From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751504AbdEJDE2 (ORCPT ); Tue, 9 May 2017 23:04:28 -0400 Received: from mail-pf0-f172.google.com ([209.85.192.172]:34060 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbdEJDE0 (ORCPT ); Tue, 9 May 2017 23:04:26 -0400 Date: Tue, 9 May 2017 20:04:24 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Joonas Lahtinen cc: Hugh Dickins , "J. R. Okajima" , Andrea Arcangeli , chris@chris-wilson.co.uk, daniel.vetter@ffwll.ch, jani.nikula@intel.com, linux-kernel@vger.kernel.org Subject: Re: Q. drm/i915 shrinker, synchronize_rcu_expedited() from handlers In-Reply-To: <1494230651.3367.2.camel@linux.intel.com> Message-ID: References: <7743.1493532478@jrobl> <20170430094348.GA5970@redhat.com> <16988.1493604328@jrobl> <1493977180.3551.24.camel@linux.intel.com> <1494230651.3367.2.camel@linux.intel.com> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="0-867880703-1494385464=:3043" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-867880703-1494385464=:3043 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE On Mon, 8 May 2017, Joonas Lahtinen wrote: > On pe, 2017-05-05 at 14:57 -0700, Hugh Dickins wrote: > > On Fri, 5 May 2017, Joonas Lahtinen wrote: > > > On ma, 2017-05-01 at 11:05 +0900, J. R. Okajima wrote: > > > > Thanx for the reply. > > > >=C2=A0 > > > > Andrea Arcangeli: > > > > >=C2=A0 > > > > > Yes I already reported this, my original fix was way more efficie= nt > > > > > (and also safer considering the above) than what landed upstream.= My > > > > > feedback was ignored though. > > > > >=C2=A0 > > > > > https://lists.freedesktop.org/archives/intel-gfx/2017-April/12541= 4.html > > > >=C2=A0 > > > > I see. > > > > Actually on my test system for v4.11-rc8, kthreadd, kworker, kswapd= and > > > > others all stopped working due to the synchronize_rcu_expedited cal= l > > > > from i915_gem_shrinker_count. It is definitly a show stopper for me= as > > > > an i915 user. > > >=C2=A0 > > > Filing a bug in freedesktop.org with all the details is the fastest w= ay > > > of getting help. Without the bug (and with such little information as > > > the previous e-mail) it's hard to estimate the extent and nature of t= he > > > bug. > > >=C2=A0 > > > I've anyway gone and prepared a patch to drop the RCU sync completely > > > from shrinker phase, as discussed originally with Chris. > >=20 > > Is that a patch that will be suitable for 4.11-stable?=C2=A0 Please do = post > > it here.=C2=A0 I had not experienced this i915-induced hang at all when > > Andrea first mentioned it, nor even on 4.11-rc8; but now with 4.11 > > final I can get it fairly easily (I haven't tried Andrea's fix yet). >=20 > Please try: >=20 > https://patchwork.freedesktop.org/patch/154713/ >=20 > If it works, a Tested-by: would be appreciated. Yes, that works for me, thank you. Tested-by: Hugh Dickins But the linked patch seems to be lacking a Reported-by (not me) tag, a Fixes tag, a Cc stable tag, and any indication in the Subject or commit message that this patch is something needed to fix hangs observed by several people - it just sounds like a minor cleanup. Hugh --0-867880703-1494385464=:3043--