@@ -1883,6 +1883,16 @@ config TEST_BPF
If unsure, say N.
+config TEST_MOD_ALLOC
+ bool "Tests for module allocator/vmalloc"
+ help
+ This builds the "test_mod_alloc" module that performs performance
+ and functional tests on the module text section allocator. The module
+ uses X86_64 module text sizes for simulations, for other architectures
+ it will be less accurate.
+
+ If unsure, say N.
+
config FIND_BIT_BENCHMARK
tristate "Test find_bit functions"
help
@@ -58,6 +58,7 @@ UBSAN_SANITIZE_test_ubsan.o := y
obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
obj-$(CONFIG_TEST_LKM) += test_module.o
+obj-$(CONFIG_TEST_MOD_ALLOC) += test_mod_alloc.o
obj-$(CONFIG_TEST_OVERFLOW) += test_overflow.o
obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
obj-$(CONFIG_TEST_SORT) += test_sort.o
new file mode 100644
@@ -0,0 +1,354 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/moduleloader.h>
+#include <linux/random.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+
+struct mod { int filesize; int coresize; int initsize; };
+
+/* ==== Begin optional logging ==== */
+
+/*
+ * Note: for more accurate test results add this to mm/vmalloc.c:
+ * void debug_purge_vmap_area_lazy(void)
+ * {
+ * purge_vmap_area_lazy();
+ * }
+ * and replace the below with:
+ * extern void debug_purge_vmap_area_lazy(void);
+ */
+static void debug_purge_vmap_area_lazy(void)
+{
+}
+
+
+/*
+ * Note: In order to get an accurate count for the tlb flushes triggered in
+ * vmalloc, create a counter in vmalloc.c: with this method signature and export
+ * it. Then replace the below with: __purge_vmap_area_lazy
+ * extern unsigned long get_tlb_flushes_vmalloc(void);
+ */
+static unsigned long get_tlb_flushes_vmalloc(void)
+{
+ return 0;
+}
+
+/* ==== End optional logging ==== */
+
+
+#define MAX_ALLOC_CNT 20000
+#define ITERS 1000
+
+struct vm_alloc {
+ void *core;
+ unsigned long core_size;
+ void *init;
+};
+
+static struct vm_alloc *allocs_vm;
+static long mod_cnt;
+static DEFINE_MUTEX(test_mod_alloc_mutex);
+
+const static int core_hist[10] = {1, 5, 21, 46, 141, 245, 597, 2224, 1875, 0};
+const static int init_hist[10] = {0, 0, 0, 0, 10, 19, 70, 914, 3906, 236};
+const static int file_hist[10] = {6, 20, 55, 86, 286, 551, 918, 2024, 1028,
+ 181};
+
+const static int bins[10] = {5000000, 2000000, 1000000, 500000, 200000, 100000,
+ 50000, 20000, 10000, 5000};
+/*
+ * Rough approximation of the X86_64 module size distribution.
+ */
+static int get_mod_rand_size(const int *hist)
+{
+ int area_under = get_random_long() % 5155;
+ int i;
+ int last_bin = bins[0] + 1;
+ int sum = 0;
+
+ for (i = 0; i <= 9; i++) {
+ sum += hist[i];
+ if (area_under <= sum)
+ return bins[i]
+ + (get_random_long() % (last_bin - bins[i]));
+ last_bin = bins[i];
+ }
+ return 4096;
+}
+
+static struct mod get_rand_module(void)
+{
+ struct mod ret;
+
+ ret.coresize = get_mod_rand_size(core_hist);
+ ret.initsize = get_mod_rand_size(init_hist);
+ ret.filesize = get_mod_rand_size(file_hist);
+ return ret;
+}
+
+static void do_test_alloc_fail(void)
+{
+ struct vm_alloc *cur_alloc;
+ struct mod cur_mod;
+ void *file;
+ int mod_n, free_mod_n;
+ unsigned long fail = 0;
+ int iter;
+
+ for (iter = 0; iter < ITERS; iter++) {
+ pr_info("Running iteration: %d\n", iter);
+ memset(allocs_vm, 0, mod_cnt * sizeof(struct vm_alloc));
+ debug_purge_vmap_area_lazy();
+ for (mod_n = 0; mod_n < mod_cnt; mod_n++) {
+ cur_mod = get_rand_module();
+ cur_alloc = &allocs_vm[mod_n];
+
+ /* Allocate */
+ file = vmalloc(cur_mod.filesize);
+ cur_alloc->core = module_alloc(cur_mod.coresize);
+ cur_alloc->init = module_alloc(cur_mod.initsize);
+
+ /* Clean up everything except core */
+ if (!cur_alloc->core || !cur_alloc->init) {
+ fail++;
+ vfree(file);
+ if (cur_alloc->init)
+ vfree(cur_alloc->init);
+ break;
+ }
+ vfree(cur_alloc->init);
+ vfree(file);
+ }
+
+ /* Clean up core sizes */
+ for (free_mod_n = 0; free_mod_n < mod_n; free_mod_n++) {
+ cur_alloc = &allocs_vm[free_mod_n];
+ if (cur_alloc->core)
+ vfree(cur_alloc->core);
+ }
+ }
+ pr_info("Failures(%ld modules): %lu\n", mod_cnt, fail);
+}
+
+#if defined(CONFIG_X86_64) && defined(CONFIG_RANDOMIZE_BASE)
+static int is_in_backup(void *addr)
+{
+ return (unsigned long)addr >= MODULES_VADDR + MODULES_RAND_LEN;
+}
+#else
+static int is_in_backup(void *addr)
+{
+ return 0;
+}
+#endif
+
+static void do_test_last_perf(void)
+{
+ struct vm_alloc *cur_alloc;
+ struct mod cur_mod;
+ void *file;
+ int mod_n, mon_n_free;
+ unsigned long fail = 0;
+ int iter;
+ ktime_t start, diff;
+ ktime_t total_last = 0;
+ ktime_t total_all = 0;
+
+ /*
+ * The number of last core allocations for each iteration that were
+ * allocated in the backup area.
+ */
+ int last_in_bk = 0;
+
+ /*
+ * The total number of core allocations that were in the backup area for
+ * all iterations.
+ */
+ int total_in_bk = 0;
+
+ /* The number of iterations where the count was more than 1 */
+ int cnt_more_than_1 = 0;
+
+ /*
+ * The number of core allocations that were in the backup area for the
+ * current iteration.
+ */
+ int cur_in_bk = 0;
+
+ unsigned long before_tlbs;
+ unsigned long tlb_cnt_total;
+ unsigned long tlb_cur;
+ unsigned long total_tlbs = 0;
+
+ pr_info("Starting %d iterations of %ld modules\n", ITERS, mod_cnt);
+
+ for (iter = 0; iter < ITERS; iter++) {
+ debug_purge_vmap_area_lazy();
+ before_tlbs = get_tlb_flushes_vmalloc();
+ memset(allocs_vm, 0, mod_cnt * sizeof(struct vm_alloc));
+ tlb_cnt_total = 0;
+ cur_in_bk = 0;
+ for (mod_n = 0; mod_n < mod_cnt; mod_n++) {
+ /* allocate how the module allocator allocates */
+
+ cur_mod = get_rand_module();
+ cur_alloc = &allocs_vm[mod_n];
+ file = vmalloc(cur_mod.filesize);
+
+ tlb_cur = get_tlb_flushes_vmalloc();
+
+ start = ktime_get();
+ cur_alloc->core = module_alloc(cur_mod.coresize);
+ diff = ktime_get() - start;
+
+ cur_alloc->init = module_alloc(cur_mod.initsize);
+
+ /* Collect metrics */
+ if (is_in_backup(cur_alloc->core)) {
+ cur_in_bk++;
+ if (mod_n == mod_cnt - 1)
+ last_in_bk++;
+ }
+ total_all += diff;
+
+ if (mod_n == mod_cnt - 1)
+ total_last += diff;
+
+ tlb_cnt_total += get_tlb_flushes_vmalloc() - tlb_cur;
+
+ /* If there is a failure, quit. init/core freed later */
+ if (!cur_alloc->core || !cur_alloc->init) {
+ fail++;
+ vfree(file);
+ break;
+ }
+ /* Init sections do not last long so free here */
+ vfree(cur_alloc->init);
+ cur_alloc->init = NULL;
+ vfree(file);
+ }
+
+ /* Collect per iteration metrics */
+ total_in_bk += cur_in_bk;
+ if (cur_in_bk > 1)
+ cnt_more_than_1++;
+ total_tlbs += get_tlb_flushes_vmalloc() - before_tlbs;
+
+ /* Collect per iteration metrics */
+ for (mon_n_free = 0; mon_n_free < mod_cnt; mon_n_free++) {
+ cur_alloc = &allocs_vm[mon_n_free];
+ vfree(cur_alloc->init);
+ vfree(cur_alloc->core);
+ }
+ }
+
+ if (fail)
+ pr_info("There was an alloc failure, results invalid!\n");
+
+ pr_info("num\t\tall(ns)\t\tlast(ns)");
+ pr_info("%ld\t\t%llu\t\t%llu\n", mod_cnt,
+ total_all / (ITERS * mod_cnt),
+ total_last / ITERS);
+
+ if (IS_ENABLED(CONFIG_X86_64) && IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
+ pr_info("Last module in backup count = %d\n", last_in_bk);
+ pr_info("Total modules in backup = %d\n", total_in_bk);
+ pr_info(">1 module in backup count = %d\n", cnt_more_than_1);
+ }
+ /*
+ * This will usually hide info when the instrumentation is not in place.
+ */
+ if (tlb_cnt_total)
+ pr_info("TLB Flushes: %lu\n", tlb_cnt_total);
+}
+
+static void do_test(int test)
+{
+ switch (test) {
+ case 1:
+ do_test_alloc_fail();
+ break;
+ case 2:
+ do_test_last_perf();
+ break;
+ default:
+ pr_info("Unknown test\n");
+ }
+}
+
+static ssize_t device_file_write(struct file *filp, const char *user_buf,
+ size_t count, loff_t *offp)
+{
+ char buf[100];
+ long input_num;
+
+ if (count >= sizeof(buf) - 1) {
+ pr_info("Command too long\n");
+ return count;
+ }
+
+ if (!mutex_trylock(&test_mod_alloc_mutex)) {
+ pr_info("test_mod_alloc busy\n");
+ return count;
+ }
+
+ if (copy_from_user(buf, user_buf, count))
+ goto error;
+
+ buf[count] = 0;
+
+ if (kstrtol(buf+1, 10, &input_num))
+ goto error;
+
+ switch (buf[0]) {
+ case 'm':
+ if (input_num > 0 && input_num <= MAX_ALLOC_CNT) {
+ pr_info("New module count: %ld\n", input_num);
+ mod_cnt = input_num;
+ if (allocs_vm)
+ vfree(allocs_vm);
+ allocs_vm = vmalloc(sizeof(struct vm_alloc) * mod_cnt);
+ } else
+ pr_info("more than %d not supported\n", MAX_ALLOC_CNT);
+ break;
+ case 't':
+ if (!mod_cnt) {
+ pr_info("Set module count first\n");
+ break;
+ }
+
+ do_test(input_num);
+ break;
+ default:
+ pr_info("Unknown command\n");
+ }
+ goto done;
+error:
+ pr_info("Could not process input\n");
+done:
+ mutex_unlock(&test_mod_alloc_mutex);
+ return count;
+}
+
+static const char *dv_name = "mod_alloc_test";
+const static struct file_operations test_mod_alloc_fops = {
+ .owner = THIS_MODULE,
+ .write = device_file_write,
+};
+
+static int __init mod_alloc_test_init(void)
+{
+ debugfs_create_file(dv_name, 0400, NULL, NULL, &test_mod_alloc_fops);
+
+ return 0;
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(mod_alloc_test_init);
new file mode 100755
@@ -0,0 +1,29 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+UNMOUNT_DEBUG_FS=0
+if ! mount | grep -q debugfs; then
+ if mount -t debugfs none /sys/kernel/debug/; then
+ UNMOUNT_DEBUG_FS=1
+ else
+ echo "Could not mount debug fs."
+ exit 1
+ fi
+fi
+
+if [ ! -e /sys/kernel/debug/mod_alloc_test ]; then
+ echo "Test module not found, did you build kernel with TEST_MOD_ALLOC?"
+ exit 1
+fi
+
+echo "Beginning module_alloc performance tests."
+
+for i in `seq 1000 1000 8000`; do
+ echo m$i>/sys/kernel/debug/mod_alloc_test
+ echo t2>/sys/kernel/debug/mod_alloc_test
+done
+
+echo "Module_alloc performance tests ended."
+
+if [ $UNMOUNT_DEBUG_FS -eq 1 ]; then
+ umount /sys/kernel/debug/
+fi