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2022-11-08maple_tree: reorganize testing to restore module testingLiam Howlett5-4/+35792
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>
2022-09-26lib/test_maple_tree: add testing for maple treeLiam R. Howlett1-2/+7
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 <Liam.Howlett@oracle.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26radix tree test suite: add lockdep_is_held to headerLiam R. Howlett1-0/+2
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 <Liam.Howlett@oracle.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26radix tree test suite: add support for slab bulk APIsLiam R. Howlett1-2/+116
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 <Liam.Howlett@Oracle.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26radix tree test suite: add allocation counts and size to kmem_cacheLiam R. Howlett1-1/+27
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 <Liam.Howlett@Oracle.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26radix tree test suite: add kmem_cache_set_non_kernel()Liam R. Howlett1-2/+14
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 <Liam.Howlett@Oracle.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26radix tree test suite: add pr_err defineLiam R. Howlett1-0/+1
define pr_err to printk Link: https://lkml.kernel.org/r/20220906194824.2110408-3-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26Maple Tree: add new data structureLiam R. Howlett5-0/+74
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>
2022-04-22tools: Add kmem_cache_alloc_lru()Matthew Wilcox (Oracle)1-1/+2
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) <willy@infradead.org> Reported-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Li Wang <liwang@redhat.com>
2022-02-20tools: Move gfp.h and slab.h from radix-tree to libKarolina Drobnik4-88/+2
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 <karolinadrobnik@gmail.com> Signed-off-by: Mike Rapoport <rppt@kernel.org> Link: https://lore.kernel.org/r/b76ddb8a12fdf9870b55c1401213e44f5e0d0da3.1643796665.git.karolinadrobnik@gmail.com
2021-11-30tools: Fix math.h breakageMatthew Wilcox (Oracle)1-0/+3
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 <andriy.shevchenko@linux.intel.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-01idr test suite: Improve reporting from idr_find_test_1Matthew Wilcox (Oracle)1-1/+10
Instead of just reporting an assertion failure, report enough information that we can start diagnosing exactly went wrong. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2021-04-01idr test suite: Create anchor before launching throbberMatthew Wilcox (Oracle)1-2/+2
The throbber could race with creation of the anchor entry and cause the IDR to have zero entries in it, which would cause the test to fail. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2021-04-01idr test suite: Take RCU read lock in idr_find_test_1Matthew Wilcox (Oracle)1-0/+4
When run on a single CPU, this test would frequently access already-freed memory. Due to timing, this bug never showed up on multi-CPU tests. Reported-by: Chris von Recklinghausen <crecklin@redhat.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2021-04-01radix tree test suite: Register the main thread with the RCU libraryMatthew Wilcox (Oracle)3-0/+6
Several test runners register individual worker threads with the RCU library, but neglect to register the main thread, which can lead to objects being freed while the main thread is in what appears to be an RCU critical section. Reported-by: Chris von Recklinghausen <crecklin@redhat.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2021-03-30radix tree test suite: Fix compilationMatthew Wilcox (Oracle)1-0/+0
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) <willy@infradead.org>
2020-10-07ida: Free allocated bitmap in error pathMatthew Wilcox (Oracle)1-0/+29
If a bitmap needs to be allocated, and then by the time the thread is scheduled to be run again all the indices which would satisfy the allocation have been allocated then we would leak the allocation. Almost impossible to hit in practice, but a trivial fix. Found by Coverity. Fixes: f32f004cddf8 ("ida: Convert to XArray") Reported-by: coverity-bot <keescook+coverity-bot@chromium.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-10-07radix tree test suite: Fix compilationMatthew Wilcox (Oracle)3-4/+9
Introducing local_lock broke compilation; fix it all up. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-04-03Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdxLinus Torvalds1-0/+1
Pull SPDX updates from Greg KH: "Here are three SPDX patches for 5.7-rc1. One fixes up the SPDX tag for a single driver, while the other two go through the tree and add SPDX tags for all of the .gitignore files as needed. Nothing too complex, but you will get a merge conflict with your current tree, that should be trivial to handle (one file modified by two things, one file deleted.) All three of these have been in linux-next for a while, with no reported issues other than the merge conflict" * tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: ASoC: MT6660: make spdxcheck.py happy .gitignore: add SPDX License Identifier .gitignore: remove too obvious comments
2020-03-25.gitignore: add SPDX License IdentifierMasahiro Yamada1-0/+1
Add SPDX License Identifier to all .gitignore files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-12xarray: Fix early termination of xas_for_each_markedMatthew Wilcox (Oracle)4-2/+91
xas_for_each_marked() is using entry == NULL as a termination condition of the iteration. When xas_for_each_marked() is used protected only by RCU, this can however race with xas_store(xas, NULL) in the following way: TASK1 TASK2 page_cache_delete() find_get_pages_range_tag() xas_for_each_marked() xas_find_marked() off = xas_find_chunk() xas_store(&xas, NULL) xas_init_marks(&xas); ... rcu_assign_pointer(*slot, NULL); entry = xa_entry(off); And thus xas_for_each_marked() terminates prematurely possibly leading to missed entries in the iteration (translating to missing writeback of some pages or a similar problem). If we find a NULL entry that has been marked, skip it (unless we're trying to allocate an entry). Reported-by: Jan Kara <jack@suse.cz> CC: stable@vger.kernel.org Fixes: ef8e5717db01 ("page cache: Convert delete_batch to XArray") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-02-27radix tree test suite: Support kmem_cache alignmentMatthew Wilcox (Oracle)2-15/+23
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) <willy@infradead.org>
2019-07-08Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-1/+1
Pull RCU updates from Ingo Molnar: "The changes in this cycle are: - RCU flavor consolidation cleanups and optmizations - Documentation updates - Miscellaneous fixes - SRCU updates - RCU-sync flavor consolidation - Torture-test updates - Linux-kernel memory-consistency-model updates, most notably the addition of plain C-language accesses" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits) tools/memory-model: Improve data-race detection tools/memory-model: Change definition of rcu-fence tools/memory-model: Expand definition of barrier tools/memory-model: Do not use "herd" to refer to "herd7" tools/memory-model: Fix comment in MP+poonceonces.litmus Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic() rcu: Don't return a value from rcu_assign_pointer() rcu: Force inlining of rcu_read_lock() rcu: Fix irritating whitespace error in rcu_assign_pointer() rcu: Upgrade sync_exp_work_done() to smp_mb() rcutorture: Upper case solves the case of the vanishing NULL pointer torture: Suppress propagating trace_printk() warning rcutorture: Dump trace buffer for callback pipe drain failures torture: Add --trust-make to suppress "make clean" torture: Make --cpus override idleness calculations torture: Run kernel build in source directory torture: Add function graph-tracing cheat sheet torture: Capture qemu output rcutorture: Tweak kvm options rcutorture: Add trivial RCU implementation ...
2019-06-29Merge tag 'xarray-5.2-rc6' of git://git.infradead.org/users/willy/linux-daxLinus Torvalds1-0/+46
Pull XArray fixes from Matthew Wilcox: - Account XArray nodes for the page cache to the appropriate cgroup (Johannes Weiner) - Fix idr_get_next() when called under the RCU lock (Matthew Wilcox) - Add a test for xa_insert() (Matthew Wilcox) * tag 'xarray-5.2-rc6' of git://git.infradead.org/users/willy/linux-dax: XArray tests: Add check_insert idr: Fix idr_get_next race with idr_remove mm: fix page cache convergence regression
2019-06-28Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcuIngo Molnar1-1/+1
Pull rcu/next + tools/memory-model changes from Paul E. McKenney: - RCU flavor consolidation cleanups and optmizations - Documentation updates - Miscellaneous fixes - SRCU updates - RCU-sync flavor consolidation - Torture-test updates - Linux-kernel memory-consistency-model updates, most notably the addition of plain C-language accesses Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-13rcu: Don't return a value from rcu_assign_pointer()Andrea Parri1-1/+1
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 <andrea.parri@amarulasolutions.com> Cc: "Paul E. McKenney" <paulmck@linux.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: rcu@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sasha Levin <sashal@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288Thomas Gleixner4-36/+4
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 263 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-02idr: Fix idr_get_next race with idr_removeMatthew Wilcox (Oracle)1-0/+46
If the entry is deleted from the IDR between the call to radix_tree_iter_find() and rcu_dereference_raw(), idr_get_next() will return NULL, which will end the iteration prematurely. We should instead continue to the next entry in the IDR. This only happens if the iteration is protected by the RCU lock. Most IDR users use a spinlock or semaphore to exclude simultaneous modifications. It was noticed once the PID allocator was converted to use the IDR, as it uses the RCU lock, but there may be other users elsewhere in the kernel. We can't use the normal pattern of calling radix_tree_deref_retry() (which catches both a retry entry in a leaf node and a node entry in the root) as the IDR supports storing entries which are unaligned, which will trigger an infinite loop if they are encountered. Instead, we have to explicitly check whether the entry is a retry entry. Fixes: 0a835c4f090a ("Reimplement IDR and IDA using the radix tree") Reported-by: Brendan Gregg <bgregg@netflix.com> Tested-by: Brendan Gregg <bgregg@netflix.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2018-12-06radix tree: Don't return retry entries from lookupMatthew Wilcox4-0/+82
Commit 66ee620f06f9 ("idr: Permit any valid kernel pointer to be stored") changed the radix tree lookup so that it stops when reaching the bottom of the tree. However, the condition was added in the wrong place, making it possible to return retry entries to the caller. Reorder the tests to check for the retry entry before checking whether we're at the bottom of the tree. The retry entry should never be found in the tree root, so it's safe to defer the check until the end of the loop. Add a regression test to the test-suite to be sure this doesn't come back. Fixes: 66ee620f06f9 ("idr: Permit any valid kernel pointer to be stored") Reported-by: Greg Kurz <groug@kaod.org> Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree: Remove multiorder supportMatthew Wilcox1-1/+0
All users have now been converted to the XArray. Removing the support reduces code size and ensures new users will use the XArray instead. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree test: Convert multiorder tests to XArrayMatthew Wilcox1-56/+49
This is the last remaining user of the multiorder functionality of the radix tree. Test the XArray instead. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree tests: Convert item_delete_rcu to XArrayMatthew Wilcox2-3/+3
In preparation for the removal of the multiorder radix tree code, convert item_delete_rcu() to use the XArray so it can still be called for XArrays containing multi-index entries. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree tests: Convert item_kill_tree to XArrayMatthew Wilcox1-21/+9
In preparation for the removal of the multiorder radix tree code, convert item_kill_tree() to use the XArray so it can still be called for XArrays containing multi-index entries. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree tests: Move item_insert_orderMatthew Wilcox3-11/+22
The remaining tests are not suitable for moving in-kernel, so move item_insert_order() into multiorder.c, make it static and make it use the XArray. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree test suite: Remove multiorder benchmarkingMatthew Wilcox1-29/+21
The multiorder radix tree code is being removed, so remove the benchmarking of its performance. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree test suite: Remove __item_insertMatthew Wilcox2-7/+1
Inline it into its one caller Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21xarray: Move multiorder_check to in-kernel testsMatthew Wilcox1-48/+0
This version is a little less thorough in order to be a little quicker, but tests the important edge cases. Also test adding a multiorder entry at a non-canonical index, and erasing it. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21xarray: Move multiorder_shrink to kernel testsMatthew Wilcox1-173/+0
Test this functionality inside the kernel as well as in userspace. Also remove insert_bug() as there's no comparable thing to test in the XArray code. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21xarray: Move multiorder account test in-kernelMatthew Wilcox1-24/+0
Move this test to the in-kernel test suite, and enhance it to test several different orders. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree test suite: Convert iteration test to XArrayMatthew Wilcox3-58/+63
With no code left in the kernel using the multiorder radix tree, convert the iteration test from the radix tree to the XArray. It's unlikely to suffer the same bug as the radix tree, but this test will prevent that bug from ever creeping into the XArray implementation. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree test suite: Convert tag_tagged_items to XArrayMatthew Wilcox8-57/+46
The tag_tagged_items() function is supposed to test the page-writeback tagging code. Since that has been converted to the XArray, there's not much point in testing the radix tree's tagging code. This requires using the pthread mutex embedded in the xarray instead of an external lock, so remove the pthread mutexes which protect xarrays/radix trees. Also remove radix_tree_iter_tag_set() as this was the last user. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree: Remove radix_tree_clear_tagsMatthew Wilcox1-29/+0
The page cache was the only user of this interface and it has now been converted to the XArray. Transform the test into a test of xas_init_marks(). Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree: Remove split/join codeMatthew Wilcox2-338/+0
radix_tree_split and radix_tree_join were never used upstream. Remove them; if they're needed in future they will be replaced by XArray equivalents. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree: Remove radix_tree_update_node_tMatthew Wilcox1-1/+1
The only user of this functionality was the workingset code, and it's now been converted to the XArray. Remove __radix_tree_delete_node() entirely as it was also only used by the workingset code. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21shmem: Convert find_swap_entry to XArrayMatthew Wilcox3-84/+0
This is a 1:1 conversion. The major part of this patch is converting the test framework from userspace to kernel space and mirroring the algorithm now used in find_swap_entry(). Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21radix tree test suite: Convert regression1 to XArrayMatthew Wilcox1-39/+19
Now the page cache lookup is using the XArray, let's convert this regression test from the radix tree API to the XArray so it's testing roughly the same thing it was testing before. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21page cache: Convert find_get_pages_contig to XArrayMatthew Wilcox1-23/+0
There's no direct replacement for radix_tree_for_each_contig() in the XArray API as it's an unusual thing to do. Instead, open-code a loop using xas_next(). This removes the only user of radix_tree_for_each_contig() so delete the iterator from the API and the test suite code for it. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21ida: Convert to XArrayMatthew Wilcox1-5/+3
Use the XA_TRACK_FREE ability to track which entries have a free bit, similarly to how it uses the radix tree's IDR_FREE tag. This eliminates the per-cpu ida_bitmap preload, and fixes the memory consumption regression I introduced when making the IDR able to store any pointer. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21xarray: Add XArray unconditional store operationsMatthew Wilcox4-1/+39
xa_store() differs from radix_tree_insert() in that it will overwrite an existing element in the array rather than returning an error. This is the behaviour which most users want, and those that want more complex behaviour generally want to use the xas family of routines anyway. For memory allocation, xa_store() will first attempt to request memory from the slab allocator; if memory is not immediately available, it will drop the xa_lock and allocate memory, keeping a pointer in the xa_state. It does not use the per-CPU cache, although those will continue to exist until all radix tree users are converted to the xarray. This patch also includes xa_erase() and __xa_erase() for a streamlined way to store NULL. Since there is no need to allocate memory in order to store a NULL in the XArray, we do not need to trouble the user with deciding what memory allocation flags to use. Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21xarray: Add XArray load operationMatthew Wilcox7-2/+38
The xa_load function brings with it a lot of infrastructure; xa_empty(), xa_is_err(), and large chunks of the XArray advanced API that are used to implement xa_load. As the test-suite demonstrates, it is possible to use the XArray functions on a radix tree. The radix tree functions depend on the GFP flags being stored in the root of the tree, so it's not possible to use the radix tree functions on an XArray. Signed-off-by: Matthew Wilcox <willy@infradead.org>