Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762595Ab3JQTP3 (ORCPT ); Thu, 17 Oct 2013 15:15:29 -0400 Received: from a9-99.smtp-out.amazonses.com ([54.240.9.99]:52014 "EHLO a9-99.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762432Ab3JQTPZ (ORCPT ); Thu, 17 Oct 2013 15:15:25 -0400 Date: Thu, 17 Oct 2013 19:15:23 +0000 From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Andrew Morton cc: Joonsoo Kim , Pekka Enberg , 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 In-Reply-To: <20131016133457.60fa71f893cd2962d8ec6ff3@linux-foundation.org> Message-ID: <00000141c7d7ff58-44f388c4-da4a-4438-84a3-a2edb161b6a4-000000@email.amazonses.com> References: <1381913052-23875-1-git-send-email-iamjoonsoo.kim@lge.com> <20131016133457.60fa71f893cd2962d8ec6ff3@linux-foundation.org> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 2013.10.17-54.240.9.99 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 718 Lines: 16 On Wed, 16 Oct 2013, Andrew Morton wrote: > 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. This issue has bitten us when SLUB was first introduced. We found out the hard way f.e. that the mapping field had meaning in various contexts for a slab page. -- 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/