From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755596Ab3C1MYL (ORCPT ); Thu, 28 Mar 2013 08:24:11 -0400 Received: from mga11.intel.com ([192.55.52.93]:25848 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754918Ab3C1MYJ (ORCPT ); Thu, 28 Mar 2013 08:24:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,925,1355126400"; d="scan'208";a="309721674" From: "Kirill A. Shutemov" To: Dave Hansen Cc: "Kirill A. Shutemov" , 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 , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <514C773A.6070000@sr71.net> References: <1363283435-7666-1-git-send-email-kirill.shutemov@linux.intel.com> <1363283435-7666-15-git-send-email-kirill.shutemov@linux.intel.com> <514C773A.6070000@sr71.net> Subject: Re: [PATCHv2, RFC 14/30] thp, mm: naive support of thp in generic read/write routines Content-Transfer-Encoding: 7bit Message-Id: <20130328122557.2D6A7E0085@blue.fi.intel.com> Date: Thu, 28 Mar 2013 14:25:57 +0200 (EET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Hansen wrote: > On 03/14/2013 10:50 AM, Kirill A. Shutemov wrote: > > From: "Kirill A. Shutemov" > > > > For now we still write/read at most PAGE_CACHE_SIZE bytes a time. > > > > This implementation doesn't cover address spaces with backing store. > ... > > --- a/mm/filemap.c > > +++ b/mm/filemap.c > > @@ -1165,12 +1165,23 @@ find_page: > > if (unlikely(page == NULL)) > > goto no_cached_page; > > } > > + if (PageTransTail(page)) { > > + page_cache_release(page); > > + page = find_get_page(mapping, > > + index & ~HPAGE_CACHE_INDEX_MASK); > > + if (!PageTransHuge(page)) { > > + page_cache_release(page); > > + goto find_page; > > + } > > + } > > So, we're going to do a read of a file, and we pulled a tail page out of > the page cache. Why can't we just deal with the tail page directly? Good point. I'll redo it once again. First I thought to make it possible to read/write more PAGE_SIZE at once. If not take this option in account for now, it's possible to make code much cleaner. -- Kirill A. Shutemov From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx148.postini.com [74.125.245.148]) by kanga.kvack.org (Postfix) with SMTP id E5B4F6B0005 for ; Thu, 28 Mar 2013 08:24:09 -0400 (EDT) From: "Kirill A. Shutemov" In-Reply-To: <514C773A.6070000@sr71.net> References: <1363283435-7666-1-git-send-email-kirill.shutemov@linux.intel.com> <1363283435-7666-15-git-send-email-kirill.shutemov@linux.intel.com> <514C773A.6070000@sr71.net> Subject: Re: [PATCHv2, RFC 14/30] thp, mm: naive support of thp in generic read/write routines Content-Transfer-Encoding: 7bit Message-Id: <20130328122557.2D6A7E0085@blue.fi.intel.com> Date: Thu, 28 Mar 2013 14:25:57 +0200 (EET) Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: "Kirill A. Shutemov" , 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 , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Dave Hansen wrote: > On 03/14/2013 10:50 AM, Kirill A. Shutemov wrote: > > From: "Kirill A. Shutemov" > > > > For now we still write/read at most PAGE_CACHE_SIZE bytes a time. > > > > This implementation doesn't cover address spaces with backing store. > ... > > --- a/mm/filemap.c > > +++ b/mm/filemap.c > > @@ -1165,12 +1165,23 @@ find_page: > > if (unlikely(page == NULL)) > > goto no_cached_page; > > } > > + if (PageTransTail(page)) { > > + page_cache_release(page); > > + page = find_get_page(mapping, > > + index & ~HPAGE_CACHE_INDEX_MASK); > > + if (!PageTransHuge(page)) { > > + page_cache_release(page); > > + goto find_page; > > + } > > + } > > So, we're going to do a read of a file, and we pulled a tail page out of > the page cache. Why can't we just deal with the tail page directly? Good point. I'll redo it once again. First I thought to make it possible to read/write more PAGE_SIZE at once. If not take this option in account for now, it's possible to make code much cleaner. -- Kirill A. Shutemov -- 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