Re: [PATCH 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter

From: Oscar Salvador <osalvador@suse.de>
To: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux MM Mailing List <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
	Eric Dumazet <edumazet@google.com>,
	Waiman Long <longman@redhat.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Ammar Faizi <ammarfaizi2@gmail.com>
Subject: Re: [PATCH 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter
Date: Fri, 2 Sep 2022 05:33:23 +0200	[thread overview]
Message-ID: <YxF5g4Q1rpJztg59@localhost.localdomain> (raw)
In-Reply-To: <9f2ef1ac-c0a1-eb77-8e68-e9a60bc8efd2@gnuweeb.org>

On Thu, Sep 01, 2022 at 03:16:44PM +0700, Ammar Faizi wrote:
> On 9/1/22 11:42 AM, Oscar Salvador wrote:
> > +static unsigned long last_stack = 0;
> 
> This @last_stack can just be a static local variable in the new
> function you wrote, read_page_owner_stacks(), since no other
> functions use it.

We could certainly do that.

> 
> > +static ssize_t read_page_owner_stacks(struct file *file, char __user *buf,
> > +				      size_t count, loff_t *pos)
> > +{
> > +	char *kbuf;
> > +	int ret = 0;
> > +
> > +	count = min_t(size_t, count, PAGE_SIZE);
> > +	kbuf = kmalloc(count, GFP_KERNEL);
> > +	if (!kbuf)
> > +		return ENOMEM;
> 
> Missing a negative sign, return -ENOMEM;

Oh yes, I overlooked that.

Thanks!

-- 
Oscar Salvador
SUSE Labs