Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753938Ab3JSWj7 (ORCPT ); Sat, 19 Oct 2013 18:39:59 -0400 Received: from mga02.intel.com ([134.134.136.20]:1176 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753662Ab3JSWj4 (ORCPT ); Sat, 19 Oct 2013 18:39:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,531,1378882800"; d="scan'208";a="421714639" From: Andi Kleen To: Andrew Morton Cc: Joonsoo Kim , Pekka Enberg , Christoph Lameter , Joonsoo Kim , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wanpeng Li Subject: Re: [PATCH v2 00/15] slab: overload struct slab over struct page to reduce memory usage References: <1381913052-23875-1-git-send-email-iamjoonsoo.kim@lge.com> <20131016133457.60fa71f893cd2962d8ec6ff3@linux-foundation.org> Date: Sat, 19 Oct 2013 15:39:34 -0700 In-Reply-To: <20131016133457.60fa71f893cd2962d8ec6ff3@linux-foundation.org> (Andrew Morton's message of "Wed, 16 Oct 2013 13:34:57 -0700") Message-ID: <8738nwvqah.fsf@tassilo.jf.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1060 Lines: 28 Andrew Morton writes: > > One example is mm/memory-failure.c:memory_failure(). It starts with a > raw pfn, uses that to get at the `struct page', then starts playing > around with it. Will that code still work correctly when some of the > page's fields have been overlayed with slab-specific contents? As long as PageSlab() works correctly memory_failure should be happy. > > This issue hasn't been well thought through. Given a random struct > page, there isn't any protocol to determine what it actually *is*. > It's a plain old variant record, but it lacks the agreed-upon tag field > which tells users which variant is currently in use. PageSlab() should work for this right? For the generic case it may not though. -Andi -- ak@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/