From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [RFC] Heads up on sys_fallocate() Date: Mon, 5 Mar 2007 12:49:45 +0100 Message-ID: <20070305114945.GB454@lazybastard.org> References: <20070117094658.GA17390@amitarora.in.ibm.com> <1172789056.11165.42.camel@kleikamp.austin.ibm.com> <20070301233819.GB31072@infradead.org> <200703032345.33137.arnd@arndb.de> <0DA8B217-DDD4-4E05-B000-DEBE3BE55B94@cam.ac.uk> <45EB4A55.3060908@redhat.com> <20070305001621.GB18691@lazybastard.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Ulrich Drepper , Arnd Bergmann , Christoph Hellwig , Dave Kleikamp , Andrew Morton , "Amit K. Arora" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, suparna@in.ibm.com, cmm@us.ibm.com, alex@clusterfs.com, suzuki@in.ibm.com To: Anton Altaparmakov Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, 5 March 2007 00:32:14 +0000, Anton Altaparmakov wrote: >=20 > I don't know how your compression algorithm works [...] LogFS is designed for flash media, so it does not have to worry much about reducing disk seeks. It is log-structured, which simplifies compression further. When writing a block, it basically compresses it and appends it to the log. Writes only have to be byte-aligned, so no space is lost for padding. The bad news for posix_fallocate() is that even if libc is smart enough to write random data, mmap() can still cause problems. If the VM decides to write a given page twice, the second write compresses better and the medium has filled up between the two writes, the users will hav= e fun. J=C3=B6rn --=20 Joern's library part 9: http://www.scl.ameslab.gov/Publications/Gus/TwelveWays.html - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html