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 --- 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); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/