From: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCH 2/6] mm: Optimise find_subpage for !THP
Date: Mon, 2 Mar 2020 20:11:21 -0800 [thread overview]
Message-ID: <20200303041125.19358-3-willy@infradead.org> (raw)
In-Reply-To: <20200303041125.19358-1-willy@infradead.org>
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
If THP is disabled, find_subpage can become a no-op.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/pagemap.h | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index b4ea3a5d00e5..8785f60b05f8 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -333,14 +333,19 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
mapping_gfp_mask(mapping));
}
-static inline struct page *find_subpage(struct page *page, pgoff_t offset)
+/*
+ * Given the page we found in the page cache, return the page corresponding
+ * to this offset in the file
+ */
+static inline struct page *find_subpage(struct page *head, pgoff_t offset)
{
- if (PageHuge(page))
- return page;
+ /* HugeTLBfs wants the head page regardless */
+ if (PageHuge(head))
+ return head;
- VM_BUG_ON_PAGE(PageTail(page), page);
+ VM_BUG_ON_PAGE(PageTail(head), head);
- return page + (offset & (compound_nr(page) - 1));
+ return head + (offset & (hpage_nr_pages(head) - 1));
}
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
--
2.25.1
next prev parent reply other threads:[~2020-03-03 4:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-03 4:11 [PATCH 0/6] Misc MM patches Matthew Wilcox
2020-03-03 4:11 ` [PATCH 1/6] mm: Use vm_fault error code directly Matthew Wilcox
2020-03-03 4:11 ` Matthew Wilcox [this message]
2020-03-03 21:28 ` [PATCH 2/6] mm: Optimise find_subpage for !THP Alexander Duyck
2020-03-03 21:47 ` Matthew Wilcox
2020-03-05 9:54 ` William Kucharski
2020-03-03 4:11 ` [PATCH 3/6] mm: Remove CONFIG_TRANSPARENT_HUGE_PAGECACHE Matthew Wilcox
2020-03-03 21:52 ` Alexander Duyck
2020-03-03 22:34 ` Matthew Wilcox
2020-03-03 22:54 ` Alexander Duyck
2020-03-04 2:06 ` Matthew Wilcox
2020-03-03 4:11 ` [PATCH 4/6] mm: Use VM_BUG_ON_PAGE in clear_page_dirty_for_io Matthew Wilcox
2020-03-03 4:11 ` [PATCH 5/6] mm: Unexport find_get_entry Matthew Wilcox
2020-03-03 4:11 ` [PATCH 6/6] mm: Rewrite pagecache_get_page documentation Matthew Wilcox
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