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| author | Hugh Dickins <hugh@veritas.com> | 2005-06-22 02:15:11 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-06-22 03:46:21 +0200 |
| commit | d296e9cd02c92e576ecce5344026a4df4353cdb2 (patch) | |
| tree | 76af62c5d2c16e89672f71f2f4c7a65aa36ff914 /mm/rmap.c | |
| parent | [PATCH] get_user_pages: kill get_page_map (diff) | |
| download | linux-d296e9cd02c92e576ecce5344026a4df4353cdb2.tar.xz linux-d296e9cd02c92e576ecce5344026a4df4353cdb2.zip | |
[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 <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/rmap.c')
0 files changed, 0 insertions, 0 deletions