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We are calculating the pgoff as an offset, since we have vma_add_pgoff()
and vma_sub_pgoff() available, just offset this value directly and use
__vma_set_range() for vma->vm_[start, end] values.
We take care to update the range before offsetting the page offset, so the
adjusted VMA's vm_start and vm_pgoff are mutually consistent at the point
the page offset helpers operate - this matters once vma_set_pgoff() comes
to assert invariants which relate the two.
Doing so lays the foundation for future work which allows for use of
virtual page offsets for MAP_PRIVATE-file backed mappings.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-27-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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vma_shrink() is only used by relocate_vma_down() to shrink the tail of a
VMA. Therefore neither the start nor the pgoff parameters make any sense.
It seemed we were passing the pgoff parameter solely to satisfy
vma_set_range()'s requirement for pgoff being specified.
Since vma_set_range() is now isolated to vma.c, we can simply introduce
__vma_set_range() which sets only vma->vm_[start, end], and invoke this
instead, removing start and pgoff from vma_shrink() altogether.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-26-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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With __install_special_mapping() moved to vma.c, vma_set_range() can be
made into a static function there and is now completely isolated from the
rest of mm.
While we're here, we can also remove the insert_vm_struct() declaration
from mm.h - the function is implemented in vma.c and already declared in
vma.h, and has no users outside of mm.
Also update the VMA userland tests to reflect this change.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-25-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This function is operating on VMAs and rightly belongs in vma.c, where it
can be subject to VMA userland testing and allows us to isolate it from the
rest of mm.
The _install_special_mapping() function will remain in mmap.c as a wrapper,
since this is used by architecture-specific code.
Doing so allows us to isolate more functions in vma.c for the same reasons.
This forms part of work to allow for tracking MAP_PRIVATE file-backed
mappings by their anonymous virtual page offset, as doing so allows us to
isolate and keep code that interacts with this together.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-24-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add helpers for adding or subtracting to a VMA's page offset, exposed
internally for VMA users within mm in mm/vma.h.
This is to lay the foundations for tracking anonymous page offset for
MAP_PRIVATE file-backed mappings, where adding and subtracting from this
value must be reflected in both the file and anonymous offsets.
These are used on VMA split and downward stack expansion.
No functional change intended.
[akpm@linux-foundation.org: use linear_page_delta() in __split_vma(), per Vlastimal & Lorenzo]
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-23-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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vma_assert_write_locked() and vma_assert_attached() are useful for their
own purposes, however VMA code absolutely does allow the modification of
non-write locked VMAs if they are at that point detached (i.e. unreachable
from anywhere).
It's therefore useful to be able to assert that a VMA is either
detached (modification doesn't matter) or write locked (you're explicitly
locked for modification).
Therefore introduce vma_assert_can_modify() for this purpose.
While we're here, make vma_is_attached() available generally - if
!CONFIG_PER_VMA_LOCK, then there's no sense in which a VMA is
detached (vma_mark_detached() is a noop), so have this default to true in
this case.
Also update VMA userland tests to reflect this change, correcting the
previously open-coded vma_assert_[attached,detached]() there.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-22-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There are a number of places where we open code what linear_page_index()
and linear_page_delta() calculate.
Replace this code with the appropriate functions for consistency.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-21-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> [DRM]
Acked-by: Kai Huang <kai.huang@intel.com> # for sgx
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Pedro Falcato <pfalcato@suse.de> # for mm
Reviewed-by: Ackerley Tng <ackerleytng@google.com> [guest_memfd]
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This is doing what linear_page_index() does, so eliminate it and replace it
with linear_page_index().
Update the VMA userland tests to reflect this change.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-20-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Be consistent in using vma_start_pgoff() and vma_end_pgoff(), which clearly
indicates which part of the VMA the page offset refers to and aids
greppability.
This is part of a broader series laying the ground to provide a virtual
page offset for MAP_PRIVATE-file backed anon folios.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-19-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> # for kernel/dma
Reviewed-by: Gregory Price <gourry@gourry.net>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There are many instances in which linear_page_index() (as well as
linear_page_delta()) is open-coded, which is confusing and inconsistent.
Additionally, vma->vm_pgoff doesn't necessarily make it clear that this is
the page offset of the start of the VMA range.
Doing so also aids greppability.
So use vma_start_pgoff() in favour of directly accessing vma->vm_pgoff, and
linear_page_index() where we can.
This also lays the ground for future changes which will add an anonymous
page offset in order to be able to index MAP_PRIVATE-file backed anon
folios in terms of their virtual page offset.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-18-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: SJ Park <sj@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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It's often useful to obtain the number of pages a given address lies at
within a VMA.
Add linear_page_delta() to determine this and update linear_page_index() to
make use of it.
Add comments to describe both linear_page_delta() and linear_page_index().
We refer the reader to the comment for vma_start_pgoff() so we don't
duplicate information about the meaning of a VMA's page offset, which is
also less likely to result in bitrot.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-17-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Adjust the stack expansion functions expand_upwards() and
expand_downwards() such that they are expressed in terms of named constant
values, and make use of vma_start_pgoff().
This clearly documents that we are referencing the page offset of the start
of the VMA.
Additionally this cleans up the overflow check in expand_upwards().
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-16-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add comments with ASCII diagrams to describe what we're doing, avoid
dubious use of PHYS_PFN(), and use vma_start_pgoff().
The most complicated scenario represented here is vmg->__adjust_next_start
- when this is set, vmg->[start, end] actually indicate the range to be
retained, so take special care to describe this accurately.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-15-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Break up the existing very large conditional, add comments and use
vma_[start/end]_pgoff() to make clearer what we're doing here.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-14-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In the VMA logic we often need to determine the number of pages in the
specified merge range, as well as the start and end page offsets of that
range.
Introduce and use helpers for these purposes.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-13-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This file implements code for the interval trees used by the file and anon
rmap implementation, so belongs in the rmap section.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-12-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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To be consistent with the newly renamed mapping_rmap_tree_*(), rename the
anon_vma_interval_tree_*() helpers to anon_rmap_tree_*().
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-11-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Rename parameters used by anon_vma_interval_tree_*() functions: 'node' to
'avc', 'start/first' to 'pgoff_start', and 'last' to 'pgoff_last' to make
clear what is being passed.
Also, express page offsets in terms of pgoff_t to be consistent.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-10-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Similar to what we did with mapping_rmap_tree*(), let's declare
anon_vma_interval_tree*() in terms of anon_vma rather than rb_root_cached.
In each case the rb tree referenced is &anon_vma->rb_root, so just pass
anon_vma and the functions can figure this out themselves.
Also update the VMA userland tests to reflect the change.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-9-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The family of vma_interval_tree_() functions manipulate the
address_space (which, of course, is generally referred to as 'mapping')
reverse mapping, but are named the 'VMA' interval tree.
VMAs may be mapped by an anon_vma, an address_space, or both. Therefore
calling the mapping interval tree a 'VMA' interval tree is rather
confusing.
This is also inconsistent with the anon_vma_interval_tree_*() functions
which explicitly reference the rmap object to which they pertain.
Rename the vma_interval_tree_*() functions to mapping_rmap_tree_*() to
correct this.
We will rename the anon rmap functions similarly in a subsequent patch.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-8-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
It's not necessary to declare these functions static inline as they are
contained within a single compilation unit.
This makes the anonymous interval tree code consistent with the newly
updated file-backed interval tree code.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-7-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The file-backed mapping interval tree functions vma_interval_tree_*()
accept a raw rb_root_cached pointer to determine the tree in which they are
operating.
However, in each case, this is always associated with an address_space data
type.
So simply pass a pointer to that instead to simplify the code, and more
clearly differentiate between these operations and those concerning
anonymous mappings.
While we're here, make the generated interval tree functions static as they
do not need to be used externally (any previously existing external users
have now been removed).
We also rename VMA parameters from 'node' to 'vma' as calling this a node
is simply confusing, update the input index types to pgoff_t since they
reference page offsets and rename the parameters to pgoff_start and
pgoff_last.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-6-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Update the file comment to clarify that both file-backed and anonymous
interval trees are provided, referencing the relevant data types for
clarity.
Also add comments to indicate which parts of the file apply to each.
While we're here, convert the VM_BUG_ON_VMA() to VM_WARN_ON_ONCE_VMA().
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-5-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We already have vma_last_pgoff() which retrieves the last page offset
within a VMA.
However, code often wishes to span a page offset range, which requires the
exclusive end of this range.
So provide this in vma_end_pgoff() and update vma_last_pgoff() to use this
function.
Also update the VMA userland tests to reflect the change.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-4-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now we have the vma_start_pgoff() helper, update the merge tests to make
use of it for consistency.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-3-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Describe what vma_start_pgoff() and vma_last_pgoff() actually provide in
detail.
This is in order that we can differentiate this between functions that will
be added in a subsequent patch which provide a different page offset.
We go to lengths to describe the edge cases that can be run into here.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-2-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: make VMA page offset handling more consistent", v2.
This series performs a series of cleanups and improvements around how the
vma->vm_pgoff field is used.
Folios belonging to file-backed mappings are simply indexed by the page
offset within the file they map (excepting pfnmap and driver mappings
which sometimes do things different).
However, anonymous folios belonging to pure anonymous mappings are indexed
by their "virtual" page offset, which is equal to addr >> PAGE_SHIFT at
the time at which the VMA was first faulted in.
The page offset of a VMA is stored in vma->vm_pgoff and indicates the page
offset of the start of the VMA range, whether it be file-backed or
anonymous.
The work here both cleans up how we reference this field, as well as
laying the foundations for a future series which addresses the
inconsistency of CoW'd folios in MAP_PRIVATE-file backed mappings, which
are indexed as if they were file-backed but behave as if they were
anonymous.
This future series will make it such that all anonymous folios are indexed
by virtual page offset whether belonging to VMAs who satisfy
vma_is_anonymous() or MAP_PRIVATE-mapped file-backed mappings.
This series:
* Exposes vma_start_pgoff() and updates the kernel to use it consistently.
* Adds and uses the useful vma_end_pgoff() helper.
* Parameterises the file-backed mapping helpers vma_interval_tree_*()
by address_space rather than rb_root_cached.
* Renames: the misleadingly-named vma_interval_tree_*() helpers to
mapping_rmap_tree_*() to be consistent with the renamed
anon_rmap_tree_*().
* Parameterises anon_rmap_tree_*() by anon_vma.
* Moves mm/interval_tree.c to the rmap section.
* Adds vmg_*() helpers for page offset.
* Clarifies the confusing vmg_adjust_set_range() function.
* Introduces linear_page_delta() to provide relative pgoff within a VMA.
* Replaces open-coded versions of linear_page_delta() and
linear_page_index() with invocations of these functions.
* Introduces and uses vma_assert_can_modify() to account for whether a VMA
can be modified (detached or write locked).
* Adds and uses vma_[add,sub]_pgoff() to adjust VMA page offset.
* Moves __install_special_mapping() to vma.c.
* Makes vma_set_range() static and internal to vma.c.
* Introduces and makes use of vma_set_pgoff().
* Fixes incorrect vma.h header inclusion.
* Defaults VMA userland tests to 64-bit vma flags size.
* Updates VMA userland tests to give better output on failure.
* Various smaller cleanups.
* Updated the vma_set_pgoff() assert to account for MAP_PRIVATE /dev/zero
correctly.
This patch (of 33):
vma_last_pgoff() already lives there, so it's a bit odd to keep
vma_start_pgoff() in mm/interval_tree.c. Move them together.
These each return unsigned long, which pgoff_t is typedef'd to. Make this
consistent and have these functions return pgoff_t instead.
Additionally, express vma_last_pgoff() in terms of vma_start_pgoff(), since
we wrap the vma->vm_pgoff access, we may as well use it here.
Also while we're here, const-ify the VMA and cleanup a bit.
Also update the VMA userland tests to reflect the change.
No functional change intended.
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-0-2a5aa403d977@kernel.org
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-1-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Several GPU SVM paths take mmap_read_lock() only to call hmm_range_fault()
and open-code mmu interval sequence setup before each HMM walk. They also
retry -EBUSY until HMM_RANGE_DEFAULT_TIMEOUT expires.
Use hmm_range_fault_unlocked_timeout() for those faults. The HMM helper
now owns mmap_lock acquisition and refreshes range->notifier_seq for its
internal retries, while GPU SVM keeps its existing driver-lock validation
with mmu_interval_read_retry() after a successful fault.
drm_gpusvm_scan_mm() and drm_gpusvm_range_evict() pass
HMM_RANGE_DEFAULT_TIMEOUT as the helper retry budget for each HMM fault
attempt. drm_gpusvm_get_pages() keeps its existing absolute outer
deadline because it can be reached from GPU page-fault workers, where
fatal signals from the faulting process cannot stop an endless
invalidation retry loop. It passes the remaining time from that deadline
to HMM for each fault attempt.
Leave drm_gpusvm_check_pages() on hmm_range_fault() because that path is
called with the mmap lock already held by its caller.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-8-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
aie2_populate_range() takes mmap_read_lock() only around
hmm_range_fault(). It also open-codes the mmu interval sequence setup
before each HMM walk and retries -EBUSY until HMM_RANGE_DEFAULT_TIMEOUT
expires.
Use hmm_range_fault_unlocked_timeout() instead. The HMM helper now owns
the mmap lock and refreshes mapp->range.notifier_seq for its internal
retries, so the driver only needs to call the helper and then validate the
sequence before marking the mapping populated.
Pass HMM_RANGE_DEFAULT_TIMEOUT as the helper retry budget for each HMM
population attempt. This scopes the timeout to repeated HMM notifier
retries while preserving the existing outer loop that moves between
invalid mappings and restarts when the interval is invalidated before the
driver updates its mapping state.
Keep returning -ETIME when the HMM retry budget expires, matching the
driver's existing timeout error convention.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-7-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
ib_umem_odp_map_dma_and_lock() takes mmap_read_lock() only around
hmm_range_fault(), then retries -EBUSY until HMM_RANGE_DEFAULT_TIMEOUT
expires.
Use hmm_range_fault_unlocked_timeout() instead. The HMM helper now owns
the mmap lock and refreshes range->notifier_seq for its internal retries.
ODP keeps using HMM_RANGE_DEFAULT_TIMEOUT for each HMM fault attempt,
while interval invalidation retries continue to be handled by the existing
outer loop.
ODP still validates the interval notifier sequence while holding
umem_mutex before DMA mapping pages.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-6-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
nouveau_range_fault() takes mmap_read_lock() only to call
hmm_range_fault(). It also keeps a single HMM_RANGE_DEFAULT_TIMEOUT
deadline across both HMM -EBUSY retries and post-fault
mmu_interval_read_retry() retries.
Use hmm_range_fault_unlocked_timeout() instead. The HMM helper now owns
the mmap lock and refreshes range->notifier_seq for its internal retries.
Nouveau keeps its existing absolute deadline in the outer loop and passes
the remaining jiffies to the helper for each fault attempt, so retries
caused by mmu_interval_read_retry() do not reset the overall retry budget.
Nouveau still validates the interval notifier sequence while holding
svmm->mutex before programming the GPU mapping.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-5-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
MSHV currently faults movable memory regions by taking mmap_read_lock()
around hmm_range_fault(). That prevents the fault path from handling VMAs
whose fault handlers need to drop mmap_lock, such as userfaultfd-backed
mappings.
Use hmm_range_fault_unlocked_timeout() instead. Passing a timeout of 0
preserves MSHV's existing unbounded retry behavior while letting the HMM
helper own mmap_lock acquisition and refresh range->notifier_seq
internally before walking the range. After the fault succeeds, MSHV still
takes mreg_mutex and checks mmu_interval_read_retry() before installing
the pages into the region, so the existing invalidation synchronization is
preserved.
Fold the small fault-and-lock helper into mshv_region_range_fault(), since
the remaining retry path is just the standard "fault, take the driver
lock, check the interval notifier sequence" pattern.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-4-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add test_hmm coverage for the HMM lock-dropping fault path. The test
module gets a new HMM_DMIRROR_READ_UNLOCKED ioctl that calls
hmm_range_fault_unlocked_timeout() with a timeout of 0, exercising the
unbounded retry mode while allowing the mmap lock to be dropped during
fault handling.
Add a userfaultfd_read selftest that registers an anonymous mapping with
UFFDIO_REGISTER_MODE_MISSING, services the faults from a handler thread
with UFFDIO_COPY, and verifies that HMM can read back the data supplied by
the handler. This exercises the path where handle_mm_fault() drops
mmap_lock and hmm_range_fault_unlocked_timeout() restarts the walk
internally.
Assisted-by: GitHub-Copilot:claude-opus-4.6
Link: https://lore.kernel.org/20260723-hmm-v10-v11-3-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
hmm_range_fault() requires the caller to hold the mmap read lock for the
duration of the call. This is incompatible with mappings whose fault
handler may release the mmap lock, notably userfaultfd-managed regions,
where handle_mm_fault() can return VM_FAULT_RETRY or VM_FAULT_COMPLETED
after dropping the lock. Drivers that need to populate device page tables
for such mappings have no way to do so today.
Add hmm_range_fault_unlocked_timeout() for callers that do not need to
hold mmap_lock across any work outside the HMM fault itself. The helper
takes mmap_read_lock_killable() internally, calls the common HMM fault
implementation, and releases the lock before returning if it is still
held. The timeout is specified in jiffies; passing 0 retries
indefinitely, while a non-zero timeout makes the helper return -EBUSY when
the retry budget expires. The retry deadline is set before refreshing the
notifier sequence and acquiring mmap_lock, so contended mmap_lock
acquisition is included in the retry budget. After acquiring mmap_lock,
the helper also rejects unstable address spaces before walking page
tables.
When handle_mm_fault() drops mmap_lock, or when the range is invalidated,
hmm_range_fault_unlocked_timeout() refreshes range->notifier_seq and
retries the walk internally. If the lock was dropped, the retry deadline
is also restarted because a lock-dropping fault handler made progress.
Ordinary -EBUSY retries keep the existing deadline, preserving the
caller's timeout policy for repeated mmu-notifier invalidations.
The caller only needs to perform the usual post-success
mmu_interval_read_retry() check while holding its update lock before
consuming the pfns. If mmap_lock acquisition is interrupted or a fatal
signal is pending during retry handling, -EINTR is returned instead.
The common implementation conditionally sets FAULT_FLAG_ALLOW_RETRY and
FAULT_FLAG_KILLABLE only for hmm_range_fault_unlocked_timeout(). The
existing hmm_range_fault() path still passes no locked state, does not
allow handle_mm_fault() to drop mmap_lock, and remains a thin wrapper
preserving the existing API contract for current callers.
The previous refactor that moved page fault handling out of the page-table
walk callbacks is what makes this change small. Faults now run after
walk_page_range() has unwound, with only mmap_lock held, so dropping it
does not interact with the walker's pte spinlock or hugetlb_vma_lock.
Hugetlb regions therefore participate in the unlocked path uniformly with
PTE- and PMD-level mappings; no special case is required.
Documentation/mm/hmm.rst is updated with a description of the new API and
the recommended caller pattern.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-2-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/hmm: Add mmap lock-drop support for userfaultfd-backed
mappings", v11.
This series extends the HMM framework to support userfaultfd-backed memory
by allowing the mmap read lock to be dropped during hmm_range_fault().
Some page fault handlers most notably userfaultfd require the mmap lock to
be released so that userspace can resolve the fault. The current HMM
interface never sets FAULT_FLAG_ALLOW_RETRY, making it impossible to fault
in pages from userfaultfd-registered regions.
This series follows the established int *locked pattern from
get_user_pages_remote() in mm/gup.c. A new helper function,
hmm_range_fault_locked(), accepts an int *locked parameter. When the mmap
lock is dropped during fault resolution (VM_FAULT_RETRY or
VM_FAULT_COMPLETED), the function returns 0 with *locked = 0, signalling
the caller to restart its walk. The existing hmm_range_fault() is
refactored into a thin wrapper that passes NULL, preserving current
behavior for all existing callers.
Possible approaches to lift this limitation are documented in
Documentation/mm/hmm.rst.
This patch (of 8):
hmm_range_fault() currently triggers page faults from inside the
page-table walk callbacks: hmm_vma_walk_pmd(), hmm_vma_walk_pud(),
hmm_vma_walk_hugetlb_entry() and the pte-level helper all call
hmm_vma_fault(), which in turn calls handle_mm_fault() while the walker
still holds nested locks. The pte spinlock is dropped explicitly by each
caller, and the hugetlb path manually drops and retakes
hugetlb_vma_lock_read around the fault to dodge a deadlock against the
walk framework's unconditional unlock.
This layering does not extend cleanly to fault handlers that may release
mmap_lock (VM_FAULT_RETRY, VM_FAULT_COMPLETED). If the lock is dropped
while walk_page_range() is mid-traversal, the VMA can be freed before the
walk framework's matching hugetlb_vma_unlock_read(), turning that unlock
into a use-after-free.
Split the responsibilities the way get_user_pages() does. Walk callbacks
become inspect-only: when they detect a range that needs to be faulted in,
they record it in struct hmm_vma_walk and return a private sentinel
(HMM_FAULT_PENDING). The outer loop in hmm_range_fault() then drops out
of walk_page_range(), invokes a new helper hmm_do_fault() that calls
handle_mm_fault() with only mmap_lock held, and restarts the walk so the
now-present entries are collected into hmm_pfns.
No functional change for existing callers. As a side effect the hugetlb
callback no longer needs the hugetlb_vma_{un}lock_read dance, and every
fault-path exit from the callbacks now releases the pte spinlock on a
single, common path. This refactor is also a precursor for adding an
unlockable variant of hmm_range_fault() in a follow-up patch.
Link: https://lore.kernel.org/20260723-hmm-v10-v11-0-c55b003a4b61@gmail.com
Link: https://lore.kernel.org/20260723-hmm-v10-v11-1-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
hmm doesn't currently build well with MMU_NOTIFIER=n:
With microblaze
https://download.01.org/0day-ci/archive/20260702/202607021433.DYT5fDqE-lkp@intel.com/config
(CONFIG_MMU_NOTIFIER=n):
mm/hmm.c: In function 'hmm_range_fault_unlocked_timeout':
mm/hmm.c:804:25: error: implicit declaration of function 'mmu_interval_read_begin'; did you mean 'mmu_interval_check_retry'? [-Wimplicit-function-declaration]
804 | mmu_interval_read_begin(range->notifier);
| ^~~~~~~~~~~~~~~~~~~~~~~
| mmu_interval_check_retry
Quoting Stanislav:
: Documentation/mm/hmm.rst explicitly states:
:
: "Address space mirroring's main objective is to allow duplication of a
: range of CPU page table into a device page table; HMM helps keep both
: synchronized. A device driver that wants to mirror a process address
: space must start with the registration of a mmu_interval_notifier"
:
: I think making CONFIG_HMM_MIRROR dependent on the CONFIG_MMU_NOTIFIER
: is the right thing to do.
So select MMU_NOTIFIER if hmm.c is to be compiled.
Cc: David Hildenbrand <david@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Stanislav Kinsburskii <skinsburskii@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Update DAMON ABI document for the newly added probe weight sysfs file.
Link: https://lore.kernel.org/20260710134651.18084-20-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Update DAMON usage document for newly added probe weight file.
Link: https://lore.kernel.org/20260710134651.18084-19-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Update DAMON design document for the attributes only monitoring mode.
Link: https://lore.kernel.org/20260710134651.18084-18-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Implement a new sysfs file, 'weight', under probe directory. Users will
be able to set the probe weight and enable the attributes only monitoring
using it.
Link: https://lore.kernel.org/20260710134651.18084-17-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
DAMON monitors only data attributes when probe weights are set. However,
the function for detecting it is intentionally returning false always.
The intention was to make changes for complete support of the mode in a
safe and incremental way. Now all the building blocks are made. Complete
the mode detection function so that the mode can really start working.
Link: https://lore.kernel.org/20260710134651.18084-16-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When probe weights are set, DAMON merges regions based on their probe hits
weighted sum. But the merge threshold is calculated based on the access
frequency. Update it to retrieve the maximum probe hits weighted sum in
the snapshot from apply_probes() ops callback, and generate the threshold
based on it.
Link: https://lore.kernel.org/20260710134651.18084-15-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When probe weights are set, DAMON merge logic works with the probe hits
weighted sum. The core logic is setting the merge threshold based on the
access frequency, though. Before using probe hits based threshold, rename
the variables to look more general.
Link: https://lore.kernel.org/20260710134651.18084-14-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When probe weights are set, the prepare_access_checks() ops callback is
not invoked, so sampling addresses of regions are unset. Ask
apply_probes() to set those together in the case.
Link: https://lore.kernel.org/20260710134651.18084-13-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When users set probe weights, they are interested in the data attributes.
Not necessarily they are interested in data access patterns. Disable the
data access monitoring in the case.
Link: https://lore.kernel.org/20260710134651.18084-12-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
damon_probe_hits_wsum() could overflow in weird setups. Users could set
the weight unreasonably high. They could also set the aggregation
interval unreasonably high compared to the sampling interval. Such user
setup is unlikely. Even if such setup is used, damon_has_probe_weights()
always returns false, so the overflow cannot happen. The function may be
completed in future, though. Even if the overflow happens, the
consequence is degraded monitoring results for the unreasonable setup. It
is just a trivial user experience issue.
It is still better to be prevented unless the cost is expensive. Avoid
the overflow by adding the parameter validation in the core layer
parameters validation function.
Link: https://lore.kernel.org/20260710134651.18084-11-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When any damon_probe->weight is set, DAMON will do only probe monitoring.
probe_hits is 'unsigned char'. It could overflow when the aggregation
interval is larger than the sampling interval times 256.
damon_as_probe_weights() always return false, so such overflow cannot
happen. Even if it happens, it only degrades the monitoring results.
That said, the overflow is not intentional. It is better to be prevented
as long as the cost is not expensive. Disallow the overflow by adding a
validation logic on the core layer parameters validation function.
Link: https://lore.kernel.org/20260710134651.18084-10-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When probe weights are set, users may want DAMON monitoring results to be
optimized for the weights. For that, regions adjustment should work for
the weighted sum of probe hits. Extend damon_merge_regions_of() to detect
if the weights are set, and work with probe hits in the case.
The weights setup detection function is incomplete. It always returns
false. It is intentional, so that more changes to completely support
weights can be made in an incremental but safe way. Until the function is
completed, all changes depend on it is no-op, so DAMON works in the
current mode.
Link: https://lore.kernel.org/20260710134651.18084-9-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use of abs() in damon_merge_regions_of() could cause a silent integer
overflow since the macro casts unsigned int to signed int. It is unlikely
to have such a large value for nr_accesses. Even though it happens, the
user impact is just degraded monitoring results. Users showing bad
monitoring results for weird setup is quite trivial. But the code is
obviously wrong. Use abs_diff() instead.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260710134651.18084-8-sj@kernel.org
Link: https://lore.kernel.org/20260705213817.100841-1-sj@kernel.org/ [1]
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
apply_probes() ops implementation in DAMON_PADDR is ignoring
return_max_wsum. Respect it.
Link: https://lore.kernel.org/20260710134651.18084-7-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
