From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id CB3066007EE for ; Mon, 23 Aug 2010 12:04:41 -0400 (EDT) Date: Mon, 23 Aug 2010 11:04:38 -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: <20100823135559.GS19797@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> <20100823130315.GQ19797@csn.ul.ie> <20100823135559.GS19797@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: > > When the vm gets into a state where continual reclaim is necessary then > > the counters are not that frequently updated. If the machine is already > > slowing down due to reclaim then the vm can likely affort more frequent > > counter updates. > > > > Ok, but is that better than this patch? Decreasing the size of the window by > reducing the threshold still leaves a window. There is still a small amount > of drift by summing up all the deltas but you get a much more accurate count > at the point of time it was important to know. In order to make that decision we would need to know what deltas make a significant difference. Would be also important to know if there are any other counters that have issues. If so then the reduction of the thresholds is addressing these problems in a number of counters. I have no objection against this approach here but it may just be bandaid on a larger issue that could be approached in a cleaner way. -- 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