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authorUladzislau Rezki (Sony) <urezki@gmail.com>2019-03-05 15:43:34 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 21:07:15 -0800
commit3f21a6b7ef207892841feecc3b9216e1a29c745f (patch)
tree647f3e3c8eea81e484f145a0583479fbe7f1e235 /tools/testing
parent153178edc7819b5c550e5d498d50697ff9d5f223 (diff)
downloadlinux-3f21a6b7ef207892841feecc3b9216e1a29c745f.tar.bz2
vmalloc: add test driver to analyse vmalloc allocator
This adds a new kernel module for analysis of vmalloc allocator. It is only enabled as a module. There are two main reasons this module should be used for: performance evaluation and stressing of vmalloc subsystem. It consists of several test cases. As of now there are 8. The module has five parameters we can specify to change its the behaviour. 1) run_test_mask - set of tests to be run id: 1, name: fix_size_alloc_test id: 2, name: full_fit_alloc_test id: 4, name: long_busy_list_alloc_test id: 8, name: random_size_alloc_test id: 16, name: fix_align_alloc_test id: 32, name: random_size_align_alloc_test id: 64, name: align_shift_alloc_test id: 128, name: pcpu_alloc_test By default all tests are in run test mask. If you want to select some specific tests it is possible to pass the mask. For example for first, second and fourth tests we go 11 value. 2) test_repeat_count - how many times each test should be repeated By default it is one time per test. It is possible to pass any number. As high the value is the test duration gets increased. 3) test_loop_count - internal test loop counter. By default it is set to 1000000. 4) single_cpu_test - use one CPU to run the tests By default this parameter is set to false. It means that all online CPUs execute tests. By setting it to 1, the tests are executed by first online CPU only. 5) sequential_test_order - run tests in sequential order By default this parameter is set to false. It means that before running tests the order is shuffled. It is possible to make it sequential, just set it to 1. Performance analysis: In order to evaluate performance of vmalloc allocations, usually it makes sense to use only one CPU that runs tests, use sequential order, number of repeat tests can be different as well as set of test mask. For example if we want to run all tests, to use one CPU and repeat each test 3 times. Insert the module passing following parameters: single_cpu_test=1 sequential_test_order=1 test_repeat_count=3 with following output: <snip> Summary: fix_size_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 901177 usec Summary: full_fit_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 1039341 usec Summary: long_busy_list_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 11775763 usec Summary: random_size_alloc_test passed 3: failed: 0 repeat: 3 loops: 1000000 avg: 6081992 usec Summary: fix_align_alloc_test passed: 3 failed: 0 repeat: 3, loops: 1000000 avg: 2003712 usec Summary: random_size_align_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 2895689 usec Summary: align_shift_alloc_test passed: 0 failed: 3 repeat: 3 loops: 1000000 avg: 573 usec Summary: pcpu_alloc_test passed: 3 failed: 0 repeat: 3 loops: 1000000 avg: 95802 usec All test took CPU0=192945605995 cycles <snip> The align_shift_alloc_test is expected to be failed. Stressing: In order to stress the vmalloc subsystem we run all available test cases on all available CPUs simultaneously. In order to prevent constant behaviour pattern, the test cases array is shuffled by default to randomize the order of test execution. For example if we want to run all tests(default), use all online CPUs(default) with shuffled order(default) and to repeat each test 30 times. The command would be like: modprobe vmalloc_test test_repeat_count=30 Expected results are the system is alive, there are no any BUG_ONs or Kernel Panics the tests are completed, no memory leaks. [urezki@gmail.com: fix 32-bit builds] Link: http://lkml.kernel.org/r/20190106214839.ffvjvmrn52uqog7k@pc636 [urezki@gmail.com: make CONFIG_TEST_VMALLOC depend on CONFIG_MMU] Link: http://lkml.kernel.org/r/20190219085441.s6bg2gpy4esny5vw@pc636 Link: http://lkml.kernel.org/r/20190103142108.20744-3-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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