From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx140.postini.com [74.125.245.140]) by kanga.kvack.org (Postfix) with SMTP id BEE466B0062 for ; Mon, 16 Sep 2013 11:18:34 -0400 (EDT) Date: Mon, 16 Sep 2013 17:18:22 +0200 From: Peter Zijlstra Subject: Re: [PATCH 14/50] sched: Set the scan rate proportional to the memory usage of the task being scanned Message-ID: <20130916151822.GE9326@twins.programming.kicks-ass.net> References: <1378805550-29949-1-git-send-email-mgorman@suse.de> <1378805550-29949-15-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1378805550-29949-15-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Rik van Riel , Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML On Tue, Sep 10, 2013 at 10:31:54AM +0100, Mel Gorman wrote: > @@ -860,9 +908,14 @@ void task_numa_fault(int node, int pages, bool migrated) > * If pages are properly placed (did not migrate) then scan slower. > * This is reset periodically in case of phase changes > */ > - if (!migrated) > - p->numa_scan_period = min(sysctl_numa_balancing_scan_period_max, > + if (!migrated) { > + /* Initialise if necessary */ > + if (!p->numa_scan_period_max) > + p->numa_scan_period_max = task_scan_max(p); > + > + p->numa_scan_period = min(p->numa_scan_period_max, > p->numa_scan_period + jiffies_to_msecs(10)); So the next patch changes the jiffies_to_msec() thing.. is that really worth a whole separate patch? Also, I really don't believe any of that is 'right', increasing the scan period by a fixed amount for every !migrated page is just wrong. Firstly; there's the migration throttle which basically guarantees that most pages aren't migrated -- even when they ought to be, thus inflating the period. Secondly; assume a _huge_ process, so large that even a small fraction of non-migrated pages will completely clip the scan period. -- 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