From patchwork Fri Nov 16 18:39:05 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 1756921 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 9B29A4005F for ; Fri, 16 Nov 2012 18:40:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752695Ab2KPSk3 (ORCPT ); Fri, 16 Nov 2012 13:40:29 -0500 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:53337 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752601Ab2KPSk1 (ORCPT ); Fri, 16 Nov 2012 13:40:27 -0500 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 17 Nov 2012 04:36:25 +1000 Received: from d23relay05.au.ibm.com (202.81.31.247) by e23smtp09.au.ibm.com (202.81.31.206) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Sat, 17 Nov 2012 04:36:23 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id qAGITlih60096578; Sat, 17 Nov 2012 05:29:47 +1100 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qAGIeJLd026917; Sat, 17 Nov 2012 05:40:21 +1100 Received: from srivatsabhat.in.ibm.com ([9.78.194.93]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id qAGIeC7W026814; Sat, 17 Nov 2012 05:40:13 +1100 Message-ID: <50A68849.2030401@linux.vnet.ibm.com> Date: Sat, 17 Nov 2012 00:09:05 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: akpm@linux-foundation.org, mgorman@suse.de, mjg59@srcf.ucam.org, paulmck@linux.vnet.ibm.com, dave@linux.vnet.ibm.com, maxime.coquelin@stericsson.com, loic.pallardy@stericsson.com, arjan@linux.intel.com, kmpark@infradead.org, kamezawa.hiroyu@jp.fujitsu.com, lenb@kernel.org, rjw@sisk.pl CC: "Srivatsa S. Bhat" , gargankita@gmail.com, amit.kachhap@linaro.org, svaidy@linux.vnet.ibm.com, thomas.abraham@linaro.org, santosh.shilimkar@ti.com, linux-pm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, andi@firstfloor.org, SrinivasPandruvada Subject: [RFC PATCH UPDATED 4/8] mm: Add helpers to retrieve node region and zone region for a given page References: <20121106195026.6941.24662.stgit@srivatsabhat.in.ibm.com> <20121106195310.6941.91123.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20121106195310.6941.91123.stgit@srivatsabhat.in.ibm.com> x-cbid: 12111618-3568-0000-0000-000002C7443C Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org This version of the patch includes a bug-fix for page_node_region_id() which used to break the NUMA case. ---------------------------------------------------------------------> From: Srivatsa S. Bhat Subject: mm: Add helpers to retrieve node region and zone region for a given page Given a page, we would like to have an efficient mechanism to find out the node memory region and the zone memory region to which it belongs. Since the node is assumed to be divided into equal-sized node memory regions, the node memory region index can be obtained by simply right-shifting the page's pfn by 'mem_region_shift'. But finding the corresponding zone memory region's index in the zone is not that straight-forward. To have a O(1) algorithm to find it out, define a zone_region_idx[] array to store the zone memory region indices for every node memory region. To illustrate, consider the following example: |<---------------------Node---------------------->| _________________________________________________ | Node mem reg 0 | Node mem reg 1 | |_______________________|_________________________| _________________________________________________ | ZONE_DMA | ZONE_NORMAL | |_______________|_________________________________| In the above figure, Node mem region 0: ------------------ This region corresponds to the first zone mem region in ZONE_DMA and also the first zone mem region in ZONE_NORMAL. Hence its index array would look like this: node_regions[0].zone_region_idx[ZONE_DMA] == 0 node_regions[0].zone_region_idx[ZONE_NORMAL] == 0 Node mem region 1: ------------------ This region corresponds to the second zone mem region in ZONE_NORMAL. Hence its index array would look like this: node_regions[1].zone_region_idx[ZONE_NORMAL] == 1 Using this index array, we can quickly obtain the zone memory region to which a given page belongs. Signed-off-by: Srivatsa S. Bhat --- include/linux/mm.h | 24 ++++++++++++++++++++++++ include/linux/mmzone.h | 7 +++++++ mm/page_alloc.c | 2 ++ 3 files changed, 33 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/include/linux/mm.h b/include/linux/mm.h index 19c4fb0..32457c7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -702,6 +702,30 @@ static inline struct zone *page_zone(const struct page *page) return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]; } +static inline int page_node_region_id(const struct page *page, + const pg_data_t *pgdat) +{ + return (page_to_pfn(page) - pgdat->node_start_pfn) >> MEM_REGION_SHIFT; +} + +/** + * Return the index of the region to which the page belongs, within its zone. + * + * Given a page, find the absolute (node) region as well as the zone to which + * it belongs. Then find the region within the zone that corresponds to that + * absolute (node) region, and return its index. + */ +static inline int page_zone_region_id(const struct page *page) +{ + pg_data_t *pgdat = NODE_DATA(page_to_nid(page)); + enum zone_type z_num = page_zonenum(page); + unsigned long node_region_idx; + + node_region_idx = page_node_region_id(page, pgdat); + + return pgdat->node_regions[node_region_idx].zone_region_idx[z_num]; +} + #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) static inline void set_page_section(struct page *page, unsigned long section) { diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 9f923aa..3982354 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -336,6 +336,13 @@ struct node_mem_region { unsigned long spanned_pages; int idx; int node; + + /* + * A physical (node) region could be split across multiple zones. + * Store the indices of the corresponding regions of each such + * zone for this physical (node) region. + */ + int zone_region_idx[MAX_NR_ZONES]; struct pglist_data *pgdat; }; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c00f72d..7fd89cd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4621,6 +4621,8 @@ void init_zone_memory_regions(struct pglist_data *pgdat) end_pfn); z->zone_mem_region[idx].present_pages = end_pfn - start_pfn - absent; + + region->zone_region_idx[zone_idx(z)] = idx; idx++; }