The patch titled
Subject: include/linux/pagemap.h: optimise find_subpage for !THP
has been added to the -mm tree. Its filename is
mm-optimise-find_subpage-for-thp.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-optimise-find_subpage-for-thp.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-optimise-find_subpage-for-thp.patch
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: include/linux/pagemap.h: optimise find_subpage for !THP
If THP is disabled, find_subpage() can become a no-op by using
hpage_nr_pages() instead of compound_nr(). hpage_nr_pages() embeds a
check for PageTail, so we can drop the check here.
Link: http://lkml.kernel.org/r/20200318140253.6141-5-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/include/linux/pagemap.h~mm-optimise-find_subpage-for-thp
+++ a/include/linux/pagemap.h
@@ -341,9 +341,7 @@ static inline struct page *find_subpage(
if (PageHuge(head))
return head;
- VM_BUG_ON_PAGE(PageTail(head), head);
-
- return head + (index & (compound_nr(head) - 1));
+ return head + (index & (hpage_nr_pages(head) - 1));
}
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-improve-dump_page-for-compound-pages.patch
mm-add-pagemaph-to-the-fine-documentation.patch
mm-use-vm_fault-error-code-directly.patch
mm-rename-arguments-to-find_subpage.patch
mm-check-pagetail-in-hpage_nr_pages-even-when-thp.patch
mm-optimise-find_subpage-for-thp.patch
mm-remove-config_transparent_huge_pagecache.patch
mm-use-vm_bug_on_page-in-clear_page_dirty_for_io.patch
mm-unexport-find_get_entry.patch
mm-rewrite-pagecache_get_page-documentation.patch
proc-inline-vma_stop-into-m_stop.patch
proc-remove-m_cache_vma.patch
proc-use-ppos-instead-of-m-version.patch
seq_file-remove-m-version.patch
proc-inline-m_next_vma-into-m_next.patch
