From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f171.google.com (mail-pd0-f171.google.com [209.85.192.171]) by kanga.kvack.org (Postfix) with ESMTP id AC95C6B0036 for ; Mon, 2 Jun 2014 12:11:39 -0400 (EDT) Received: by mail-pd0-f171.google.com with SMTP id y13so3575216pdi.16 for ; Mon, 02 Jun 2014 09:11:39 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id hd2si16293016pbb.196.2014.06.02.09.11.38 for ; Mon, 02 Jun 2014 09:11:38 -0700 (PDT) Message-ID: <538CA239.3060506@intel.com> Date: Mon, 02 Jun 2014 09:11:37 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH 2/3] mm: introduce fincore() References: <20140521193336.5df90456.akpm@linux-foundation.org> <1401686699-9723-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1401686699-9723-3-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: <1401686699-9723-3-git-send-email-n-horiguchi@ah.jp.nec.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi , Andrew Morton Cc: Konstantin Khlebnikov , Wu Fengguang , Arnaldo Carvalho de Melo , Borislav Petkov , "Kirill A. Shutemov" , Johannes Weiner , Rusty Russell , David Miller , Andres Freund , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" On 06/01/2014 10:24 PM, Naoya Horiguchi wrote: > Detail about the data format being passed to userspace are explained in > inline comment, but generally in long entry format, we can choose which > information is extraced flexibly, so you don't have to waste memory by > extracting unnecessary information. And with FINCORE_SKIP_HOLE flag, > we can skip hole pages (not on memory,) which makes us avoid a flood of > meaningless zero entries when calling on extremely large (but only few > pages of it are loaded on memory) file. Something similar could be useful for hugetlbfs too. For a 1GB page, it's pretty silly to do 2^18 entries which essentially repeat the same data in an interface like this. -- 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