Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752162AbaLOOQH (ORCPT ); Mon, 15 Dec 2014 09:16:07 -0500 Received: from resqmta-po-05v.sys.comcast.net ([96.114.154.164]:50810 "EHLO resqmta-po-05v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751181AbaLOOQE (ORCPT ); Mon, 15 Dec 2014 09:16:04 -0500 Date: Mon, 15 Dec 2014 08:16:00 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Joonsoo Kim cc: akpm@linuxfoundation.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org, Thomas Gleixner , linux-mm@kvack.org, penberg@kernel.org, Jesper Dangaard Brouer Subject: Re: [PATCH 3/7] slub: Do not use c->page on free In-Reply-To: <20141215080338.GE4898@js1304-P5Q-DELUXE> Message-ID: References: <20141210163017.092096069@linux.com> <20141210163033.717707217@linux.com> <20141215080338.GE4898@js1304-P5Q-DELUXE> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Dec 2014, Joonsoo Kim wrote: > > +static bool same_slab_page(struct kmem_cache *s, struct page *page, void *p) > > +{ > > + long d = p - page->address; > > + > > + return d > 0 && d < (1 << MAX_ORDER) && d < (compound_order(page) << PAGE_SHIFT); > > +} > > + > > Somtimes, compound_order() induces one more cacheline access, because > compound_order() access second struct page in order to get order. Is there > any way to remove this? I already have code there to avoid the access if its within a MAX_ORDER page. We could probably go for a smaller setting there. PAGE_COSTLY_ORDER? -- 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/