From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 18 Jan 2008 16:28:42 +0900 From: KOSAKI Motohiro Subject: Re: [RFC][PATCH] a bit improvement of ZONE_DMA page reclaim In-Reply-To: <20080117232147.85ae8cab.akpm@linux-foundation.org> References: <20080118151822.8FAE.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080117232147.85ae8cab.akpm@linux-foundation.org> Message-Id: <20080118162434.8FB1.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Marcelo Tosatti , Rik van Riel , Daniel Spang List-ID: Hi Andrew > > on X86, ZONE_DMA is very very small. > > It is often no used at all. > > In that case page-reclaim is supposed to set all_unreclaimable and > basically ignores the zone altogether until it looks like something might > have changed. > > Is that code not working? (quite possible). please insert blow debug printk and dd if=bigfile of=/dev/null. you see "near_oom(DMA) 0 0 0" messages :) at least, I can reproduce it on my machine. my machine CPU: x86_64 1.86GHz x2 memory: 6G - kosaki Index: b/mm/vmscan.c =================================================================== --- a/mm/vmscan.c 2008-01-18 14:49:06.000000000 +0900 +++ b/mm/vmscan.c 2008-01-18 14:50:21.000000000 +0900 @@ -966,8 +966,14 @@ static int calc_reclaim_mapped(struct sc int reclaim_mapped = 0; int prev_priority; - if (scan_global_lru(sc) && zone_is_near_oom(zone)) + if (scan_global_lru(sc) && zone_is_near_oom(zone)) { + printk("near_oom(%s) %ld %ld %ld\n", + zone->name, + zone->pages_scanned, + zone_page_state(zone, NR_ACTIVE), + zone_page_state(zone, NR_INACTIVE)); return 1; + } /* * `distress' is a measure of how much trouble we're having * reclaiming pages. 0 -> no problems. 100 -> great trouble. -- 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