Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754774AbaLDUpj (ORCPT ); Thu, 4 Dec 2014 15:45:39 -0500 Received: from mail-qc0-f170.google.com ([209.85.216.170]:59788 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752979AbaLDUpi (ORCPT ); Thu, 4 Dec 2014 15:45:38 -0500 Date: Thu, 4 Dec 2014 15:45:34 -0500 From: Tejun Heo To: Christoph Lameter Cc: Leonard Crestez , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sorin Dumitru Subject: Re: [RFC v2] percpu: Add a separate function to merge free areas Message-ID: <20141204204534.GE4080@htj.dyndns.org> References: <547E3E57.3040908@ixiacom.com> <20141204175713.GE2995@htj.dyndns.org> <5480BFAA.2020106@ixiacom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Christoph. On Thu, Dec 04, 2014 at 02:28:10PM -0600, Christoph Lameter wrote: > Well this is not a common use case and that is not what the per cpu > allocator was designed for. There is bound to be signifcant fragmentation > with the current design. The design was for rare allocations when > structures are initialized. My unverified gut feeling is that fragmentation prolly is a lot less of a problem for percpu allocator given that most percpu allocations are fairly small. On the other hand, we do wanna pack them tight as percpu memory is really expensive space-wise. I could be wrong tho. Thanks. -- tejun -- 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/