On 7/29/07, Rene Herman <[EMAIL PROTECTED]> wrote: > On 07/29/2007 05:20 PM, Ray Lee wrote: > This seems to be now fixing the different problem of swap-space filling up. > I'm quite willing to for now assume I've got plenty free.
I was trying to point out that currently, as an example, memory that is linear in a process' space could be fragmented on disk when swapped out. That's today. Under a log-structured scheme, one could set it up such that something that was linear in RAM could be swapped out linearly on the drive, minimizing seeks on writeout, which will naturally minimize seeks on swap in of that same data. > > So, at some point when the system needs to fault those blocks that > > back in, it now has a linear span of sectors to read instead of asking > > the drive to bounce over twenty tracks for a hundred blocks. > > Moreover though -- what I know about log structure is that generally it > optimises for write (swapout) and might make read (swapin) worse due to > fragmentation that wouldn't happen with a regular fs structure. It looks like I'm not doing a very good job of explaining this, I'm afraid. Suffice it to say that a log structured swap would give optimization options that we don't have today. > I guess that cleaner that Alan mentioned might be involved there -- I don't > know how/what it would be doing. Then you should google on `log structured filesystem (primer OR introduction)` and read a few of the links that pop up. You might find it interesting. > I am very aware of the costs of seeks (on current magnetic media). Then perhaps you can just take it on faith -- log structured layouts are designed to help minimize seeks, read and write. Ray - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
