From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 3tFf1S5h1gzDvnq for ; Fri, 11 Nov 2016 23:12:28 +1100 (AEDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uABC8t8M113090 for ; Fri, 11 Nov 2016 07:12:26 -0500 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0a-001b2d01.pphosted.com with ESMTP id 26nc3t62cd-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 11 Nov 2016 07:12:26 -0500 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 11 Nov 2016 05:12:25 -0700 From: "Aneesh Kumar K.V" To: "Kirill A. Shutemov" Cc: akpm@linux-foundation.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 2/2] mm: THP page cache support for ppc64 In-Reply-To: <20161111101439.GB19382@node.shutemov.name> References: <20161107083441.21901-1-aneesh.kumar@linux.vnet.ibm.com> <20161107083441.21901-2-aneesh.kumar@linux.vnet.ibm.com> <20161111101439.GB19382@node.shutemov.name> Date: Fri, 11 Nov 2016 17:42:11 +0530 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <8737iy1ahw.fsf@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , "Kirill A. Shutemov" writes: > On Mon, Nov 07, 2016 at 02:04:41PM +0530, Aneesh Kumar K.V wrote: >> @@ -2953,6 +2966,13 @@ static int do_set_pmd(struct fault_env *fe, struct page *page) >> ret = VM_FAULT_FALLBACK; >> page = compound_head(page); >> >> + /* >> + * Archs like ppc64 need additonal space to store information >> + * related to pte entry. Use the preallocated table for that. >> + */ >> + if (arch_needs_pgtable_deposit() && !fe->prealloc_pte) >> + fe->prealloc_pte = pte_alloc_one(vma->vm_mm, fe->address); >> + > > -ENOMEM handling? How about if (arch_needs_pgtable_deposit() && !fe->prealloc_pte) { fe->prealloc_pte = pte_alloc_one(vma->vm_mm, fe->address); if (!fe->prealloc_pte) return VM_FAULT_OOM; } > > I think we should do this way before this point. Maybe in do_fault() or > something. doing this in do_set_pmd keeps this closer to where we set the pmd. Any reason you thing we should move it higher up the stack. We already do pte_alloc() at the same level for a non transhuge case in alloc_set_pte(). -aneesh