From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f171.google.com (mail-io0-f171.google.com [209.85.223.171]) by kanga.kvack.org (Postfix) with ESMTP id E19226B0253 for ; Fri, 21 Aug 2015 12:11:30 -0400 (EDT) Received: by iodb91 with SMTP id b91so86497180iod.1 for ; Fri, 21 Aug 2015 09:11:30 -0700 (PDT) Received: from resqmta-ch2-03v.sys.comcast.net (resqmta-ch2-03v.sys.comcast.net. [2001:558:fe21:29:69:252:207:35]) by mx.google.com with ESMTPS id e31si1701211iod.168.2015.08.21.09.11.29 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Fri, 21 Aug 2015 09:11:29 -0700 (PDT) Date: Fri, 21 Aug 2015 11:11:27 -0500 (CDT) From: Christoph Lameter 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: owner-linux-mm@kvack.org List-ID: 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 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, 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