From: Qian Cai <cai@lca.pw>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>,
Huang Ying <ying.huang@intel.com>,
linux-mm@kvack.org
Subject: Re: page cache: Store only head pages in i_pages
Date: Thu, 04 Apr 2019 17:28:02 -0400 [thread overview]
Message-ID: <1554413282.26196.40.camel@lca.pw> (raw)
In-Reply-To: <20190404134553.vuvhgmghlkiw2hgl@kshutemo-mobl1>
On Thu, 2019-04-04 at 16:45 +0300, Kirill A. Shutemov wrote:
> What about this:
>
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index f939e004c5d1..2e8438a1216a 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -335,12 +335,15 @@ static inline struct page *grab_cache_page_nowait(struct
> address_space *mapping,
>
> static inline struct page *find_subpage(struct page *page, pgoff_t offset)
> {
> - unsigned long index = page_index(page);
> + unsigned long mask;
> +
> + if (PageHuge(page))
> + return page;
>
> VM_BUG_ON_PAGE(PageTail(page), page);
> - VM_BUG_ON_PAGE(index > offset, page);
> - VM_BUG_ON_PAGE(index + (1 << compound_order(page)) <= offset, page);
> - return page - index + offset;
> +
> + mask = (1UL << compound_order(page)) - 1;
> + return page + (offset & mask);
> }
>
> struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
It works fine.
next prev parent reply other threads:[~2019-04-04 21:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1553285568.26196.24.camel@lca.pw>
2019-03-23 3:38 ` page cache: Store only head pages in i_pages Matthew Wilcox
2019-03-23 23:50 ` Qian Cai
2019-03-24 2:06 ` Matthew Wilcox
2019-03-24 2:52 ` Qian Cai
2019-03-24 3:04 ` Matthew Wilcox
2019-03-24 15:42 ` Qian Cai
2019-03-27 10:48 ` William Kucharski
2019-03-27 11:50 ` Matthew Wilcox
2019-03-29 1:43 ` Qian Cai
2019-03-29 19:59 ` Matthew Wilcox
2019-03-29 21:25 ` Qian Cai
2019-03-30 3:04 ` Matthew Wilcox
2019-03-30 14:10 ` Matthew Wilcox
2019-03-31 3:23 ` Matthew Wilcox
2019-04-01 9:18 ` Kirill A. Shutemov
2019-04-01 9:27 ` Kirill A. Shutemov
2019-04-04 13:10 ` Qian Cai
2019-04-04 13:45 ` Kirill A. Shutemov
2019-04-04 21:28 ` Qian Cai [this message]
2019-04-05 13:37 ` Kirill A. Shutemov
2019-04-05 13:51 ` Matthew Wilcox
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