Messages in this thread | | | From | "Du, Fan" <> | Subject | RE: [PATCH 5/5] dax: "Hotplug" persistent memory for use like normal RAM | Date | Fri, 25 Jan 2019 08:20:45 +0000 |
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Dan
Thanks for the insights!
Can I say, the UCE is delivered from h/w to OS in a single way in case of machine check, only PMEM/DAX stuff filter out UC address and managed in its own way by badblocks, if PMEM/DAX doesn't do so, then common RAS workflow will kick in, right?
And how about when ARS is involved but no machine check fired for the function of this patchset?
>-----Original Message----- >From: Linux-nvdimm [mailto:linux-nvdimm-bounces@lists.01.org] On Behalf >Of Dan Williams >Sent: Friday, January 25, 2019 2:28 PM >To: Jane Chu <jane.chu@oracle.com> >Cc: Tom Lendacky <thomas.lendacky@amd.com>; Michal Hocko ><mhocko@suse.com>; linux-nvdimm <linux-nvdimm@lists.01.org>; Takashi >Iwai <tiwai@suse.de>; Dave Hansen <dave.hansen@linux.intel.com>; Huang, >Ying <ying.huang@intel.com>; Linux Kernel Mailing List ><linux-kernel@vger.kernel.org>; Linux MM <linux-mm@kvack.org>; Jérôme >Glisse <jglisse@redhat.com>; Borislav Petkov <bp@suse.de>; Yaowei Bai ><baiyaowei@cmss.chinamobile.com>; Ross Zwisler <zwisler@kernel.org>; >Bjorn Helgaas <bhelgaas@google.com>; Andrew Morton ><akpm@linux-foundation.org>; Wu, Fengguang <fengguang.wu@intel.com> >Subject: Re: [PATCH 5/5] dax: "Hotplug" persistent memory for use like >normal RAM > >On Thu, Jan 24, 2019 at 10:13 PM Jane Chu <jane.chu@oracle.com> wrote: >> >> Hi, Dave, >> >> While chatting with my colleague Erwin about the patchset, it occurred >> that we're not clear about the error handling part. Specifically, >> >> 1. If an uncorrectable error is detected during a 'load' in the hot >> plugged pmem region, how will the error be handled? will it be >> handled like PMEM or DRAM? > >DRAM. > >> 2. If a poison is set, and is persistent, which entity should clear >> the poison, and badblock(if applicable)? If it's user's responsibility, >> does ndctl support the clearing in this mode? > >With persistent memory advertised via a static logical-to-physical >storage/dax device mapping, once an error develops it destroys a >physical *and* logical part of a device address space. That loss of >logical address space makes error clearing a necessity. However, with >the DRAM / "System RAM" error handling model, the OS can just offline >the page and map a different one to repair the logical address space. >So, no, ndctl will not have explicit enabling to clear volatile >errors, the OS will just dynamically offline problematic pages. >_______________________________________________ >Linux-nvdimm mailing list >Linux-nvdimm@lists.01.org >https://lists.01.org/mailman/listinfo/linux-nvdimm
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