From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lithops.sigma-star.at ([195.201.40.130]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1g2H2a-0006Oq-K7 for linux-mtd@lists.infradead.org; Tue, 18 Sep 2018 14:31:50 +0000 From: Richard Weinberger To: Andrew Worsley Cc: Artem Bityutskiy , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , "open list:UNSORTED BLOCK IMAGES (UBI)" , open list Subject: Re: [PATCH] Round UBI average erase count up to next integer Date: Tue, 18 Sep 2018 16:31:33 +0200 Message-ID: <90432329.iuebBMo885@blindfold> In-Reply-To: <20180918130521.22880-2-amworsley@gmail.com> References: <20180918130521.22880-1-amworsley@gmail.com> <20180918130521.22880-2-amworsley@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Andrew, Am Dienstag, 18. September 2018, 15:05:21 CEST schrieb Andrew Worsley: > Use a slightly larger than average EC so these PEBs will be > reinitialised with erase counts that make them less likely to > be reused than other (perhaps less worn or error-prone) PEBs > > We have more frequent ECC failures on reads of page 0 of some PEBs > which manifest itself commonly during ubiattach. We believe this is due to > "program disturb" and want those PEB to be re-used later than average. So the general idea behind the patch is that we want to hold back PEBs that lost the EC header since they must be less healthy than others? More precisely such that this PEB will be less likely picked by find_mean_wl_entry(). Did you check, doesn't this make it more likely that such a "bad" PEB is more often picked by wear leveling? It does not use find_mean_wl_entry(). Thanks, //richard