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From: Matthew Wilcox <willy@infradead.org>
To: Qian Cai <cai@lca.pw>
Cc: Huang Ying <ying.huang@intel.com>, linux-mm@kvack.org
Subject: Re: page cache: Store only head pages in i_pages
Date: Sat, 23 Mar 2019 19:06:14 -0700
Message-ID: <20190324020614.GD10344@bombadil.infradead.org> (raw)
In-Reply-To: <f26c4cce-5f71-5235-8980-86d8fcd69ce6@lca.pw>

On Sat, Mar 23, 2019 at 07:50:15PM -0400, Qian Cai wrote:
> On 3/22/19 11:38 PM, Matthew Wilcox wrote:
> > On Fri, Mar 22, 2019 at 04:12:48PM -0400, Qian Cai wrote:
> >> FYI, every thing involve swapping seems triggered a panic now since this patch.
> 
> Yes, it works.

Thanks for testing.  Kirill suggests this would be a better fix:

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 41858a3744b4..9718393ae45b 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -334,10 +334,12 @@ 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);
+
 	VM_BUG_ON_PAGE(PageTail(page), page);
-	VM_BUG_ON_PAGE(page->index > offset, page);
-	VM_BUG_ON_PAGE(page->index + compound_nr(page) <= offset, page);
-	return page - page->index + offset;
+	VM_BUG_ON_PAGE(index > offset, page);
+	VM_BUG_ON_PAGE(index + compound_nr(page) <= offset, page);
+	return page - index + offset;
 }
 
 struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);


  reply index

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 [this message]
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
2019-04-05 13:37                                 ` Kirill A. Shutemov
2019-04-05 13:51                                   ` Matthew Wilcox

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