From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966568Ab3HHUvJ (ORCPT ); Thu, 8 Aug 2013 16:51:09 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:38020 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966544Ab3HHUvH (ORCPT ); Thu, 8 Aug 2013 16:51:07 -0400 Message-ID: <1375994967.29639.4.camel@concerto> Subject: Re: [PATCH 22/23] thp, mm: split huge page on mmap file page From: Khalid Aziz To: "Kirill A. Shutemov" Cc: Andrea Arcangeli , Andrew Morton , Al Viro , Hugh Dickins , Wu Fengguang , Jan Kara , Mel Gorman , linux-mm@kvack.org, Andi Kleen , Matthew Wilcox , "Kirill A. Shutemov" , Hillf Danton , Dave Hansen , Ning Qu , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 08 Aug 2013 14:49:27 -0600 In-Reply-To: <1375582645-29274-23-git-send-email-kirill.shutemov@linux.intel.com> References: <1375582645-29274-1-git-send-email-kirill.shutemov@linux.intel.com> <1375582645-29274-23-git-send-email-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2013-08-04 at 05:17 +0300, Kirill A. Shutemov wrote: > From: "Kirill A. Shutemov" > > We are not ready to mmap file-backed tranparent huge pages. Let's split > them on fault attempt. > > Later we'll implement mmap() properly and this code path be used for > fallback cases. > > Signed-off-by: Kirill A. Shutemov > --- > mm/filemap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/filemap.c b/mm/filemap.c > index ed65af5..f7857ef 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1743,6 +1743,8 @@ retry_find: > goto no_cached_page; > } > > + if (PageTransCompound(page)) > + split_huge_page(compound_trans_head(page)); Since PageTransCompound(page) returns true for transparent huge pages as well as hugetlbfs pages, could this code split hugetlbfs pages on an mmap() on to hugetlbfs pages? hugetlbfs pages are not supposed to be split, right? > if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) { > page_cache_release(page); > return ret | VM_FAULT_RETRY; -- Khalid From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [PATCH 22/23] thp, mm: split huge page on mmap file page Date: Thu, 08 Aug 2013 14:49:27 -0600 Message-ID: <1375994967.29639.4.camel@concerto> References: <1375582645-29274-1-git-send-email-kirill.shutemov@linux.intel.com> <1375582645-29274-23-git-send-email-kirill.shutemov@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Andrea Arcangeli , Andrew Morton , Al Viro , Hugh Dickins , Wu Fengguang , Jan Kara , Mel Gorman , linux-mm@kvack.org, Andi Kleen , Matthew Wilcox , "Kirill A. Shutemov" , Hillf Danton , Dave Hansen , Ning Qu , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: "Kirill A. Shutemov" Return-path: In-Reply-To: <1375582645-29274-23-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Sun, 2013-08-04 at 05:17 +0300, Kirill A. Shutemov wrote: > From: "Kirill A. Shutemov" > > We are not ready to mmap file-backed tranparent huge pages. Let's split > them on fault attempt. > > Later we'll implement mmap() properly and this code path be used for > fallback cases. > > Signed-off-by: Kirill A. Shutemov > --- > mm/filemap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/filemap.c b/mm/filemap.c > index ed65af5..f7857ef 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1743,6 +1743,8 @@ retry_find: > goto no_cached_page; > } > > + if (PageTransCompound(page)) > + split_huge_page(compound_trans_head(page)); Since PageTransCompound(page) returns true for transparent huge pages as well as hugetlbfs pages, could this code split hugetlbfs pages on an mmap() on to hugetlbfs pages? hugetlbfs pages are not supposed to be split, right? > if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) { > page_cache_release(page); > return ret | VM_FAULT_RETRY; -- Khalid -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org