From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx168.postini.com [74.125.245.168]) by kanga.kvack.org (Postfix) with SMTP id 7E4E66B005C for ; Tue, 29 May 2012 09:16:38 -0400 (EDT) Message-ID: <1338297385.26856.74.camel@twins> Subject: Re: [PATCH 13/35] autonuma: add page structure fields From: Peter Zijlstra Date: Tue, 29 May 2012 15:16:25 +0200 In-Reply-To: <1337965359-29725-14-git-send-email-aarcange@redhat.com> References: <1337965359-29725-1-git-send-email-aarcange@redhat.com> <1337965359-29725-14-git-send-email-aarcange@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hillf Danton , Dan Smith , Linus Torvalds , Andrew Morton , Thomas Gleixner , Ingo Molnar , Paul Turner , Suresh Siddha , Mike Galbraith , "Paul E. McKenney" , Lai Jiangshan , Bharata B Rao , Lee Schermerhorn , Rik van Riel , Johannes Weiner , Srivatsa Vaddagiri , Christoph Lameter On Fri, 2012-05-25 at 19:02 +0200, Andrea Arcangeli wrote: > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 780ded7..e8dc82c 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -126,6 +126,31 @@ struct page { > struct page *first_page; /* Compound tail pages */ > }; > =20 > +#ifdef CONFIG_AUTONUMA > + /* > + * FIXME: move to pgdat section along with the memcg and allocate > + * at runtime only in presence of a numa system. > + */ > + /* > + * To modify autonuma_last_nid lockless the architecture, > + * needs SMP atomic granularity < sizeof(long), not all archs > + * have that, notably some alpha. Archs without that requires > + * autonuma_last_nid to be a long. > + */ > +#if BITS_PER_LONG > 32 > + int autonuma_migrate_nid; > + int autonuma_last_nid; > +#else > +#if MAX_NUMNODES >=3D 32768 > +#error "too many nodes" > +#endif > + /* FIXME: remember to check the updates are atomic */ > + short autonuma_migrate_nid; > + short autonuma_last_nid; > +#endif > + struct list_head autonuma_migrate_node; > +#endif > + > /* > * On machines where all RAM is mapped into kernel address space, > * we can simply calculate the virtual address. On machines with 24 bytes per page.. or ~0.6% of memory gone. This is far too great a price to pay. At LSF/MM Rik already suggested you limit the number of pages that can be migrated concurrently and use this to move the extra list_head out of struct page and into a smaller amount of extra structures, reducing the total overhead. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org