Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751692AbaFEOAQ (ORCPT ); Thu, 5 Jun 2014 10:00:16 -0400 Received: from mail-qg0-f52.google.com ([209.85.192.52]:59483 "EHLO mail-qg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751118AbaFEOAL (ORCPT ); Thu, 5 Jun 2014 10:00:11 -0400 MIME-Version: 1.0 In-Reply-To: <20140605133747.GB2942@dhcp22.suse.cz> References: <53905594d284f_71f12992fc6a@nysa.notmuch> <20140605133747.GB2942@dhcp22.suse.cz> Date: Thu, 5 Jun 2014 09:00:10 -0500 Message-ID: Subject: Re: Interactivity regression since v3.11 in mm/vmscan.c From: Felipe Contreras To: Michal Hocko Cc: Linux Kernel Mailing List , "linux-mm@kvack.org" , Andrew Morton , Linus Torvalds , Mel Gorman , KAMEZAWA Hiroyuki , Rik van Riel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 5, 2014 at 8:37 AM, Michal Hocko wrote: > On Thu 05-06-14 06:33:40, Felipe Contreras wrote: >> For a while I've noticed that my machine bogs down in certain >> situations, usually while doing heavy I/O operations, it is not just the >> I/O operations, but everything, including the graphical interface, even >> the mouse pointer. >> >> As far as I can recall this did not happen in the past. >> >> I noticed this specially on certain operations, for example updating a >> a game on Steam (to an exteranl USB 3.0 device), or copying TV episodes >> to a USB memory stick (probably flash-based). > > We had a similar report for opensuse. The common part was that there was > an IO to a slow USB device going on. Well, it's a USB 3.0 device, I can write at 250 MB/s, so it's not really that slow. And in fact, when I read and write to and from the same USB 3.0 device, I don't see the issue. >> Then I went back to the latest stable version (v3.14.5), and commented >> out the line I think is causing the slow down: >> >> if (nr_unqueued_dirty == nr_taken || nr_immediate) >> congestion_wait(BLK_RW_ASYNC, HZ/10); > > Yes, I came to the same check. I didn't have any confirmation yet so > thanks for your confirmation. I've suggested to reduce this > congestion_wait only to kswapd: > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 32c661d66a45..ef6a1c0e788c 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1566,7 +1566,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > * implies that pages are cycling through the LRU faster than > * they are written so also forcibly stall. > */ > - if (nr_unqueued_dirty == nr_taken || nr_immediate) > + if ((nr_unqueued_dirty == nr_taken || nr_immediate) && current_is_kswapd()) > congestion_wait(BLK_RW_ASYNC, HZ/10); > } Unfortunately that doesn't fix the issue for me. -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/