// 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;
        int random_array[ARRAY_SIZE(test_case_array)];
        int index, i, j;
        ktime_t kt;
        u64 delta;

        if (set_cpus_allowed_ptr(current, cpumask_of(t->cpu)) < 0)
                pr_err("Failed to set affinity to %d CPU\n", t->cpu);

        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++) {
                        if (!test_case_array[index].test_func())
                                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");