From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x233.google.com (mail-pf0-x233.google.com [IPv6:2607:f8b0:400e:c00::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3qqWxn6FbvzDqKD for ; Wed, 20 Apr 2016 16:22:05 +1000 (AEST) Received: by mail-pf0-x233.google.com with SMTP id c20so14861058pfc.1 for ; Tue, 19 Apr 2016 23:22:05 -0700 (PDT) Subject: Re: [PATCH V2 23/68] powerpc/mm: Make page table size a variable To: "Aneesh Kumar K.V" , benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au References: <1460182444-2468-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1460182444-2468-24-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <570C5437.1070900@gmail.com> <87fuuka5ts.fsf@skywalker.in.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org From: Balbir Singh Message-ID: <57171FFA.4070301@gmail.com> Date: Wed, 20 Apr 2016 16:21:46 +1000 MIME-Version: 1.0 In-Reply-To: <87fuuka5ts.fsf@skywalker.in.ibm.com> Content-Type: text/plain; charset=windows-1252 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 17/04/16 20:27, Aneesh Kumar K.V wrote: > Balbir Singh writes: > >>> index 2f818cbd8aa6..dcb9d6e94a0c 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h >>> +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h >>> @@ -5,48 +5,20 @@ >>> * for each page table entry. The PMD and PGD level use a 32b record for >>> * each entry by assuming that each entry is page aligned. >>> */ >>> -#define PTE_INDEX_SIZE 9 >>> -#define PMD_INDEX_SIZE 7 >>> -#define PUD_INDEX_SIZE 9 >>> -#define PGD_INDEX_SIZE 9 >>> +#define H_PTE_INDEX_SIZE 9 >>> +#define H_PMD_INDEX_SIZE 7 >>> +#define H_PUD_INDEX_SIZE 9 >>> +#define H_PGD_INDEX_SIZE 9 >>> >> >> Any comments on where these numbers came from? >> >> From these numbers for 4K pages we have >> >> Each PMD is 2M >> Each PUD is 256M >> Each PGD is 128G > > I am not sure I understand. We are updating linux page table details for > hash config here. This patch doesn't make any functionality change, it > just make sure few #defines are marked as a variable. > I was just stating that we need some comments about why we chose a particular split. It just helps to understand that we use. My comment was just stating that we need some additional comments and not necessarily due to your change Balbir