From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlastimil Babka Subject: Re: [REGRESSION] "Locked" and "Pss" in /proc/*/smaps are the same Date: Wed, 4 Jul 2018 10:46:52 +0200 Message-ID: References: <69eb77f7-c8cc-fdee-b44f-ad7e522b8467@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Daniel Colascione Cc: Thomas Lindroth , Andrew Morton , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm List-Id: linux-api@vger.kernel.org On 07/03/2018 06:20 PM, Daniel Colascione wrote: > On Tue, Jul 3, 2018 at 12:36 AM, Vlastimil Babka wrote: >> +CC >> >> On 07/01/2018 08:31 PM, Thomas Lindroth wrote: >>> While looking around in /proc on my v4.14.52 system I noticed that >>> all processes got a lot of "Locked" memory in /proc/*/smaps. A lot >>> more memory than a regular user can usually lock with mlock(). >>> >>> commit 493b0e9d945fa9dfe96be93ae41b4ca4b6fdb317 (v4.14-rc1) seems >>> to have changed the behavior of "Locked". > > Thanks for fixing that. I submitted a patch [1] for this bug and some > others a while ago, but the patch didn't make it into the tree because > or wasn't split up correctly or something, and I had to do other work. Hmm I see. I pondered about the patch and wondered if the scenarios it fixes are really possible for smaps_rollup. Did you observe them in practice? Namely: - when seq_file starts and stops multiple times on a single open file description - when it issues multiple show calls for the same iterator value I don't think it can happen when all positions but the last one just return SEQ_SKIP. Anyway I think the seq_file iterator API usage for smaps_rollup is unnecessary. Semantically the file shows only one "element" and that's the set of rollup values for all vmas. Letting seq_file do the iteration over vmas brings only complications? > [1] https://marc.info/?l=linux-mm&m=151927723128134&w=2 >