From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga11.intel.com ([192.55.52.93]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1X1zRM-0003NG-9Y for linux-mtd@lists.infradead.org; Tue, 01 Jul 2014 14:53:48 +0000 Message-ID: <1404226404.6841.120.camel@sauron.fi.intel.com> Subject: Re: Does UBI still place a just-tortured block first in the free block list? From: Artem Bityutskiy Reply-To: dedekind1@gmail.com To: Atlant Schmidt Date: Tue, 01 Jul 2014 17:53:24 +0300 In-Reply-To: <0A40042D85E7C84DB443060EC44B3FD36D986A2F0A@dekaexchange07.deka.local> References: <0A40042D85E7C84DB443060EC44B3FD36D986A2F0A@dekaexchange07.deka.local> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Cc: "'linux-mtd@lists.infradead.org'" , Cale Surgen List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Atlant, On Tue, 2014-07-01 at 09:11 -0400, Atlant Schmidt wrote: > Folks: > > Several years ago, the behavior of UBI was that if a block > failed to write, UBI would torture-test the block (with 0x5A > and 0xA5 patterns) and if the block passed the torture test, > it would be placed at the top of the list of available blocks. Not sure, eraseblocks are stored in an RB-tree tree which is indexed by the erase counter. Then UBI picks those with smaller erase counters first. > With this algorithm, UBI would attempt to again use the just- > tortured block for the data that was still waiting to be written. > But because the write failures were often data-dependent, in > our experience, the block would frequently again fail to store > the data to be written. It would be tortured again, passed again, > and the cycle would repeat. We've seen this cycle continue for > minutes at a time. Sounds like a possible scenario, if the PEB in question has low erase counter. > Is the algorithm still the same? Or is the just-tortured block > now placed at the bottom of the list of available blocks so that > it will only show up again later (when the data to be written > will probably be different)? I am not sure about the list you are talking about, do you just assume there is a list or you mean a specific list? I do not think this part of UBI changed for the last several years. -- Best Regards, Artem Bityutskiy