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2025-10-03Merge tag 'mm-stable-2025-10-01-19-00' of ↵Linus Torvalds1-1/+9
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - "mm, swap: improve cluster scan strategy" from Kairui Song improves performance and reduces the failure rate of swap cluster allocation - "support large align and nid in Rust allocators" from Vitaly Wool permits Rust allocators to set NUMA node and large alignment when perforning slub and vmalloc reallocs - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend DAMOS_STAT's handling of the DAMON operations sets for virtual address spaces for ops-level DAMOS filters - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren Baghdasaryan reduces mmap_lock contention during reads of /proc/pid/maps - "mm/mincore: minor clean up for swap cache checking" from Kairui Song performs some cleanup in the swap code - "mm: vm_normal_page*() improvements" from David Hildenbrand provides code cleanup in the pagemap code - "add persistent huge zero folio support" from Pankaj Raghav provides a block layer speedup by optionalls making the huge_zero_pagepersistent, instead of releasing it when its refcount falls to zero - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to the recently added Kexec Handover feature - "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo Stoakes turns mm_struct.flags into a bitmap. To end the constant struggle with space shortage on 32-bit conflicting with 64-bit's needs - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap code - "selftests/mm: Fix false positives and skip unsupported tests" from Donet Tom fixes a few things in our selftests code - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised" from David Hildenbrand "allows individual processes to opt-out of THP=always into THP=madvise, without affecting other workloads on the system". It's a long story - the [1/N] changelog spells out the considerations - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on the memdesc project. Please see https://kernelnewbies.org/MatthewWilcox/Memdescs and https://blogs.oracle.com/linux/post/introducing-memdesc - "Tiny optimization for large read operations" from Chi Zhiling improves the efficiency of the pagecache read path - "Better split_huge_page_test result check" from Zi Yan improves our folio splitting selftest code - "test that rmap behaves as expected" from Wei Yang adds some rmap selftests - "remove write_cache_pages()" from Christoph Hellwig removes that function and converts its two remaining callers - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD selftests issues - "introduce kernel file mapped folios" from Boris Burkov introduces the concept of "kernel file pages". Using these permits btrfs to account its metadata pages to the root cgroup, rather than to the cgroups of random inappropriate tasks - "mm/pageblock: improve readability of some pageblock handling" from Wei Yang provides some readability improvements to the page allocator code - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON to understand arm32 highmem - "tools: testing: Use existing atomic.h for vma/maple tests" from Brendan Jackman performs some code cleanups and deduplication under tools/testing/ - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes a couple of 32-bit issues in tools/testing/radix-tree.c - "kasan: unify kasan_enabled() and remove arch-specific implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific initialization code into a common arch-neutral implementation - "mm: remove zpool" from Johannes Weiner removes zspool - an indirection layer which now only redirects to a single thing (zsmalloc) - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a couple of cleanups in the fork code - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of adjustments at various nth_page() callsites, eventually permitting the removal of that undesirable helper function - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun creates a KASAN read-only mode for ARM, using that architecture's memory tagging feature. It is felt that a read-only mode KASAN is suitable for use in production systems rather than debug-only - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does some tidying in the hugetlb folio allocation code - "mm: establish const-correctness for pointer parameters" from Max Kellermann makes quite a number of the MM API functions more accurate about the constness of their arguments. This was getting in the way of subsystems (in this case CEPH) when they attempt to improving their own const/non-const accuracy - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of code sites which were confused over when to use free_pages() vs __free_pages() - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the mapletree code accessible to Rust. Required by nouveau and by its forthcoming successor: the new Rust Nova driver - "selftests/mm: split_huge_page_test: split_pte_mapped_thp improvements" from David Hildenbrand adds a fix and some cleanups to the thp selftesting code - "mm, swap: introduce swap table as swap cache (phase I)" from Chris Li and Kairui Song is the first step along the path to implementing "swap tables" - a new approach to swap allocation and state tracking which is expected to yield speed and space improvements. This patchset itself yields a 5-20% performance benefit in some situations - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc layer to clean up the ptdesc code a little - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some issues in our 5-level pagetable selftesting code - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan addresses a couple of minor issues in relatively new memory allocation profiling feature - "Small cleanups" from Matthew Wilcox has a few cleanups in preparation for more memdesc work - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from Quanmin Yan makes some changes to DAMON in furtherance of supporting arm highmem - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad Anjum adds that compiler check to selftests code and fixes the fallout, by removing dead code - "Improvements to Victim Process Thawing and OOM Reaper Traversal Order" from zhongjinji makes a number of improvements in the OOM killer: mainly thawing a more appropriate group of victim threads so they can release resources - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park is a bunch of small and unrelated fixups for DAMON - "mm/damon: define and use DAMON initialization check function" from SeongJae Park implement reliability and maintainability improvements to a recently-added bug fix - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from SeongJae Park provides additional transparency to userspace clients of the DAMON_STAT information - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes some constraints on khubepaged's collapsing of anon VMAs. It also increases the success rate of MADV_COLLAPSE against an anon vma - "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()" from Lorenzo Stoakes moves us further towards removal of file_operations.mmap(). This patchset concentrates upon clearing up the treatment of stacked filesystems - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau provides some fixes and improvements to mlock's tracking of large folios. /proc/meminfo's "Mlocked" field became more accurate - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from Donet Tom fixes several user-visible KSM stats inaccuracies across forks and adds selftest code to verify these counters - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses some potential but presently benign issues in KSM's mm_slot handling * tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits) mm: swap: check for stable address space before operating on the VMA mm: convert folio_page() back to a macro mm/khugepaged: use start_addr/addr for improved readability hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list alloc_tag: fix boot failure due to NULL pointer dereference mm: silence data-race in update_hiwater_rss mm/memory-failure: don't select MEMORY_ISOLATION mm/khugepaged: remove definition of struct khugepaged_mm_slot mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL hugetlb: increase number of reserving hugepages via cmdline selftests/mm: add fork inheritance test for ksm_merging_pages counter mm/ksm: fix incorrect KSM counter handling in mm_struct during fork drivers/base/node: fix double free in register_one_node() mm: remove PMD alignment constraint in execmem_vmalloc() mm/memory_hotplug: fix typo 'esecially' -> 'especially' mm/rmap: improve mlock tracking for large folios mm/filemap: map entire large folio faultaround mm/fault: try to map the entire file folio in finish_fault() mm/rmap: mlock large folios in try_to_unmap_one() mm/rmap: fix a mlock race condition in folio_referenced_one() ...
2025-09-29maple_tree: Add single node allocation support to maple stateLiam R. Howlett1-2/+7
The fast path through a write will require replacing a single node in the tree. Using a sheaf (32 nodes) is too heavy for the fast path, so special case the node store operation by just allocating one node in the maple state. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2025-09-29maple_tree: Prefilled sheaf conversion and testingLiam R. Howlett1-443/+18
Use prefilled sheaves instead of bulk allocations. This should speed up the allocations and the return path of unused allocations. Remove the push and pop of nodes from the maple state as this is now handled by the slab layer with sheaves. Testing has been removed as necessary since the features of the tree have been reduced. Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2025-09-29tools/testing: include maple-shim.c in maple.cVlastimil Babka1-9/+3
There's some duplicated code and we are about to add more functionality in maple-shared.h that we will need in the userspace maple test to be available, so include it via maple-shim.c Co-developed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2025-09-29maple_tree: Drop bulk insert supportLiam R. Howlett1-36/+0
Bulk insert mode was added to facilitate forking faster, but forking now uses __mt_dup() to duplicate the tree. The addition of sheaves has made the bulk allocations difficult to maintain - since the expected entries would preallocate into the maple state. A big part of the maple state node allocation was the ability to push nodes back onto the state for later use, which was essential to the bulk insert algorithm. Remove mas_expected_entries() and mas_destroy_rebalance() functions as well as the MA_STATE_BULK and MA_STATE_REBALANCE maple state flags since there are no users anymore. Drop the associated testing as well. Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2025-09-14maple_tree: testing fix for spanning store on 32bLiam R. Howlett1-1/+6
32 bit nodes have a larger branching factor. This affects the required value to cause a height change. Update the spanning store height test to work for both 64 and 32 bit nodes. Link: https://lkml.kernel.org/r/20250828003023.418966-3-Liam.Howlett@oracle.com Fixes: f9d3a963fef4 ("maple_tree: use height and depth consistently") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-14maple_tree: fix testing for 32 bit buildsLiam R. Howlett1-0/+3
Patch series "maple_tree: Fix testing for 32bit compiles". The maple tree test suite supports 32bit builds which causes 32bit nodes and index/last values. Some tests have too large values and must be skipped while others depend on certain actions causing the tree to be altered in another measurable way (such as the height decreasing or increasing). Two tests were added that broke 32bit testing, either by compile warnings or failures. These fixes restore the tests to a working order. Building 32bit version can be done on a 32bit platform, or by using a command like: BUILD=32 make clean maple This patch (of 2): Some tests are invalid on 32bit due to the size of the index and last. Making those tests depend on the correct build flags stops compile complaints. Link: https://lkml.kernel.org/r/20250828003023.418966-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20250828003023.418966-2-Liam.Howlett@oracle.com Fixes: 5d659bbb52a2 ("maple_tree: introduce mas_wr_store_type()") Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-10tools/testing/radix-tree: test maple tree chaining mas_preallocate() callsLiam R. Howlett1-0/+12
Testing calling multiple mas_preallocate() calls in a row after adjusting the maple state. Ensures new calls to mas_preallocate() will change the number of allocated nodes. Link: https://lkml.kernel.org/r/20250616184521.3382795-4-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Hailong Liu <hailong.liu@oppo.com> Cc: "Liam R. Howlett" <howlett@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-10testing/radix-tree/maple: increase readers and reduce delay for faster machinesLiam R. Howlett1-3/+4
Faster machines may not see the initial or updated value in the race condition. Reduce the delay so that faster machines are less likely to fail testing of the race conditions. Link: https://lkml.kernel.org/r/20250616184521.3382795-2-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <howlett@gmail.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Hailong Liu <hailong.liu@oppo.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-12maple_tree: add sufficient heightSidhartha Kumar1-0/+28
In order to support rebalancing and spanning stores using less than the worst case number of nodes, we need to track more than just the vacant height. Using only vacant height to reduce the worst case maple node allocation count can lead to a shortcoming of nodes in the following scenarios. For rebalancing writes, when a leaf node becomes insufficient, it may be combined with a sibling into a single node. This means that the parent node which has entries for this children will lose one entry. If this parent node was just meeting the minimum entries, losing one entry will now cause this parent node to be insufficient. This leads to a cascading operation of rebalancing at different levels and can lead to more node allocations than simply using vacant height can return. For spanning writes, a similar situation occurs. At the location at which a spanning write is detected, the number of ancestor nodes may similarly need to rebalanced into a smaller number of nodes and the same cascading situation could occur. To use less than the full height of the tree for the number of allocations, we also need to track the height at which a non-leaf node cannot become insufficient. This means even if a rebalance occurs to a child of this node, it currently has enough entries that it can lose one without any further action. This field is stored in the maple write state as sufficient height. In mas_prealloc_calc() when figuring out how many nodes to allocate, we check if the vacant node is lower in the tree than a sufficient node (has a larger value). If it is, we cannot use the vacant height and must use the difference in the height and sufficient height as the basis for the number of nodes needed. An off by one bug was also discovered in mast_overflow() where it is using >= rather than >. This caused extra iterations of the mas_spanning_rebalance() loop and lead to unneeded allocations. A test is also added to check the number of allocations is correct. Link: https://lkml.kernel.org/r/20250410191446.2474640-6-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-12maple_tree: use vacant nodes to reduce worst case allocationsSidhartha Kumar1-8/+71
In order to determine the store type for a maple tree operation, a walk of the tree is done through mas_wr_walk(). This function descends the tree until a spanning write is detected or we reach a leaf node. While descending, keep track of the height at which we encounter a node with available space. This is done by checking if mas->end is less than the number of slots a given node type can fit. Now that the height of the vacant node is tracked, we can use the difference between the height of the tree and the height of the vacant node to know how many levels we will have to propagate creating new nodes. Update mas_prealloc_calc() to consider the vacant height and reduce the number of worst-case allocations. Rebalancing and spanning stores are not supported and fall back to using the full height of the tree for allocations. Update preallocation testing assertions to take into account vacant height. Link: https://lkml.kernel.org/r/20250410191446.2474640-4-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-12maple_tree: use height and depth consistentlySidhartha Kumar1-0/+19
For the maple tree, the root node is defined to have a depth of 0 with a height of 1. Each level down from the node, these values are incremented by 1. Various code paths define a root with depth 1 which is inconsisent with the definition. Modify the code to be consistent with this definition. In mas_spanning_rebalance(), l_mas.depth was being used to track the height based on the number of iterations done in the main loop. This information was then used in mas_put_in_tree() to set the height. Rather than overload the l_mas.depth field to track height, simply keep track of height in the local variable new_height and directly pass this to mas_wmb_replace() which will be passed into mas_put_in_tree(). This allows up to remove writes to l_mas.depth. Link: https://lkml.kernel.org/r/20250410191446.2474640-3-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-07maple_tree: add some alloc node test caseJiazi Li1-0/+22
Add some maple_tree alloc node tese case. Link: https://lkml.kernel.org/r/20240626160631.3636515-2-Liam.Howlett@oracle.com Signed-off-by: Jiazi Li <jqqlijiazi@gmail.com> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-17maple_tree: add regression test for spanning store bugLorenzo Stoakes1-0/+84
Add a regression test to assert that, when performing a spanning store which consumes the entirety of the rightmost right leaf node does not result in maple tree corruption when doing so. This achieves this by building a test tree of 3 levels and establishing a store which ultimately results in a spanned store of this nature. Link: https://lkml.kernel.org/r/30cdc101a700d16e03ba2f9aa5d83f2efa894168.1728314403.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-17maple_tree: check for MA_STATE_BULK on setting wr_rebalanceSidhartha Kumar1-0/+26
It is possible for a bulk operation (MA_STATE_BULK is set) to enter the new_end < mt_min_slots[type] case and set wr_rebalance as a store type. This is incorrect as bulk stores do not rebalance per write, but rather after the all of the writes are done through the mas_bulk_rebalance() path. Therefore, add a check to make sure MA_STATE_BULK is not set before we return wr_rebalance as the store type. Also add a test to make sure wr_rebalance is never the store type when doing bulk operations via mas_expected_entries() This is a hotfix for this rc however it has no userspace effects as there are no users of the bulk insertion mode. Link: https://lkml.kernel.org/r/20241011214451.7286-1-sidhartha.kumar@oracle.com Fixes: 5d659bbb52a2 ("maple_tree: introduce mas_wr_store_type()") Suggested-by: Liam Howlett <liam.howlett@oracle.com> Signed-off-by: Sidhartha <sidhartha.kumar@oracle.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-25Merge tag 'memblock-v6.12-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock Pull memblock updates from Mike Rapoport: - new memblock_estimated_nr_free_pages() helper to replace totalram_pages() which is less accurate when CONFIG_DEFERRED_STRUCT_PAGE_INIT is set - fixes for memblock tests * tag 'memblock-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock: s390/mm: get estimated free pages by memblock api kernel/fork.c: get estimated free pages by memblock api mm/memblock: introduce a new helper memblock_estimated_nr_free_pages() memblock test: fix implicit declaration of function 'strscpy' memblock test: fix implicit declaration of function 'isspace' memblock test: fix implicit declaration of function 'memparse' memblock test: add the definition of __setup() memblock test: fix implicit declaration of function 'virt_to_phys' tools/testing: abstract two init.h into common include directory memblock tests: include export.h in linkage.h as kernel dose memblock tests: include memory_hotplug.h in mmzone.h as kernel dose
2024-09-02maple_tree: remove mas_destroy() from mas_nomem()Sidhartha Kumar1-4/+6
Separate call to mas_destroy() from mas_nomem() so we can check for no memory errors without destroying the current maple state in mas_store_gfp(). We then add calls to mas_destroy() to callers of mas_nomem(). Link: https://lkml.kernel.org/r/20240814161944.55347-6-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-02maple_tree: introduce mas_wr_store_type()Sidhartha Kumar1-0/+36
Introduce mas_wr_store_type() which will set the correct store type based on a walk of the tree. In mas_wr_node_store() the <= min_slots condition is changed to < as if new_end is = to mt_min_slots then there is not enough room. mas_prealloc_calc() is also introduced to abstract the calculation used to determine the number of nodes needed for a store operation. In this change a call to mas_reset() is removed in the error case of mas_prealloc(). This is only needed in the MA_STATE_REBALANCE case of mas_destroy(). We can move the call to mas_reset() directly to mas_destroy(). Also, add a test case to validate the order that we check the store type in is correct. This test models a vma expanding and then shrinking which is part of the boot process. Link: https://lkml.kernel.org/r/20240814161944.55347-5-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-02maple_tree: add test to replicate low memory race conditionsSidhartha Kumar1-0/+63
Add new callback fields to the userspace implementation of struct kmem_cache. This allows for executing callback functions in order to further test low memory scenarios where node allocation is retried. This callback can help test race conditions by calling a function when a low memory event is tested. Link: https://lkml.kernel.org/r/20240812190543.71967-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-06tools/testing: abstract two init.h into common include directoryWei Yang1-1/+1
Currently we have two test suits define its own init.h. This is a little redundant. Let's create a init.h in common include directory and merge these two into it. Signed-off-by: Wei Yang <richard.weiyang@gmail.com> CC: Mike Rapoport <rppt@kernel.org> CC: Liam R. Howlett <Liam.Howlett@oracle.com> Link: https://lore.kernel.org/r/20240712035138.24674-3-richard.weiyang@gmail.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2024-06-25tools/testing/radix-tree: add missing MODULE_DESCRIPTION definitionSidhartha Kumar1-0/+1
Userspace builds of the radix-tree testing suite fails because of commit test_maple_tree: add the missing MODULE_DESCRIPTION() macro. Add the proper defines to tools/testing/radix-tree/maple.c and tools/testing/radix-tree/xarray.c so MODULE_DESCRIPTION has a definition. This allows the build to succeed. Link: https://lkml.kernel.org/r/20240617195221.106565-1-sidhartha.kumar@oracle.com Fixes: 9f8090e8c4d1 ("test_maple_tree: add the missing MODULE_DESCRIPTION() macro") Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Jeff Johnson <quic_jjohnson@quicinc.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-21maple_tree: fix warning comparing pointer to 0Jiapeng Chong1-3/+3
Avoid pointer type value compared with 0 to make code clear. ./tools/testing/radix-tree/maple.c:34142:15-16: WARNING comparing pointer to 0. Link: https://lkml.kernel.org/r/20231208020450.7003-1-jiapeng.chong@linux.alibaba.com Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7696 Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-21sync mm-stable with mm-hotfixes-stable to pick up depended-upon changesAndrew Morton1-1/+1
2023-12-21maple_tree: do not preallocate nodes for slot storesSidhartha Kumar1-1/+1
mas_preallocate() defaults to requesting 1 node for preallocation and then ,depending on the type of store, will update the request variable. There isn't a check for a slot store type, so slot stores are preallocating the default 1 node. Slot stores do not require any additional nodes, so add a check for the slot store case that will bypass node_count_gfp(). Update the tests to reflect that slot stores do not require allocations. User visible effects of this bug include increased memory usage from the unneeded node that was allocated. Link: https://lkml.kernel.org/r/20231213205058.386589-1-sidhartha.kumar@oracle.com Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing") Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: <stable@vger.kernel.org> [6.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-12maple_tree: remove mas_searchable()Liam R. Howlett1-1/+3
Now that the status of the maple state is outside of the node, the mas_searchable() function can be dropped for easier open-coding of what is going on. Link: https://lkml.kernel.org/r/20231101171629.3612299-10-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-12maple_tree: separate ma_state node from statusLiam R. Howlett1-11/+15
The maple tree node is overloaded to keep status as well as the active node. This, unfortunately, results in a re-walk on underflow or overflow. Since the maple state has room, the status can be placed in its own enum in the structure. Once an underflow/overflow is detected, certain modes can restore the status to active and others may need to re-walk just that one node to see the entry. The status being an enum has the benefit of detecting unhandled status in switch statements. [Liam.Howlett@oracle.com: fix comments about MAS_*] Link: https://lkml.kernel.org/r/20231106154124.614247-1-Liam.Howlett@oracle.com [Liam.Howlett@oracle.com: update forking to separate maple state and node] Link: https://lkml.kernel.org/r/20231106154551.615042-1-Liam.Howlett@oracle.com [Liam.Howlett@oracle.com: fix mas_prev() state separation code] Link: https://lkml.kernel.org/r/20231207193319.4025462-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20231101171629.3612299-9-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-12maple_tree: add end of node tracking to the maple stateLiam R. Howlett1-0/+1
Analysis of the mas_for_each() iteration showed that there is a significant time spent finding the end of a node. This time can be greatly reduced if the end of the node is cached in the maple state. Care must be taken to update & invalidate as necessary. Link: https://lkml.kernel.org/r/20231101171629.3612299-5-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-11maple_tree: skip other tests when BENCH is enabledPeng Zhang1-0/+2
Skip other tests when BENCH is enabled so that performance can be measured in user space. Link: https://lkml.kernel.org/r/20231027033845.90608-8-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Mike Christie <michael.christie@oracle.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-11maple_tree: add test for mtree_dup()Peng Zhang1-0/+361
Add test for mtree_dup(). Test by duplicating different maple trees and then comparing the two trees. Includes tests for duplicating full trees and memory allocation failures on different nodes. Link: https://lkml.kernel.org/r/20231027033845.90608-6-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Mike Christie <michael.christie@oracle.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-18maple_tree: update mas_preallocate() testingLiam R. Howlett1-11/+16
Since the mas_preallocate() calculation has been updated to be more precise, the testing must also be updated to check for what is expected. Link: https://lkml.kernel.org/r/20230724183157.3939892-13-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-18maple_tree: re-introduce entry to mas_preallocate() argumentsLiam R. Howlett1-16/+16
The current preallocation strategy is to preallocate the absolute worst-case allocation for a tree modification. The entry (or NULL) is needed to know how many nodes are needed to write to the tree. Start by adding the argument to the mas_preallocate() definition. Link: https://lkml.kernel.org/r/20230724183157.3939892-8-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-18maple_tree: add test for expanding range in RCU modePeng Zhang1-0/+75
Add test for expanding range in RCU mode. If we use the fast path of the slot store to expand range in RCU mode, this test will fail. Link: https://lkml.kernel.org/r/20230628073657.75314-3-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-07-17maple_tree: fix node allocation testing on 32 bitLiam R. Howlett1-3/+3
Internal node counting was altered and the 64 bit test was updated, however the 32bit test was missed. Restore the 32bit test to a functional state. Link: https://lore.kernel.org/linux-mm/CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg53zZX_DnA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20230712173916.168805-2-Liam.Howlett@oracle.com Fixes: 541e06b772c1 ("maple_tree: remove GFP_ZERO from kmem_cache_alloc() and kmem_cache_alloc_bulk()") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-10maple_tree: add __init and __exit to test moduleLiam R. Howlett1-73/+74
The test functions are not needed after the module is removed, so mark them as such. Add __exit to the module removal function. Some other variables have been marked as const static as well. Link: https://lkml.kernel.org/r/20230518145544.1722059-20-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-10maple_tree: make test code work without debug enabledLiam R. Howlett1-1/+0
The test code is less useful without debug, but can still do general validations. Define mt_dump(), mas_dump() and mas_wr_dump() as a noop if debug is not enabled and document it in the test module information that more information can be obtained with another kernel config option. MT_BUG_ON() will report a failures without tree dumps, and the output will be less useful. Link: https://lkml.kernel.org/r/20230518145544.1722059-17-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-10maple_tree: add format option to mt_dump()Liam R. Howlett1-6/+6
Allow different formatting strings to be used when dumping the tree. Currently supports hex and decimal. Link: https://lkml.kernel.org/r/20230518145544.1722059-6-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-10maple_tree: avoid unnecessary ascendingLiam R. Howlett1-0/+4
The maple tree node limits are implied by the parent. When walking up the tree, the limit may not be known until a slot that does not have implied limits are encountered. However, if the node is the left-most or right-most node, the walking up to find that limit can be skipped. This commit also fixes the debug/testing code that was not setting the limit on walking down the tree as that optimization is not compatible with this change. Link: https://lkml.kernel.org/r/20230518145544.1722059-4-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-19maple_tree: add a test case to check maple_allocPeng Zhang1-0/+24
Add a test case to check whether the number of maple_alloc structures is actually equal to mas->alloc->total. Link: https://lkml.kernel.org/r/20230411041005.26205-2-zhangpeng.00@bytedance.com Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-06maple_tree: fix write memory barrier of nodes once dead for RCU modeLiam R. Howlett1-0/+16
During the development of the maple tree, the strategy of freeing multiple nodes changed and, in the process, the pivots were reused to store pointers to dead nodes. To ensure the readers see accurate pivots, the writers need to mark the nodes as dead and call smp_wmb() to ensure any readers can identify the node as dead before using the pivot values. There were two places where the old method of marking the node as dead without smp_wmb() were being used, which resulted in RCU readers seeing the wrong pivot value before seeing the node was dead. Fix this race condition by using mte_set_node_dead() which has the smp_wmb() call to ensure the race is closed. Add a WARN_ON() to the ma_free_rcu() call to ensure all nodes being freed are marked as dead to ensure there are no other call paths besides the two updated paths. This is necessary for the RCU mode of the maple tree. Link: https://lkml.kernel.org/r/20230227173632.3292573-6-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-02-03maple_tree: remove the parameter entry of mas_preallocateVernon Yang1-16/+16
The parameter entry of mas_preallocate is not used, so drop it. Link: https://lkml.kernel.org/r/20230110154211.1758562-1-vernon2gm@gmail.com Signed-off-by: Vernon Yang <vernon2gm@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-01-19maple_tree: remove GFP_ZERO from kmem_cache_alloc() and kmem_cache_alloc_bulk()Liam Howlett1-9/+9
Preallocations are common in the VMA code to avoid allocating under certain locking conditions. The preallocations must also cover the worst-case scenario. Removing the GFP_ZERO flag from the kmem_cache_alloc() (and bulk variant) calls will reduce the amount of time spent zeroing memory that may not be used. Only zero out the necessary area to keep track of the allocations in the maple state. Zero the entire node prior to using it in the tree. This required internal changes to node counting on allocation, so the test code is also updated. This restores some micro-benchmark performance: up to +9% in mmtests mmap1 by my testing +10% to +20% in mmap, mmapaddr, mmapmany tests reported by Red Hat Link: https://bugzilla.redhat.com/show_bug.cgi?id=2149636 Link: https://lkml.kernel.org/r/20230105160427.2988454-1-Liam.Howlett@oracle.com Signed-off-by: Liam Howlett <Liam.Howlett@oracle.com> Reported-by: Jirka Hladky <jhladky@redhat.com> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-16maple_tree: update copyright dates for test codeLiam Howlett1-2/+3
Add the span to the year of the development. Link: https://lkml.kernel.org/r/20221025173709.2718725-1-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-09maple_tree: reorganize testing to restore module testingLiam Howlett1-0/+35770
Along the development cycle, the testing code support for module/in-kernel compiles was removed. Restore this functionality by moving any internal API tests to the userspace side, as well as threading tests. Fix the lockdep issues and add a way to reduce memory usage so the tests can complete with KASAN + memleak detection. Make the tests work on 32 bit hosts where possible and detect 32 bit hosts in the radix test suite. [akpm@linux-foundation.org: fix module export] [akpm@linux-foundation.org: fix it some more] [liam.howlett@oracle.com: fix compile warnings on 32bit build in check_find()] Link: https://lkml.kernel.org/r/20221107203816.1260327-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20221028180415.3074673-1-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27Maple Tree: add new data structureLiam R. Howlett1-0/+59
Patch series "Introducing the Maple Tree" The maple tree is an RCU-safe range based B-tree designed to use modern processor cache efficiently. There are a number of places in the kernel that a non-overlapping range-based tree would be beneficial, especially one with a simple interface. If you use an rbtree with other data structures to improve performance or an interval tree to track non-overlapping ranges, then this is for you. The tree has a branching factor of 10 for non-leaf nodes and 16 for leaf nodes. With the increased branching factor, it is significantly shorter than the rbtree so it has fewer cache misses. The removal of the linked list between subsequent entries also reduces the cache misses and the need to pull in the previous and next VMA during many tree alterations. The first user that is covered in this patch set is the vm_area_struct, where three data structures are replaced by the maple tree: the augmented rbtree, the vma cache, and the linked list of VMAs in the mm_struct. The long term goal is to reduce or remove the mmap_lock contention. The plan is to get to the point where we use the maple tree in RCU mode. Readers will not block for writers. A single write operation will be allowed at a time. A reader re-walks if stale data is encountered. VMAs would be RCU enabled and this mode would be entered once multiple tasks are using the mm_struct. Davidlor said : Yes I like the maple tree, and at this stage I don't think we can ask for : more from this series wrt the MM - albeit there seems to still be some : folks reporting breakage. Fundamentally I see Liam's work to (re)move : complexity out of the MM (not to say that the actual maple tree is not : complex) by consolidating the three complimentary data structures very : much worth it considering performance does not take a hit. This was very : much a turn off with the range locking approach, which worst case scenario : incurred in prohibitive overhead. Also as Liam and Matthew have : mentioned, RCU opens up a lot of nice performance opportunities, and in : addition academia[1] has shown outstanding scalability of address spaces : with the foundation of replacing the locked rbtree with RCU aware trees. A similar work has been discovered in the academic press https://pdos.csail.mit.edu/papers/rcuvm:asplos12.pdf Sheer coincidence. We designed our tree with the intention of solving the hardest problem first. Upon settling on a b-tree variant and a rough outline, we researched ranged based b-trees and RCU b-trees and did find that article. So it was nice to find reassurances that we were on the right path, but our design choice of using ranges made that paper unusable for us. This patch (of 70): The maple tree is an RCU-safe range based B-tree designed to use modern processor cache efficiently. There are a number of places in the kernel that a non-overlapping range-based tree would be beneficial, especially one with a simple interface. If you use an rbtree with other data structures to improve performance or an interval tree to track non-overlapping ranges, then this is for you. The tree has a branching factor of 10 for non-leaf nodes and 16 for leaf nodes. With the increased branching factor, it is significantly shorter than the rbtree so it has fewer cache misses. The removal of the linked list between subsequent entries also reduces the cache misses and the need to pull in the previous and next VMA during many tree alterations. The first user that is covered in this patch set is the vm_area_struct, where three data structures are replaced by the maple tree: the augmented rbtree, the vma cache, and the linked list of VMAs in the mm_struct. The long term goal is to reduce or remove the mmap_lock contention. The plan is to get to the point where we use the maple tree in RCU mode. Readers will not block for writers. A single write operation will be allowed at a time. A reader re-walks if stale data is encountered. VMAs would be RCU enabled and this mode would be entered once multiple tasks are using the mm_struct. There is additional BUG_ON() calls added within the tree, most of which are in debug code. These will be replaced with a WARN_ON() call in the future. There is also additional BUG_ON() calls within the code which will also be reduced in number at a later date. These exist to catch things such as out-of-range accesses which would crash anyways. Link: https://lkml.kernel.org/r/20220906194824.2110408-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20220906194824.2110408-2-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>