From mboxrd@z Thu Jan 1 00:00:00 1970 From: chenyu5 Subject: Re: [RFC PATCH] PM / hibernate: make sure each resuming page is in current memory zones Date: Tue, 21 Jul 2015 09:28:32 +0800 Message-ID: <55ADA040.7050408@intel.com> References: <1435679668-13806-1-git-send-email-yu.c.chen@intel.com> <5594EFAA.1000905@intel.com> <20150706083739.GA29021@linux-rxt1.site> <1613617.2K941pjbyO@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mga01.intel.com ([192.55.52.88]:56824 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757204AbbGUBZ1 (ORCPT ); Mon, 20 Jul 2015 21:25:27 -0400 In-Reply-To: <1613617.2K941pjbyO@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org, rafael.j.wysocki@intel.com, joeyli , yex.tian@intel.com On 2015=E5=B9=B407=E6=9C=8816=E6=97=A5 08:30, Rafael J. Wysocki wrote: > On Monday, July 06, 2015 04:37:39 PM joeyli wrote: >> Hi Chen Yu, >> >> On Thu, Jul 02, 2015 at 04:00:42PM +0800, chenyu5 wrote: >>> Hi, Joey >>> thanks for your reply, >>> >>> On 2015=E5=B9=B407=E6=9C=8802=E6=97=A5 14:19, joeyli wrote: >>>> Hi Chen Yu, >>>> >>>> On Tue, Jun 30, 2015 at 11:54:28PM +0800, Chen Yu wrote: >>>>> Commit 84c91b7ae07c ("PM / hibernate: avoid unsafe pages in e820 = reserved >>>>> regions") was reverted, because this patch makes resume from hibe= rnation >>>>> on Lenovo x230 unreliable. But reverting may bring back the kerne= l >>>>> exception firstly reported in former patch. In general, there are= three >>>>> problems in current code when resuming from hibernation: >>>>> >>>>> 1.Resuming page may also be in second kernel's e820 reserved regi= on. >>>>> BIOS-e820: [mem 0x0000000069d4f000-0x0000000069e12fff] reserved >>>>> this causes kernel exception described in Commit 84c91b7ae07c >>>>> ("PM / hibernate: avoid unsafe pages in e820 reserved regions") >>>>> >>>>> 2.If Commit 84c91b7ae07c ("PM / hibernate: avoid unsafe pages in = e820 >>>>> reserved regions") is applied to fix problem 1, and if E820_RESER= VED_KERN >>>>> regions causes some regions at e820 table not page aligned, >>>>> e820_mark_nosave_regions will misjudgment the non-page aligned sp= ace to >>>>> be "hole" space and add to nosave regions, this causes resuming f= ailed. >>>>> Refer to https://bugzilla.kernel.org/show_bug.cgi?id=3D96111 for = detail. >>>>> >>>> >>>> Sorry for I am not fully understand why checking pfn_valid could a= void >>>> the above 2. issue? >>>> >>> [Yu] According to e820_mark_nosave_regions, two kinds of e820 >>> regions will be regarded as nosave: >>> a.e820.map holes between each e820entry >>> b.e820entry with (!E820_RAM && !E820_RESERVED_KERN) >>> dmesg in >>> https://bugzilla.kernel.org/show_bug.cgi?id=3D96111 >>> shows that: >>> >>> BIOS-e820: [mem 0x000000005baff000-0x00000000d684ffff] usable >>> reserve setup_data: [mem 0x000000009d3e0018-0x000000009d3f0057] usa= ble >>> PM: Registered nosave memory: [mem 0x9d3e0000-0x9d3e0fff] >>> >>> e820 map was changed by situation a, but it should not be added to >>> nosave list, right? >>> >>> and according to saveable_page, only pages in the zone will be save= d: >>> if (page_zone(page_ !=3D zone) >>> return NULL; >>> >>> The function of is_valid_orig_page in this patch treats setup_data = as >>> valid page, so I think this workaround issue 2. >>> >>> >>>> Per my understood should waiting Yinghai Lu's patches for killing >>>> E820_RESERVED_KERN to avoid the aligned problem. >>> [Yu] yes, it is a graceful solution, but I don't see that in 4.1? A= nd >>> we encountered problem 3 in our testing enviroment, so I wrote a pa= tch >>> to deal with it first. >>>> >>>> >>>> Thanks a lot! >>>> Joey Lee >>>> >> >> Thanks for your explanation, then your patch makes sense to me. >> >> Please feel free to add tag: >> >> Reviewed-by: Lee, Chun-Yi > > Patch queued up for 4.3, thanks! > Hi Rafeal, Please help drop this patch for now, QA has found some problems with this patch applied, we're working on it now. Sorry for inconvenience. Regards, Yu