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From: Borislav Petkov <bp@alien8.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: nvdimm@lists.linux.dev, Jane Chu <jane.chu@oracle.com>,
	Luis Chamberlain <mcgrof@suse.com>,
	Tony Luck <tony.luck@intel.com>
Subject: Re: [RFT PATCH] x86/pat: Fix set_mce_nospec() for pmem
Date: Mon, 13 Sep 2021 12:29:13 +0200	[thread overview]
Message-ID: <YT8n+ae3lBQjqoDs@zn.tnic> (raw)
In-Reply-To: <162561960776.1149519.9267511644788011712.stgit@dwillia2-desk3.amr.corp.intel.com>

On Tue, Jul 06, 2021 at 06:01:05PM -0700, Dan Williams wrote:
> When poison is discovered and triggers memory_failure() the physical
> page is unmapped from all process address space. However, it is not
> unmapped from kernel address space. Unlike a typical memory page that
> can be retired from use in the page allocator and marked 'not present',
> pmem needs to remain accessible given it can not be physically remapped
> or retired.

I'm surely missing something obvious but why does it need to remain
accessible? Spell it out please.

> set_memory_uc() tries to maintain consistent nominal memtype
> mappings for a given pfn, but memory_failure() is an exceptional
> condition.

That's not clear to me too. So looking at the failure:

[10683.426147] x86/PAT: fsdax_poison_v1:5018 conflicting memory types 1850600000-1850601000  uncached-minus<->write-back

set_memory_uc() marked it UC- but something? wants it to be WB. Why?

I guess I need some more info on the whole memory offlining for pmem and
why that should be done differently than with normal memory.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  parent reply	other threads:[~2021-09-13 10:29 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-07  1:01 [RFT PATCH] x86/pat: Fix set_mce_nospec() for pmem Dan Williams
2021-08-26 19:08 ` Dan Williams
2021-08-27  7:12   ` Jane Chu
2021-09-13 10:29 ` Borislav Petkov [this message]
2021-09-14 18:08   ` Dan Williams
2021-09-15 10:41     ` Borislav Petkov
2021-09-16 20:33       ` Dan Williams
2021-09-17 11:30         ` Borislav Petkov
2021-09-21  2:04           ` Dan Williams
2021-09-30 17:19             ` Borislav Petkov
2021-09-30 17:28               ` Luck, Tony
2021-09-30 19:30                 ` Borislav Petkov
2021-09-30 19:41                   ` Dan Williams
2021-09-30 19:44                   ` Luck, Tony
2021-09-30 20:01                     ` Borislav Petkov
2021-09-30 20:15                       ` Luck, Tony
2021-09-30 20:32                         ` Borislav Petkov
2021-09-30 20:39                           ` Dan Williams
2021-09-30 20:54                             ` Borislav Petkov
2021-09-30 21:05                               ` Dan Williams
2021-09-30 21:20                                 ` Borislav Petkov
2021-09-30 21:41                                   ` Dan Williams
2021-09-30 22:35                                     ` Borislav Petkov
2021-09-30 22:44                                       ` Dan Williams
2021-10-01 10:41                                         ` Borislav Petkov
2021-10-01  0:43                                       ` Jane Chu
2021-10-01  2:02                                         ` Dan Williams
2021-10-01 10:50                                           ` Borislav Petkov
2021-10-01 16:52                                             ` Dan Williams
2021-10-01 18:11                                               ` Borislav Petkov
2021-10-01 18:29                                                 ` Dan Williams
2021-10-02 10:17                                                   ` Borislav Petkov
2021-11-11  0:06                                                     ` Jane Chu
2021-11-12  0:30                                                       ` Jane Chu
2021-11-12  0:51                                                         ` Dan Williams
2021-11-12 17:57                                                           ` Jane Chu
2021-11-12 19:24                                                             ` Dan Williams
2021-11-12 22:35                                                               ` Jane Chu
2021-11-12 22:50                                                                 ` Jane Chu
2021-11-12 23:08                                                                 ` Dan Williams
2021-11-13  5:50                                                                   ` Jane Chu
2021-11-13 20:47                                                                     ` Dan Williams
2021-11-18 19:03                                                                       ` Jane Chu
2021-11-25  0:16                                                                         ` Dan Williams
2021-11-30 23:00                                                                           ` Jane Chu
2021-09-30 18:15         ` Jane Chu
2021-09-30 19:11           ` Dan Williams
2021-09-30 21:23             ` Jane Chu

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