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d296e9cd02
A small optimization to do_wp_page's check for whether to avoid copy by reusing the page already mapped. It can never share a cached file page, nor can it share a reserved page (often the empty zero page), so it's a waste of time to lock and unlock in those cases. Which nowadays can both be neatly excluded by a preliminary PageAnon test. Christoph has reported that a preliminary page_count test proved valuable for scalability here, but PageAnon covers more common cases all at once. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2233 lines
59 KiB
2233 lines
59 KiB