[RFC 4/8] p2pmem: Add debugfs "stats" file

Logan Gunthorpe
2017-03-30T22:12:35Z

From: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>

For each p2pmem instance, add a "stats" file to show
the gen_pool statistics.

Signed-off-by: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
Signed-off-by: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
Signed-off-by: Stephen Bates <sbates-pv7U853sEMVWk0Htik3J/w@public.gmane.org>
---
drivers/memory/p2pmem.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/p2pmem.h | 2 ++
2 files changed, 51 insertions(+)

diff --git a/drivers/memory/p2pmem.c b/drivers/memory/p2pmem.c
index c4ea311..71741c2 100644
--- a/drivers/memory/p2pmem.c
+++ b/drivers/memory/p2pmem.c
@@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/genalloc.h>
#include <linux/memremap.h>
+#include <linux/debugfs.h>

MODULE_DESCRIPTION("Peer 2 Peer Memory Device");
MODULE_VERSION("0.1");
@@ -27,6 +28,40 @@ MODULE_AUTHOR("Microsemi Corporation");
static struct class *p2pmem_class;
static DEFINE_IDA(p2pmem_ida);

+static struct dentry *p2pmem_debugfs_root;
+
+static int stats_show(struct seq_file *seq, void *v)
+{
+ struct p2pmem_dev *p = seq->private;
+
+ if (p->pool) {
+ seq_printf(seq, "total size: %lu\n", gen_pool_size(p->pool));
+ seq_printf(seq, "available: %lu\n", gen_pool_avail(p->pool));
+ }
+ return 0;
+}
+
+static int stats_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, stats_show, inode->i_private);
+}
+
+static const struct file_operations stats_debugfs_fops = {
+ .owner = THIS_MODULE,
+ .open = stats_open,
+ .release = single_release,
+ .read = seq_read,
+ .llseek = seq_lseek,
+};
+
+static void setup_debugfs(struct p2pmem_dev *p)
+{
+ struct dentry *de;
+
+ de = debugfs_create_file("stats", 0400, p->debugfs_root,
+ (void *)p, &stats_debugfs_fops);
+}
+
static struct p2pmem_dev *to_p2pmem(struct device *dev)
{
return container_of(dev, struct p2pmem_dev, dev);
@@ -62,6 +97,8 @@ static void p2pmem_release(struct device *dev)
{
struct p2pmem_dev *p = to_p2pmem(dev);

+ debugfs_remove_recursive(p->debugfs_root);
+
if (p->pool)
gen_pool_destroy(p->pool);

@@ -114,6 +151,13 @@ struct p2pmem_dev *p2pmem_create(struct device *parent)
if (rc)
goto err_id;

+ if (p2pmem_debugfs_root) {
+ p->debugfs_root = debugfs_create_dir(dev_name(&p->dev),
+ p2pmem_debugfs_root);
+ if (p->debugfs_root)
+ setup_debugfs(p);
+ }
+
rc = device_add(&p->dev);
if (rc)
goto err_id;
@@ -390,12 +434,17 @@ static int __init p2pmem_init(void)
if (IS_ERR(p2pmem_class))
return PTR_ERR(p2pmem_class);

+ p2pmem_debugfs_root = debugfs_create_dir("p2pmem", NULL);
+ if (!p2pmem_debugfs_root)
+ pr_info("could not create debugfs entry, continuing\n");
+
return 0;
}
module_init(p2pmem_init);

static void __exit p2pmem_exit(void)
{
+ debugfs_remove_recursive(p2pmem_debugfs_root);
class_destroy(p2pmem_class);

pr_info(KBUILD_MODNAME ": unloaded.\n");
diff --git a/include/linux/p2pmem.h b/include/linux/p2pmem.h
index 71dc1e1..4cd6f35 100644
--- a/include/linux/p2pmem.h
+++ b/include/linux/p2pmem.h
@@ -26,6 +26,8 @@ struct p2pmem_dev {
struct percpu_ref ref;
struct completion cmp;
struct gen_pool *pool;
+
+ struct dentry *debugfs_root;
};

#ifdef CONFIG_P2PMEM
--
2.1.4

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