From: David Hildenbrand <david@redhat.com>
To: Peter Xu <peterx@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Matthew Wilcox <willy@infradead.org>,
Andrea Arcangeli <aarcange@redhat.com>,
John Hubbard <jhubbard@nvidia.com>,
Mike Rapoport <rppt@kernel.org>, Vlastimil Babka <vbabka@suse.cz>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
James Houghton <jthoughton@google.com>,
Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH 3/7] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask()
Date: Tue, 20 Jun 2023 09:01:23 +0200 [thread overview]
Message-ID: <24f4a22e-7d3b-544b-320f-bba5abb92285@redhat.com> (raw)
In-Reply-To: <ZJDMFDUZdGngQbzw@x1n>
On 19.06.23 23:43, Peter Xu wrote:
> On Tue, Jun 13, 2023 at 05:53:42PM -0400, Peter Xu wrote:
>> @@ -6506,6 +6507,7 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
>> * because we hold the ptl lock and have verified pte_present().
>> */
>> WARN_ON_ONCE(try_grab_page(page, flags));
>> + *page_mask = huge_page_mask(h);
>
> Sorry, I was wrong this line. It should be:
>
> *page_mask = ~huge_page_mask(h) >> PAGE_SHIFT;
>
That's ... surprising. It feels like either page_mask or
huge_page_mask() has a misleading name ....
h->mask = ~(huge_page_size(h) - 1);
For PMDs, we do
ctx->page_mask = HPAGE_PMD_NR - 1;
Maybe
*page_mask = PHYS_PFN(huge_page_size(h)) - 1;
Would be clearer.
I guess "page_mask" should actually be "pfn_mask" ... but the meaning
regarding PAGE_MASK are still inverted ...
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2023-06-20 7:01 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-13 21:53 [PATCH 0/7] mm/gup: Unify hugetlb, speed up thp Peter Xu
2023-06-13 21:53 ` [PATCH 1/7] mm/hugetlb: Handle FOLL_DUMP well in follow_page_mask() Peter Xu
2023-06-14 23:24 ` Mike Kravetz
2023-06-16 8:08 ` David Hildenbrand
2023-06-13 21:53 ` [PATCH 2/7] mm/hugetlb: Fix hugetlb_follow_page_mask() on permission checks Peter Xu
2023-06-14 15:31 ` David Hildenbrand
2023-06-14 15:46 ` Peter Xu
2023-06-14 15:57 ` David Hildenbrand
2023-06-15 0:11 ` Mike Kravetz
2023-06-13 21:53 ` [PATCH 3/7] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask() Peter Xu
2023-06-15 0:17 ` Mike Kravetz
2023-06-16 8:11 ` David Hildenbrand
2023-06-19 21:43 ` Peter Xu
2023-06-20 7:01 ` David Hildenbrand [this message]
2023-06-20 14:40 ` Peter Xu
2023-06-13 21:53 ` [PATCH 4/7] mm/hugetlb: Prepare hugetlb_follow_page_mask() for FOLL_PIN Peter Xu
2023-06-14 14:57 ` David Hildenbrand
2023-06-14 15:11 ` Peter Xu
2023-06-14 15:17 ` David Hildenbrand
2023-06-14 15:31 ` Peter Xu
2023-06-14 15:47 ` David Hildenbrand
2023-06-14 15:51 ` Peter Xu
2023-06-15 0:25 ` Mike Kravetz
2023-06-15 19:42 ` Peter Xu
2023-06-13 21:53 ` [PATCH 5/7] mm/gup: Cleanup next_page handling Peter Xu
2023-06-17 19:48 ` Lorenzo Stoakes
2023-06-17 20:00 ` Lorenzo Stoakes
2023-06-19 19:18 ` Peter Xu
2023-06-13 21:53 ` [PATCH 6/7] mm/gup: Accelerate thp gup even for "pages != NULL" Peter Xu
2023-06-14 14:58 ` Matthew Wilcox
2023-06-14 15:19 ` Peter Xu
2023-06-14 15:35 ` Peter Xu
2023-06-17 20:27 ` Lorenzo Stoakes
2023-06-19 19:37 ` Peter Xu
2023-06-19 20:24 ` Peter Xu
2023-06-13 21:53 ` [PATCH 7/7] mm/gup: Retire follow_hugetlb_page() Peter Xu
2023-06-14 14:37 ` Jason Gunthorpe
2023-06-17 20:40 ` Lorenzo Stoakes
2023-06-19 19:41 ` Peter Xu
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