diff options
Diffstat (limited to '')
| -rw-r--r-- | mm/damon/dbgfs.c | 1114 |
1 files changed, 1114 insertions, 0 deletions
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c new file mode 100644 index 000000000..b3f454a5c --- /dev/null +++ b/mm/damon/dbgfs.c @@ -0,0 +1,1114 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DAMON Debugfs Interface + * + * Author: SeongJae Park <sjpark@amazon.de> + */ + +#define pr_fmt(fmt) "damon-dbgfs: " fmt + +#include <linux/damon.h> +#include <linux/debugfs.h> +#include <linux/file.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/page_idle.h> +#include <linux/slab.h> + +static struct damon_ctx **dbgfs_ctxs; +static int dbgfs_nr_ctxs; +static struct dentry **dbgfs_dirs; +static DEFINE_MUTEX(damon_dbgfs_lock); + +/* + * Returns non-empty string on success, negative error code otherwise. + */ +static char *user_input_str(const char __user *buf, size_t count, loff_t *ppos) +{ + char *kbuf; + ssize_t ret; + + /* We do not accept continuous write */ + if (*ppos) + return ERR_PTR(-EINVAL); + + kbuf = kmalloc(count + 1, GFP_KERNEL | __GFP_NOWARN); + if (!kbuf) + return ERR_PTR(-ENOMEM); + + ret = simple_write_to_buffer(kbuf, count + 1, ppos, buf, count); + if (ret != count) { + kfree(kbuf); + return ERR_PTR(-EIO); + } + kbuf[ret] = '\0'; + + return kbuf; +} + +static ssize_t dbgfs_attrs_read(struct file *file, + char __user *buf, size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char kbuf[128]; + int ret; + + mutex_lock(&ctx->kdamond_lock); + ret = scnprintf(kbuf, ARRAY_SIZE(kbuf), "%lu %lu %lu %lu %lu\n", + ctx->attrs.sample_interval, ctx->attrs.aggr_interval, + ctx->attrs.ops_update_interval, + ctx->attrs.min_nr_regions, ctx->attrs.max_nr_regions); + mutex_unlock(&ctx->kdamond_lock); + + return simple_read_from_buffer(buf, count, ppos, kbuf, ret); +} + +static ssize_t dbgfs_attrs_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + struct damon_attrs attrs; + char *kbuf; + ssize_t ret; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + if (sscanf(kbuf, "%lu %lu %lu %lu %lu", + &attrs.sample_interval, &attrs.aggr_interval, + &attrs.ops_update_interval, + &attrs.min_nr_regions, + &attrs.max_nr_regions) != 5) { + ret = -EINVAL; + goto out; + } + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) { + ret = -EBUSY; + goto unlock_out; + } + + ret = damon_set_attrs(ctx, &attrs); + if (!ret) + ret = count; +unlock_out: + mutex_unlock(&ctx->kdamond_lock); +out: + kfree(kbuf); + return ret; +} + +/* + * Return corresponding dbgfs' scheme action value (int) for the given + * damos_action if the given damos_action value is valid and supported by + * dbgfs, negative error code otherwise. + */ +static int damos_action_to_dbgfs_scheme_action(enum damos_action action) +{ + switch (action) { + case DAMOS_WILLNEED: + return 0; + case DAMOS_COLD: + return 1; + case DAMOS_PAGEOUT: + return 2; + case DAMOS_HUGEPAGE: + return 3; + case DAMOS_NOHUGEPAGE: + return 4; + case DAMOS_STAT: + return 5; + default: + return -EINVAL; + } +} + +static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len) +{ + struct damos *s; + int written = 0; + int rc; + + damon_for_each_scheme(s, c) { + rc = scnprintf(&buf[written], len - written, + "%lu %lu %u %u %u %u %d %lu %lu %lu %u %u %u %d %lu %lu %lu %lu %lu %lu %lu %lu %lu\n", + s->pattern.min_sz_region, + s->pattern.max_sz_region, + s->pattern.min_nr_accesses, + s->pattern.max_nr_accesses, + s->pattern.min_age_region, + s->pattern.max_age_region, + damos_action_to_dbgfs_scheme_action(s->action), + s->quota.ms, s->quota.sz, + s->quota.reset_interval, + s->quota.weight_sz, + s->quota.weight_nr_accesses, + s->quota.weight_age, + s->wmarks.metric, s->wmarks.interval, + s->wmarks.high, s->wmarks.mid, s->wmarks.low, + s->stat.nr_tried, s->stat.sz_tried, + s->stat.nr_applied, s->stat.sz_applied, + s->stat.qt_exceeds); + if (!rc) + return -ENOMEM; + + written += rc; + } + return written; +} + +static ssize_t dbgfs_schemes_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char *kbuf; + ssize_t len; + + kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); + if (!kbuf) + return -ENOMEM; + + mutex_lock(&ctx->kdamond_lock); + len = sprint_schemes(ctx, kbuf, count); + mutex_unlock(&ctx->kdamond_lock); + if (len < 0) + goto out; + len = simple_read_from_buffer(buf, count, ppos, kbuf, len); + +out: + kfree(kbuf); + return len; +} + +static void free_schemes_arr(struct damos **schemes, ssize_t nr_schemes) +{ + ssize_t i; + + for (i = 0; i < nr_schemes; i++) + kfree(schemes[i]); + kfree(schemes); +} + +/* + * Return corresponding damos_action for the given dbgfs input for a scheme + * action if the input is valid, negative error code otherwise. + */ +static enum damos_action dbgfs_scheme_action_to_damos_action(int dbgfs_action) +{ + switch (dbgfs_action) { + case 0: + return DAMOS_WILLNEED; + case 1: + return DAMOS_COLD; + case 2: + return DAMOS_PAGEOUT; + case 3: + return DAMOS_HUGEPAGE; + case 4: + return DAMOS_NOHUGEPAGE; + case 5: + return DAMOS_STAT; + default: + return -EINVAL; + } +} + +/* + * Converts a string into an array of struct damos pointers + * + * Returns an array of struct damos pointers that converted if the conversion + * success, or NULL otherwise. + */ +static struct damos **str_to_schemes(const char *str, ssize_t len, + ssize_t *nr_schemes) +{ + struct damos *scheme, **schemes; + const int max_nr_schemes = 256; + int pos = 0, parsed, ret; + unsigned int action_input; + enum damos_action action; + + schemes = kmalloc_array(max_nr_schemes, sizeof(scheme), + GFP_KERNEL); + if (!schemes) + return NULL; + + *nr_schemes = 0; + while (pos < len && *nr_schemes < max_nr_schemes) { + struct damos_access_pattern pattern = {}; + struct damos_quota quota = {}; + struct damos_watermarks wmarks; + + ret = sscanf(&str[pos], + "%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u %u %lu %lu %lu %lu%n", + &pattern.min_sz_region, &pattern.max_sz_region, + &pattern.min_nr_accesses, + &pattern.max_nr_accesses, + &pattern.min_age_region, + &pattern.max_age_region, + &action_input, "a.ms, + "a.sz, "a.reset_interval, + "a.weight_sz, "a.weight_nr_accesses, + "a.weight_age, &wmarks.metric, + &wmarks.interval, &wmarks.high, &wmarks.mid, + &wmarks.low, &parsed); + if (ret != 18) + break; + action = dbgfs_scheme_action_to_damos_action(action_input); + if ((int)action < 0) + goto fail; + + if (pattern.min_sz_region > pattern.max_sz_region || + pattern.min_nr_accesses > pattern.max_nr_accesses || + pattern.min_age_region > pattern.max_age_region) + goto fail; + + if (wmarks.high < wmarks.mid || wmarks.high < wmarks.low || + wmarks.mid < wmarks.low) + goto fail; + + pos += parsed; + scheme = damon_new_scheme(&pattern, action, "a, &wmarks); + if (!scheme) + goto fail; + + schemes[*nr_schemes] = scheme; + *nr_schemes += 1; + } + return schemes; +fail: + free_schemes_arr(schemes, *nr_schemes); + return NULL; +} + +static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char *kbuf; + struct damos **schemes; + ssize_t nr_schemes = 0, ret; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + schemes = str_to_schemes(kbuf, count, &nr_schemes); + if (!schemes) { + ret = -EINVAL; + goto out; + } + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) { + ret = -EBUSY; + goto unlock_out; + } + + damon_set_schemes(ctx, schemes, nr_schemes); + ret = count; + nr_schemes = 0; + +unlock_out: + mutex_unlock(&ctx->kdamond_lock); + free_schemes_arr(schemes, nr_schemes); +out: + kfree(kbuf); + return ret; +} + +static ssize_t sprint_target_ids(struct damon_ctx *ctx, char *buf, ssize_t len) +{ + struct damon_target *t; + int id; + int written = 0; + int rc; + + damon_for_each_target(t, ctx) { + if (damon_target_has_pid(ctx)) + /* Show pid numbers to debugfs users */ + id = pid_vnr(t->pid); + else + /* Show 42 for physical address space, just for fun */ + id = 42; + + rc = scnprintf(&buf[written], len - written, "%d ", id); + if (!rc) + return -ENOMEM; + written += rc; + } + if (written) + written -= 1; + written += scnprintf(&buf[written], len - written, "\n"); + return written; +} + +static ssize_t dbgfs_target_ids_read(struct file *file, + char __user *buf, size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + ssize_t len; + char ids_buf[320]; + + mutex_lock(&ctx->kdamond_lock); + len = sprint_target_ids(ctx, ids_buf, 320); + mutex_unlock(&ctx->kdamond_lock); + if (len < 0) + return len; + + return simple_read_from_buffer(buf, count, ppos, ids_buf, len); +} + +/* + * Converts a string into an integers array + * + * Returns an array of integers array if the conversion success, or NULL + * otherwise. + */ +static int *str_to_ints(const char *str, ssize_t len, ssize_t *nr_ints) +{ + int *array; + const int max_nr_ints = 32; + int nr; + int pos = 0, parsed, ret; + + *nr_ints = 0; + array = kmalloc_array(max_nr_ints, sizeof(*array), GFP_KERNEL); + if (!array) + return NULL; + while (*nr_ints < max_nr_ints && pos < len) { + ret = sscanf(&str[pos], "%d%n", &nr, &parsed); + pos += parsed; + if (ret != 1) + break; + array[*nr_ints] = nr; + *nr_ints += 1; + } + + return array; +} + +static void dbgfs_put_pids(struct pid **pids, int nr_pids) +{ + int i; + + for (i = 0; i < nr_pids; i++) + put_pid(pids[i]); +} + +/* + * Converts a string into an struct pid pointers array + * + * Returns an array of struct pid pointers if the conversion success, or NULL + * otherwise. + */ +static struct pid **str_to_pids(const char *str, ssize_t len, ssize_t *nr_pids) +{ + int *ints; + ssize_t nr_ints; + struct pid **pids; + + *nr_pids = 0; + + ints = str_to_ints(str, len, &nr_ints); + if (!ints) + return NULL; + + pids = kmalloc_array(nr_ints, sizeof(*pids), GFP_KERNEL); + if (!pids) + goto out; + + for (; *nr_pids < nr_ints; (*nr_pids)++) { + pids[*nr_pids] = find_get_pid(ints[*nr_pids]); + if (!pids[*nr_pids]) { + dbgfs_put_pids(pids, *nr_pids); + kfree(ints); + kfree(pids); + return NULL; + } + } + +out: + kfree(ints); + return pids; +} + +/* + * dbgfs_set_targets() - Set monitoring targets. + * @ctx: monitoring context + * @nr_targets: number of targets + * @pids: array of target pids (size is same to @nr_targets) + * + * This function should not be called while the kdamond is running. @pids is + * ignored if the context is not configured to have pid in each target. On + * failure, reference counts of all pids in @pids are decremented. + * + * Return: 0 on success, negative error code otherwise. + */ +static int dbgfs_set_targets(struct damon_ctx *ctx, ssize_t nr_targets, + struct pid **pids) +{ + ssize_t i; + struct damon_target *t, *next; + + damon_for_each_target_safe(t, next, ctx) { + if (damon_target_has_pid(ctx)) + put_pid(t->pid); + damon_destroy_target(t); + } + + for (i = 0; i < nr_targets; i++) { + t = damon_new_target(); + if (!t) { + damon_for_each_target_safe(t, next, ctx) + damon_destroy_target(t); + if (damon_target_has_pid(ctx)) + dbgfs_put_pids(pids, nr_targets); + return -ENOMEM; + } + if (damon_target_has_pid(ctx)) + t->pid = pids[i]; + damon_add_target(ctx, t); + } + + return 0; +} + +static ssize_t dbgfs_target_ids_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + bool id_is_pid = true; + char *kbuf; + struct pid **target_pids = NULL; + ssize_t nr_targets; + ssize_t ret; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + if (!strncmp(kbuf, "paddr\n", count)) { + id_is_pid = false; + nr_targets = 1; + } + + if (id_is_pid) { + target_pids = str_to_pids(kbuf, count, &nr_targets); + if (!target_pids) { + ret = -ENOMEM; + goto out; + } + } + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) { + if (id_is_pid) + dbgfs_put_pids(target_pids, nr_targets); + ret = -EBUSY; + goto unlock_out; + } + + /* remove previously set targets */ + dbgfs_set_targets(ctx, 0, NULL); + if (!nr_targets) { + ret = count; + goto unlock_out; + } + + /* Configure the context for the address space type */ + if (id_is_pid) + ret = damon_select_ops(ctx, DAMON_OPS_VADDR); + else + ret = damon_select_ops(ctx, DAMON_OPS_PADDR); + if (ret) + goto unlock_out; + + ret = dbgfs_set_targets(ctx, nr_targets, target_pids); + if (!ret) + ret = count; + +unlock_out: + mutex_unlock(&ctx->kdamond_lock); + kfree(target_pids); +out: + kfree(kbuf); + return ret; +} + +static ssize_t sprint_init_regions(struct damon_ctx *c, char *buf, ssize_t len) +{ + struct damon_target *t; + struct damon_region *r; + int target_idx = 0; + int written = 0; + int rc; + + damon_for_each_target(t, c) { + damon_for_each_region(r, t) { + rc = scnprintf(&buf[written], len - written, + "%d %lu %lu\n", + target_idx, r->ar.start, r->ar.end); + if (!rc) + return -ENOMEM; + written += rc; + } + target_idx++; + } + return written; +} + +static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char *kbuf; + ssize_t len; + + kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); + if (!kbuf) + return -ENOMEM; + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) { + mutex_unlock(&ctx->kdamond_lock); + len = -EBUSY; + goto out; + } + + len = sprint_init_regions(ctx, kbuf, count); + mutex_unlock(&ctx->kdamond_lock); + if (len < 0) + goto out; + len = simple_read_from_buffer(buf, count, ppos, kbuf, len); + +out: + kfree(kbuf); + return len; +} + +static int add_init_region(struct damon_ctx *c, int target_idx, + struct damon_addr_range *ar) +{ + struct damon_target *t; + struct damon_region *r, *prev; + unsigned long idx = 0; + int rc = -EINVAL; + + if (ar->start >= ar->end) + return -EINVAL; + + damon_for_each_target(t, c) { + if (idx++ == target_idx) { + r = damon_new_region(ar->start, ar->end); + if (!r) + return -ENOMEM; + damon_add_region(r, t); + if (damon_nr_regions(t) > 1) { + prev = damon_prev_region(r); + if (prev->ar.end > r->ar.start) { + damon_destroy_region(r, t); + return -EINVAL; + } + } + rc = 0; + } + } + return rc; +} + +static int set_init_regions(struct damon_ctx *c, const char *str, ssize_t len) +{ + struct damon_target *t; + struct damon_region *r, *next; + int pos = 0, parsed, ret; + int target_idx; + struct damon_addr_range ar; + int err; + + damon_for_each_target(t, c) { + damon_for_each_region_safe(r, next, t) + damon_destroy_region(r, t); + } + + while (pos < len) { + ret = sscanf(&str[pos], "%d %lu %lu%n", + &target_idx, &ar.start, &ar.end, &parsed); + if (ret != 3) + break; + err = add_init_region(c, target_idx, &ar); + if (err) + goto fail; + pos += parsed; + } + + return 0; + +fail: + damon_for_each_target(t, c) { + damon_for_each_region_safe(r, next, t) + damon_destroy_region(r, t); + } + return err; +} + +static ssize_t dbgfs_init_regions_write(struct file *file, + const char __user *buf, size_t count, + loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char *kbuf; + ssize_t ret = count; + int err; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) { + ret = -EBUSY; + goto unlock_out; + } + + err = set_init_regions(ctx, kbuf, ret); + if (err) + ret = err; + +unlock_out: + mutex_unlock(&ctx->kdamond_lock); + kfree(kbuf); + return ret; +} + +static ssize_t dbgfs_kdamond_pid_read(struct file *file, + char __user *buf, size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char *kbuf; + ssize_t len; + + kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); + if (!kbuf) + return -ENOMEM; + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) + len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid); + else + len = scnprintf(kbuf, count, "none\n"); + mutex_unlock(&ctx->kdamond_lock); + if (!len) + goto out; + len = simple_read_from_buffer(buf, count, ppos, kbuf, len); + +out: + kfree(kbuf); + return len; +} + +static int damon_dbgfs_open(struct inode *inode, struct file *file) +{ + file->private_data = inode->i_private; + + return nonseekable_open(inode, file); +} + +static const struct file_operations attrs_fops = { + .open = damon_dbgfs_open, + .read = dbgfs_attrs_read, + .write = dbgfs_attrs_write, +}; + +static const struct file_operations schemes_fops = { + .open = damon_dbgfs_open, + .read = dbgfs_schemes_read, + .write = dbgfs_schemes_write, +}; + +static const struct file_operations target_ids_fops = { + .open = damon_dbgfs_open, + .read = dbgfs_target_ids_read, + .write = dbgfs_target_ids_write, +}; + +static const struct file_operations init_regions_fops = { + .open = damon_dbgfs_open, + .read = dbgfs_init_regions_read, + .write = dbgfs_init_regions_write, +}; + +static const struct file_operations kdamond_pid_fops = { + .open = damon_dbgfs_open, + .read = dbgfs_kdamond_pid_read, +}; + +static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx) +{ + const char * const file_names[] = {"attrs", "schemes", "target_ids", + "init_regions", "kdamond_pid"}; + const struct file_operations *fops[] = {&attrs_fops, &schemes_fops, + &target_ids_fops, &init_regions_fops, &kdamond_pid_fops}; + int i; + + for (i = 0; i < ARRAY_SIZE(file_names); i++) + debugfs_create_file(file_names[i], 0600, dir, ctx, fops[i]); +} + +static void dbgfs_before_terminate(struct damon_ctx *ctx) +{ + struct damon_target *t, *next; + + if (!damon_target_has_pid(ctx)) + return; + + mutex_lock(&ctx->kdamond_lock); + damon_for_each_target_safe(t, next, ctx) { + put_pid(t->pid); + damon_destroy_target(t); + } + mutex_unlock(&ctx->kdamond_lock); +} + +static struct damon_ctx *dbgfs_new_ctx(void) +{ + struct damon_ctx *ctx; + + ctx = damon_new_ctx(); + if (!ctx) + return NULL; + + if (damon_select_ops(ctx, DAMON_OPS_VADDR) && + damon_select_ops(ctx, DAMON_OPS_PADDR)) { + damon_destroy_ctx(ctx); + return NULL; + } + ctx->callback.before_terminate = dbgfs_before_terminate; + return ctx; +} + +static void dbgfs_destroy_ctx(struct damon_ctx *ctx) +{ + damon_destroy_ctx(ctx); +} + +/* + * Make a context of @name and create a debugfs directory for it. + * + * This function should be called while holding damon_dbgfs_lock. + * + * Returns 0 on success, negative error code otherwise. + */ +static int dbgfs_mk_context(char *name) +{ + struct dentry *root, **new_dirs, *new_dir; + struct damon_ctx **new_ctxs, *new_ctx; + + if (damon_nr_running_ctxs()) + return -EBUSY; + + new_ctxs = krealloc(dbgfs_ctxs, sizeof(*dbgfs_ctxs) * + (dbgfs_nr_ctxs + 1), GFP_KERNEL); + if (!new_ctxs) + return -ENOMEM; + dbgfs_ctxs = new_ctxs; + + new_dirs = krealloc(dbgfs_dirs, sizeof(*dbgfs_dirs) * + (dbgfs_nr_ctxs + 1), GFP_KERNEL); + if (!new_dirs) + return -ENOMEM; + dbgfs_dirs = new_dirs; + + root = dbgfs_dirs[0]; + if (!root) + return -ENOENT; + + new_dir = debugfs_create_dir(name, root); + /* Below check is required for a potential duplicated name case */ + if (IS_ERR(new_dir)) + return PTR_ERR(new_dir); + dbgfs_dirs[dbgfs_nr_ctxs] = new_dir; + + new_ctx = dbgfs_new_ctx(); + if (!new_ctx) { + debugfs_remove(new_dir); + dbgfs_dirs[dbgfs_nr_ctxs] = NULL; + return -ENOMEM; + } + + dbgfs_ctxs[dbgfs_nr_ctxs] = new_ctx; + dbgfs_fill_ctx_dir(dbgfs_dirs[dbgfs_nr_ctxs], + dbgfs_ctxs[dbgfs_nr_ctxs]); + dbgfs_nr_ctxs++; + + return 0; +} + +static ssize_t dbgfs_mk_context_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + char *kbuf; + char *ctx_name; + ssize_t ret; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + ctx_name = kmalloc(count + 1, GFP_KERNEL); + if (!ctx_name) { + kfree(kbuf); + return -ENOMEM; + } + + /* Trim white space */ + if (sscanf(kbuf, "%s", ctx_name) != 1) { + ret = -EINVAL; + goto out; + } + + mutex_lock(&damon_dbgfs_lock); + ret = dbgfs_mk_context(ctx_name); + if (!ret) + ret = count; + mutex_unlock(&damon_dbgfs_lock); + +out: + kfree(kbuf); + kfree(ctx_name); + return ret; +} + +/* + * Remove a context of @name and its debugfs directory. + * + * This function should be called while holding damon_dbgfs_lock. + * + * Return 0 on success, negative error code otherwise. + */ +static int dbgfs_rm_context(char *name) +{ + struct dentry *root, *dir, **new_dirs; + struct inode *inode; + struct damon_ctx **new_ctxs; + int i, j; + int ret = 0; + + if (damon_nr_running_ctxs()) + return -EBUSY; + + root = dbgfs_dirs[0]; + if (!root) + return -ENOENT; + + dir = debugfs_lookup(name, root); + if (!dir) + return -ENOENT; + + inode = d_inode(dir); + if (!S_ISDIR(inode->i_mode)) { + ret = -EINVAL; + goto out_dput; + } + + new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs), + GFP_KERNEL); + if (!new_dirs) { + ret = -ENOMEM; + goto out_dput; + } + + new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs), + GFP_KERNEL); + if (!new_ctxs) { + ret = -ENOMEM; + goto out_new_dirs; + } + + for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) { + if (dbgfs_dirs[i] == dir) { + debugfs_remove(dbgfs_dirs[i]); + dbgfs_destroy_ctx(dbgfs_ctxs[i]); + continue; + } + new_dirs[j] = dbgfs_dirs[i]; + new_ctxs[j++] = dbgfs_ctxs[i]; + } + + kfree(dbgfs_dirs); + kfree(dbgfs_ctxs); + + dbgfs_dirs = new_dirs; + dbgfs_ctxs = new_ctxs; + dbgfs_nr_ctxs--; + + goto out_dput; + +out_new_dirs: + kfree(new_dirs); +out_dput: + dput(dir); + return ret; +} + +static ssize_t dbgfs_rm_context_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + char *kbuf; + ssize_t ret; + char *ctx_name; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + ctx_name = kmalloc(count + 1, GFP_KERNEL); + if (!ctx_name) { + kfree(kbuf); + return -ENOMEM; + } + + /* Trim white space */ + if (sscanf(kbuf, "%s", ctx_name) != 1) { + ret = -EINVAL; + goto out; + } + + mutex_lock(&damon_dbgfs_lock); + ret = dbgfs_rm_context(ctx_name); + if (!ret) + ret = count; + mutex_unlock(&damon_dbgfs_lock); + +out: + kfree(kbuf); + kfree(ctx_name); + return ret; +} + +static ssize_t dbgfs_monitor_on_read(struct file *file, + char __user *buf, size_t count, loff_t *ppos) +{ + char monitor_on_buf[5]; + bool monitor_on = damon_nr_running_ctxs() != 0; + int len; + + len = scnprintf(monitor_on_buf, 5, monitor_on ? "on\n" : "off\n"); + + return simple_read_from_buffer(buf, count, ppos, monitor_on_buf, len); +} + +static ssize_t dbgfs_monitor_on_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + ssize_t ret; + char *kbuf; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + /* Remove white space */ + if (sscanf(kbuf, "%s", kbuf) != 1) { + kfree(kbuf); + return -EINVAL; + } + + mutex_lock(&damon_dbgfs_lock); + if (!strncmp(kbuf, "on", count)) { + int i; + + for (i = 0; i < dbgfs_nr_ctxs; i++) { + if (damon_targets_empty(dbgfs_ctxs[i])) { + kfree(kbuf); + mutex_unlock(&damon_dbgfs_lock); + return -EINVAL; + } + } + ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs, true); + } else if (!strncmp(kbuf, "off", count)) { + ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); + } else { + ret = -EINVAL; + } + mutex_unlock(&damon_dbgfs_lock); + + if (!ret) + ret = count; + kfree(kbuf); + return ret; +} + +static const struct file_operations mk_contexts_fops = { + .write = dbgfs_mk_context_write, +}; + +static const struct file_operations rm_contexts_fops = { + .write = dbgfs_rm_context_write, +}; + +static const struct file_operations monitor_on_fops = { + .read = dbgfs_monitor_on_read, + .write = dbgfs_monitor_on_write, +}; + +static int __init __damon_dbgfs_init(void) +{ + struct dentry *dbgfs_root; + const char * const file_names[] = {"mk_contexts", "rm_contexts", + "monitor_on"}; + const struct file_operations *fops[] = {&mk_contexts_fops, + &rm_contexts_fops, &monitor_on_fops}; + int i; + + dbgfs_root = debugfs_create_dir("damon", NULL); + + for (i = 0; i < ARRAY_SIZE(file_names); i++) + debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL, + fops[i]); + dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]); + + dbgfs_dirs = kmalloc(sizeof(dbgfs_root), GFP_KERNEL); + if (!dbgfs_dirs) { + debugfs_remove(dbgfs_root); + return -ENOMEM; + } + dbgfs_dirs[0] = dbgfs_root; + + return 0; +} + +/* + * Functions for the initialization + */ + +static int __init damon_dbgfs_init(void) +{ + int rc = -ENOMEM; + + mutex_lock(&damon_dbgfs_lock); + dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL); + if (!dbgfs_ctxs) + goto out; + dbgfs_ctxs[0] = dbgfs_new_ctx(); + if (!dbgfs_ctxs[0]) { + kfree(dbgfs_ctxs); + goto out; + } + dbgfs_nr_ctxs = 1; + + rc = __damon_dbgfs_init(); + if (rc) { + kfree(dbgfs_ctxs[0]); + kfree(dbgfs_ctxs); + pr_err("%s: dbgfs init failed\n", __func__); + } + +out: + mutex_unlock(&damon_dbgfs_lock); + return rc; +} + +module_init(damon_dbgfs_init); + +#include "dbgfs-test.h" |