Re: [RFC] Heads up on sys_fallocate()
From: Jörn Engel <joern@lazybastard.org>
Date: 2007-03-05 13:24:35
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linux-fsdevel, lkml
On Mon, 5 March 2007 00:32:14 +0000, Anton Altaparmakov wrote:
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 have fun. Jörn -- 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