From: Oscar Salvador <osalvador@suse.de>
To: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux MM Mailing List <linux-mm@kvack.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>
Subject: Re: [PATCH 3/3] mm,page_owner: Filter out stacks by a threshold counter
Date: Fri, 2 Sep 2022 05:36:31 +0200 [thread overview]
Message-ID: <YxF6P++FVKvIUiQq@localhost.localdomain> (raw)
In-Reply-To: <3c69f09e-1e34-73f9-b38b-733971ef38cb@gnuweeb.org>
On Thu, Sep 01, 2022 at 03:31:51PM +0700, Ammar Faizi wrote:
> On 9/1/22 11:42 AM, Oscar Salvador wrote:> +static ssize_t read_page_owner_threshold(struct file *file, char __user *buf,
> > + kbuf = kmalloc(count, GFP_KERNEL);
> > + if (!kbuf)
> > + return ENOMEM;
>
> Missing a negative sign, return -ENOMEM.
Will fix.
> > +static ssize_t write_page_owner_threshold(struct file *file, const 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);
>
> This looks overestimating to me. For unsigned long, on a 64-bit system
> has max val 18446744073709551615 (20 chars).
>
> You can use stack a allocated local variable with length 21. No need
> to use kmalloc(). The same way with the read() op.
Probably could do that, but I'll go with Michal's option and will use
seq_file.
Thanks!
--
Oscar Salvador
SUSE Labs
next prev parent reply other threads:[~2022-09-02 3:36 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 4:42 [PATCH 0/3] page_owner: print stacks and their counter Oscar Salvador
2022-09-01 4:42 ` [PATCH 1/3] lib/stackdepot: Add a refcount field in stack_record Oscar Salvador
2022-09-01 8:24 ` Marco Elver
2022-09-01 8:38 ` Michal Hocko
2022-09-01 9:18 ` Marco Elver
2022-09-01 10:01 ` Michal Hocko
2022-09-01 10:20 ` Marco Elver
2022-09-05 20:53 ` Andrey Konovalov
2022-09-02 3:27 ` Oscar Salvador
2022-09-01 4:42 ` [PATCH 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter Oscar Salvador
2022-09-01 8:16 ` Ammar Faizi
2022-09-02 3:33 ` Oscar Salvador
2022-09-01 19:29 ` kernel test robot
2022-09-02 0:56 ` kernel test robot
2022-09-01 4:42 ` [PATCH 3/3] mm,page_owner: Filter out stacks by a threshold counter Oscar Salvador
2022-09-01 8:31 ` Ammar Faizi
2022-09-02 3:36 ` Oscar Salvador [this message]
2022-09-01 8:40 ` Michal Hocko
2022-09-02 3:37 ` Oscar Salvador
2022-09-01 8:32 ` [PATCH 0/3] page_owner: print stacks and their counter Michal Hocko
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