From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751823Ab2CHHIp (ORCPT ); Thu, 8 Mar 2012 02:08:45 -0500 Received: from mail-ww0-f44.google.com ([74.125.82.44]:40540 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751498Ab2CHHIo (ORCPT ); Thu, 8 Mar 2012 02:08:44 -0500 Date: Thu, 8 Mar 2012 09:08:35 +0200 From: Shmulik Ladkani To: Richard Weinberger Cc: dedekind1@gmail.com, tglx@linutronix.de, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, tim.bird@am.sony.com Subject: Re: [RFC][PATCH 0/7] UBI checkpointing support Message-ID: <20120308090835.032fe13a@pixies.home.jungo.com> In-Reply-To: <4F57D0C4.1050605@linutronix.de> References: <1329250006-22944-1-git-send-email-rw@linutronix.de> <1331138007.3463.16.camel@sauron.fi.intel.com> <4F57D0C4.1050605@linutronix.de> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.9; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 07 Mar 2012 22:19:00 +0100 Richard Weinberger wrote: > >> All these operations scan a limited number of erase blocks which makes > >> the UBI init O(1) and independent of the device size. > > > > Well, is it really true? The larger is the flash the more you read and > > process anyway, and it is still linear, but the multiplier becomes very > > small, so this is a huge improvement. > > Yes. :) > > Using checkpointing UBI only has to scan a fixed (independent of the > flash size!) number of blocks. But doesn't the CP data (sorry, UBIUBI data :) need to have one 'struct ubi_cp_ec' descriptor for each used/free PEB, and as such the maximum number of 'ubi_cp_ec' descriptors is total device PEBs, meaning CP data is still linearly scaled to device size (with a very small multiplier)? Regards, Shmulik