From: Alistair Popple <alistair@popple.id.au>
To: bharata@linux.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org, Ram Pai <linuxram@us.ibm.com>
Subject: Re: [PATCH] powerpc/book3s_hv_uvmem: Check for failed page migration
Date: Mon, 07 Dec 2020 10:55:49 +1100 [thread overview]
Message-ID: <7619698.bcDb2GHn21@cleo> (raw)
In-Reply-To: <20201204101841.GA621541@in.ibm.com>
On Friday, 4 December 2020 9:18:41 PM AEDT Bharata B Rao wrote:
>
> Reviewed-by: Bharata B Rao <bharata@linux.ibm.com>
>
> Did you actually hit this scenario with secure VMs where a UV-paged-in
> page was later found to be not migratable?
No, this was found by inspection. I have no way of testing this but we had a
similar issue in Nouveau and I think you would have a similar issue here
although it might be hard to hit.
migrate_vma_pages() will fail a page migration if a CPU thread has raced and
established a non-zero page PTE for the address. See migrate_vma_insert_page()
for the implementation. It will also fail if something else has taken a
reference on the page after calling migrate_vma_setup(), but that is less
likely as any existing pages will have been isolated.
- Alistair
> Regards,
> Bharata.
>
next prev parent reply other threads:[~2020-12-06 23:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 5:08 [PATCH] powerpc/book3s_hv_uvmem: Check for failed page migration Alistair Popple
2020-12-04 10:18 ` Bharata B Rao
2020-12-04 16:52 ` Ram Pai
2020-12-07 0:13 ` Alistair Popple
2020-12-06 23:55 ` Alistair Popple [this message]
2020-12-08 14:20 ` Ram Pai
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