a new DAMOS filter type for active pages
  fs/dax: don't disassociate zero page entries
  MM documentation: add "Unaccepted" meminfo entry
  selftests/mm: add commentary about 9pfs bugs
  fork: use __vmalloc_node() for stack allocation
  docs/mm: Physical Memory: Populate the "Zones" section
  xen: balloon: update the NR_BALLOON_PAGES state
  hv_balloon: update the NR_BALLOON_PAGES state
  balloon_compaction: update the NR_BALLOON_PAGES state
  meminfo: add a per node counter for balloon drivers
  mm: remove references to folio in __memcg_kmem_uncharge_page()
  ...
 2025-04-01 09:29:18 -07:00
Linus Torvalds
bcb044256d Merge tag 'sched_ext-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext 
Pull sched_ext updates from Tejun Heo:

 - Add mechanism to count and report internal events. This significantly
   improves visibility on subtle corner conditions.

 - The default idle CPU selection logic is revamped and improved in
   multiple ways including being made topology aware.

 - sched_ext was disabling ttwu_queue for simplicity, which can be
   costly when hardware topology is more complex. Implement
   SCX_OPS_ALLOWED_QUEUED_WAKEUP so that BPF schedulers can selectively
   enable ttwu_queue.

 - tools/sched_ext updates to improve compatibility among others.

 - Other misc updates and fixes.

 - sched_ext/for-6.14-fixes were pulled a few times to receive
   prerequisite fixes and resolve conflicts.

* tag 'sched_ext-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (42 commits)
  sched_ext: idle: Refactor scx_select_cpu_dfl()
  sched_ext: idle: Honor idle flags in the built-in idle selection policy
  sched_ext: Skip per-CPU tasks in scx_bpf_reenqueue_local()
  sched_ext: Add trace point to track sched_ext core events
  sched_ext: Change the event type from u64 to s64
  sched_ext: Documentation: add task lifecycle summary
  tools/sched_ext: Provide a compatible helper for scx_bpf_events()
  selftests/sched_ext: Add NUMA-aware scheduler test
  tools/sched_ext: Provide consistent access to scx flags
  sched_ext: idle: Fix scx_bpf_pick_any_cpu_node() behavior
  sched_ext: idle: Introduce scx_bpf_nr_node_ids()
  sched_ext: idle: Introduce node-aware idle cpu kfunc helpers
  sched_ext: idle: Per-node idle cpumasks
  sched_ext: idle: Introduce SCX_OPS_BUILTIN_IDLE_PER_NODE
  sched_ext: idle: Make idle static keys private
  sched/topology: Introduce for_each_node_numadist() iterator
  mm/numa: Introduce nearest_node_nodemask()
  nodemask: numa: reorganize inclusion path
  nodemask: add nodes_copy()
  tools/sched_ext: Sync with scx repo
  ...
 2025-03-24 17:23:48 -07:00
David Hildenbrand
003fde4492 mm: convert folio_likely_mapped_shared() to folio_maybe_mapped_shared() 
Let's reuse our new MM ownership tracking infrastructure for large folios
to make folio_likely_mapped_shared() never return false negatives -- never
indicating "not mapped shared" although the folio *is* mapped shared. 
With that, we can rename it to folio_maybe_mapped_shared() and get rid of
the dependency on the mapcount of the first folio page.

The semantics are now arguably clearer: no mixture of "false negatives"
and "false positives", only the remaining possibility for "false
positives".

Thoroughly document the new semantics.  We might now detect that a large
folio is "maybe mapped shared" although it *no longer* is -- but once was.
Now, if more than two MMs mapped a folio at the same time, and the MM
mapping the folio exclusively at the end is not one tracked in the two
folio MM slots, we will detect the folio as "maybe mapped shared".

For anonymous folios, usually (except weird corner cases) all PTEs that
target a "maybe mapped shared" folio are R/O.  As soon as a child process
would write to them (iow, actively use them), we would CoW and effectively
replace these PTEs.  Most cases (below) are not expected to really matter
with large anonymous folios for this reason.

Most importantly, there will be no change at all for:
* small folios
* hugetlb folios
* PMD-mapped PMD-sized THPs (single mapping)

This change has the potential to affect existing callers of
folio_likely_mapped_shared() -> folio_maybe_mapped_shared():

(1) fs/proc/task_mmu.c: no change (hugetlb)

(2) khugepaged counts PTEs that target shared folios towards
    max_ptes_shared (default: HPAGE_PMD_NR / 2), meaning we could skip a
    collapse where we would have previously collapsed.  This only applies
    to anonymous folios and is not expected to matter in practice.

    Worth noting that this change sorts out case (A) documented in
    commit 1bafe96e89 ("mm/khugepaged: replace page_mapcount() check by
    folio_likely_mapped_shared()") by removing the possibility for "false
    negatives".

(3) MADV_COLD / MADV_PAGEOUT / MADV_FREE will not try splitting
    PTE-mapped THPs that are considered shared but not fully covered by
    the requested range, consequently not processing them.

    PMD-mapped PMD-sized THP are not affected, or when all PTEs are
    covered.  These functions are usually only called on anon/file folios
    that are exclusively mapped most of the time (no other file mappings
    or no fork()), so the "false negatives" are not expected to matter in
    practice.

(4) mbind() / migrate_pages() / move_pages() will refuse to migrate
    shared folios unless MPOL_MF_MOVE_ALL is effective (requires
    CAP_SYS_NICE).  We will now reject some folios that could be migrated.

    Similar to (3), especially with MPOL_MF_MOVE_ALL, so this is not
    expected to matter in practice.

    Note that cpuset_migrate_mm_workfn() calls do_migrate_pages() with
    MPOL_MF_MOVE_ALL.

(5) NUMA hinting

    mm/migrate.c:migrate_misplaced_folio_prepare() will skip file
    folios that are probably shared libraries (-> "mapped shared" and
    executable).  This check would have detected it as a shared library at
    some point (at least 3 MMs mapping it), so detecting it afterwards
    does not sound wrong (still a shared library).  Not expected to
    matter.

    mm/memory.c:numa_migrate_check() will indicate TNF_SHARED in
    MAP_SHARED file mappings when encountering a shared folio.  Similar
    reasoning, not expected to matter.

    mm/mprotect.c:change_pte_range() will skip folios detected as
    shared in CoW mappings.  Similarly, this is not expected to matter in
    practice, but if it would ever be a problem we could relax that check
    a bit (e.g., basing it on the average page-mapcount in a folio),
    because it was only an optimization when many (e.g., 288) processes
    were mapping the same folios -- see commit 859d4adc34 ("mm: numa: do
    not trap faults on shared data section pages.")

(6) mm/rmap.c:folio_referenced_one() will skip exclusive swapbacked
    folios in dying processes.  Applies to anonymous folios only.  Without
    "false negatives", we'll now skip all actually shared ones.  Skipping
    ones that are actually exclusive won't really matter, it's a pure
    optimization, and is not expected to matter in practice.

In theory, one can detect the problematic scenario: folio_mapcount() > 0
and no folio MM slot is occupied ("state unknown").  One could reset the
MM slots while doing an rmap walk, which migration / folio split already
do when setting everything up.  Further, when batching PTEs we might
naturally learn about a owner (e.g., folio_mapcount() == nr_ptes) and
could update the owner.  However, we'll defer that until the scenarios
where it would really matter are clear.

Link: https://lkml.kernel.org/r/20250303163014.1128035-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-03-17 22:06:46 -07:00
Andrea Righi
16d79f2a4f mm/numa: Introduce nearest_node_nodemask() 
Introduce the new helper nearest_node_nodemask() to find the closest
node in a specified nodemask from a given starting node.

Returns MAX_NUMNODES if no node is found.

Suggested-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Acked-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
 2025-02-16 06:52:19 -10:00
David Hildenbrand
4c640f1280 mm/hugetlb: rename isolate_hugetlb() to folio_isolate_hugetlb() 
Let's make the function name match "folio_isolate_lru()", and add some
kernel doc.

Link: https://lkml.kernel.org/r/20250113131611.2554758-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-01-25 20:22:41 -08:00
Luiz Capitulino
6bf9b5b40a mm: alloc_pages_bulk: rename API 
The previous commit removed the page_list argument from
alloc_pages_bulk_noprof() along with the alloc_pages_bulk_list() function.

Now that only the *_array() flavour of the API remains, we can do the
following renaming (along with the _noprof() ones):

  alloc_pages_bulk_array -> alloc_pages_bulk
  alloc_pages_bulk_array_mempolicy -> alloc_pages_bulk_mempolicy
  alloc_pages_bulk_array_node -> alloc_pages_bulk_node

Link: https://lkml.kernel.org/r/275a3bbc0be20fbe9002297d60045e67ab3d4ada.1734991165.git.luizcap@redhat.com
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-01-25 20:22:31 -08:00
Luiz Capitulino
c8b979530f mm: alloc_pages_bulk_noprof: drop page_list argument 
Patch series "mm: alloc_pages_bulk: small API refactor", v2.

Today, alloc_pages_bulk_noprof() supports two arguments to return
allocated pages: a linked list and an array.  There are also higher level
APIs for both.

However, the linked list API has apparently never been used.  So, this
series removes it along with the list API and also refactors the remaining
API naming for consistency.


This patch (of 2):

commit 387ba26fb1 ("mm/page_alloc: add a bulk page allocator") added
__alloc_pages_bulk() along with the page_list argument.  The next commit
0f87d9d30f ("mm/page_alloc: add an array-based interface to the bulk
page allocator") added the array-based argument.  As it turns out, the
page_list argument has no users in the current tree (if it ever had any). 
Dropping it allows for a slight simplification and eliminates some
unnecessary checks, now that page_array is required.

Also, note that the removal of the page_list argument was proposed before
in the thread below, where Matthew Wilcox mentions that:

  """
  Iterating a linked list is _expensive_.  It is about 10x quicker to
  iterate an array than a linked list.
  """
  (https://lore.kernel.org/linux-mm/20231025093254.xvomlctwhcuerzky@techsingularity.net)

Link: https://lkml.kernel.org/r/cover.1734991165.git.luizcap@redhat.com
Link: https://lkml.kernel.org/r/f1c75db91d08cafd211eca6a3b199b629d4ffe16.1734991165.git.luizcap@redhat.com
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-01-25 20:22:31 -08:00
Matthew Wilcox (Oracle)
642975242e mm/mempolicy: add alloc_frozen_pages() 
Provide an interface to allocate pages from the page allocator without
incrementing their refcount.  This saves an atomic operation on free,
which may be beneficial to some users (eg slab).

Link: https://lkml.kernel.org/r/20241125210149.2976098-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-01-13 22:40:33 -08:00
Matthew Wilcox (Oracle)
38558b2460 mm: make alloc_pages_mpol() static 
All callers outside mempolicy.c now use folio_alloc_mpol() thanks to
Kefeng's cleanups, so we can remove this as a visible symbol.

And also remove the alloc_hooks for alloc_pages_mpol(), since all users
in mempolicy.c are using the nonprof version.

Link: https://lkml.kernel.org/r/20241125210149.2976098-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-01-13 22:40:31 -08:00
Honggyu Kim
264a88cafd mm/mempolicy: count MPOL_WEIGHTED_INTERLEAVE to "interleave_hit" 
Commit fa3bea4e1f introduced MPOL_WEIGHTED_INTERLEAVE but it missed
adding its counter to "interleave_hit" of numastat, which is located at
/sys/devices/system/node/nodeN/ directory.

It'd be better to add weighted interleving counter info to the existing
"interleave_hit" instead of introducing a new counter
"weighted_interleave_hit".

Link: https://lkml.kernel.org/r/20241227095737.645-1-honggyu.kim@sk.com
Fixes: fa3bea4e1f ("mm/mempolicy: introduce MPOL_WEIGHTED_INTERLEAVE for weighted interleaving")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com>
Tested-by: Yunjeong Mun <yunjeong.mun@sk.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2025-01-12 19:03:35 -08:00
David Hildenbrand
091c1dd2d4 mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM 
We currently assume that there is at least one VMA in a MM, which isn't
true.

So we might end up having find_vma() return NULL, to then de-reference
NULL.  So properly handle find_vma() returning NULL.

This fixes the report:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline]
RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194
Code: ...
RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000
RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044
RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1
R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003
R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8
FS:  00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709
 __do_sys_migrate_pages mm/mempolicy.c:1727 [inline]
 __se_sys_migrate_pages mm/mempolicy.c:1723 [inline]
 __x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

[akpm@linux-foundation.org: add unlikely()]
Link: https://lkml.kernel.org/r/20241120201151.9518-1-david@redhat.com
Fixes: 39743889aa ("[PATCH] Swap Migration V5: sys_migrate_pages interface")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: syzbot+3511625422f7aa637f0d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/673d2696.050a0220.3c9d61.012f.GAE@google.com/T/
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-12-05 19:54:43 -08:00
Matthew Wilcox (Oracle)
713da0b33b mm: renovate page_address_in_vma() 
This function doesn't modify any of its arguments, so if we make a few
other functions take const pointers, we can make page_address_in_vma()
take const pointers too.  All of its callers have the containing folio
already, so pass that in as an argument instead of recalculating it.  Also
add kernel-doc

Link: https://lkml.kernel.org/r/20241005200121.3231142-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-11-07 14:38:07 -08:00
Kefeng Wang
6359c39c9d mm: remove unused hugepage for vma_alloc_folio() 
The hugepage parameter was deprecated since commit ddc1a5cbc0
("mempolicy: alloc_pages_mpol() for NUMA policy without vma"), for
PMD-sized THP, it still tries only preferred node if possible in
vma_alloc_folio() by checking the order of the folio allocation.

Link: https://lkml.kernel.org/r/20241010061556.1846751-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-11-06 20:11:12 -08:00
Tanya Agarwal
1cd1a4e71b mm/mempolicy: fix comments for better documentation 
Fix typo in mempolicy.h and Correct the number of allowed memory policy

Link: https://lkml.kernel.org/r/20240926183516.4034-2-tanyaagarwal25699@gmail.com
Signed-off-by: Tanya Agarwal <tanyaagarwal25699@gmail.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: Anup Sharma <anupnewsmail@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-11-05 16:56:25 -08:00
Kaiyang Zhao
f77f0c7514 mm,memcg: provide per-cgroup counters for NUMA balancing operations 
The ability to observe the demotion and promotion decisions made by the
kernel on a per-cgroup basis is important for monitoring and tuning
containerized workloads on machines equipped with tiered memory.

Different containers in the system may experience drastically different
memory tiering actions that cannot be distinguished from the global
counters alone.

For example, a container running a workload that has a much hotter memory
accesses will likely see more promotions and fewer demotions, potentially
depriving a colocated container of top tier memory to such an extent that
its performance degrades unacceptably.

For another example, some containers may exhibit longer periods between
data reuse, causing much more numa_hint_faults than numa_pages_migrated. 
In this case, tuning hot_threshold_ms may be appropriate, but the signal
can easily be lost if only global counters are available.

In the long term, we hope to introduce per-cgroup control of promotion and
demotion actions to implement memory placement policies in tiering.

This patch set adds seven counters to memory.stat in a cgroup:
numa_pages_migrated, numa_pte_updates, numa_hint_faults, pgdemote_kswapd,
pgdemote_khugepaged, pgdemote_direct and pgpromote_success.  pgdemote_*
and pgpromote_success are also available in memory.numa_stat.

count_memcg_events_mm() is added to count multiple event occurrences at
once, and get_mem_cgroup_from_folio() is added because we need to get a
reference to the memcg of a folio before it's migrated to track
numa_pages_migrated.  The accounting of PGDEMOTE_* is moved to
shrink_inactive_list() before being changed to per-cgroup.

[kaiyang2@cs.cmu.edu: add documentation of the memcg counters in cgroup-v2.rst]
  Link: https://lkml.kernel.org/r/20240814235122.252309-1-kaiyang2@cs.cmu.edu
Link: https://lkml.kernel.org/r/20240814174227.30639-1-kaiyang2@cs.cmu.edu
Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-03 21:15:36 -07:00
Wei Yang
29943248af mm: improve code consistency with zonelist_* helper functions 
Replace direct access to zoneref->zone, zoneref->zone_idx, or
zone_to_nid(zoneref->zone) with the corresponding zonelist_* helper
functions for consistency.

No functional change.

Link: https://lkml.kernel.org/r/20240729091717.464-1-shivankg@amd.com
Co-developed-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-01 20:25:55 -07:00
Linus Torvalds
7a3fad30fd Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random 
Pull random number generator updates from Jason Donenfeld:
 "This adds getrandom() support to the vDSO.

  First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
  lets the kernel zero out pages anytime under memory pressure, which
  enables allocating memory that never gets swapped to disk but also
  doesn't count as being mlocked.

  Then, the vDSO implementation of getrandom() is introduced in a
  generic manner and hooked into random.c.

  Next, this is implemented on x86. (Also, though it's not ready for
  this pull, somebody has begun an arm64 implementation already)

  Finally, two vDSO selftests are added.

  There are also two housekeeping cleanup commits"

* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  MAINTAINERS: add random.h headers to RNG subsection
  random: note that RNDGETPOOL was removed in 2.6.9-rc2
  selftests/vDSO: add tests for vgetrandom
  x86: vdso: Wire up getrandom() vDSO implementation
  random: introduce generic vDSO getrandom() implementation
  mm: add MAP_DROPPABLE for designating always lazily freeable mappings
 2024-07-24 10:29:50 -07:00
Jason A. Donenfeld
9651fcedf7 mm: add MAP_DROPPABLE for designating always lazily freeable mappings 
The vDSO getrandom() implementation works with a buffer allocated with a
new system call that has certain requirements:

- It shouldn't be written to core dumps.
  * Easy: VM_DONTDUMP.
- It should be zeroed on fork.
  * Easy: VM_WIPEONFORK.

- It shouldn't be written to swap.
  * Uh-oh: mlock is rlimited.
  * Uh-oh: mlock isn't inherited by forks.

- It shouldn't reserve actual memory, but it also shouldn't crash when
  page faulting in memory if none is available
  * Uh-oh: VM_NORESERVE means segfaults.

It turns out that the vDSO getrandom() function has three really nice
characteristics that we can exploit to solve this problem:

1) Due to being wiped during fork(), the vDSO code is already robust to
   having the contents of the pages it reads zeroed out midway through
   the function's execution.

2) In the absolute worst case of whatever contingency we're coding for,
   we have the option to fallback to the getrandom() syscall, and
   everything is fine.

3) The buffers the function uses are only ever useful for a maximum of
   60 seconds -- a sort of cache, rather than a long term allocation.

These characteristics mean that we can introduce VM_DROPPABLE, which
has the following semantics:

a) It never is written out to swap.
b) Under memory pressure, mm can just drop the pages (so that they're
   zero when read back again).
c) It is inherited by fork.
d) It doesn't count against the mlock budget, since nothing is locked.
e) If there's not enough memory to service a page fault, it's not fatal,
   and no signal is sent.

This way, allocations used by vDSO getrandom() can use:

    VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE

And there will be no problem with OOMing, crashing on overcommitment,
using memory when not in use, not wiping on fork(), coredumps, or
writing out to swap.

In order to let vDSO getrandom() use this, expose these via mmap(2) as
MAP_DROPPABLE.

Note that this involves removing the MADV_FREE special case from
sort_folio(), which according to Yu Zhao is unnecessary and will simply
result in an extra call to shrink_folio_list() in the worst case. The
chunk removed reenables the swapbacked flag, which we don't want for
VM_DROPPABLE, and we can't conditionalize it here because there isn't a
vma reference available.

Finally, the provided self test ensures that this is working as desired.

Cc: linux-mm@kvack.org
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
 2024-07-19 20:22:12 +02:00
Tvrtko Ursulin
af649773fb mm/numa_balancing: teach mpol_to_str about the balancing mode 
Since balancing mode was added in bda420b985 ("numa balancing: migrate
on fault among multiple bound nodes"), it was possible to set this mode
but it wouldn't be shown in /proc/<pid>/numa_maps since there was no
support for it in the mpol_to_str() helper.

Furthermore, because the balancing mode sets the MPOL_F_MORON flag, it
would be displayed as 'default' due a workaround introduced a few years
earlier in 8790c71a18 ("mm/mempolicy.c: fix mempolicy printing in
numa_maps").

To tidy this up we implement two changes:

Replace the MPOL_F_MORON check by pointer comparison against the
preferred_node_policy array.  By doing this we generalise the current
special casing and replace the incorrect 'default' with the correct 'bind'
for the mode.

Secondly, we add a string representation and corresponding handling for
the MPOL_F_NUMA_BALANCING flag.

With the two changes together we start showing the balancing flag when it
is set and therefore complete the fix.

Representation format chosen is to separate multiple flags with vertical
bars, following what existed long time ago in kernel 2.6.25.  But as
between then and now there wasn't a way to display multiple flags, this
patch does not change the format in practice.

Some /proc/<pid>/numa_maps output examples:

 555559580000 bind=balancing:0-1,3 file=...
 555585800000 bind=balancing|static:0,2 file=...
 555635240000 prefer=relative:0 file=

Link: https://lkml.kernel.org/r/20240708075632.95857-1-tursulin@igalia.com
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Fixes: bda420b985 ("numa balancing: migrate on fault among multiple bound nodes")
References: 8790c71a18 ("mm/mempolicy.c: fix mempolicy printing in numa_maps")
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-17 21:08:54 -07:00
Christophe Leroy
e6c0c03245 mm: provide mm_struct and address to huge_ptep_get() 
On powerpc 8xx huge_ptep_get() will need to know whether the given ptep is
a PTE entry or a PMD entry.  This cannot be known with the PMD entry
itself because there is no easy way to know it from the content of the
entry.

So huge_ptep_get() will need to know either the size of the page or get
the pmd.

In order to be consistent with huge_ptep_get_and_clear(), give mm and
address to huge_ptep_get().

Link: https://lkml.kernel.org/r/cc00c70dd384298796a4e1b25d6c4eb306d3af85.1719928057.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-12 15:52:15 -07:00
Kefeng Wang
1d9cb7852b mm: mempolicy: use folio_alloc_mpol() in alloc_migration_target_by_mpol() 
Convert to use folio_alloc_mpol() to make vma_alloc_folio_noprof() to use
folio throughout.

Link: https://lkml.kernel.org/r/20240515070709.78529-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-03 19:29:53 -07:00
Kefeng Wang
3174d70cf6 mm: mempolicy: use folio_alloc_mpol_noprof() in vma_alloc_folio_noprof() 
Convert to use folio_alloc_mpol_noprof() to make vma_alloc_folio_noprof()
to use folio throughout.

Link: https://lkml.kernel.org/r/20240515070709.78529-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-03 19:29:52 -07:00
Kefeng Wang
a19621ed4e mm: add folio_alloc_mpol() 
Patch series "mm: convert to folio_alloc_mpol()".


This patch (of 4):

This adds a new folio_alloc_mpol() like folio_alloc() but allocate folio
according to NUMA mempolicy.

Link: https://lkml.kernel.org/r/20240515070709.78529-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240515070709.78529-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-03 19:29:52 -07:00
Matthew Wilcox (Oracle)
e06d03d559 mm: add pmd_folio() 
Convert directly from a pmd to a folio without going through another
representation first.  For now this is just a slightly shorter way to
write it, but it might end up being more efficient later.

Link: https://lkml.kernel.org/r/20240326202833.523759-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:56:19 -07:00
Matthew Wilcox (Oracle)
5beaee54a3 mm: add is_huge_zero_folio() 
This is the folio equivalent of is_huge_zero_page().  It doesn't add any
efficiency, but it does prevent the caller from passing a tail page and
getting confused when the predicate returns false.

Link: https://lkml.kernel.org/r/20240326202833.523759-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:56:18 -07:00
David Hildenbrand
ebb34f78d7 mm: convert folio_estimated_sharers() to folio_likely_mapped_shared() 
Callers of folio_estimated_sharers() only care about "mapped shared vs. 
mapped exclusively", not the exact estimate of sharers.  Let's consolidate
and unify the condition users are checking.  While at it clarify the
semantics and extend the discussion on the fuzziness.

Use the "likely mapped shared" terminology to better express what the
(adjusted) function actually checks.

Whether a partially-mappable folio is more likely to not be partially
mapped than partially mapped is debatable.  In the future, we might be
able to improve our estimate for partially-mappable folios, though.

Note that we will now consistently detect "mapped shared" only if the
first subpage is actually mapped multiple times.  When the first subpage
is not mapped, we will consistently detect it as "mapped exclusively". 
This change should currently only affect the usage in
madvise_free_pte_range() and queue_folios_pte_range() for large folios: if
the first page was already unmapped, we would have skipped the folio.

[david@redhat.com: folio_likely_mapped_shared() kerneldoc fixup]
  Link: https://lkml.kernel.org/r/dd0ad9f2-2d7a-45f3-9ba3-979488c7dd27@redhat.com
Link: https://lkml.kernel.org/r/20240227201548.857831-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:56:08 -07:00
Baolin Wang
42d0c3fbb5 mm: hugetlb: make the hugetlb migration strategy consistent 
As discussed in previous thread [1], there is an inconsistency when
handing hugetlb migration.  When handling the migration of freed hugetlb,
it prevents fallback to other NUMA nodes in
alloc_and_dissolve_hugetlb_folio().  However, when dealing with in-use
hugetlb, it allows fallback to other NUMA nodes in
alloc_hugetlb_folio_nodemask(), which can break the per-node hugetlb pool
and might result in unexpected failures when node bound workloads doesn't
get what is asssumed available.

To make hugetlb migration strategy more clear, we should list all the scenarios
of hugetlb migration and analyze whether allocation fallback is permitted:

1) Memory offline: will call dissolve_free_huge_pages() to free the
   freed hugetlb, and call do_migrate_range() to migrate the in-use
   hugetlb.  Both can break the per-node hugetlb pool, but as this is an
   explicit offlining operation, no better choice.  So should allow the
   hugetlb allocation fallback.

2) Memory failure: same as memory offline.  Should allow fallback to a
   different node might be the only option to handle it, otherwise the
   impact of poisoned memory can be amplified.

3) Longterm pinning: will call migrate_longterm_unpinnable_pages() to
   migrate in-use and not-longterm-pinnable hugetlb, which can break the
   per-node pool.  But we should fail to longterm pinning if can not
   allocate on current node to avoid breaking the per-node pool.

4) Syscalls (mbind, migrate_pages, move_pages): these are explicit
   users operation to move pages to other nodes, so fallback to other
   nodes should not be prohibited.

5) alloc_contig_range: used by CMA allocation and virtio-mem
   fake-offline to allocate given range of pages.  Now the freed hugetlb
   migration is not allowed to fallback, to keep consistency, the in-use
   hugetlb migration should be also not allowed to fallback.

6) alloc_contig_pages: used by kfence, pgtable_debug etc.  The strategy
   should be consistent with that of alloc_contig_range().

Based on the analysis of the various scenarios above, introducing a new
helper to determine whether fallback is permitted according to the
migration reason..

[1] https://lore.kernel.org/all/6f26ce22d2fcd523418a085f2c588fe0776d46e7.1706794035.git.baolin.wang@linux.alibaba.com/
Link: https://lkml.kernel.org/r/3519fcd41522817307a05b40fb551e2e17e68101.1709719720.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:56:06 -07:00
Baolin Wang
e42dfe4e0a mm: record the migration reason for struct migration_target_control 
Patch series "make the hugetlb migration strategy consistent", v2.

As discussed in previous thread [1], there is an inconsistency when
handling hugetlb migration.  When handling the migration of freed hugetlb,
it prevents fallback to other NUMA nodes in
alloc_and_dissolve_hugetlb_folio().  However, when dealing with in-use
hugetlb, it allows fallback to other NUMA nodes in
alloc_hugetlb_folio_nodemask(), which can break the per-node hugetlb pool
and might result in unexpected failures when node bound workloads doesn't
get what is asssumed available.

This patchset tries to make the hugetlb migration strategy more clear
and consistent. Please find details in each patch.

[1]
https://lore.kernel.org/all/6f26ce22d2fcd523418a085f2c588fe0776d46e7.1706794035.git.baolin.wang@linux.alibaba.com/


This patch (of 2):

To support different hugetlb allocation strategies during hugetlb
migration based on various migration reasons, record the migration reason
in the migration_target_control structure as a preparation.

Link: https://lkml.kernel.org/r/cover.1709719720.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/7b95d4981e07211f57139fc5b1f7ce91b920cee4.1709719720.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:56:06 -07:00
Suren Baghdasaryan
b951aaff50 mm: enable page allocation tagging 
Redefine page allocators to record allocation tags upon their invocation. 
Instrument post_alloc_hook and free_pages_prepare to modify current
allocation tag.

[surenb@google.com: undo _noprof additions in the documentation]
  Link: https://lkml.kernel.org/r/20240326231453.1206227-3-surenb@google.com
Link: https://lkml.kernel.org/r/20240321163705.3067592-19-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:55:54 -07:00
Donet Tom
133d04b1ee mm/numa_balancing: allow migrate on protnone reference with MPOL_PREFERRED_MANY policy 
commit bda420b985 ("numa balancing: migrate on fault among multiple
bound nodes") added support for migrate on protnone reference with
MPOL_BIND memory policy.  This allowed numa fault migration when the
executing node is part of the policy mask for MPOL_BIND.  This patch
extends migration support to MPOL_PREFERRED_MANY policy.

Currently, we cannot specify MPOL_PREFERRED_MANY with the mempolicy flag
MPOL_F_NUMA_BALANCING.  This causes issues when we want to use
NUMA_BALANCING_MEMORY_TIERING.  To effectively use the slow memory tier,
the kernel should not allocate pages from the slower memory tier via
allocation control zonelist fallback.  Instead, we should move cold pages
from the faster memory node via memory demotion.  For a page allocation,
kswapd is only woken up after we try to allocate pages from all nodes in
the allocation zone list.  This implies that, without using memory
policies, we will end up allocating hot pages in the slower memory tier.

MPOL_PREFERRED_MANY was added by commit b27abaccf8 ("mm/mempolicy: add
MPOL_PREFERRED_MANY for multiple preferred nodes") to allow better
allocation control when we have memory tiers in the system.  With
MPOL_PREFERRED_MANY, the user can use a policy node mask consisting only
of faster memory nodes.  When we fail to allocate pages from the faster
memory node, kswapd would be woken up, allowing demotion of cold pages to
slower memory nodes.

With the current kernel, such usage of memory policies implies we can't do
page promotion from a slower memory tier to a faster memory tier using
numa fault.  This patch fixes this issue.

For MPOL_PREFERRED_MANY, if the executing node is in the policy node mask,
we allow numa migration to the executing nodes.  If the executing node is
not in the policy node mask, we do not allow numa migration.

Example:
On a 2-sockets system, NUMA node N0, N1 and N2 are in socket 0,
N3 in socket 1. N0, N1 and N3 have fast memory and CPU, while
N2 has slow memory and no CPU.  For a workload, we may use
MPOL_PREFERRED_MANY with nodemask N0 and N1 set because the workload
runs on CPUs of socket 0 at most times. Then, even if the workload
runs on CPUs of N3 occasionally, we will not try to migrate the workload
pages from N2 to N3 because users may want to avoid cross-socket access
as much as possible in the long term.

In below table, Process is the Process executing node and
Curr Loc Pgs is the numa node where page present(folio node)
===========================================================
Process  Policy  Curr Loc Pgs     Observation
-----------------------------------------------------------
N0       N0 N1      N1         Pages Migrated from N1 to N0
N0       N0 N1      N2         Pages Migrated from N2 to N0
N0       N0 N1      N3	       Pages Migrated from N3 to N0

N3       N0 N1      N0         Pages NOT Migrated  to N3
N3       N0 N1      N1         Pages NOT Migrated  to N3
N3       N0 N1      N2	       Pages NOT Migrated  to N3
------------------------------------------------------------

Link: https://lkml.kernel.org/r/158acc57319129aa46d50fd64c9330f3e7c7b4bf.1711373653.git.donettom@linux.ibm.com
Link: https://lkml.kernel.org/r/369d6a58758396335fd1176d97bbca4e7730d75a.1709909210.git.donettom@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:55:49 -07:00
Donet Tom
f8fd525ba3 mm/mempolicy: use numa_node_id() instead of cpu_to_node() 
Patch series "Allow migrate on protnone reference with MPOL_PREFERRED_MANY
policy:, v4.

This patchset is to optimize the cross-socket memory access with
MPOL_PREFERRED_MANY policy.

To test this patch we ran the following test on a 3 node system.
 Node 0 - 2GB   - Tier 1
 Node 1 - 11GB  - Tier 1
 Node 6 - 10GB  - Tier 2

Below changes are made to memcached to set the memory policy,
It select Node0 and Node1 as preferred nodes.

   #include <numaif.h>
   #include <numa.h>

    unsigned long nodemask;
    int ret;

    nodemask = 0x03;
    ret = set_mempolicy(MPOL_PREFERRED_MANY | MPOL_F_NUMA_BALANCING,
                                               &nodemask, 10);
    /* If MPOL_F_NUMA_BALANCING isn't supported,
     * fall back to MPOL_PREFERRED_MANY */
    if (ret < 0 && errno == EINVAL){
       printf("set mem policy normal\n");
        ret = set_mempolicy(MPOL_PREFERRED_MANY, &nodemask, 10);
    }
    if (ret < 0) {
       perror("Failed to call set_mempolicy");
       exit(-1);
    }

Test Procedure:
===============
1. Make sure memory tiring and demotion are enabled.
2. Start memcached.

   # ./memcached -b 100000 -m 204800 -u root -c 1000000 -t 7
       -d -s "/tmp/memcached.sock"

3. Run memtier_benchmark to store 3200000 keys.

  #./memtier_benchmark -S "/tmp/memcached.sock" --protocol=memcache_binary
    --threads=1 --pipeline=1 --ratio=1:0 --key-pattern=S:S --key-minimum=1
    --key-maximum=3200000 -n allkeys -c 1 -R -x 1 -d 1024

4. Start a memory eater on node 0 and 1. This will demote all memcached
   pages to node 6.
5. Make sure all the memcached pages got demoted to lower tier by reading
   /proc/<memcaced PID>/numa_maps.

    # cat /proc/2771/numa_maps
     ---
    default anon=1009 dirty=1009 active=0 N6=1009 kernelpagesize_kB=64
    default anon=1009 dirty=1009 active=0 N6=1009 kernelpagesize_kB=64
     ---

6. Kill memory eater.
7. Read the pgpromote_success counter.
8. Start reading the keys by running memtier_benchmark.

  #./memtier_benchmark -S "/tmp/memcached.sock" --protocol=memcache_binary
   --pipeline=1 --distinct-client-seed --ratio=0:3 --key-pattern=R:R
   --key-minimum=1 --key-maximum=3200000 -n allkeys
   --threads=64 -c 1 -R -x 6

9. Read the pgpromote_success counter.

Test Results:
=============
Without Patch
------------------
1. pgpromote_success  before test
Node 0:  pgpromote_success 11
Node 1:  pgpromote_success 140974

pgpromote_success  after test
Node 0:  pgpromote_success 11
Node 1:  pgpromote_success 140974

2. Memtier-benchmark result.
AGGREGATED AVERAGE RESULTS (6 runs)
==================================================================
Type    Ops/sec   Hits/sec   Misses/sec  Avg. Latency  p50 Latency
------------------------------------------------------------------
Sets     0.00       ---         ---        ---          ---
Gets    305792.03  305791.93   0.10       0.18949       0.16700
Waits    0.00       ---         ---        ---          ---
Totals  305792.03  305791.93   0.10       0.18949       0.16700

======================================
p99 Latency  p99.9 Latency  KB/sec
-------------------------------------
---          ---            0.00
0.44700     1.71100        11542.69
---           ---            ---
0.44700     1.71100        11542.69

With Patch
---------------
1. pgpromote_success  before test
Node 0:  pgpromote_success 5
Node 1:  pgpromote_success 89386

pgpromote_success  after test
Node 0:  pgpromote_success 57895
Node 1:  pgpromote_success 141463

2. Memtier-benchmark result.
AGGREGATED AVERAGE RESULTS (6 runs)
====================================================================
Type    Ops/sec    Hits/sec  Misses/sec  Avg. Latency  p50 Latency
--------------------------------------------------------------------
Sets     0.00        ---       ---        ---           ---
Gets    521942.24  521942.07  0.17       0.11459        0.10300
Waits    0.00        ---       ---         ---          ---
Totals  521942.24  521942.07  0.17       0.11459        0.10300

=======================================
p99 Latency  p99.9 Latency  KB/sec
---------------------------------------
 ---          ---            0.00
0.23100      0.31900        19701.68
---          ---             ---
0.23100      0.31900        19701.68


Test Result Analysis:
=====================
1. With patch we could observe pages are getting promoted.
2. Memtier-benchmark results shows that, with the patch,
   performance has increased more than 50%.

 Ops/sec without fix -  305792.03
 Ops/sec with fix    -  521942.24


This patch (of 2):

Instead of using 'cpu_to_node()', we use 'numa_node_id()', which is
quicker.  smp_processor_id is guaranteed to be stable in the
'mpol_misplaced()' function because it is called with ptl held. 
lockdep_assert_held was added to ensure that.

No functional change in this patch.

[donettom@linux.ibm.com: add "* @vmf: structure describing the fault" comment]
  Link: https://lkml.kernel.org/r/d8b993ea9dccfac0bc3ed61d3a81f4ac5f376e46.1711002865.git.donettom@linux.ibm.com
Link: https://lkml.kernel.org/r/cover.1711373653.git.donettom@linux.ibm.com
Link: https://lkml.kernel.org/r/6059f034f436734b472d066db69676fb3a459864.1711373653.git.donettom@linux.ibm.com
Link: https://lkml.kernel.org/r/cover.1709909210.git.donettom@linux.ibm.com
Link: https://lkml.kernel.org/r/744646531af02cc687cde8ae788fb1779e99d02c.1709909210.git.donettom@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:55:48 -07:00
Matthew Wilcox (Oracle)
f1cce6f7fa mm/mempolicy: use a folio in do_mbind() 
We actually add folios to the pagelist already, but then work with them as
pages.  Removes a call to compound_head() in PageKsm() and removes a
reference to page->index.

Link: https://lkml.kernel.org/r/20240229153015.1996829-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Gregory Price <gregory.price@memverge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-03-06 13:04:18 -08:00
Gregory Price
274519ed41 mm/mempolicy: protect task interleave functions with tsk->mems_allowed_seq 
In the event of rebind, pol->nodemask can change at the same time as an
allocation occurs.  We can detect this with tsk->mems_allowed_seq and
prevent a miscount or an allocation failure from occurring.

The same thing happens in the allocators to detect failure, but this can
prevent spurious failures in a much smaller critical section.

[gourry.memverge@gmail.com: weighted interleave checks wrong parameter]
  Link: https://lkml.kernel.org/r/20240206192853.3589-1-gregory.price@memverge.com
Link: https://lkml.kernel.org/r/20240202170238.90004-5-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-02-22 10:24:47 -08:00
Gregory Price
fa3bea4e1f mm/mempolicy: introduce MPOL_WEIGHTED_INTERLEAVE for weighted interleaving 
When a system has multiple NUMA nodes and it becomes bandwidth hungry,
using the current MPOL_INTERLEAVE could be an wise option.

However, if those NUMA nodes consist of different types of memory such as
socket-attached DRAM and CXL/PCIe attached DRAM, the round-robin based
interleave policy does not optimally distribute data to make use of their
different bandwidth characteristics.

Instead, interleave is more effective when the allocation policy follows
each NUMA nodes' bandwidth weight rather than a simple 1:1 distribution.

This patch introduces a new memory policy, MPOL_WEIGHTED_INTERLEAVE,
enabling weighted interleave between NUMA nodes.  Weighted interleave
allows for proportional distribution of memory across multiple numa nodes,
preferably apportioned to match the bandwidth of each node.

For example, if a system has 1 CPU node (0), and 2 memory nodes (0,1),
with bandwidth of (100GB/s, 50GB/s) respectively, the appropriate weight
distribution is (2:1).

Weights for each node can be assigned via the new sysfs extension:
/sys/kernel/mm/mempolicy/weighted_interleave/

For now, the default value of all nodes will be `1`, which matches the
behavior of standard 1:1 round-robin interleave.  An extension will be
added in the future to allow default values to be registered at kernel and
device bringup time.

The policy allocates a number of pages equal to the set weights.  For
example, if the weights are (2,1), then 2 pages will be allocated on node0
for every 1 page allocated on node1.

The new flag MPOL_WEIGHTED_INTERLEAVE can be used in set_mempolicy(2)
and mbind(2).

Some high level notes about the pieces of weighted interleave:

current->il_prev:
    Tracks the node previously allocated from.

current->il_weight:
    The active weight of the current node (current->il_prev)
    When this reaches 0, current->il_prev is set to the next node
    and current->il_weight is set to the next weight.

weighted_interleave_nodes:
    Counts the number of allocations as they occur, and applies the
    weight for the current node.  When the weight reaches 0, switch
    to the next node.  Operates only on task->mempolicy.

weighted_interleave_nid:
    Gets the total weight of the nodemask as well as each individual
    node weight, then calculates the node based on the given index.
    Operates on VMA policies.

bulk_array_weighted_interleave:
    Gets the total weight of the nodemask as well as each individual
    node weight, then calculates the number of "interleave rounds" as
    well as any delta ("partial round").  Calculates the number of
    pages for each node and allocates them.

    If a node was scheduled for interleave via interleave_nodes, the
    current weight will be allocated first.

    Operates only on the task->mempolicy.

One piece of complexity is the interaction between a recent refactor which
split the logic to acquire the "ilx" (interleave index) of an allocation
and the actually application of the interleave.  If a call to
alloc_pages_mpol() were made with a weighted-interleave policy and ilx set
to NO_INTERLEAVE_INDEX, weighted_interleave_nodes() would operate on a VMA
policy - violating the description above.

An inspection of all callers of alloc_pages_mpol() shows that all external
callers set ilx to `0`, an index value, or will call get_vma_policy() to
acquire the ilx.

For example, mm/shmem.c may call into alloc_pages_mpol.  The call stacks
all set (pgoff_t ilx) or end up in `get_vma_policy()`.  This enforces the
`weighted_interleave_nodes()` and `weighted_interleave_nid()` policy
requirements (task/vma respectively).

Link: https://lkml.kernel.org/r/20240202170238.90004-4-gregory.price@memverge.com
Suggested-by: Hasan Al Maruf <Hasan.Maruf@amd.com>
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Co-developed-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Co-developed-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Co-developed-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Co-developed-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Co-developed-by: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Signed-off-by: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-02-22 10:24:46 -08:00