Hi, Babu,
On 8/21/23 16:30, Babu Moger wrote:
The default resource group and its files are created during kernel
init time. Upcoming changes will make some resctrl files optional
based on a mount parameter. If optional files are to be added to the
default group based on the mount option, then each new file needs to
be created separately and call kernfs_activate() again.
Create all files of the default resource group during resctrl
mount, destroyed during unmount, to avoid scattering resctrl
file addition across two separate code flows.
Suggested-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
arch/x86/kernel/cpu/resctrl/internal.h | 2 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 55 +++++++++++++++-----------
2 files changed, 33 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index b09e7abd1299..44ad98f8c7af 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -611,5 +611,7 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
void __init thread_throttle_mode_init(void);
void __init mbm_config_rftype_init(const char *config);
void rdt_staged_configs_clear(void);
+int rdtgroup_setup_root(struct rdt_fs_context *ctx);
+void rdtgroup_destroy_root(void);
These two functions are called only in rdtgroup.c. Why are they exposed
here?
#endif /* _ASM_X86_RESCTRL_INTERNAL_H */
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 80a4f76bc34b..98f9f880c30b 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2516,10 +2516,14 @@ static int rdt_get_tree(struct fs_context *fc)
goto out;
}
- ret = rdt_enable_ctx(ctx);
+ ret = rdtgroup_setup_root(ctx);
if (ret)
goto out;
+ ret = rdt_enable_ctx(ctx);
+ if (ret)
+ goto out_root;
+
ret = schemata_list_create();
if (ret) {
schemata_list_destroy();
@@ -2528,6 +2532,12 @@ static int rdt_get_tree(struct fs_context *fc)
closid_init();
+ ret = rdtgroup_add_files(rdtgroup_default.kn, RFTYPE_CTRL_BASE);
+ if (ret)
+ goto out_schemata_free;
+
+ kernfs_activate(rdtgroup_default.kn);
+
ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
if (ret < 0)
goto out_schemata_free;
@@ -2584,6 +2594,8 @@ static int rdt_get_tree(struct fs_context *fc)
schemata_list_destroy();
out_ctx:
rdt_disable_ctx();
+out_root:
+ rdtgroup_destroy_root();
out:
rdt_last_cmd_clear();
mutex_unlock(&rdtgroup_mutex);
@@ -2654,7 +2666,6 @@ static int rdt_init_fs_context(struct fs_context *fc)
if (!ctx)
return -ENOMEM;
- ctx->kfc.root = rdt_root;
ctx->kfc.magic = RDTGROUP_SUPER_MAGIC;
fc->fs_private = &ctx->kfc;
fc->ops = &rdt_fs_context_ops;
@@ -2824,6 +2835,7 @@ static void rdt_kill_sb(struct super_block *sb)
rdt_pseudo_lock_release();
rdtgroup_default.mode = RDT_MODE_SHAREABLE;
schemata_list_destroy();
+ rdtgroup_destroy_root();
static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
static_branch_disable_cpuslocked(&rdt_mon_enable_key);
static_branch_disable_cpuslocked(&rdt_enable_key);
@@ -3705,10 +3717,8 @@ static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
.show_options = rdtgroup_show_options,
};
-static int __init rdtgroup_setup_root(void)
+int rdtgroup_setup_root(struct rdt_fs_context *ctx)
Since rdtgroup_setup_root() is called only in this file, need to add
"static".
{
- int ret;
-
rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,
KERNFS_ROOT_CREATE_DEACTIVATED |
KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,
@@ -3716,6 +3726,20 @@ static int __init rdtgroup_setup_root(void)
if (IS_ERR(rdt_root))
return PTR_ERR(rdt_root);
+ ctx->kfc.root = rdt_root;
+ rdtgroup_default.kn = kernfs_root_to_node(rdt_root);
+
+ return 0;
+}
+
+void rdtgroup_destroy_root(void)
Ditto.
+{
+ kernfs_destroy_root(rdt_root);
+ rdtgroup_default.kn = NULL;
+}
+
+static void __init rdtgroup_setup_default(void)
+{
mutex_lock(&rdtgroup_mutex);
rdtgroup_default.closid = 0;
@@ -3725,19 +3749,7 @@ static int __init rdtgroup_setup_root(void)
list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);
- ret = rdtgroup_add_files(kernfs_root_to_node(rdt_root), RFTYPE_CTRL_BASE);
- if (ret) {
- kernfs_destroy_root(rdt_root);
- goto out;
- }
-
- rdtgroup_default.kn = kernfs_root_to_node(rdt_root);
- kernfs_activate(rdtgroup_default.kn);
-
-out:
mutex_unlock(&rdtgroup_mutex);
-
- return ret;
}
static void domain_destroy_mon_state(struct rdt_domain *d)
@@ -3859,13 +3871,11 @@ int __init rdtgroup_init(void)
seq_buf_init(&last_cmd_status, last_cmd_status_buf,
sizeof(last_cmd_status_buf));
- ret = rdtgroup_setup_root();
- if (ret)
- return ret;
+ rdtgroup_setup_default();
ret = sysfs_create_mount_point(fs_kobj, "resctrl");
if (ret)
- goto cleanup_root;
+ return ret;
ret = register_filesystem(&rdt_fs_type);
if (ret)
@@ -3898,8 +3908,6 @@ int __init rdtgroup_init(void)
cleanup_mountpoint:
sysfs_remove_mount_point(fs_kobj, "resctrl");
-cleanup_root:
- kernfs_destroy_root(rdt_root);
return ret;
}
@@ -3909,5 +3917,4 @@ void __exit rdtgroup_exit(void)
debugfs_remove_recursive(debugfs_resctrl);
unregister_filesystem(&rdt_fs_type);
sysfs_remove_mount_point(fs_kobj, "resctrl");
- kernfs_destroy_root(rdt_root);
}
Thanks.
-Fenghua
