Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752200AbbHUQLe (ORCPT ); Fri, 21 Aug 2015 12:11:34 -0400 Received: from resqmta-ch2-07v.sys.comcast.net ([69.252.207.39]:51009 "EHLO resqmta-ch2-07v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752002AbbHUQLa (ORCPT ); Fri, 21 Aug 2015 12:11:30 -0400 Date: Fri, 21 Aug 2015 11:11:27 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@east.gentwo.org To: "Kirill A. Shutemov" cc: Andrew Morton , "Kirill A. Shutemov" , Hugh Dickins , Andrea Arcangeli , Dave Hansen , Vlastimil Babka , Johannes Weiner , Michal Hocko , David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv3 4/5] mm: make compound_head() robust In-Reply-To: <20150821121028.GB12016@node.dhcp.inet.fi> Message-ID: References: <1439976106-137226-1-git-send-email-kirill.shutemov@linux.intel.com> <1439976106-137226-5-git-send-email-kirill.shutemov@linux.intel.com> <20150820163643.dd87de0c1a73cb63866b2914@linux-foundation.org> <20150821121028.GB12016@node.dhcp.inet.fi> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 636 Lines: 16 On Fri, 21 Aug 2015, Kirill A. Shutemov wrote: > > Is this really true? For example if it's a slab page, will that page > > ever be inspected by code which is looking for the PageTail bit? > > +Christoph. > > What we know for sure is that space is not used in tail pages, otherwise > it would collide with current compound_dtor. Sl*b allocators only do a virt_to_head_page on tail pages. -- 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/