Monitoring tools that want to find out which resctrl CTRL
and MONITOR groups a task belongs to must currently read
the "tasks" file in every group until they locate the process
ID.
Add an additional file /proc/{pid}/resctrl to provide this
information.
For example:
cat /proc/1193/resctrl
CTRL_MON:/ctrl_grp0
MON:/ctrl_grp0/mon_groups/mon_grp0
If the resctrl filesystem has not been mounted,
reading /proc/{pid}/resctrl returns an empty string.
Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
---
v2: Reduce indentation level in proc_resctrl_show()
according to Boris's suggestion.
Create the include/linux/resctrl.h header and
declare proc_resctrl_show() in this file, so
that other architectures would probably use it
in the future. Different architectures should
implement architectural specific proc_resctrl_show()
accordingly.
v3: Return empty string if the resctrl filesystem has
not been mounted per Boris's suggestion.
Rename the config from CPU_RESCTRL to PROC_CPU_RESCTRL
to better represent its usage. Move PROC_CPU_RESCTRL
from arch/Kconfig to fs/proc/Kconfig.
And let PROC_CPU_RESCTRL to be depended on PROC_FS.
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 52 ++++++++++++++++++++++++++
fs/proc/Kconfig | 4 ++
fs/proc/base.c | 7 ++++
include/linux/resctrl.h | 16 ++++++++
5 files changed, 80 insertions(+)
create mode 100644 include/linux/resctrl.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8ef85139553f..252364d18887 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -455,6 +455,7 @@ config X86_CPU_RESCTRL
bool "x86 CPU resource control support"
depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
select KERNFS
+ select PROC_CPU_RESCTRL if PROC_FS
help
Enable x86 CPU resource control support.
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 2e3b06d6bbc6..657c21ffbdfa 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -725,6 +725,58 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
return ret;
}
+#ifdef CONFIG_PROC_CPU_RESCTRL
+
+int proc_resctrl_show(struct seq_file *s, struct pid_namespace *ns,
+ struct pid *pid, struct task_struct *tsk)
+{
+ struct rdtgroup *rdtg;
+ int ret = 0;
+
+ mutex_lock(&rdtgroup_mutex);
+
+ /* Return empty if resctrl has not been mounted. */
+ if (!static_branch_unlikely(&rdt_enable_key))
+ goto unlock;
+
+ list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) {
+ struct rdtgroup *crg;
+
+ /*
+ * Task information is only relevant for shareable
+ * and exclusive groups.
+ */
+ if (rdtg->mode != RDT_MODE_SHAREABLE &&
+ rdtg->mode != RDT_MODE_EXCLUSIVE)
+ continue;
+
+ if (rdtg->closid != tsk->closid)
+ continue;
+
+ seq_printf(s, "CTRL_MON:/%s\n", rdtg->kn->name);
+ list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
+ mon.crdtgrp_list) {
+ if (tsk->rmid != crg->mon.rmid)
+ continue;
+ seq_printf(s, "MON:%s%s/mon_groups/%s\n",
+ rdtg == &rdtgroup_default ? "" : "/",
+ rdtg->kn->name, crg->kn->name);
+ goto unlock;
+ }
+ goto unlock;
+ }
+ /*
+ * The above search should succeed. Otherwise return
+ * with an error.
+ */
+ ret = -ENOENT;
+unlock:
+ mutex_unlock(&rdtgroup_mutex);
+
+ return ret;
+}
+#endif
+
static int rdt_last_cmd_status_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig
index cb5629bd5fff..ae96a339d24d 100644
--- a/fs/proc/Kconfig
+++ b/fs/proc/Kconfig
@@ -103,3 +103,7 @@ config PROC_CHILDREN
config PROC_PID_ARCH_STATUS
def_bool n
depends on PROC_FS
+
+config PROC_CPU_RESCTRL
+ def_bool n
+ depends on PROC_FS
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ebea9501afb8..0e4b8bf2b986 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -94,6 +94,7 @@
#include <linux/sched/debug.h>
#include <linux/sched/stat.h>
#include <linux/posix-timers.h>
+#include <linux/resctrl.h>
#include <trace/events/oom.h>
#include "internal.h"
#include "fd.h"
@@ -3060,6 +3061,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#endif
#ifdef CONFIG_CGROUPS
ONE("cgroup", S_IRUGO, proc_cgroup_show),
+#endif
+#ifdef CONFIG_PROC_CPU_RESCTRL
+ ONE("resctrl", S_IRUGO, proc_resctrl_show),
#endif
ONE("oom_score", S_IRUGO, proc_oom_score),
REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations),
@@ -3460,6 +3464,9 @@ static const struct pid_entry tid_base_stuff[] = {
#endif
#ifdef CONFIG_CGROUPS
ONE("cgroup", S_IRUGO, proc_cgroup_show),
+#endif
+#ifdef CONFIG_PROC_CPU_RESCTRL
+ ONE("resctrl", S_IRUGO, proc_resctrl_show),
#endif
ONE("oom_score", S_IRUGO, proc_oom_score),
REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adj_operations),
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
new file mode 100644
index 000000000000..50b147784d55
--- /dev/null
+++ b/include/linux/resctrl.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _RESCTRL_H
+#define _RESCTRL_H
+
+#ifdef CONFIG_PROC_CPU_RESCTRL
+
+#include <linux/proc_fs.h>
+
+int proc_resctrl_show(struct seq_file *m,
+ struct pid_namespace *ns,
+ struct pid *pid,
+ struct task_struct *tsk);
+
+#endif
+
+#endif /* _RESCTRL_H */
--
2.17.1
