From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 734E76B025F for ; Mon, 14 Aug 2017 03:30:21 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id k190so121772019pge.9 for ; Mon, 14 Aug 2017 00:30:21 -0700 (PDT) Received: from lgeamrelo12.lge.com (LGEAMRELO12.lge.com. [156.147.23.52]) by mx.google.com with ESMTP id a90si4217835plc.816.2017.08.14.00.30.18 for ; Mon, 14 Aug 2017 00:30:19 -0700 (PDT) Date: Mon, 14 Aug 2017 16:29:00 +0900 From: Byungchul Park Subject: Re: [PATCH v8 06/14] lockdep: Detect and handle hist_lock ring buffer overwrite Message-ID: <20170814072900.GL20323@X58A-UD3R> References: <20170810115922.kegrfeg6xz7mgpj4@tardis> <016b01d311d1$d02acfa0$70806ee0$@lge.com> <20170810125133.2poixhni4d5aqkpy@tardis> <20170810131737.skdyy4qcxlikbyeh@tardis> <20170811034328.GH20323@X58A-UD3R> <20170811080329.3ehu7pp7lcm62ji6@tardis> <20170811085201.GI20323@X58A-UD3R> <20170811094448.GJ20323@X58A-UD3R> <20170814070522.wwj4as2hk2o7avlu@tardis> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170814070522.wwj4as2hk2o7avlu@tardis> Sender: owner-linux-mm@kvack.org List-ID: To: Boqun Feng Cc: Byungchul Park , Peter Zijlstra , Ingo Molnar , tglx@linutronix.de, Michel Lespinasse , kirill@shutemov.name, "linux-kernel@vger.kernel.org" , linux-mm@kvack.org, akpm@linux-foundation.org, willy@infradead.org, npiggin@gmail.com, kernel-team@lge.com On Mon, Aug 14, 2017 at 03:05:22PM +0800, Boqun Feng wrote: > > 1. Boqun's approach > > My approach requires(additionally): > > MAX_XHLOCKS_NR * sizeof(unsigned int) // because of the hist_id field in hist_lock > > bytes per task. > > > 2. Peterz's approach > > And Peter's approach requires(additionally): > > 1 * sizeof(unsigned int) > > bytes per task. > > So basically we need some tradeoff between memory footprints and history > precision here. I see what you intended. Then, Peterz's one looks better. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org