kernel.git/tools/testing/radix-tree/main.c, branch linux-4.11.y

ida: Free correct IDA bitmap

2017-03-07T18:18:23Z

There's a relatively rare race where we look at the per-cpu preallocated IDA bitmap, see it's NULL, allocate a new one, and atomically update it. If the kmalloc() happened to sleep and we were rescheduled to a different CPU, or an interrupt came in at the exact right time, another task might have successfully allocated a bitmap and already deposited it. I forgot what the semantics of cmpxchg() were and ended up freeing the wrong bitmap leading to KASAN reporting a use-after-free. Dmitry found the bug with syzkaller & wrote the patch. I wrote the test case that will reproduce the bug without his patch being applied. Reported-by: Dmitry Vyukov Signed-off-by: Matthew Wilcox

radix tree test suite: Run iteration tests for longer

2017-02-14T02:44:08Z

If the -l flag is set, run the tests for 100 seconds each instead of the normal 10 seconds. Signed-off-by: Matthew Wilcox Reviewed-by: Rehas Sachdeva

radix tree test suite: Dial down verbosity with -v

2017-02-14T02:44:04Z

Make the output of radix tree test suite less verbose by default and add -v and -vv command line options for increasing level of verbosity. Signed-off-by: Rehas Sachdeva Signed-off-by: Matthew Wilcox

Reimplement IDR and IDA using the radix tree

2017-02-14T02:44:01Z

The IDR is very similar to the radix tree. It has some functionality that the radix tree did not have (alloc next free, cyclic allocation, a callback-based for_each, destroy tree), which is readily implementable on top of the radix tree. A few small changes were needed in order to use a tag to represent nodes with free space below them. More extensive changes were needed to support storing NULL as a valid entry in an IDR. Plain radix trees still interpret NULL as a not-present entry. The IDA is reimplemented as a client of the newly enhanced radix tree. As in the current implementation, it uses a bitmap at the last level of the tree. Signed-off-by: Matthew Wilcox Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Tejun Heo Signed-off-by: Andrew Morton

radix tree test suite: check multiorder iteration

2016-12-15T00:04:10Z

The random iteration test only inserts order-0 entries currently. Update it to insert entries of order between 7 and 0. Also make the maximum index configurable, make some variables static, make the test duration variable, remove some useless spinning, and add a fifth thread which calls tag_tagged_items(). Link: http://lkml.kernel.org/r/1480369871-5271-62-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

radix-tree: delete radix_tree_range_tag_if_tagged()

2016-12-15T00:04:10Z

This is an exceptionally complicated function with just one caller (tag_pages_for_writeback). We devote a large portion of the runtime of the test suite to testing this one function which has one caller. By introducing the new function radix_tree_iter_tag_set(), we can eliminate all of the complexity while keeping the performance. The caller can now use a fairly standard radix_tree_for_each() loop, and it doesn't need to worry about tricksy things like 'start' wrapping. The test suite continues to spend a large amount of time investigating this function, but now it's testing the underlying primitives such as radix_tree_iter_resume() and the radix_tree_for_each_tagged() iterator which are also used by other parts of the kernel. Link: http://lkml.kernel.org/r/1480369871-5271-57-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

radix-tree: delete radix_tree_locate_item()

2016-12-15T00:04:10Z

This rather complicated function can be better implemented as an iterator. It has only one caller, so move the functionality to the only place that needs it. Update the test suite to follow the same pattern. Link: http://lkml.kernel.org/r/1480369871-5271-56-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Acked-by: Konstantin Khlebnikov Tested-by: Kirill A. Shutemov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

radix tree test suite: use rcu_barrier

2016-12-15T00:04:09Z

Calling rcu_barrier() allows all of the rcu-freed memory to be actually returned to the pool, and allows nr_allocated to return to 0. As well as allowing diffs between runs to be more useful, it also lets us pinpoint leaks more effectively. Link: http://lkml.kernel.org/r/1480369871-5271-44-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

radix tree test suite: benchmark for iterator

2016-12-15T00:04:09Z

This adds simple benchmark for iterator similar to one I've used for commit 78c1d78488a3 ("radix-tree: introduce bit-optimized iterator") Building with make BENCHMARK=1 set radix tree order to 6, this allows to get performance comparable to in kernel performance. Link: http://lkml.kernel.org/r/1480369871-5271-43-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Konstantin Khlebnikov Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

radix tree test suite: make runs more reproducible

2016-12-15T00:04:09Z

Instead of reseeding the random number generator every time around the loop in big_gang_check(), seed it at the beginning of execution. Use rand_r() and an independent base seed for each thread in iteration_test() so they don't stomp all over each others state. Since this particular test depends on the kernel scheduler, the iteration test can't be reproduced based purely on the random seed, but at least it won't pollute the other tests. Print the seed, and allow the seed to be specified so that a run which hits a problem can be reproduced. Link: http://lkml.kernel.org/r/1480369871-5271-41-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds