From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx114.postini.com [74.125.245.114]) by kanga.kvack.org (Postfix) with SMTP id B40556B0031 for ; Tue, 6 Aug 2013 12:59:12 -0400 (EDT) Message-ID: <52012B35.90801@intel.com> Date: Tue, 06 Aug 2013 09:58:29 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [RFC PATCH 3/4] mm: add zbud flag to page flags References: <1375771361-8388-1-git-send-email-k.kozlowski@samsung.com> <1375771361-8388-4-git-send-email-k.kozlowski@samsung.com> In-Reply-To: <1375771361-8388-4-git-send-email-k.kozlowski@samsung.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Krzysztof Kozlowski Cc: Seth Jennings , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Mel Gorman , Bartlomiej Zolnierkiewicz , Marek Szyprowski , Kyungmin Park On 08/05/2013 11:42 PM, Krzysztof Kozlowski wrote: > +#ifdef CONFIG_ZBUD > + /* Allocated by zbud. Flag is necessary to find zbud pages to unuse > + * during migration/compaction. > + */ > + PG_zbud, > +#endif Do you _really_ need an absolutely new, unshared page flag? The zbud code doesn't really look like it uses any of the space in 'struct page'. I think you could pretty easily alias PG_zbud=PG_slab, then use the page->{private,slab_cache} (or some other unused field) in 'struct page' to store a cookie to differentiate slab and zbud 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