linux-dev/tools/testing/radix-tree, branch master

maple_tree: reorganize testing to restore module testing

2022-11-08T23:57:22Z

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 Signed-off-by: Andrew Morton

lib/test_maple_tree: add testing for maple tree

2022-09-27T02:46:14Z

This is a test suite that uses the radix test infrastructure. It has been split into its own commit to allow for easier review of the maple tree code. The testing includes: - Allocation of nodes - gfp flag allocation checks - Expansion & contraction of tree - preallocation checks - tree navigation by next/prev - tree navigation by iterators (mas_for_each, etc) - Number of nodes for a given number of entries - Generic tree construction tests - Addition and removal of entries in forward and reverse numerical indexes - gap searching both forward and reverse - Combining gaps by overwriting entries in different ways - splitting right-most node - splitting left-most node - overwriting multiple slots - overwriting across different levels of the tree - overwriting the middle of a tree - causing a 3-way split up to the root by overwriting the last slot and first slot of different nodes and spanning different levels - RCU stress testing of the tree with threads - Duplication of the tree by entry count - Tests which were generated by fuzzers have been added. - A large number of tests which come from recording crashing in a VM and reconstructing the tree (see check_erase2_set()) Link: https://lkml.kernel.org/r/20220906194824.2110408-8-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

radix tree test suite: add lockdep_is_held to header

2022-09-27T02:46:14Z

maple tree uses lockdep_is_held, so define it as external in the header. Link: https://lkml.kernel.org/r/20220906194824.2110408-7-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

radix tree test suite: add support for slab bulk APIs

2022-09-27T02:46:14Z

Add support for kmem_cache_free_bulk() and kmem_cache_alloc_bulk() to the radix tree test suite. Link: https://lkml.kernel.org/r/20220906194824.2110408-6-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

radix tree test suite: add allocation counts and size to kmem_cache

2022-09-27T02:46:14Z

Add functions to get the number of allocations, and total allocations from a kmem_cache. Also add a function to get the allocated size and a way to zero the total allocations. Link: https://lkml.kernel.org/r/20220906194824.2110408-5-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

radix tree test suite: add kmem_cache_set_non_kernel()

2022-09-27T02:46:13Z

kmem_cache_set_non_kernel() is a mechanism to allow a certain number of kmem_cache_alloc requests to succeed even when GFP_KERNEL is not set in the flags. This functionality allows for testing different paths though the code. Link: https://lkml.kernel.org/r/20220906194824.2110408-4-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Matthew Wilcox (Oracle) Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

radix tree test suite: add pr_err define

2022-09-27T02:46:13Z

define pr_err to printk Link: https://lkml.kernel.org/r/20220906194824.2110408-3-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

Maple Tree: add new data structure

2022-09-27T02:46:13Z

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 Signed-off-by: Matthew Wilcox (Oracle) Tested-by: David Howells Tested-by: Sven Schnelle Tested-by: Yu Zhao Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Catalin Marinas Cc: SeongJae Park Cc: Will Deacon Signed-off-by: Andrew Morton

tools: Add kmem_cache_alloc_lru()

2022-04-22T18:24:28Z

Turn kmem_cache_alloc() into a wrapper around kmem_cache_alloc_lru(). Fixes: 9bbdc0f32409 ("xarray: use kmem_cache_alloc_lru to allocate xa_node") Signed-off-by: Matthew Wilcox (Oracle) Reported-by: Liam R. Howlett Reported-by: Li Wang

tools: Move gfp.h and slab.h from radix-tree to lib

2022-02-20T06:44:37Z

Merge radix-tree definitions from gfp.h and slab.h with these in tools/lib, so they can be used in other test suites. Fix style issues in slab.h. Update radix-tree test files. Signed-off-by: Karolina Drobnik Signed-off-by: Mike Rapoport Link: https://lore.kernel.org/r/b76ddb8a12fdf9870b55c1401213e44f5e0d0da3.1643796665.git.karolinadrobnik@gmail.com