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Thu, 1 Sep 2022 08:40:33 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id q2MHFwFwEGMSOQAAMHmgww (envelope-from ); Thu, 01 Sep 2022 08:40:33 +0000 Date: Thu, 1 Sep 2022 10:40:32 +0200 From: Michal Hocko To: Oscar Salvador Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Vlastimil Babka , Eric Dumazet , Waiman Long , Suren Baghdasaryan Subject: Re: [PATCH 3/3] mm,page_owner: Filter out stacks by a threshold counter Message-ID: References: <20220901044249.4624-1-osalvador@suse.de> <20220901044249.4624-4-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220901044249.4624-4-osalvador@suse.de> ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=elM7XrD+; spf=pass (imf07.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com; 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dmarc=pass (policy=quarantine) header.from=suse.com X-Rspam-User: X-Stat-Signature: 4y8obbg5ag1hi1gi6ifa3mf9wnqy6np7 X-Rspamd-Queue-Id: A63734004A X-Rspamd-Server: rspam09 X-HE-Tag: 1662021634-336217 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 01-09-22 06:42:49, Oscar Salvador wrote: [...] > +static ssize_t read_page_owner_threshold(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); > + > + if (*pos >= count) > + return 0; > + > + kbuf = kmalloc(count, GFP_KERNEL); No, you do not want to trigger user defined allocation like that. I would use seq_file. -- Michal Hocko SUSE Labs