linux/lib/test_vmalloc.c

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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>
2019-03-05 23:43:34 +00:00
// SPDX-License-Identifier: GPL-2.0
/*
* Test module for stress and analyze performance of vmalloc allocator.
* (C) 2018 Uladzislau Rezki (Sony) <urezki@gmail.com>
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/random.h>
#include <linux/kthread.h>
#include <linux/moduleparam.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/rwsem.h>
#include <linux/mm.h>
#define __param(type, name, init, msg) \
static type name = init; \
module_param(name, type, 0444); \
MODULE_PARM_DESC(name, msg) \
__param(bool, single_cpu_test, false,
"Use single first online CPU to run tests");
__param(bool, sequential_test_order, false,
"Use sequential stress tests order");
__param(int, test_repeat_count, 1,
"Set test repeat counter");
__param(int, test_loop_count, 1000000,
"Set test loop counter");
__param(int, run_test_mask, INT_MAX,
"Set tests specified in the mask.\n\n"
"\t\tid: 1, name: fix_size_alloc_test\n"
"\t\tid: 2, name: full_fit_alloc_test\n"
"\t\tid: 4, name: long_busy_list_alloc_test\n"
"\t\tid: 8, name: random_size_alloc_test\n"
"\t\tid: 16, name: fix_align_alloc_test\n"
"\t\tid: 32, name: random_size_align_alloc_test\n"
"\t\tid: 64, name: align_shift_alloc_test\n"
"\t\tid: 128, name: pcpu_alloc_test\n"
/* Add a new test case description here. */
);
/*
* Depends on single_cpu_test parameter. If it is true, then
* use first online CPU to trigger a test on, otherwise go with
* all online CPUs.
*/
static cpumask_t cpus_run_test_mask = CPU_MASK_NONE;
/*
* Read write semaphore for synchronization of setup
* phase that is done in main thread and workers.
*/
static DECLARE_RWSEM(prepare_for_test_rwsem);
/*
* Completion tracking for worker threads.
*/
static DECLARE_COMPLETION(test_all_done_comp);
static atomic_t test_n_undone = ATOMIC_INIT(0);
static inline void
test_report_one_done(void)
{
if (atomic_dec_and_test(&test_n_undone))
complete(&test_all_done_comp);
}
static int random_size_align_alloc_test(void)
{
unsigned long size, align, rnd;
void *ptr;
int i;
for (i = 0; i < test_loop_count; i++) {
get_random_bytes(&rnd, sizeof(rnd));
/*
* Maximum 1024 pages, if PAGE_SIZE is 4096.
*/
align = 1 << (rnd % 23);
/*
* Maximum 10 pages.
*/
size = ((rnd % 10) + 1) * PAGE_SIZE;
ptr = __vmalloc_node_range(size, align,
VMALLOC_START, VMALLOC_END,
GFP_KERNEL | __GFP_ZERO,
PAGE_KERNEL,
0, 0, __builtin_return_address(0));
if (!ptr)
return -1;
vfree(ptr);
}
return 0;
}
/*
* This test case is supposed to be failed.
*/
static int align_shift_alloc_test(void)
{
unsigned long align;
void *ptr;
int i;
for (i = 0; i < BITS_PER_LONG; i++) {
align = ((unsigned long) 1) << i;
ptr = __vmalloc_node_range(PAGE_SIZE, align,
VMALLOC_START, VMALLOC_END,
GFP_KERNEL | __GFP_ZERO,
PAGE_KERNEL,
0, 0, __builtin_return_address(0));
if (!ptr)
return -1;
vfree(ptr);
}
return 0;
}
static int fix_align_alloc_test(void)
{
void *ptr;
int i;
for (i = 0; i < test_loop_count; i++) {
ptr = __vmalloc_node_range(5 * PAGE_SIZE,
THREAD_ALIGN << 1,
VMALLOC_START, VMALLOC_END,
GFP_KERNEL | __GFP_ZERO,
PAGE_KERNEL,
0, 0, __builtin_return_address(0));
if (!ptr)
return -1;
vfree(ptr);
}
return 0;
}
static int random_size_alloc_test(void)
{
unsigned int n;
void *p;
int i;
for (i = 0; i < test_loop_count; i++) {
get_random_bytes(&n, sizeof(i));
n = (n % 100) + 1;
p = vmalloc(n * PAGE_SIZE);
if (!p)
return -1;
*((__u8 *)p) = 1;
vfree(p);
}
return 0;
}
static int long_busy_list_alloc_test(void)
{
void *ptr_1, *ptr_2;
void **ptr;
int rv = -1;
int i;
ptr = vmalloc(sizeof(void *) * 15000);
if (!ptr)
return rv;
for (i = 0; i < 15000; i++)
ptr[i] = vmalloc(1 * PAGE_SIZE);
for (i = 0; i < test_loop_count; i++) {
ptr_1 = vmalloc(100 * PAGE_SIZE);
if (!ptr_1)
goto leave;
ptr_2 = vmalloc(1 * PAGE_SIZE);
if (!ptr_2) {
vfree(ptr_1);
goto leave;
}
*((__u8 *)ptr_1) = 0;
*((__u8 *)ptr_2) = 1;
vfree(ptr_1);
vfree(ptr_2);
}
/* Success */
rv = 0;
leave:
for (i = 0; i < 15000; i++)
vfree(ptr[i]);
vfree(ptr);
return rv;
}
static int full_fit_alloc_test(void)
{
void **ptr, **junk_ptr, *tmp;
int junk_length;
int rv = -1;
int i;
junk_length = fls(num_online_cpus());
junk_length *= (32 * 1024 * 1024 / PAGE_SIZE);
ptr = vmalloc(sizeof(void *) * junk_length);
if (!ptr)
return rv;
junk_ptr = vmalloc(sizeof(void *) * junk_length);
if (!junk_ptr) {
vfree(ptr);
return rv;
}
for (i = 0; i < junk_length; i++) {
ptr[i] = vmalloc(1 * PAGE_SIZE);
junk_ptr[i] = vmalloc(1 * PAGE_SIZE);
}
for (i = 0; i < junk_length; i++)
vfree(junk_ptr[i]);
for (i = 0; i < test_loop_count; i++) {
tmp = vmalloc(1 * PAGE_SIZE);
if (!tmp)
goto error;
*((__u8 *)tmp) = 1;
vfree(tmp);
}
/* Success */
rv = 0;
error:
for (i = 0; i < junk_length; i++)
vfree(ptr[i]);
vfree(ptr);
vfree(junk_ptr);
return rv;
}
static int fix_size_alloc_test(void)
{
void *ptr;
int i;
for (i = 0; i < test_loop_count; i++) {
ptr = vmalloc(3 * PAGE_SIZE);
if (!ptr)
return -1;
*((__u8 *)ptr) = 0;
vfree(ptr);
}
return 0;
}
static int
pcpu_alloc_test(void)
{
int rv = 0;
#ifndef CONFIG_NEED_PER_CPU_KM
void __percpu **pcpu;
size_t size, align;
int i;
pcpu = vmalloc(sizeof(void __percpu *) * 35000);
if (!pcpu)
return -1;
for (i = 0; i < 35000; i++) {
unsigned int r;
get_random_bytes(&r, sizeof(i));
size = (r % (PAGE_SIZE / 4)) + 1;
/*
* Maximum PAGE_SIZE
*/
get_random_bytes(&r, sizeof(i));
align = 1 << ((i % 11) + 1);
pcpu[i] = __alloc_percpu(size, align);
if (!pcpu[i])
rv = -1;
}
for (i = 0; i < 35000; i++)
free_percpu(pcpu[i]);
vfree(pcpu);
#endif
return rv;
}
struct test_case_desc {
const char *test_name;
int (*test_func)(void);
};
static struct test_case_desc test_case_array[] = {
{ "fix_size_alloc_test", fix_size_alloc_test },
{ "full_fit_alloc_test", full_fit_alloc_test },
{ "long_busy_list_alloc_test", long_busy_list_alloc_test },
{ "random_size_alloc_test", random_size_alloc_test },
{ "fix_align_alloc_test", fix_align_alloc_test },
{ "random_size_align_alloc_test", random_size_align_alloc_test },
{ "align_shift_alloc_test", align_shift_alloc_test },
{ "pcpu_alloc_test", pcpu_alloc_test },
/* Add a new test case here. */
};
struct test_case_data {
int test_failed;
int test_passed;
u64 time;
};
/* Split it to get rid of: WARNING: line over 80 characters */
static struct test_case_data
per_cpu_test_data[NR_CPUS][ARRAY_SIZE(test_case_array)];
static struct test_driver {
struct task_struct *task;
unsigned long start;
unsigned long stop;
int cpu;
} per_cpu_test_driver[NR_CPUS];
static void shuffle_array(int *arr, int n)
{
unsigned int rnd;
int i, j, x;
for (i = n - 1; i > 0; i--) {
get_random_bytes(&rnd, sizeof(rnd));
/* Cut the range. */
j = rnd % i;
/* Swap indexes. */
x = arr[i];
arr[i] = arr[j];
arr[j] = x;
}
}
static int test_func(void *private)
{
struct test_driver *t = private;
cpumask_t newmask = CPU_MASK_NONE;
int random_array[ARRAY_SIZE(test_case_array)];
int index, i, j, ret;
ktime_t kt;
u64 delta;
cpumask_set_cpu(t->cpu, &newmask);
set_cpus_allowed_ptr(current, &newmask);
for (i = 0; i < ARRAY_SIZE(test_case_array); i++)
random_array[i] = i;
if (!sequential_test_order)
shuffle_array(random_array, ARRAY_SIZE(test_case_array));
/*
* Block until initialization is done.
*/
down_read(&prepare_for_test_rwsem);
t->start = get_cycles();
for (i = 0; i < ARRAY_SIZE(test_case_array); i++) {
index = random_array[i];
/*
* Skip tests if run_test_mask has been specified.
*/
if (!((run_test_mask & (1 << index)) >> index))
continue;
kt = ktime_get();
for (j = 0; j < test_repeat_count; j++) {
ret = test_case_array[index].test_func();
if (!ret)
per_cpu_test_data[t->cpu][index].test_passed++;
else
per_cpu_test_data[t->cpu][index].test_failed++;
}
/*
* Take an average time that test took.
*/
delta = (u64) ktime_us_delta(ktime_get(), kt);
do_div(delta, (u32) test_repeat_count);
per_cpu_test_data[t->cpu][index].time = delta;
}
t->stop = get_cycles();
up_read(&prepare_for_test_rwsem);
test_report_one_done();
/*
* Wait for the kthread_stop() call.
*/
while (!kthread_should_stop())
msleep(10);
return 0;
}
static void
init_test_configurtion(void)
{
/*
* Reset all data of all CPUs.
*/
memset(per_cpu_test_data, 0, sizeof(per_cpu_test_data));
if (single_cpu_test)
cpumask_set_cpu(cpumask_first(cpu_online_mask),
&cpus_run_test_mask);
else
cpumask_and(&cpus_run_test_mask, cpu_online_mask,
cpu_online_mask);
if (test_repeat_count <= 0)
test_repeat_count = 1;
if (test_loop_count <= 0)
test_loop_count = 1;
}
static void do_concurrent_test(void)
{
int cpu, ret;
/*
* Set some basic configurations plus sanity check.
*/
init_test_configurtion();
/*
* Put on hold all workers.
*/
down_write(&prepare_for_test_rwsem);
for_each_cpu(cpu, &cpus_run_test_mask) {
struct test_driver *t = &per_cpu_test_driver[cpu];
t->cpu = cpu;
t->task = kthread_run(test_func, t, "vmalloc_test/%d", cpu);
if (!IS_ERR(t->task))
/* Success. */
atomic_inc(&test_n_undone);
else
pr_err("Failed to start kthread for %d CPU\n", cpu);
}
/*
* Now let the workers do their job.
*/
up_write(&prepare_for_test_rwsem);
/*
* Sleep quiet until all workers are done with 1 second
* interval. Since the test can take a lot of time we
* can run into a stack trace of the hung task. That is
* why we go with completion_timeout and HZ value.
*/
do {
ret = wait_for_completion_timeout(&test_all_done_comp, HZ);
} while (!ret);
for_each_cpu(cpu, &cpus_run_test_mask) {
struct test_driver *t = &per_cpu_test_driver[cpu];
int i;
if (!IS_ERR(t->task))
kthread_stop(t->task);
for (i = 0; i < ARRAY_SIZE(test_case_array); i++) {
if (!((run_test_mask & (1 << i)) >> i))
continue;
pr_info(
"Summary: %s passed: %d failed: %d repeat: %d loops: %d avg: %llu usec\n",
test_case_array[i].test_name,
per_cpu_test_data[cpu][i].test_passed,
per_cpu_test_data[cpu][i].test_failed,
test_repeat_count, test_loop_count,
per_cpu_test_data[cpu][i].time);
}
pr_info("All test took CPU%d=%lu cycles\n",
cpu, t->stop - t->start);
}
}
static int vmalloc_test_init(void)
{
do_concurrent_test();
return -EAGAIN; /* Fail will directly unload the module */
}
static void vmalloc_test_exit(void)
{
}
module_init(vmalloc_test_init)
module_exit(vmalloc_test_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Uladzislau Rezki");
MODULE_DESCRIPTION("vmalloc test module");