From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>,
akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it
Date: Mon, 2 Dec 2019 11:03:15 +0300 [thread overview]
Message-ID: <20191202080315.oqtm3q7cyfkl5rma@box.shutemov.name> (raw)
In-Reply-To: <20191128212226.sfrhfs5m3q7m6tly@master>
On Thu, Nov 28, 2019 at 09:22:26PM +0000, Wei Yang wrote:
> On Thu, Nov 28, 2019 at 11:32:55AM +0300, Kirill A. Shutemov wrote:
> >On Thu, Nov 28, 2019 at 09:03:20AM +0800, Wei Yang wrote:
> >> At this point, we are sure page is PageTransHuge, which means
> >> hpage_nr_pages is HPAGE_PMD_NR.
> >>
> >> This is safe to use PMD_SIZE instead of calculating it.
> >>
> >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> >> ---
> >> mm/page_vma_mapped.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> >> index eff4b4520c8d..76e03650a3ab 100644
> >> --- a/mm/page_vma_mapped.c
> >> +++ b/mm/page_vma_mapped.c
> >> @@ -223,7 +223,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> >> if (pvmw->address >= pvmw->vma->vm_end ||
> >> pvmw->address >=
> >> __vma_address(pvmw->page, pvmw->vma) +
> >> - hpage_nr_pages(pvmw->page) * PAGE_SIZE)
> >> + PMD_SIZE)
> >> return not_found(pvmw);
> >> /* Did we cross page table boundary? */
> >> if (pvmw->address % PMD_SIZE == 0) {
> >
> >It is dubious cleanup. Maybe page_size(pvmw->page) instead? It will not
> >break if we ever get PUD THP pages.
> >
>
> Thanks for your comment.
>
> I took a look into the code again and found I may miss something.
>
> I found we support PUD THP pages, whilc hpage_nr_pages() just return
> HPAGE_PMD_NR on PageTransHuge. Why this is not possible to return PUD number?
We only support PUD THP for DAX. Means, we don't have struct page for it.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-12-02 8:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 1:03 [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it Wei Yang
2019-11-28 1:03 ` [PATCH 2/2] mm/page_vma_mapped: page table boundary is already guaranteed Wei Yang
2019-11-28 8:31 ` Kirill A. Shutemov
2019-11-28 21:09 ` Wei Yang
2019-11-28 22:39 ` Matthew Wilcox
2019-11-29 8:30 ` Wei Yang
2019-11-29 11:18 ` Matthew Wilcox
2019-12-02 6:53 ` Wei Yang
2019-11-28 8:32 ` [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it Kirill A. Shutemov
2019-11-28 21:22 ` Wei Yang
2019-12-02 8:03 ` Kirill A. Shutemov [this message]
2019-12-02 8:54 ` Wei Yang
2019-12-02 22:21 ` Wei Yang
2019-12-03 9:47 ` Kirill A. Shutemov
2019-12-03 15:14 ` Wei Yang
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