Avoid expensive lookups of virtual addresses from page structs by
storing the vmalloc address in page->private. We can then avoid
the vmalloc_address() in the get_xxxx_pagexxxx() functions and
simply return page->private.
Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>
---
mm/page_alloc.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c 2007-09-18 18:35:55.000000000 -0700
+++ linux-2.6/mm/page_alloc.c 2007-09-18 18:36:01.000000000 -0700
@@ -1276,6 +1276,11 @@ struct page *vcompound_alloc(gfp_t gfp_m
if (!addr)
goto abort;
+ /*
+ * Give the caller a chance to avoid an expensive vmalloc_addr()
+ * call.
+ */
+ pages[0]->private = (unsigned long)addr;
return pages[0];
abort:
@@ -1534,6 +1539,8 @@ fastcall unsigned long __get_free_pages(
page = alloc_pages(gfp_mask, order);
if (!page)
return 0;
+ if (unlikely(PageVcompound(page)))
+ return page->private;
return (unsigned long) page_address(page);
}
@@ -1550,9 +1557,11 @@ fastcall unsigned long get_zeroed_page(g
VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
- if (page)
- return (unsigned long) page_address(page);
- return 0;
+ if (!page)
+ return 0;
+ if (unlikely(PageVcompound(page)))
+ return page->private;
+ return (unsigned long) page_address(page);
}
EXPORT_SYMBOL(get_zeroed_page);
--
-
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