mm/damon/sysfs-schemes: implement probe dir

Implement sysfs directory for showing per-probe hits count of each region.

Link: https://lore.kernel.org/20260518234119.97569-17-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 3b66c3a757b2aaa6c939f2bc6f311e2d3e7b6c69..7e21e78d77512a6656a8361198e8ec20aed9177a 100644 (file)
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -10,12 +10,40 @@
 
 #include "sysfs-common.h"
 
+/*
+ * probe directory
+ */
+
+struct damos_sysfs_probe {
+       struct kobject kobj;
+};
+
+static struct damos_sysfs_probe *damos_sysfs_probe_alloc(void)
+{
+       return kzalloc_obj(struct damos_sysfs_probe);
+}
+
+static void damos_sysfs_probe_release(struct kobject *kobj)
+{
+       struct damos_sysfs_probe *probe = container_of(kobj,
+                       struct damos_sysfs_probe, kobj);
+
+       kfree(probe);
+}
+
+static const struct kobj_type damos_sysfs_probe_ktype = {
+       .release = damos_sysfs_probe_release,
+       .sysfs_ops = &kobj_sysfs_ops,
+};
+
 /*
  * probes directory
  */
 
 struct damos_sysfs_probes {
        struct kobject kobj;
+       struct damos_sysfs_probe **probes_arr;
+       int nr;
 };
 
 static struct damos_sysfs_probes *damos_sysfs_probes_alloc(void)
@@ -23,6 +51,60 @@ static struct damos_sysfs_probes *damos_sysfs_probes_alloc(void)
        return kzalloc_obj(struct damos_sysfs_probes);
 }
 
+static void damos_sysfs_probes_rm_dirs(struct damos_sysfs_probes *probes)
+{
+       struct damos_sysfs_probe **probes_arr = probes->probes_arr;
+       int i;
+
+       for (i = 0; i < probes->nr; i++)
+               kobject_put(&probes_arr[i]->kobj);
+       probes->nr = 0;
+       kfree(probes_arr);
+       probes->probes_arr = NULL;
+}
+
+static int damos_sysfs_probes_add_dirs(struct damos_sysfs_probes *probes,
+               struct damon_ctx *ctx)
+{
+       struct damon_probe *probe;
+       struct damos_sysfs_probe **probes_arr;
+       int i = 0;
+
+       damon_for_each_probe(probe, ctx)
+               i++;
+
+       if (!i)
+               return 0;
+
+       probes_arr = kmalloc_objs(*probes_arr, i);
+       if (!probes_arr)
+               return -ENOMEM;
+       probes->probes_arr = probes_arr;
+
+       i = 0;
+       damon_for_each_probe(probe, ctx) {
+               struct damos_sysfs_probe *sys_probe;
+               int err;
+
+               sys_probe = damos_sysfs_probe_alloc();
+               if (!sys_probe) {
+                       damos_sysfs_probes_rm_dirs(probes);
+                       return -ENOMEM;
+               }
+               err = kobject_init_and_add(&sys_probe->kobj,
+                               &damos_sysfs_probe_ktype, &probes->kobj, "%d",
+                               i);
+               if (err) {
+                       kobject_put(&sys_probe->kobj);
+                       damos_sysfs_probes_rm_dirs(probes);
+                       return err;
+               }
+               probes_arr[i++] = sys_probe;
+               probes->nr++;
+       }
+       return 0;
+}
+
 static void damos_sysfs_probes_release(struct kobject *kobj)
 {
        struct damos_sysfs_probes *probes = container_of(kobj,
@@ -67,7 +149,8 @@ static struct damon_sysfs_scheme_region *damon_sysfs_scheme_region_alloc(
 }
 
 static int damos_sysfs_region_add_dirs(
-               struct damon_sysfs_scheme_region *region)
+               struct damon_sysfs_scheme_region *region,
+               struct damon_ctx *ctx)
 {
        struct damos_sysfs_probes *probes = damos_sysfs_probes_alloc();
        int err;
@@ -76,18 +159,24 @@ static int damos_sysfs_region_add_dirs(
                return -ENOMEM;
        err = kobject_init_and_add(&probes->kobj, &damos_sysfs_probes_ktype,
                        &region->kobj, "probes");
-       if (err) {
-               kobject_put(&probes->kobj);
-               return err;
-       }
+       if (err)
+               goto fail;
+       err = damos_sysfs_probes_add_dirs(probes, ctx);
+       if (err)
+               goto fail;
 
        region->probes = probes;
        return 0;
+
+fail:
+       kobject_put(&probes->kobj);
+       return err;
 }
 
 static void damos_sysfs_region_rm_dirs(
                struct damon_sysfs_scheme_region *region)
 {
+       damos_sysfs_probes_rm_dirs(region->probes);
        kobject_put(&region->probes->kobj);
 }
 
@@ -3051,7 +3140,7 @@ void damos_sysfs_populate_region_dir(struct damon_sysfs_schemes *sysfs_schemes,
                                &sysfs_regions->kobj, "%d",
                                sysfs_regions->nr_regions))
                goto out;
-       if (damos_sysfs_region_add_dirs(region))
+       if (damos_sysfs_region_add_dirs(region, ctx))
                goto out;
 
        list_add_tail(&region->list, &sysfs_regions->regions_list);