From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x244.google.com (mail-pa0-x244.google.com [IPv6:2607:f8b0:400e:c03::244]) (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 3rqhNd74lVzDqxj for ; Thu, 14 Jul 2016 13:42:41 +1000 (AEST) Received: by mail-pa0-x244.google.com with SMTP id ez1so551873pab.3 for ; Wed, 13 Jul 2016 20:42:41 -0700 (PDT) Date: Thu, 14 Jul 2016 13:42:27 +1000 From: Balbir Singh To: "Aneesh Kumar K.V" Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH for-4.8 03/12] powerpc/mm: use _raw variant of page table accessors Message-ID: <20160714034227.GC18277@balbir.ozlabs.ibm.com> Reply-To: bsingharora@gmail.com References: <1468402531-4914-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1468402531-4914-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1468402531-4914-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Jul 13, 2016 at 03:05:22PM +0530, Aneesh Kumar K.V wrote: > This switch few of the page table accessor to use the __raw variant ^^ switches ^^ accessors > and does the cpu to big endian conversion of constants. This helps in > generating better code. > > For ex: a pgd_none(pgd) check with and without fix is listed below > > Without fix: > ------------ > 2240: 20 00 61 eb ld r27,32(r1) > /* PGD level */ > typedef struct { __be64 pgd; } pgd_t; > static inline unsigned long pgd_val(pgd_t x) > { > return be64_to_cpu(x.pgd); > > 2244: 22 00 66 78 rldicl r6,r3,32,32 > 2248: 3e 40 7d 54 rotlwi r29,r3,8 > 224c: 0e c0 7d 50 rlwimi r29,r3,24,0,7 > 2250: 3e 40 c5 54 rotlwi r5,r6,8 > 2254: 2e c4 7d 50 rlwimi r29,r3,24,16,23 > 2258: 0e c0 c5 50 rlwimi r5,r6,24,0,7 > 225c: 2e c4 c5 50 rlwimi r5,r6,24,16,23 > 2260: c6 07 bd 7b rldicr r29,r29,32,31 > 2264: 78 2b bd 7f or r29,r29,r5 > if (pgd_none(pgd)) > 2268: 00 00 bd 2f cmpdi cr7,r29,0 > 226c: 54 03 9e 41 beq cr7,25c0 <__get_user_pages_fast+0x500> > > With fix: > --------- > 2370: 20 00 61 eb ld r27,32(r1) > if (pgd_none(pgd)) > 2374: 00 00 bd 2f cmpdi cr7,r29,0 > 2378: a8 03 9e 41 beq cr7,2720 <__get_user_pages_fast+0x530> > break; > Signed-off-by: Aneesh Kumar K.V > --- Acked-by: Balbir Singh