From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 7DA576B0261 for ; Thu, 12 Jan 2017 11:16:49 -0500 (EST) Received: by mail-pf0-f198.google.com with SMTP id f144so59232070pfa.3 for ; Thu, 12 Jan 2017 08:16:49 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id u84si9657494pgb.258.2017.01.12.08.16.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Jan 2017 08:16:48 -0800 (PST) Date: Thu, 12 Jan 2017 17:16:43 +0100 From: Peter Zijlstra Subject: Re: [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace Message-ID: <20170112161643.GB3144@twins.programming.kicks-ass.net> References: <1481260331-360-1-git-send-email-byungchul.park@lge.com> <1481260331-360-6-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1481260331-360-6-git-send-email-byungchul.park@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Byungchul Park Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, npiggin@gmail.com On Fri, Dec 09, 2016 at 02:12:01PM +0900, Byungchul Park wrote: > check_prev_add() saves a stack trace of the current. But crossrelease > feature needs to use a separate stack trace of another context in > check_prev_add(). So make it use a separate stack trace instead of one > of the current. > So I was thinking, can't we make check_prevs_add() create the stack trace unconditionally but record if we used it or not, and then return the entries when unused. All that is serialized by graph_lock anyway and that way we already pass a stack into check_prev_add() so we can easily pass in a different one. I think that removes a bunch of tricky and avoids all the new tricky. -- 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