Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751218AbdHXFqA (ORCPT ); Thu, 24 Aug 2017 01:46:00 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:32995 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751019AbdHXFp7 (ORCPT ); Thu, 24 Aug 2017 01:45:59 -0400 From: js1304@gmail.com X-Google-Original-From: iamjoonsoo.kim@lge.com To: Andrew Morton Cc: Michal Hocko , Vlastimil Babka , Mel Gorman , Johannes Weiner , "Aneesh Kumar K . V" , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH] mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request Date: Thu, 24 Aug 2017 14:45:46 +0900 Message-Id: <1503553546-27450-1-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2445 Lines: 71 From: Joonsoo Kim Freepage on ZONE_HIGHMEM doesn't work for kernel memory so it's not that important to reserve. When ZONE_MOVABLE is used, this problem would theorectically cause to decrease usable memory for GFP_HIGHUSER_MOVABLE allocation request which is mainly used for page cache and anon page allocation. So, fix it. And, defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES - 1 size makes code complex. For example, if there is highmem system, following reserve ratio is activated for *NORMAL ZONE* which would be easyily misleading people. #ifdef CONFIG_HIGHMEM 32 #endif This patch also fix this situation by defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES and place "#ifdef" to right place. Reviewed-by: Aneesh Kumar K.V Acked-by: Vlastimil Babka Signed-off-by: Joonsoo Kim --- include/linux/mmzone.h | 2 +- mm/page_alloc.c | 11 ++++++----- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e7e92c8..e5f134b 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -882,7 +882,7 @@ int min_free_kbytes_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); -extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; +extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES]; int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *); int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 90b1996..6faa53d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -202,17 +202,18 @@ static void __free_pages_ok(struct page *page, unsigned int order); * TBD: should special case ZONE_DMA32 machines here - in those we normally * don't need any ZONE_NORMAL reservation */ -int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { +int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = { #ifdef CONFIG_ZONE_DMA - 256, + [ZONE_DMA] = 256, #endif #ifdef CONFIG_ZONE_DMA32 - 256, + [ZONE_DMA32] = 256, #endif + [ZONE_NORMAL] = 32, #ifdef CONFIG_HIGHMEM - 32, + [ZONE_HIGHMEM] = INT_MAX, #endif - 32, + [ZONE_MOVABLE] = INT_MAX, }; EXPORT_SYMBOL(totalram_pages); -- 2.7.4