From: Andrew Morton <akpm@linux-foundation.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
alex.sierra@amd.com, willy@infradead.org, hch@lst.de,
Felix.Kuehling@amd.com, apopple@nvidia.com, david@redhat.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm: re-allow pinning of zero pfns (again)
Date: Sat, 27 Aug 2022 18:40:21 -0700 [thread overview]
Message-ID: <20220827184021.4e100b9eda3a9141217ec60d@linux-foundation.org> (raw)
In-Reply-To: <033c2e8d-8ba9-3e0b-9dee-7d0973c708fa@nvidia.com>
On Sat, 27 Aug 2022 17:59:32 -0700 John Hubbard <jhubbard@nvidia.com> wrote:
>
> /* The zero page is always allowed to be pinned. */
Wow, that's really verbose :)
--- a/include/linux/mm.h~mm-re-allow-pinning-of-zero-pfns-again-fix
+++ a/include/linux/mm.h
@@ -1544,11 +1544,7 @@ static inline bool is_longterm_pinnable_
if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
return false;
#endif
- /*
- * The zero page might reside in a movable zone, however it may not
- * be migrated and can therefore be pinned. The vfio subsystem pins
- * user mappings including the zero page for IOMMU translation.
- */
+ /* The zero page may always be pinned */
if (is_zero_pfn(page_to_pfn(page)))
return true;
_
next prev parent reply other threads:[~2022-08-28 1:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-10 16:53 [PATCH v2] mm: re-allow pinning of zero pfns (again) Alex Williamson
2022-08-26 19:01 ` Laba, SlawomirX
2022-08-28 0:59 ` John Hubbard
2022-08-28 1:40 ` Andrew Morton [this message]
2022-08-28 12:37 ` Alex Williamson
2022-08-28 17:16 ` John Hubbard
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