Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755454Ab3COPDz (ORCPT ); Fri, 15 Mar 2013 11:03:55 -0400 Received: from mga02.intel.com ([134.134.136.20]:53629 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754349Ab3COPDo (ORCPT ); Fri, 15 Mar 2013 11:03:44 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,850,1355126400"; d="scan'208";a="302777096" From: "Kirill A. Shutemov" To: Hillf Danton 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" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: <1363283435-7666-1-git-send-email-kirill.shutemov@linux.intel.com> <1363283435-7666-9-git-send-email-kirill.shutemov@linux.intel.com> <20130315132333.B8205E0085@blue.fi.intel.com> <20130315135026.32B58E0085@blue.fi.intel.com> Subject: Re: [PATCHv2, RFC 08/30] thp, mm: rewrite add_to_page_cache_locked() to support huge pages Content-Transfer-Encoding: 7bit Message-Id: <20130315150522.8BF97E0085@blue.fi.intel.com> Date: Fri, 15 Mar 2013 17:05:22 +0200 (EET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1851 Lines: 52 Hillf Danton wrote: > On Fri, Mar 15, 2013 at 9:50 PM, Kirill A. Shutemov > wrote: > > Hillf Danton wrote: > >> On Fri, Mar 15, 2013 at 9:23 PM, Kirill A. Shutemov > >> wrote: > >> > Hillf Danton wrote: > >> >> On Fri, Mar 15, 2013 at 1:50 AM, Kirill A. Shutemov > >> >> wrote: > >> >> > + page_cache_get(page); > >> >> > + spin_lock_irq(&mapping->tree_lock); > >> >> > + page->mapping = mapping; > >> >> > + page->index = offset; > >> >> > + error = radix_tree_insert(&mapping->page_tree, offset, page); > >> >> > + if (unlikely(error)) > >> >> > + goto err; > >> >> > + if (PageTransHuge(page)) { > >> >> > + int i; > >> >> > + for (i = 1; i < HPAGE_CACHE_NR; i++) { > >> >> struct page *tail = page + i; to easy reader > >> >> > >> >> > + page_cache_get(page + i); > >> >> s/page_cache_get/get_page_foll/ ? > >> > > >> > Why? > >> > > >> see follow_trans_huge_pmd() please. > > > > Sorry, I fail to see how follow_trans_huge_pmd() is relevant here. > > Could you elaborate? > > > Lets see the code > > page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; > //page is tail now > VM_BUG_ON(!PageCompound(page)); > if (flags & FOLL_GET) > get_page_foll(page); > //raise page count with the foll function > > thus I raised question. get_page_foll() is designed to be part of follow_page*() call chain. get_page() can handle compound pages properly. -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/