From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id AD4816B03B6 for ; Mon, 23 Aug 2010 08:56:44 -0400 (EDT) Date: Mon, 23 Aug 2010 07:56:40 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake In-Reply-To: <1282550442-15193-3-git-send-email-mel@csn.ul.ie> Message-ID: References: <1282550442-15193-1-git-send-email-mel@csn.ul.ie> <1282550442-15193-3-git-send-email-mel@csn.ul.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Andrew Morton , Linux Kernel List , linux-mm@kvack.org, Rik van Riel , Johannes Weiner , Minchan Kim , KAMEZAWA Hiroyuki , KOSAKI Motohiro List-ID: On Mon, 23 Aug 2010, Mel Gorman wrote: > This patch introduces zone_nr_free_pages() to take a slightly more accurate > estimate of NR_FREE_PAGES while kswapd is awake. The estimate is not perfect > and may result in cache line bounces but is expected to be lighter than the > IPI calls necessary to continually drain the per-cpu counters while kswapd > is awake. The delta of the counters could also be reduced to increase accuracy. See refresh_zone_stat_thresholds(). Also would it be possible to add the summation function to vmstat? It may be useful elsewhere. A new function like zone_page_state_snapshot() or so? -- 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