From: Hugh Dickins Date: Wed, 22 Jun 2005 00:15:11 +0000 (-0700) Subject: [PATCH] do_wp_page: cannot share file page X-Git-Tag: v2.6.13-rc4~130^2~202^2~132 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d296e9cd02c92e576ecce5344026a4df4353cdb2;p=pandora-kernel.git [PATCH] do_wp_page: cannot share file page 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed