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Subject[tip:x86/cache] x86/intel_rdt/cqm: Add mount,umount support
Commit-ID:  4af4a88e0c9246990f95c88eeba781265f27c58e
Gitweb: http://git.kernel.org/tip/4af4a88e0c9246990f95c88eeba781265f27c58e
Author: Vikas Shivappa <vikas.shivappa@linux.intel.com>
AuthorDate: Tue, 25 Jul 2017 14:14:41 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 1 Aug 2017 22:41:27 +0200

x86/intel_rdt/cqm: Add mount,umount support

Add monitoring support during mount and unmount. Since root directory is
a "ctrl_mon" directory which can control and monitor resources create
the "mon_groups" directory which can hold monitor groups and a
"mon_data" directory which would hold all monitoring data like the rest
of resource groups.

The mount succeeds if either of monitoring or control/allocation is
enabled. If only monitoring is enabled user can still create monitor
groups under the "/sys/fs/resctrl/mon_groups/" and any mkdir under root
would fail. If only control/allocation is enabled all of the monitoring
related directories/files would not exist and resctrl would work in
legacy mode.

Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-23-git-send-email-vikas.shivappa@linux.intel.com

---
arch/x86/kernel/cpu/intel_rdt.h | 4 +++
arch/x86/kernel/cpu/intel_rdt_monitor.c | 1 +
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 61 +++++++++++++++++++++++++++++---
3 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index 7fcaa5f..92a5d30 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -22,6 +22,8 @@
#define RMID_VAL_ERROR BIT_ULL(63)
#define RMID_VAL_UNAVAIL BIT_ULL(62)

+DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
+
/**
* struct mon_evt - Entry in the event list of a resource
* @evtid: event id
@@ -59,6 +61,8 @@ extern bool rdt_alloc_capable;
extern bool rdt_mon_capable;
extern unsigned int rdt_mon_features;

+DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
+
enum rdt_group_type {
RDTCTRL_GROUP = 0,
RDTMON_GROUP,
diff --git a/arch/x86/kernel/cpu/intel_rdt_monitor.c b/arch/x86/kernel/cpu/intel_rdt_monitor.c
index f8f06f5..6ae5cf5 100644
--- a/arch/x86/kernel/cpu/intel_rdt_monitor.c
+++ b/arch/x86/kernel/cpu/intel_rdt_monitor.c
@@ -343,6 +343,7 @@ void mon_event_count(void *info)
}
}
}
+
static int dom_data_init(struct rdt_resource *r)
{
struct rmid_entry *entry = NULL;
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index e619081..0a7be9b 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -35,6 +35,8 @@
#include <asm/intel_rdt_sched.h>
#include "intel_rdt.h"

+DEFINE_STATIC_KEY_FALSE(rdt_enable_key);
+DEFINE_STATIC_KEY_FALSE(rdt_mon_enable_key);
DEFINE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
static struct kernfs_root *rdt_root;
struct rdtgroup rdtgroup_default;
@@ -43,6 +45,12 @@ LIST_HEAD(rdt_all_groups);
/* Kernel fs node for "info" directory under root */
static struct kernfs_node *kn_info;

+/* Kernel fs node for "mon_groups" directory under root */
+static struct kernfs_node *kn_mongrp;
+
+/* Kernel fs node for "mon_data" directory under root */
+static struct kernfs_node *kn_mondata;
+
/*
* Trivial allocator for CLOSIDs. Since h/w only supports a small number,
* we can keep a bitmap of free CLOSIDs in a single integer.
@@ -1044,6 +1052,10 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn)
}
}

+static int mkdir_mondata_all(struct kernfs_node *parent_kn,
+ struct rdtgroup *prgrp,
+ struct kernfs_node **mon_data_kn);
+
static struct dentry *rdt_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
@@ -1055,7 +1067,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
/*
* resctrl file system can only be mounted once.
*/
- if (static_branch_unlikely(&rdt_alloc_enable_key)) {
+ if (static_branch_unlikely(&rdt_enable_key)) {
dentry = ERR_PTR(-EBUSY);
goto out;
}
@@ -1074,15 +1086,47 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
goto out_cdp;
}

+ if (rdt_mon_capable) {
+ ret = mongroup_create_dir(rdtgroup_default.kn,
+ NULL, "mon_groups",
+ &kn_mongrp);
+ if (ret) {
+ dentry = ERR_PTR(ret);
+ goto out_info;
+ }
+ kernfs_get(kn_mongrp);
+
+ ret = mkdir_mondata_all(rdtgroup_default.kn,
+ &rdtgroup_default, &kn_mondata);
+ if (ret) {
+ dentry = ERR_PTR(ret);
+ goto out_mongrp;
+ }
+ kernfs_get(kn_mondata);
+ rdtgroup_default.mon.mon_data_kn = kn_mondata;
+ }
+
dentry = kernfs_mount(fs_type, flags, rdt_root,
RDTGROUP_SUPER_MAGIC, NULL);
if (IS_ERR(dentry))
- goto out_destroy;
+ goto out_mondata;

- static_branch_enable(&rdt_alloc_enable_key);
+ if (rdt_alloc_capable)
+ static_branch_enable(&rdt_alloc_enable_key);
+ if (rdt_mon_capable)
+ static_branch_enable(&rdt_mon_enable_key);
+
+ if (rdt_alloc_capable || rdt_mon_capable)
+ static_branch_enable(&rdt_enable_key);
goto out;

-out_destroy:
+out_mondata:
+ if (rdt_mon_capable)
+ kernfs_remove(kn_mondata);
+out_mongrp:
+ if (rdt_mon_capable)
+ kernfs_remove(kn_mongrp);
+out_info:
kernfs_remove(kn_info);
out_cdp:
cdp_disable();
@@ -1204,6 +1248,9 @@ static void rmdir_all_sub(void)
rdt_move_group_tasks(NULL, &rdtgroup_default, NULL);

list_for_each_entry_safe(rdtgrp, tmp, &rdt_all_groups, rdtgroup_list) {
+ /* Free any child rmids */
+ free_all_child_rdtgrp(rdtgrp);
+
/* Remove each rdtgroup other than root */
if (rdtgrp == &rdtgroup_default)
continue;
@@ -1216,6 +1263,8 @@ static void rmdir_all_sub(void)
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);

+ free_rmid(rdtgrp->mon.rmid);
+
kernfs_remove(rdtgrp->kn);
list_del(&rdtgrp->rdtgroup_list);
kfree(rdtgrp);
@@ -1226,6 +1275,8 @@ static void rmdir_all_sub(void)
put_online_cpus();

kernfs_remove(kn_info);
+ kernfs_remove(kn_mongrp);
+ kernfs_remove(kn_mondata);
}

static void rdt_kill_sb(struct super_block *sb)
@@ -1240,6 +1291,8 @@ static void rdt_kill_sb(struct super_block *sb)
cdp_disable();
rmdir_all_sub();
static_branch_disable(&rdt_alloc_enable_key);
+ static_branch_disable(&rdt_mon_enable_key);
+ static_branch_disable(&rdt_enable_key);
kernfs_kill_sb(sb);
mutex_unlock(&rdtgroup_mutex);
}
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