kernel/linux.git/tools/testing/radix-tree/linux, branch v6.6.131

maple_tree: add init and exit to test module

2023-06-09T23:25:31+00:00

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 Suggested-by: Andrew Morton Cc: David Binderman Cc: Peng Zhang Cc: Sergey Senozhatsky Cc: Vernon Yang Cc: Wei Yang Signed-off-by: Andrew Morton

radix tree test suite: add lockdep_is_held to header

2022-09-27T02:46:14+00:00

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 pr_err define

2022-09-27T02:46:13+00:00

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

2022-09-27T02:46:13+00:00

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

2022-02-20T06:44:37+00:00

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

tools: Fix math.h breakage

2021-11-30T17:14:42+00:00

Commit 98e1385ef24b ("include/linux/radix-tree.h: replace kernel.h with the necessary inclusions") broke the radix tree test suite in two different ways; first by including math.h which didn't exist in the tools directory, and second by removing an implicit include of spinlock.h before lockdep.h. Fix both issues. Cc: Andy Shevchenko Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Andy Shevchenko Signed-off-by: Linus Torvalds

radix tree test suite: Fix compilation

2021-03-30T17:44:35+00:00

Commit 4bba4c4bb09a added tools/include/linux/compiler_types.h which includes linux/compiler-gcc.h. Unfortunately, we had our own (empty) compiler_types.h which overrode the one added by that commit, and so we lost the definition of __must_be_array(). Removing our empty compiler_types.h fixes the problem and reduces our divergence from the rest of the tools. Signed-off-by: Matthew Wilcox (Oracle)

radix tree test suite: Fix compilation

2020-10-07T13:07:49+00:00

Introducing local_lock broke compilation; fix it all up. Signed-off-by: Matthew Wilcox (Oracle)

radix tree test suite: Support kmem_cache alignment

2020-02-27T17:25:47+00:00

The radix tree doesn't use alignment, so the argument was ignored. The maple tree needs its nodes to be aligned, so we need to pay attention to the alignment argument. Also change the types of 'size' and 'align' to unsigned int to match commit f4957d5bd0916. Signed-off-by: Matthew Wilcox (Oracle)

rcu: Don't return a value from rcu_assign_pointer()

2019-06-13T22:38:34+00:00

Quoting Paul [1]: "Given that a quick (and perhaps error-prone) search of the uses of rcu_assign_pointer() in v5.1 didn't find a single use of the return value, let's please instead change the documentation and implementation to eliminate the return value." [1] https://lkml.kernel.org/r/20190523135013.GL28207@linux.ibm.com Signed-off-by: Andrea Parri Cc: "Paul E. McKenney" Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes Cc: rcu@vger.kernel.org Cc: Peter Zijlstra Cc: Will Deacon Cc: Mark Rutland Cc: Matthew Wilcox Cc: Sasha Levin Signed-off-by: Paul E. McKenney

kernel/linux.git/tools/testing/radix-tree/linux, branch v6.6.131

maple_tree: add __init and __exit to test module

radix tree test suite: add lockdep_is_held to header

radix tree test suite: add pr_err define

Maple Tree: add new data structure

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

tools: Fix math.h breakage

radix tree test suite: Fix compilation

radix tree test suite: Fix compilation

radix tree test suite: Support kmem_cache alignment

rcu: Don't return a value from rcu_assign_pointer()

maple_tree: add init and exit to test module