On Thu, 26 Jul 2007 12:27:30 +0200 Ingo Molnar <[EMAIL PROTECTED]> wrote:
> > * Andrew Morton <[EMAIL PROTECTED]> wrote: > > > > > > ( we _do_ want to baloon the dentry cache otherwise - for things like > > > > > "find" - having a fast VFS is important. But known-use-once things > > > > > like the daily updatedb job can clearly be annotated properly. ) > > > > > > > > Mutter. /proc/sys/vm/vfs_cache_pressure has been there for what, > > > > three years? Are any distros raising it during the updatedb run yet? > > > > > > but ... that's system-wide, and the 'dont baloon the dcache' is only a > > > property of updatedb. > > > > Sure, but it's practical, isn't it? Who runs (and cares about) > > vfs-intensive workloads during their wee-small-hours updatedb run? > > there's another side-effect: it likely results in the zapping of > thousands of dentries that were cached nicely before. So we might > exchange 'all my apps are swapped out' experience with 'all file access > is slow'. The latter is _probably_ still an improvement over the > balooning, but i'm not sure. Yup. Nobody has begun to think about preserving dcache/icache across load shifts yet, afaik. Hard. > What we _really_ want is an updatedb that > does not disturb the dcache. Well. Hopefully this time next year you can prep a 16MB container and toss your updatedb inside that. Maybe set its peak disk bandwidth utilisation too. However that won't work ;) because I don't think anyone is looking at containerisation of vfs cache memory yet. Perhaps full-on openvz has it, dunno. But updatedb is a special case, because it is so vfs-intensive. For lots of other workloads (those which use heaps of pagecache), resource management via containerisation will work nicely. - 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/
