From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756137AbYAPWUo (ORCPT ); Wed, 16 Jan 2008 17:20:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754087AbYAPWPX (ORCPT ); Wed, 16 Jan 2008 17:15:23 -0500 Received: from ns2.suse.de ([195.135.220.15]:38253 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753947AbYAPWPP (ORCPT ); Wed, 16 Jan 2008 17:15:15 -0500 From: Andi Kleen References: <200801161114.239449000@suse.de> In-Reply-To: <200801161114.239449000@suse.de> To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, jbeulich@novell.com, venkatesh.pallipadi@intel.com Subject: [PATCH] [15/36] CPA: Change kernel_map_pages to not use c_p_a() Message-Id: <20080116221514.554BA150C8@wotan.suse.de> Date: Wed, 16 Jan 2008 23:15:14 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CONFIG_DEBUG_PAGEALLOC uses change_page_attr to map/unmap mappings for catching stray kernel mappings. But standard c_p_a() does a lot of unnecessary work for this simple case with pre-split mappings. Change kernel_map_pages to just access the page table directly which is simpler and faster. I also fixed it to use INVLPG if available. This is required for changes to c_p_a() later that make it use kmalloc. Without this we would risk infinite recursion. Also in general things are easier when sleeping is allowed. Signed-off-by: Andi Kleen Acked-by: Jan Beulich --- arch/x86/mm/pageattr_32.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) Index: linux/arch/x86/mm/pageattr_32.c =================================================================== --- linux.orig/arch/x86/mm/pageattr_32.c +++ linux/arch/x86/mm/pageattr_32.c @@ -274,22 +274,36 @@ void global_flush_tlb(void) } #ifdef CONFIG_DEBUG_PAGEALLOC +/* Map or unmap pages in the kernel direct mapping for kernel debugging. */ void kernel_map_pages(struct page *page, int numpages, int enable) { + unsigned long addr; + int i; + if (PageHighMem(page)) return; + addr = (unsigned long)page_address(page); if (!enable) - debug_check_no_locks_freed(page_address(page), - numpages * PAGE_SIZE); + debug_check_no_locks_freed((void *)addr, numpages * PAGE_SIZE); + + /* Bootup has forced 4K pages so this is very simple */ + + for (i = 0; i < numpages; i++, addr += PAGE_SIZE, page++) { + int level; + pte_t *pte = lookup_address(addr, &level); - /* the return value is ignored - the calls cannot fail, - * large pages are disabled at boot time. - */ - change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); - /* we should perform an IPI and flush all tlbs, - * but that can deadlock->flush only current cpu. - */ - __flush_tlb_all(); + BUG_ON(level != 3); + if (enable) { + set_pte_atomic(pte, mk_pte(page, PAGE_KERNEL)); + /* + * We should perform an IPI and flush all tlbs, + * but that can deadlock->flush only current cpu. + */ + __flush_tlb_one(addr); + } else { + kpte_clear_flush(pte, addr); + } + } } #endif