From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f71.google.com (mail-pa0-f71.google.com [209.85.220.71]) by kanga.kvack.org (Postfix) with ESMTP id 24AA26B0253 for ; Wed, 27 Jul 2016 12:40:59 -0400 (EDT) Received: by mail-pa0-f71.google.com with SMTP id ca5so1986403pac.0 for ; Wed, 27 Jul 2016 09:40:59 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTP id xq3si7081788pac.194.2016.07.27.09.40.56 for ; Wed, 27 Jul 2016 09:40:58 -0700 (PDT) Subject: Re: [PATCH v2 repost 6/7] mm: add the related functions to get free page info References: <1469582616-5729-1-git-send-email-liang.z.li@intel.com> <1469582616-5729-7-git-send-email-liang.z.li@intel.com> From: Dave Hansen Message-ID: <5798E418.7080608@intel.com> Date: Wed, 27 Jul 2016 09:40:56 -0700 MIME-Version: 1.0 In-Reply-To: <1469582616-5729-7-git-send-email-liang.z.li@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Liang Li , linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, dgilbert@redhat.com, quintela@redhat.com, Andrew Morton , Vlastimil Babka , Mel Gorman , "Michael S. Tsirkin" , Paolo Bonzini , Cornelia Huck , Amit Shah On 07/26/2016 06:23 PM, Liang Li wrote: > + for_each_migratetype_order(order, t) { > + list_for_each(curr, &zone->free_area[order].free_list[t]) { > + pfn = page_to_pfn(list_entry(curr, struct page, lru)); > + if (pfn >= start_pfn && pfn <= end_pfn) { > + page_num = 1UL << order; > + if (pfn + page_num > end_pfn) > + page_num = end_pfn - pfn; > + bitmap_set(bitmap, pfn - start_pfn, page_num); > + } > + } > + } Nit: The 'page_num' nomenclature really confused me here. It is the number of bits being set in the bitmap. Seems like calling it nr_pages or num_pages would be more appropriate. Isn't this bitmap out of date by the time it's send up to the hypervisor? Is there something that makes the inaccuracy OK here? -- 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