Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754898Ab2JVOQj (ORCPT ); Mon, 22 Oct 2012 10:16:39 -0400 Received: from mail-vc0-f174.google.com ([209.85.220.174]:59628 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754560Ab2JVOQi (ORCPT ); Mon, 22 Oct 2012 10:16:38 -0400 Date: Mon, 22 Oct 2012 10:16:34 -0400 From: Konrad Rzeszutek Wilk To: Yinghai Lu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jacob Shin , Tejun Heo , Stefano Stabellini , linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/19] x86, mm: Align start address to correct big page size Message-ID: <20121022141633.GB14193@konrad-lan.dumpdata.com> References: <1350593430-24470-1-git-send-email-yinghai@kernel.org> <1350593430-24470-3-git-send-email-yinghai@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1350593430-24470-3-git-send-email-yinghai@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3260 Lines: 99 >On Thu, Oct 18, 2012 at 01:50:10PM -0700, Yinghai Lu wrote: I am pretty sure I gave you some ideas of how to fix up the commit description in earlier reviews, but it looks like you missed them. Let me write them here once more. > We are going to use buffer in BRK to pre-map page table buffer. What buffer? Is buffer the same thing as page table? > > Page table buffer could be only page aligned, but range around it are .. ranges > ram too, we could use bigger page to map it to avoid small pages. > > We will adjust page_size_mask in next patch to use big page size for Instead of saying "next patch" - include the title of the patch so that one can search for it. > small ram range. > > Before that, this patch will make start address to be aligned down s/will make/made/ > according to bigger page size, otherwise entry in page page will > not have correct value. I would structure this git commit description to first introduce the problem. Say at the start of the patch: "Before this patch, the start address was aligned down according to bigger a page size (1GB, 2MB). This is a problem b/c an entry in the page table will not have correct value. " Here can you explain why it does not have the correct value? > > Signed-off-by: Yinghai Lu > --- > arch/x86/mm/init_32.c | 1 + > arch/x86/mm/init_64.c | 5 +++-- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c > index 11a5800..27f7fc6 100644 > --- a/arch/x86/mm/init_32.c > +++ b/arch/x86/mm/init_32.c > @@ -310,6 +310,7 @@ repeat: > __pgprot(PTE_IDENT_ATTR | > _PAGE_PSE); > > + pfn &= PMD_MASK >> PAGE_SHIFT; > addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + > PAGE_OFFSET + PAGE_SIZE-1; > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index ab558eb..f40f383 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -461,7 +461,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, > pages++; > spin_lock(&init_mm.page_table_lock); > set_pte((pte_t *)pmd, > - pfn_pte(address >> PAGE_SHIFT, > + pfn_pte((address & PMD_MASK) >> PAGE_SHIFT, > __pgprot(pgprot_val(prot) | _PAGE_PSE))); > spin_unlock(&init_mm.page_table_lock); > last_map_addr = next; > @@ -536,7 +536,8 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, > pages++; > spin_lock(&init_mm.page_table_lock); > set_pte((pte_t *)pud, > - pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE)); > + pfn_pte((addr & PUD_MASK) >> PAGE_SHIFT, > + PAGE_KERNEL_LARGE)); > spin_unlock(&init_mm.page_table_lock); > last_map_addr = next; > continue; > -- > 1.7.7 > > -- > 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/ > -- 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/