From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>
Subject: Re: [PATCH 02/11] mm/memory: Remove page fault assumption of compound page size
Date: Wed, 9 Sep 2020 17:29:04 +0300 [thread overview]
Message-ID: <20200909142904.acca6gthbffk3jwq@box> (raw)
In-Reply-To: <20200908195539.25896-3-willy@infradead.org>
On Tue, Sep 08, 2020 at 08:55:29PM +0100, Matthew Wilcox (Oracle) wrote:
> A compound page in the page cache will not necessarily be of PMD size,
> so check explicitly.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> mm/memory.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 602f4283122f..4b35b4e71e64 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3562,13 +3562,14 @@ static vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
> unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> pmd_t entry;
> int i;
> - vm_fault_t ret;
> + vm_fault_t ret = VM_FAULT_FALLBACK;
>
> if (!transhuge_vma_suitable(vma, haddr))
> - return VM_FAULT_FALLBACK;
> + return ret;
>
> - ret = VM_FAULT_FALLBACK;
> page = compound_head(page);
> + if (page_order(page) != HPAGE_PMD_ORDER)
> + return ret;
Maybe also VM_BUG_ON_PAGE(page_order(page) > HPAGE_PMD_ORDER, page)?
Just in case.
>
> /*
> * Archs like ppc64 need additonal space to store information
> --
> 2.28.0
>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-09-09 14:29 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 19:55 [PATCH 00/11] Remove assumptions of THP size Matthew Wilcox (Oracle)
2020-09-08 19:55 ` [PATCH 01/11] mm/filemap: Fix page cache removal for arbitrary sized THPs Matthew Wilcox (Oracle)
2020-09-09 14:27 ` Kirill A. Shutemov
2020-09-15 7:13 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 02/11] mm/memory: Remove page fault assumption of compound page size Matthew Wilcox (Oracle)
2020-09-09 14:29 ` Kirill A. Shutemov [this message]
2020-09-09 14:50 ` Matthew Wilcox
2020-09-11 14:51 ` Kirill A. Shutemov
2020-09-08 19:55 ` [PATCH 03/11] mm/page_owner: Change split_page_owner to take a count Matthew Wilcox (Oracle)
2020-09-09 14:42 ` Kirill A. Shutemov
2020-09-15 7:17 ` SeongJae Park
2020-10-13 13:52 ` Matthew Wilcox
2020-09-08 19:55 ` [PATCH 04/11] mm/huge_memory: Fix total_mapcount assumption of page size Matthew Wilcox (Oracle)
2020-09-15 7:21 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 05/11] mm/huge_memory: Fix split " Matthew Wilcox (Oracle)
2020-09-15 7:23 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 06/11] mm/huge_memory: Fix page_trans_huge_mapcount assumption of THP size Matthew Wilcox (Oracle)
2020-09-09 14:45 ` Kirill A. Shutemov
2020-09-15 7:24 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 07/11] mm/huge_memory: Fix can_split_huge_page " Matthew Wilcox (Oracle)
2020-09-09 14:46 ` Kirill A. Shutemov
2020-09-15 7:25 ` SeongJae Park
2020-09-16 1:44 ` Huang, Ying
2020-09-08 19:55 ` [PATCH 08/11] mm/rmap: Fix assumptions " Matthew Wilcox (Oracle)
2020-09-09 14:47 ` Kirill A. Shutemov
2020-09-15 7:27 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 09/11] mm/truncate: Fix truncation for pages of arbitrary size Matthew Wilcox (Oracle)
2020-09-09 14:50 ` Kirill A. Shutemov
2020-09-15 7:36 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 10/11] mm/page-writeback: Support tail pages in wait_for_stable_page Matthew Wilcox (Oracle)
2020-09-09 14:53 ` Kirill A. Shutemov
2020-09-15 7:37 ` SeongJae Park
2020-09-08 19:55 ` [PATCH 11/11] mm/vmscan: Allow arbitrary sized pages to be paged out Matthew Wilcox (Oracle)
2020-09-09 14:55 ` Kirill A. Shutemov
2020-09-15 7:40 ` SeongJae Park
2020-09-15 12:52 ` Matthew Wilcox
2020-09-16 1:40 ` Huang, Ying
2020-09-16 6:09 ` SeongJae Park
2020-09-30 12:13 ` Matthew Wilcox
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