Messages in this thread Patch in this message |  | | From | Tony Luck <> | | Subject | [PATCH v14 30/32] fs/resctrl: Provide interface to create architecture specific debugfs area | | Date | Mon, 24 Nov 2025 10:54:07 -0800 |
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All files below /sys/fs/resctrl are considered user ABI.
This leaves no place for architectures to provide additional interfaces.
Add resctrl_debugfs_mon_info_arch_mkdir() which creates a directory in the debugfs file system for a monitoring resource. Naming follows the layout of the main resctrl hierarchy:
/sys/kernel/debug/resctrl/info/{resource}_MON/{arch}
The {arch} last level directory name matches the output of the user level "uname -m" command.
Architecture code may use this directory for debug information, or for minor tuning of features. It must not be used for basic feature enabling as debugfs may not be configured/mounted on production systems.
Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> --- include/linux/resctrl.h | 10 ++++++++++ fs/resctrl/rdtgroup.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+)
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 8623e450619a..b862a9dd785b 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -702,6 +702,16 @@ bool resctrl_arch_get_io_alloc_enabled(struct rdt_resource *r); extern unsigned int resctrl_rmid_realloc_threshold; extern unsigned int resctrl_rmid_realloc_limit; +/** + * resctrl_debugfs_mon_info_arch_mkdir() - Create a debugfs info directory. + * Removed by resctrl_exit(). + * @r: Resource (must be mon_capable). + * + * Return: NULL if resource is not monitoring capable, + * dentry pointer on success, or ERR_PTR(-ERROR) on failure. + */ +struct dentry *resctrl_debugfs_mon_info_arch_mkdir(struct rdt_resource *r); + int resctrl_init(void); void resctrl_exit(void); diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index d49ffc56ea61..d13291d71adf 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -24,6 +24,7 @@ #include <linux/sched/task.h> #include <linux/slab.h> #include <linux/user_namespace.h> +#include <linux/utsname.h> #include <uapi/linux/magic.h> @@ -75,6 +76,8 @@ static void rdtgroup_destroy_root(void); struct dentry *debugfs_resctrl; +static struct dentry *debugfs_resctrl_info; + /* * Memory bandwidth monitoring event to use for the default CTRL_MON group * and each new CTRL_MON group created by the user. Only relevant when @@ -4599,6 +4602,31 @@ int resctrl_init(void) return ret; } +/* + * Create /sys/kernel/debug/resctrl/info/{r->name}_MON/{arch} directory + * by request for architecture to use for debugging or minor tuning. + * Basic functionality of features must not be controlled by files + * added to this directory as debugfs may not be configured/mounted + * on production systems. + */ +struct dentry *resctrl_debugfs_mon_info_arch_mkdir(struct rdt_resource *r) +{ + struct dentry *moninfodir; + char name[32]; + + if (!r->mon_capable) + return NULL; + + if (!debugfs_resctrl_info) + debugfs_resctrl_info = debugfs_create_dir("info", debugfs_resctrl); + + sprintf(name, "%s_MON", r->name); + + moninfodir = debugfs_create_dir(name, debugfs_resctrl_info); + + return debugfs_create_dir(utsname()->machine, moninfodir); +} + static bool resctrl_online_domains_exist(void) { struct rdt_resource *r; @@ -4650,6 +4678,7 @@ void resctrl_exit(void) debugfs_remove_recursive(debugfs_resctrl); debugfs_resctrl = NULL; + debugfs_resctrl_info = NULL; unregister_filesystem(&rdt_fs_type); /* -- 2.51.1
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