From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qa0-f48.google.com (mail-qa0-f48.google.com [209.85.216.48]) by kanga.kvack.org (Postfix) with ESMTP id 044076B0037 for ; Thu, 5 Jun 2014 10:00:11 -0400 (EDT) Received: by mail-qa0-f48.google.com with SMTP id i13so1421091qae.7 for ; Thu, 05 Jun 2014 07:00:11 -0700 (PDT) Received: from mail-qa0-x232.google.com (mail-qa0-x232.google.com [2607:f8b0:400d:c00::232]) by mx.google.com with ESMTPS id i5si8420274qay.10.2014.06.05.07.00.11 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 05 Jun 2014 07:00:11 -0700 (PDT) Received: by mail-qa0-f50.google.com with SMTP id j15so1380279qaq.23 for ; Thu, 05 Jun 2014 07:00:11 -0700 (PDT) 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 Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Linux Kernel Mailing List , "linux-mm@kvack.org" , Andrew Morton , Linus Torvalds , Mel Gorman , KAMEZAWA Hiroyuki , Rik van Riel 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, 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