From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3ryWV14vlZzDqPb for ; Mon, 25 Jul 2016 16:26:01 +1000 (AEST) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u6P6NdeL045743 for ; Mon, 25 Jul 2016 02:25:59 -0400 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0b-001b2d01.pphosted.com with ESMTP id 24c2qujyf1-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 25 Jul 2016 02:25:58 -0400 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 25 Jul 2016 00:25:58 -0600 From: "Aneesh Kumar K.V" To: Nicholas Piggin Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH for-4.8 V2 00/10] Use jump label for cpu/mmu_has_feature In-Reply-To: <20160725152201.03788ccb@roar.ozlabs.ibm.com> References: <1469265163-1491-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20160725152201.03788ccb@roar.ozlabs.ibm.com> Date: Mon, 25 Jul 2016 11:55:50 +0530 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87shuykzdd.fsf@skywalker.in.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Nicholas Piggin writes: > On Sat, 23 Jul 2016 14:42:33 +0530 > "Aneesh Kumar K.V" wrote: > >> Changes from V1: >> * Update "powerpc/mm: Convert early cpu/mmu feature check to use the >> new helpers" based on resend code changes in this area. >> >> We now do feature fixup early and hence we can reduce the usage of >> __cpu/__mmu_has_feature. > > Is there a particular reason for for-4.8? > > I've only just started following this development so it might be > obvious, but if you could add some small justifications for why > a patch or series is done, it would be of great help to me. The goal is to reduce the impact of radix series on existing MMU function. With radix series, we do if (radix_enabled()) radix_function() else hash_function() We did try to reduce the impact in most code path like linux page table accessors by moving linux pte bits around to match the radix/hardware requirements. But we still have other code paths where we do the above conditional. Now for-4.8 is mainly because, I was trying to make sure 4.8 release will have a good performing radix/hash implementation which distros can base their kernel on. This series was posted to external list multiple times and I didn't receive many objections to the series. Hence I was thinking it to be a good idea to get it upstream by 4.8. -aneesh