Re: [PATCH 1/2] mac80211: Show pending txqlen in debugfs.

[Ben Greear]

On 12/05/2016 06:54 AM, Johannes Berg wrote:

On Mon, 2016-12-05 at 06:47 -0800, Ben Greear wrote:


On 12/05/2016 05:59 AM, Johannes Berg wrote:


+static ssize_t misc_read(struct file *file, char __user *user_buf,


+size_t count, loff_t *ppos)
+{
+   struct ieee80211_local *local = file->private_data;
+   size_t bufsz = 1000;
+   char *buf = kzalloc(bufsz, GFP_KERNEL);


You need at most IEEE80211_MAX_QUEUES * 16 (==256) which I think
you
can put on the stack?


I actually run with 64 queues in my tree,


Heh, well, in that case the 1000 is actually potentially too small for
you :) (it'll work because there never are many packets on the queues
though)


and either way, I thought large-ish things on the stack were frowned
upon for systems that want to run smaller stacks?


Yeah but the limit is more like 1KB :)

Maybe allocate, but actually do 16*NUM_QUEUES? The 1000 is just
arbitrarily magic in there.


Sounds good, I'll respin it.

Thanks,
Ben



johannes



--
Ben Greear 
Candela Technologies Inc  http://www.candelatech.com

Re: [PATCH 1/2] mac80211: Show pending txqlen in debugfs.

[Johannes Berg]

On Mon, 2016-12-05 at 06:47 -0800, Ben Greear wrote:
> 
> On 12/05/2016 05:59 AM, Johannes Berg wrote:
> > 
> > +static ssize_t misc_read(struct file *file, char __user *user_buf,
> > > 
> > > +  size_t count, loff_t *ppos)
> > > +{
> > > + struct ieee80211_local *local = file->private_data;
> > > + size_t bufsz = 1000;
> > > + char *buf = kzalloc(bufsz, GFP_KERNEL);
> > 
> > You need at most IEEE80211_MAX_QUEUES * 16 (==256) which I think
> > you
> > can put on the stack?
> 
> I actually run with 64 queues in my tree, 

Heh, well, in that case the 1000 is actually potentially too small for
you :) (it'll work because there never are many packets on the queues
though)

> and either way, I thought large-ish things on the stack were frowned
> upon for systems that want to run smaller stacks?

Yeah but the limit is more like 1KB :)

Maybe allocate, but actually do 16*NUM_QUEUES? The 1000 is just
arbitrarily magic in there.

johannes

Re: [PATCH 1/2] mac80211: Show pending txqlen in debugfs.

[Johannes Berg]

+static ssize_t misc_read(struct file *file, char __user *user_buf,
> +  size_t count, loff_t *ppos)
> +{
> + struct ieee80211_local *local = file->private_data;
> + size_t bufsz = 1000;
> + char *buf = kzalloc(bufsz, GFP_KERNEL);

You need at most IEEE80211_MAX_QUEUES * 16 (==256) which I think you
can put on the stack?

johannes

Re: [PATCH 1/2] mac80211: Show pending txqlen in debugfs.

[Ben Greear]

On 12/05/2016 05:59 AM, Johannes Berg wrote:

+static ssize_t misc_read(struct file *file, char __user *user_buf,

+size_t count, loff_t *ppos)
+{
+   struct ieee80211_local *local = file->private_data;
+   size_t bufsz = 1000;
+   char *buf = kzalloc(bufsz, GFP_KERNEL);


You need at most IEEE80211_MAX_QUEUES * 16 (==256) which I think you
can put on the stack?


I actually run with 64 queues in my tree, and either way, I thought large-ish
things on the stack were frowned upon for systems that want to run smaller 
stacks?

Thanks,
Ben

--
Ben Greear 
Candela Technologies Inc  http://www.candelatech.com

[PATCH 1/2] mac80211: Show pending txqlen in debugfs.

[greearb]

From: Ben Greear 

Could be useful for debugging memory consumption issues,
and perhaps power-save as well.

Signed-off-by: Ben Greear 
---

This is against 4.7.10+

 net/mac80211/debugfs.c | 26 ++
 1 file changed, 26 insertions(+)

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index b251b2f7..0b49b43 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -162,6 +162,30 @@ static ssize_t hwflags_read(struct file *file, char __user 
*user_buf,
return rv;
 }
 
+static ssize_t misc_read(struct file *file, char __user *user_buf,
+size_t count, loff_t *ppos)
+{
+   struct ieee80211_local *local = file->private_data;
+   size_t bufsz = 1000;
+   char *buf = kzalloc(bufsz, GFP_KERNEL);
+   char *pos = buf, *end = buf + bufsz - 1;
+   ssize_t rv;
+   int i;
+   int ln;
+
+   pos += scnprintf(pos, end - pos, "pending:\n");
+
+   for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
+   ln = skb_queue_len(>pending[i]);
+   pos += scnprintf(pos, end - pos, "[%i] %d\n",
+i, ln);
+   }
+
+   rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
+   kfree(buf);
+   return rv;
+}
+
 static ssize_t queues_read(struct file *file, char __user *user_buf,
   size_t count, loff_t *ppos)
 {
@@ -182,6 +206,7 @@ static ssize_t queues_read(struct file *file, char __user 
*user_buf,
 
 DEBUGFS_READONLY_FILE_OPS(hwflags);
 DEBUGFS_READONLY_FILE_OPS(queues);
+DEBUGFS_READONLY_FILE_OPS(misc);
 
 /* statistics stuff */
 
@@ -250,6 +275,7 @@ void debugfs_hw_add(struct ieee80211_local *local)
DEBUGFS_ADD(total_ps_buffered);
DEBUGFS_ADD(wep_iv);
DEBUGFS_ADD(queues);
+   DEBUGFS_ADD(misc);
 #ifdef CONFIG_PM
DEBUGFS_ADD_MODE(reset, 0200);
 #endif
-- 
2.4.11