All of lore.kernel.org
 help / color / mirror / Atom feed
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.


  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 ` 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1554413282.26196.40.camel@lca.pw \
    --to=cai@lca.pw \
    --cc=kirill@shutemov.name \
    --cc=linux-mm@kvack.org \
    --cc=willy@infradead.org \
    --cc=ying.huang@intel.com \
    --subject='Re: page cache: Store only head pages in i_pages' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.