Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [29/36] CPA: Only unmap kernel init pages in text mapping when CONFIG_DEBUG_RODATA is set | Date | Wed, 16 Jan 2008 23:15:29 +0100 (CET) |
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Otherwise the kernel will likely always run with 4K pages instead of 2MB pages, which is costly in terms of TLBs.
Also optimize it a little bit by using only a single change_page_attr() calls. This is particularly useful if debugging is enabled inside it because it spams the logs much less.
Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Jan Beulich <jbeulich@novell.com>
--- arch/x86/mm/init_64.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
Index: linux/arch/x86/mm/init_64.c =================================================================== --- linux.orig/arch/x86/mm/init_64.c +++ linux/arch/x86/mm/init_64.c @@ -694,13 +694,16 @@ void free_init_pages(char *what, unsigne init_page_count(virt_to_page(addr)); memset((void *)(addr & ~(PAGE_SIZE-1)), POISON_FREE_INITMEM, PAGE_SIZE); - if (addr >= __START_KERNEL_map) - change_page_attr_addr(addr, 1, __pgprot(0)); free_page(addr); totalram_pages++; } - if (addr > __START_KERNEL_map) +#ifdef CONFIG_DEBUG_RODATA + if (begin >= __START_KERNEL_map) { + change_page_attr_addr(begin, (end - begin)/PAGE_SIZE, + __pgprot(0)); global_flush_tlb(); + } +#endif } void free_initmem(void)
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