From: Vlastimil Babka <vbabka@suse.cz>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Dave Hansen <dave@sr71.net>,
linux-kernel@vger.kernel.org
Cc: x86@kernel.org, linux-mm@kvack.org,
torvalds@linux-foundation.org, akpm@linux-foundation.org,
bp@alien8.de, ak@linux.intel.com, mhocko@suse.com
Subject: Re: [PATCH 0/4] [RFC][v4] Workaround for Xeon Phi PTE A/D bits erratum
Date: Wed, 13 Jul 2016 14:10:07 +0200 [thread overview]
Message-ID: <829f2f03-8492-841d-869f-7fd7add9cb27@suse.cz> (raw)
In-Reply-To: <9c09c63c-5c2a-20a4-d68b-a6dc2f88ecaa@suse.cz>
On 07/13/2016 01:37 PM, Vlastimil Babka wrote:
>> > With the errata, don't you have a situation where a processor in the second
>> > category will write and set D despite P having been cleared (due to the
>> > race) and thus causing us to miss the transfer of that D to the struct
>> > page and essentially completely miss that the physical page is dirty ?
> Seems to me like this is indeed possible, but...
Nevermind, I have read the v3 thread now, where Dave says [1] that
setting the D bit due to the erratum doesn't mean that the page is
really actually written to (it's not). So there shouldn't be any true
dirty bit to leave behind.
[1] http://marc.info/?l=linux-mm&m=146738965614826&w=2
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next prev parent reply other threads:[~2016-07-13 12:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 17:46 Dave Hansen
2016-07-01 17:47 ` [PATCH 1/4] x86, swap: move swap offset/type up in PTE to work around erratum Dave Hansen
2016-07-01 17:47 ` [PATCH 2/4] x86, pagetable: ignore A/D bits in pte/pmd/pud_none() Dave Hansen
2016-07-01 17:47 ` [PATCH 3/4] x86: disallow running with 32-bit PTEs to work around erratum Dave Hansen
2016-07-01 17:47 ` [PATCH 4/4] x86: use pte_none() to test for empty PTE Dave Hansen
2016-07-01 22:28 ` [PATCH 0/4] [RFC][v4] Workaround for Xeon Phi PTE A/D bits erratum Benjamin Herrenschmidt
2016-07-13 11:37 ` Vlastimil Babka
2016-07-13 12:10 ` Vlastimil Babka [this message]
2016-07-13 14:04 ` Dave Hansen
2016-07-08 0:19 Dave Hansen
2016-07-13 9:54 ` Vlastimil Babka
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