--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DAMON sysfs Interface
+ *
+ * Copyright (c) 2022 SeongJae Park <sj@kernel.org>
+ */
+
+#include <linux/damon.h>
+#include <linux/kobject.h>
+#include <linux/pid.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+static DEFINE_MUTEX(damon_sysfs_lock);
+
+/*
+ * unsigned long range directory
+ */
+
+struct damon_sysfs_ul_range {
+ struct kobject kobj;
+ unsigned long min;
+ unsigned long max;
+};
+
+static struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
+ unsigned long min,
+ unsigned long max)
+{
+ struct damon_sysfs_ul_range *range = kmalloc(sizeof(*range),
+ GFP_KERNEL);
+
+ if (!range)
+ return NULL;
+ range->kobj = (struct kobject){};
+ range->min = min;
+ range->max = max;
+
+ return range;
+}
+
+static ssize_t min_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct damon_sysfs_ul_range *range = container_of(kobj,
+ struct damon_sysfs_ul_range, kobj);
+
+ return sysfs_emit(buf, "%lu\n", range->min);
+}
+
+static ssize_t min_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct damon_sysfs_ul_range *range = container_of(kobj,
+ struct damon_sysfs_ul_range, kobj);
+ unsigned long min;
+ int err;
+
+ err = kstrtoul(buf, 0, &min);
+ if (err)
+ return -EINVAL;
+
+ range->min = min;
+ return count;
+}
+
+static ssize_t max_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct damon_sysfs_ul_range *range = container_of(kobj,
+ struct damon_sysfs_ul_range, kobj);
+
+ return sysfs_emit(buf, "%lu\n", range->max);
+}
+
+static ssize_t max_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct damon_sysfs_ul_range *range = container_of(kobj,
+ struct damon_sysfs_ul_range, kobj);
+ unsigned long max;
+ int err;
+
+ err = kstrtoul(buf, 0, &max);
+ if (err)
+ return -EINVAL;
+
+ range->max = max;
+ return count;
+}
+
+static void damon_sysfs_ul_range_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_ul_range, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_ul_range_min_attr =
+ __ATTR_RW_MODE(min, 0600);
+
+static struct kobj_attribute damon_sysfs_ul_range_max_attr =
+ __ATTR_RW_MODE(max, 0600);
+
+static struct attribute *damon_sysfs_ul_range_attrs[] = {
+ &damon_sysfs_ul_range_min_attr.attr,
+ &damon_sysfs_ul_range_max_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_ul_range);
+
+static struct kobj_type damon_sysfs_ul_range_ktype = {
+ .release = damon_sysfs_ul_range_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_ul_range_groups,
+};
+
+/*
+ * target directory
+ */
+
+struct damon_sysfs_target {
+ struct kobject kobj;
+ int pid;
+};
+
+static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_target), GFP_KERNEL);
+}
+
+static ssize_t pid_target_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_target *target = container_of(kobj,
+ struct damon_sysfs_target, kobj);
+
+ return sysfs_emit(buf, "%d\n", target->pid);
+}
+
+static ssize_t pid_target_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_target *target = container_of(kobj,
+ struct damon_sysfs_target, kobj);
+ int err = kstrtoint(buf, 0, &target->pid);
+
+ if (err)
+ return -EINVAL;
+ return count;
+}
+
+static void damon_sysfs_target_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_target, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_target_pid_attr =
+ __ATTR_RW_MODE(pid_target, 0600);
+
+static struct attribute *damon_sysfs_target_attrs[] = {
+ &damon_sysfs_target_pid_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_target);
+
+static struct kobj_type damon_sysfs_target_ktype = {
+ .release = damon_sysfs_target_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_target_groups,
+};
+
+/*
+ * targets directory
+ */
+
+struct damon_sysfs_targets {
+ struct kobject kobj;
+ struct damon_sysfs_target **targets_arr;
+ int nr;
+};
+
+static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_targets), GFP_KERNEL);
+}
+
+static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets)
+{
+ struct damon_sysfs_target **targets_arr = targets->targets_arr;
+ int i;
+
+ for (i = 0; i < targets->nr; i++)
+ kobject_put(&targets_arr[i]->kobj);
+ targets->nr = 0;
+ kfree(targets_arr);
+ targets->targets_arr = NULL;
+}
+
+static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets,
+ int nr_targets)
+{
+ struct damon_sysfs_target **targets_arr, *target;
+ int err, i;
+
+ damon_sysfs_targets_rm_dirs(targets);
+ if (!nr_targets)
+ return 0;
+
+ targets_arr = kmalloc_array(nr_targets, sizeof(*targets_arr),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!targets_arr)
+ return -ENOMEM;
+ targets->targets_arr = targets_arr;
+
+ for (i = 0; i < nr_targets; i++) {
+ target = damon_sysfs_target_alloc();
+ if (!target) {
+ damon_sysfs_targets_rm_dirs(targets);
+ return -ENOMEM;
+ }
+
+ err = kobject_init_and_add(&target->kobj,
+ &damon_sysfs_target_ktype, &targets->kobj,
+ "%d", i);
+ if (err)
+ goto out;
+
+ targets_arr[i] = target;
+ targets->nr++;
+ }
+ return 0;
+
+out:
+ damon_sysfs_targets_rm_dirs(targets);
+ kobject_put(&target->kobj);
+ return err;
+}
+
+static ssize_t nr_targets_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_targets *targets = container_of(kobj,
+ struct damon_sysfs_targets, kobj);
+
+ return sysfs_emit(buf, "%d\n", targets->nr);
+}
+
+static ssize_t nr_targets_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_targets *targets = container_of(kobj,
+ struct damon_sysfs_targets, kobj);
+ int nr, err = kstrtoint(buf, 0, &nr);
+
+ if (err)
+ return err;
+ if (nr < 0)
+ return -EINVAL;
+
+ if (!mutex_trylock(&damon_sysfs_lock))
+ return -EBUSY;
+ err = damon_sysfs_targets_add_dirs(targets, nr);
+ mutex_unlock(&damon_sysfs_lock);
+ if (err)
+ return err;
+
+ return count;
+}
+
+static void damon_sysfs_targets_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_targets, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_targets_nr_attr =
+ __ATTR_RW_MODE(nr_targets, 0600);
+
+static struct attribute *damon_sysfs_targets_attrs[] = {
+ &damon_sysfs_targets_nr_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_targets);
+
+static struct kobj_type damon_sysfs_targets_ktype = {
+ .release = damon_sysfs_targets_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_targets_groups,
+};
+
+/*
+ * intervals directory
+ */
+
+struct damon_sysfs_intervals {
+ struct kobject kobj;
+ unsigned long sample_us;
+ unsigned long aggr_us;
+ unsigned long update_us;
+};
+
+static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc(
+ unsigned long sample_us, unsigned long aggr_us,
+ unsigned long update_us)
+{
+ struct damon_sysfs_intervals *intervals = kmalloc(sizeof(*intervals),
+ GFP_KERNEL);
+
+ if (!intervals)
+ return NULL;
+
+ intervals->kobj = (struct kobject){};
+ intervals->sample_us = sample_us;
+ intervals->aggr_us = aggr_us;
+ intervals->update_us = update_us;
+ return intervals;
+}
+
+static ssize_t sample_us_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_intervals *intervals = container_of(kobj,
+ struct damon_sysfs_intervals, kobj);
+
+ return sysfs_emit(buf, "%lu\n", intervals->sample_us);
+}
+
+static ssize_t sample_us_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_intervals *intervals = container_of(kobj,
+ struct damon_sysfs_intervals, kobj);
+ unsigned long us;
+ int err = kstrtoul(buf, 0, &us);
+
+ if (err)
+ return -EINVAL;
+
+ intervals->sample_us = us;
+ return count;
+}
+
+static ssize_t aggr_us_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct damon_sysfs_intervals *intervals = container_of(kobj,
+ struct damon_sysfs_intervals, kobj);
+
+ return sysfs_emit(buf, "%lu\n", intervals->aggr_us);
+}
+
+static ssize_t aggr_us_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct damon_sysfs_intervals *intervals = container_of(kobj,
+ struct damon_sysfs_intervals, kobj);
+ unsigned long us;
+ int err = kstrtoul(buf, 0, &us);
+
+ if (err)
+ return -EINVAL;
+
+ intervals->aggr_us = us;
+ return count;
+}
+
+static ssize_t update_us_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_intervals *intervals = container_of(kobj,
+ struct damon_sysfs_intervals, kobj);
+
+ return sysfs_emit(buf, "%lu\n", intervals->update_us);
+}
+
+static ssize_t update_us_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_intervals *intervals = container_of(kobj,
+ struct damon_sysfs_intervals, kobj);
+ unsigned long us;
+ int err = kstrtoul(buf, 0, &us);
+
+ if (err)
+ return -EINVAL;
+
+ intervals->update_us = us;
+ return count;
+}
+
+static void damon_sysfs_intervals_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_intervals, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_intervals_sample_us_attr =
+ __ATTR_RW_MODE(sample_us, 0600);
+
+static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr =
+ __ATTR_RW_MODE(aggr_us, 0600);
+
+static struct kobj_attribute damon_sysfs_intervals_update_us_attr =
+ __ATTR_RW_MODE(update_us, 0600);
+
+static struct attribute *damon_sysfs_intervals_attrs[] = {
+ &damon_sysfs_intervals_sample_us_attr.attr,
+ &damon_sysfs_intervals_aggr_us_attr.attr,
+ &damon_sysfs_intervals_update_us_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_intervals);
+
+static struct kobj_type damon_sysfs_intervals_ktype = {
+ .release = damon_sysfs_intervals_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_intervals_groups,
+};
+
+/*
+ * monitoring_attrs directory
+ */
+
+struct damon_sysfs_attrs {
+ struct kobject kobj;
+ struct damon_sysfs_intervals *intervals;
+ struct damon_sysfs_ul_range *nr_regions_range;
+};
+
+static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
+{
+ struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL);
+
+ if (!attrs)
+ return NULL;
+ attrs->kobj = (struct kobject){};
+ return attrs;
+}
+
+static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
+{
+ struct damon_sysfs_intervals *intervals;
+ struct damon_sysfs_ul_range *nr_regions_range;
+ int err;
+
+ intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
+ if (!intervals)
+ return -ENOMEM;
+
+ err = kobject_init_and_add(&intervals->kobj,
+ &damon_sysfs_intervals_ktype, &attrs->kobj,
+ "intervals");
+ if (err)
+ goto put_intervals_out;
+ attrs->intervals = intervals;
+
+ nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000);
+ if (!nr_regions_range) {
+ err = -ENOMEM;
+ goto put_intervals_out;
+ }
+
+ err = kobject_init_and_add(&nr_regions_range->kobj,
+ &damon_sysfs_ul_range_ktype, &attrs->kobj,
+ "nr_regions");
+ if (err)
+ goto put_nr_regions_intervals_out;
+ attrs->nr_regions_range = nr_regions_range;
+ return 0;
+
+put_nr_regions_intervals_out:
+ kobject_put(&nr_regions_range->kobj);
+ attrs->nr_regions_range = NULL;
+put_intervals_out:
+ kobject_put(&intervals->kobj);
+ attrs->intervals = NULL;
+ return err;
+}
+
+static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
+{
+ kobject_put(&attrs->nr_regions_range->kobj);
+ kobject_put(&attrs->intervals->kobj);
+}
+
+static void damon_sysfs_attrs_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_attrs, kobj));
+}
+
+static struct attribute *damon_sysfs_attrs_attrs[] = {
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_attrs);
+
+static struct kobj_type damon_sysfs_attrs_ktype = {
+ .release = damon_sysfs_attrs_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_attrs_groups,
+};
+
+/*
+ * context directory
+ */
+
+/* This should match with enum damon_ops_id */
+static const char * const damon_sysfs_ops_strs[] = {
+ "vaddr",
+ "paddr",
+};
+
+struct damon_sysfs_context {
+ struct kobject kobj;
+ enum damon_ops_id ops_id;
+ struct damon_sysfs_attrs *attrs;
+ struct damon_sysfs_targets *targets;
+};
+
+static struct damon_sysfs_context *damon_sysfs_context_alloc(
+ enum damon_ops_id ops_id)
+{
+ struct damon_sysfs_context *context = kmalloc(sizeof(*context),
+ GFP_KERNEL);
+
+ if (!context)
+ return NULL;
+ context->kobj = (struct kobject){};
+ context->ops_id = ops_id;
+ return context;
+}
+
+static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context)
+{
+ struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc();
+ int err;
+
+ if (!attrs)
+ return -ENOMEM;
+ err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype,
+ &context->kobj, "monitoring_attrs");
+ if (err)
+ goto out;
+ err = damon_sysfs_attrs_add_dirs(attrs);
+ if (err)
+ goto out;
+ context->attrs = attrs;
+ return 0;
+
+out:
+ kobject_put(&attrs->kobj);
+ return err;
+}
+
+static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context)
+{
+ struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc();
+ int err;
+
+ if (!targets)
+ return -ENOMEM;
+ err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype,
+ &context->kobj, "targets");
+ if (err) {
+ kobject_put(&targets->kobj);
+ return err;
+ }
+ context->targets = targets;
+ return 0;
+}
+
+static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context)
+{
+ int err;
+
+ err = damon_sysfs_context_set_attrs(context);
+ if (err)
+ return err;
+
+ err = damon_sysfs_context_set_targets(context);
+ if (err)
+ goto put_attrs_out;
+ return 0;
+
+put_attrs_out:
+ kobject_put(&context->attrs->kobj);
+ context->attrs = NULL;
+ return err;
+}
+
+static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
+{
+ damon_sysfs_attrs_rm_dirs(context->attrs);
+ kobject_put(&context->attrs->kobj);
+ damon_sysfs_targets_rm_dirs(context->targets);
+ kobject_put(&context->targets->kobj);
+}
+
+static ssize_t operations_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_context *context = container_of(kobj,
+ struct damon_sysfs_context, kobj);
+
+ return sysfs_emit(buf, "%s\n", damon_sysfs_ops_strs[context->ops_id]);
+}
+
+static ssize_t operations_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_context *context = container_of(kobj,
+ struct damon_sysfs_context, kobj);
+ enum damon_ops_id id;
+
+ for (id = 0; id < NR_DAMON_OPS; id++) {
+ if (sysfs_streq(buf, damon_sysfs_ops_strs[id])) {
+ /* Support only vaddr */
+ if (id != DAMON_OPS_VADDR)
+ return -EINVAL;
+ context->ops_id = id;
+ return count;
+ }
+ }
+ return -EINVAL;
+}
+
+static void damon_sysfs_context_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_context, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_context_operations_attr =
+ __ATTR_RW_MODE(operations, 0600);
+
+static struct attribute *damon_sysfs_context_attrs[] = {
+ &damon_sysfs_context_operations_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_context);
+
+static struct kobj_type damon_sysfs_context_ktype = {
+ .release = damon_sysfs_context_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_context_groups,
+};
+
+/*
+ * contexts directory
+ */
+
+struct damon_sysfs_contexts {
+ struct kobject kobj;
+ struct damon_sysfs_context **contexts_arr;
+ int nr;
+};
+
+static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_contexts), GFP_KERNEL);
+}
+
+static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts)
+{
+ struct damon_sysfs_context **contexts_arr = contexts->contexts_arr;
+ int i;
+
+ for (i = 0; i < contexts->nr; i++) {
+ damon_sysfs_context_rm_dirs(contexts_arr[i]);
+ kobject_put(&contexts_arr[i]->kobj);
+ }
+ contexts->nr = 0;
+ kfree(contexts_arr);
+ contexts->contexts_arr = NULL;
+}
+
+static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts,
+ int nr_contexts)
+{
+ struct damon_sysfs_context **contexts_arr, *context;
+ int err, i;
+
+ damon_sysfs_contexts_rm_dirs(contexts);
+ if (!nr_contexts)
+ return 0;
+
+ contexts_arr = kmalloc_array(nr_contexts, sizeof(*contexts_arr),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!contexts_arr)
+ return -ENOMEM;
+ contexts->contexts_arr = contexts_arr;
+
+ for (i = 0; i < nr_contexts; i++) {
+ context = damon_sysfs_context_alloc(DAMON_OPS_VADDR);
+ if (!context) {
+ damon_sysfs_contexts_rm_dirs(contexts);
+ return -ENOMEM;
+ }
+
+ err = kobject_init_and_add(&context->kobj,
+ &damon_sysfs_context_ktype, &contexts->kobj,
+ "%d", i);
+ if (err)
+ goto out;
+
+ err = damon_sysfs_context_add_dirs(context);
+ if (err)
+ goto out;
+
+ contexts_arr[i] = context;
+ contexts->nr++;
+ }
+ return 0;
+
+out:
+ damon_sysfs_contexts_rm_dirs(contexts);
+ kobject_put(&context->kobj);
+ return err;
+}
+
+static ssize_t nr_contexts_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_contexts *contexts = container_of(kobj,
+ struct damon_sysfs_contexts, kobj);
+
+ return sysfs_emit(buf, "%d\n", contexts->nr);
+}
+
+static ssize_t nr_contexts_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_contexts *contexts = container_of(kobj,
+ struct damon_sysfs_contexts, kobj);
+ int nr, err;
+
+ err = kstrtoint(buf, 0, &nr);
+ if (err)
+ return err;
+ /* TODO: support multiple contexts per kdamond */
+ if (nr < 0 || 1 < nr)
+ return -EINVAL;
+
+ if (!mutex_trylock(&damon_sysfs_lock))
+ return -EBUSY;
+ err = damon_sysfs_contexts_add_dirs(contexts, nr);
+ mutex_unlock(&damon_sysfs_lock);
+ if (err)
+ return err;
+
+ return count;
+}
+
+static void damon_sysfs_contexts_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_contexts, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_contexts_nr_attr
+ = __ATTR_RW_MODE(nr_contexts, 0600);
+
+static struct attribute *damon_sysfs_contexts_attrs[] = {
+ &damon_sysfs_contexts_nr_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_contexts);
+
+static struct kobj_type damon_sysfs_contexts_ktype = {
+ .release = damon_sysfs_contexts_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_contexts_groups,
+};
+
+/*
+ * kdamond directory
+ */
+
+struct damon_sysfs_kdamond {
+ struct kobject kobj;
+ struct damon_sysfs_contexts *contexts;
+ struct damon_ctx *damon_ctx;
+};
+
+static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_kdamond), GFP_KERNEL);
+}
+
+static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond)
+{
+ struct damon_sysfs_contexts *contexts;
+ int err;
+
+ contexts = damon_sysfs_contexts_alloc();
+ if (!contexts)
+ return -ENOMEM;
+
+ err = kobject_init_and_add(&contexts->kobj,
+ &damon_sysfs_contexts_ktype, &kdamond->kobj,
+ "contexts");
+ if (err) {
+ kobject_put(&contexts->kobj);
+ return err;
+ }
+ kdamond->contexts = contexts;
+
+ return err;
+}
+
+static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond)
+{
+ damon_sysfs_contexts_rm_dirs(kdamond->contexts);
+ kobject_put(&kdamond->contexts->kobj);
+}
+
+static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ return -EINVAL;
+}
+
+static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ return -EINVAL;
+}
+
+static ssize_t pid_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return -EINVAL;
+}
+
+static void damon_sysfs_kdamond_release(struct kobject *kobj)
+{
+ struct damon_sysfs_kdamond *kdamond = container_of(kobj,
+ struct damon_sysfs_kdamond, kobj);
+
+ if (kdamond->damon_ctx)
+ damon_destroy_ctx(kdamond->damon_ctx);
+ kfree(container_of(kobj, struct damon_sysfs_kdamond, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_kdamond_state_attr =
+ __ATTR_RW_MODE(state, 0600);
+
+static struct kobj_attribute damon_sysfs_kdamond_pid_attr =
+ __ATTR_RO_MODE(pid, 0400);
+
+static struct attribute *damon_sysfs_kdamond_attrs[] = {
+ &damon_sysfs_kdamond_state_attr.attr,
+ &damon_sysfs_kdamond_pid_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_kdamond);
+
+static struct kobj_type damon_sysfs_kdamond_ktype = {
+ .release = damon_sysfs_kdamond_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_kdamond_groups,
+};
+
+/*
+ * kdamonds directory
+ */
+
+struct damon_sysfs_kdamonds {
+ struct kobject kobj;
+ struct damon_sysfs_kdamond **kdamonds_arr;
+ int nr;
+};
+
+static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_kdamonds), GFP_KERNEL);
+}
+
+static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
+{
+ struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr;
+ int i;
+
+ for (i = 0; i < kdamonds->nr; i++) {
+ damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]);
+ kobject_put(&kdamonds_arr[i]->kobj);
+ }
+ kdamonds->nr = 0;
+ kfree(kdamonds_arr);
+ kdamonds->kdamonds_arr = NULL;
+}
+
+static int damon_sysfs_nr_running_ctxs(struct damon_sysfs_kdamond **kdamonds,
+ int nr_kdamonds)
+{
+ int nr_running_ctxs = 0;
+ int i;
+
+ for (i = 0; i < nr_kdamonds; i++) {
+ struct damon_ctx *ctx = kdamonds[i]->damon_ctx;
+
+ if (!ctx)
+ continue;
+ mutex_lock(&ctx->kdamond_lock);
+ if (ctx->kdamond)
+ nr_running_ctxs++;
+ mutex_unlock(&ctx->kdamond_lock);
+ }
+ return nr_running_ctxs;
+}
+
+static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
+ int nr_kdamonds)
+{
+ struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
+ int err, i;
+
+ if (damon_sysfs_nr_running_ctxs(kdamonds->kdamonds_arr, kdamonds->nr))
+ return -EBUSY;
+
+ damon_sysfs_kdamonds_rm_dirs(kdamonds);
+ if (!nr_kdamonds)
+ return 0;
+
+ kdamonds_arr = kmalloc_array(nr_kdamonds, sizeof(*kdamonds_arr),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!kdamonds_arr)
+ return -ENOMEM;
+ kdamonds->kdamonds_arr = kdamonds_arr;
+
+ for (i = 0; i < nr_kdamonds; i++) {
+ kdamond = damon_sysfs_kdamond_alloc();
+ if (!kdamond) {
+ damon_sysfs_kdamonds_rm_dirs(kdamonds);
+ return -ENOMEM;
+ }
+
+ err = kobject_init_and_add(&kdamond->kobj,
+ &damon_sysfs_kdamond_ktype, &kdamonds->kobj,
+ "%d", i);
+ if (err)
+ goto out;
+
+ err = damon_sysfs_kdamond_add_dirs(kdamond);
+ if (err)
+ goto out;
+
+ kdamonds_arr[i] = kdamond;
+ kdamonds->nr++;
+ }
+ return 0;
+
+out:
+ damon_sysfs_kdamonds_rm_dirs(kdamonds);
+ kobject_put(&kdamond->kobj);
+ return err;
+}
+
+static ssize_t nr_kdamonds_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
+ struct damon_sysfs_kdamonds, kobj);
+
+ return sysfs_emit(buf, "%d\n", kdamonds->nr);
+}
+
+static ssize_t nr_kdamonds_store(struct kobject *kobj,
+ struct kobj_attribute *attr, const char *buf, size_t count)
+{
+ struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
+ struct damon_sysfs_kdamonds, kobj);
+ int nr, err;
+
+ err = kstrtoint(buf, 0, &nr);
+ if (err)
+ return err;
+ if (nr < 0)
+ return -EINVAL;
+
+ if (!mutex_trylock(&damon_sysfs_lock))
+ return -EBUSY;
+ err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
+ mutex_unlock(&damon_sysfs_lock);
+ if (err)
+ return err;
+
+ return count;
+}
+
+static void damon_sysfs_kdamonds_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_kdamonds_nr_attr =
+ __ATTR_RW_MODE(nr_kdamonds, 0600);
+
+static struct attribute *damon_sysfs_kdamonds_attrs[] = {
+ &damon_sysfs_kdamonds_nr_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_kdamonds);
+
+static struct kobj_type damon_sysfs_kdamonds_ktype = {
+ .release = damon_sysfs_kdamonds_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_kdamonds_groups,
+};
+
+/*
+ * damon user interface directory
+ */
+
+struct damon_sysfs_ui_dir {
+ struct kobject kobj;
+ struct damon_sysfs_kdamonds *kdamonds;
+};
+
+static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_ui_dir), GFP_KERNEL);
+}
+
+static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
+{
+ struct damon_sysfs_kdamonds *kdamonds;
+ int err;
+
+ kdamonds = damon_sysfs_kdamonds_alloc();
+ if (!kdamonds)
+ return -ENOMEM;
+
+ err = kobject_init_and_add(&kdamonds->kobj,
+ &damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
+ "kdamonds");
+ if (err) {
+ kobject_put(&kdamonds->kobj);
+ return err;
+ }
+ ui_dir->kdamonds = kdamonds;
+ return err;
+}
+
+static void damon_sysfs_ui_dir_release(struct kobject *kobj)
+{
+ kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj));
+}
+
+static struct attribute *damon_sysfs_ui_dir_attrs[] = {
+ NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_ui_dir);
+
+static struct kobj_type damon_sysfs_ui_dir_ktype = {
+ .release = damon_sysfs_ui_dir_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = damon_sysfs_ui_dir_groups,
+};
+
+static int __init damon_sysfs_init(void)
+{
+ struct kobject *damon_sysfs_root;
+ struct damon_sysfs_ui_dir *admin;
+ int err;
+
+ damon_sysfs_root = kobject_create_and_add("damon", mm_kobj);
+ if (!damon_sysfs_root)
+ return -ENOMEM;
+
+ admin = damon_sysfs_ui_dir_alloc();
+ if (!admin) {
+ kobject_put(damon_sysfs_root);
+ return -ENOMEM;
+ }
+ err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype,
+ damon_sysfs_root, "admin");
+ if (err)
+ goto out;
+ err = damon_sysfs_ui_dir_add_dirs(admin);
+ if (err)
+ goto out;
+ return 0;
+
+out:
+ kobject_put(&admin->kobj);
+ kobject_put(damon_sysfs_root);
+ return err;
+}
+subsys_initcall(damon_sysfs_init);