From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 534CE1A0076 for ; Sat, 13 Feb 2016 16:08:45 +1100 (AEDT) Received: from localhost by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 12 Feb 2016 22:08:41 -0700 Received: from b01cxnp22033.gho.pok.ibm.com (b01cxnp22033.gho.pok.ibm.com [9.57.198.23]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id 8EBC93E40030 for ; Fri, 12 Feb 2016 22:08:38 -0700 (MST) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u1D58c0N33816690 for ; Sat, 13 Feb 2016 05:08:38 GMT Received: from d01av02.pok.ibm.com (localhost [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u1D58bnJ006104 for ; Sat, 13 Feb 2016 00:08:37 -0500 From: "Aneesh Kumar K.V" To: Paul Mackerras Cc: benh@kernel.crashing.org, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Subject: Re: [PATCH V2 01/29] powerpc/mm: add _PAGE_HASHPTE similar to 4K hash In-Reply-To: <20160212024906.GB13831@oak.ozlabs.ibm.com> References: <1454923241-6681-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1454923241-6681-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20160212024906.GB13831@oak.ozlabs.ibm.com> Date: Sat, 13 Feb 2016 10:38:32 +0530 Message-ID: <8737sxrycv.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Paul Mackerras writes: > On Mon, Feb 08, 2016 at 02:50:13PM +0530, Aneesh Kumar K.V wrote: >> Not really needed. But this brings it back to as it was before > > If it's not really needed, what's the motivation for putting this > patch in? You need to explain where you are heading with this patch. I explained this in the last review. What confused me in the beginning was difference between 4k and 64k page size. I was trying to find out whether we miss a hpte flush in any scenario because of this. ie, a pte update on a linux pte, for which we are doing a parallel hash pte insert. After looking at it closer my understanding is this won't happen because pte update also look at _PAGE_BUSY and we will wait for hash pte insert to finish before going ahead with the pte update. But to avoid further confusion I was wondering whether we should keep this closer to what we have with __hash_page_4k. Hence the statement "Not really needed". I will add more information in the commit message. > >> Check this >> 41743a4e34f0777f51c1cf0675b91508ba143050 > > The SHA1 is useful, but you need to be more explicit - something like > > "This partially reverts commit 41743a4e34f0 ("powerpc: Free a PTE bit > on ppc64 with 64K pages", 2008-06-11)." > ok -aneesh