Merge branch 'slab/for-7.1/misc' into slab/for-next

Merge misc slab changes that are not related to sheaves. Various
improvements for sysfs, debugging and testing.

Author: Vlastimil Babka (SUSE)

MAINTAINERS

@@ -24354,6 +24354,7 @@ F:	Documentation/admin-guide/mm/slab.rst
 F:	Documentation/mm/slab.rst
 F:	include/linux/mempool.h
 F:	include/linux/slab.h
+F:	lib/tests/slub_kunit.c
 F:	mm/failslab.c
 F:	mm/mempool.c
 F:	mm/slab.h

lib/tests/slub_kunit.c

@@ -7,6 +7,7 @@
 #include <linux/kernel.h>
 #include <linux/rcupdate.h>
 #include <linux/delay.h>
+#include <linux/perf_event.h>
 #include "../mm/slab.h"
 
 static struct kunit_resource resource;
@@ -291,6 +292,94 @@ static void test_krealloc_redzone_zeroing(struct kunit *test)
 	kmem_cache_destroy(s);
 }
 
+#ifdef CONFIG_PERF_EVENTS
+#define NR_ITERATIONS 1000
+#define NR_OBJECTS 1000
+static void *objects[NR_OBJECTS];
+
+struct test_nolock_context {
+	struct kunit *test;
+	int callback_count;
+	int alloc_ok;
+	int alloc_fail;
+	struct perf_event *event;
+};
+
+static struct perf_event_attr hw_attr = {
+	.type = PERF_TYPE_HARDWARE,
+	.config = PERF_COUNT_HW_CPU_CYCLES,
+	.size = sizeof(struct perf_event_attr),
+	.pinned = 1,
+	.disabled = 1,
+	.freq = 1,
+	.sample_freq = 100000,
+};
+
+static void overflow_handler_test_kmalloc_kfree_nolock(struct perf_event *event,
+						       struct perf_sample_data *data,
+						       struct pt_regs *regs)
+{
+	void *objp;
+	gfp_t gfp;
+	struct test_nolock_context *ctx = event->overflow_handler_context;
+
+	/* __GFP_ACCOUNT to test kmalloc_nolock() in alloc_slab_obj_exts() */
+	gfp = (ctx->callback_count % 2) ? 0 : __GFP_ACCOUNT;
+	objp = kmalloc_nolock(64, gfp, NUMA_NO_NODE);
+
+	if (objp)
+		ctx->alloc_ok++;
+	else
+		ctx->alloc_fail++;
+
+	kfree_nolock(objp);
+	ctx->callback_count++;
+}
+
+static void test_kmalloc_kfree_nolock(struct kunit *test)
+{
+	int i, j;
+	struct test_nolock_context ctx = { .test = test };
+	struct perf_event *event;
+	bool alloc_fail = false;
+
+	event = perf_event_create_kernel_counter(&hw_attr, -1, current,
+						 overflow_handler_test_kmalloc_kfree_nolock,
+						 &ctx);
+	if (IS_ERR(event))
+		kunit_skip(test, "Failed to create perf event");
+	ctx.event = event;
+	perf_event_enable(ctx.event);
+	for (i = 0; i < NR_ITERATIONS; i++) {
+		for (j = 0; j < NR_OBJECTS; j++) {
+			gfp_t gfp = (i % 2) ? GFP_KERNEL : GFP_KERNEL_ACCOUNT;
+
+			objects[j] = kmalloc(64, gfp);
+			if (!objects[j]) {
+				j--;
+				while (j >= 0)
+					kfree(objects[j--]);
+				alloc_fail = true;
+				goto cleanup;
+			}
+		}
+		for (j = 0; j < NR_OBJECTS; j++)
+			kfree(objects[j]);
+	}
+
+cleanup:
+	perf_event_disable(ctx.event);
+	perf_event_release_kernel(ctx.event);
+
+	kunit_info(test, "callback_count: %d, alloc_ok: %d, alloc_fail: %d\n",
+		   ctx.callback_count, ctx.alloc_ok, ctx.alloc_fail);
+
+	if (alloc_fail)
+		kunit_skip(test, "Allocation failed");
+	KUNIT_EXPECT_EQ(test, 0, slab_errors);
+}
+#endif
+
 static int test_init(struct kunit *test)
 {
 	slab_errors = 0;
@@ -315,6 +404,9 @@ static struct kunit_case test_cases[] = {
 	KUNIT_CASE(test_kfree_rcu_wq_destroy),
 	KUNIT_CASE(test_leak_destroy),
 	KUNIT_CASE(test_krealloc_redzone_zeroing),
+#ifdef CONFIG_PERF_EVENTS
+	KUNIT_CASE_SLOW(test_kmalloc_kfree_nolock),
+#endif
 	{}
 };
 

mm/Kconfig

@@ -172,6 +172,7 @@ config SLUB
 config KVFREE_RCU_BATCHED
 	def_bool y
 	depends on !SLUB_TINY && !TINY_RCU
+	depends on !RCU_STRICT_GRACE_PERIOD
 
 config SLUB_TINY
 	bool "Configure for minimal memory footprint"

mm/slub.c

@@ -8975,7 +8975,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
 	return len;
 }
 
-#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
+#define to_slab_attr(n) container_of_const(n, struct slab_attribute, attr)
 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
 
 struct slab_attribute {
@@ -8985,10 +8985,10 @@ struct slab_attribute {
 };
 
 #define SLAB_ATTR_RO(_name) \
-	static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
+	static const struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
 
 #define SLAB_ATTR(_name) \
-	static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
+	static const struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
 
 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
 {
@@ -9382,7 +9382,7 @@ static ssize_t skip_kfence_store(struct kmem_cache *s,
 SLAB_ATTR(skip_kfence);
 #endif
 
-static struct attribute *slab_attrs[] = {
+static const struct attribute *const slab_attrs[] = {
 	&slab_size_attr.attr,
 	&object_size_attr.attr,
 	&objs_per_slab_attr.attr,
@@ -9459,15 +9459,13 @@ static struct attribute *slab_attrs[] = {
 	NULL
 };
 
-static const struct attribute_group slab_attr_group = {
-	.attrs = slab_attrs,
-};
+ATTRIBUTE_GROUPS(slab);
 
 static ssize_t slab_attr_show(struct kobject *kobj,
 				struct attribute *attr,
 				char *buf)
 {
-	struct slab_attribute *attribute;
+	const struct slab_attribute *attribute;
 	struct kmem_cache *s;
 
 	attribute = to_slab_attr(attr);
@@ -9483,7 +9481,7 @@ static ssize_t slab_attr_store(struct kobject *kobj,
 				struct attribute *attr,
 				const char *buf, size_t len)
 {
-	struct slab_attribute *attribute;
+	const struct slab_attribute *attribute;
 	struct kmem_cache *s;
 
 	attribute = to_slab_attr(attr);
@@ -9508,6 +9506,7 @@ static const struct sysfs_ops slab_sysfs_ops = {
 static const struct kobj_type slab_ktype = {
 	.sysfs_ops = &slab_sysfs_ops,
 	.release = kmem_cache_release,
+	.default_groups = slab_groups,
 };
 
 static struct kset *slab_kset;
@@ -9595,10 +9594,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	if (err)
 		goto out;
 
-	err = sysfs_create_group(&s->kobj, &slab_attr_group);
-	if (err)
-		goto out_del_kobj;
-
 	if (!unmergeable) {
 		/* Setup first alias */
 		sysfs_slab_alias(s, s->name);
@@ -9607,9 +9602,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	if (!unmergeable)
 		kfree(name);
 	return err;
-out_del_kobj:
-	kobject_del(&s->kobj);
-	goto out;
 }
 
 void sysfs_slab_unlink(struct kmem_cache *s)