On Fri, 2007-07-27 at 13:09 +0200, Rene Herman wrote: > On 07/27/2007 11:26 AM, Mike Galbraith wrote: >
> > Updatedb finishes, freeing some ram (doesn't matter how much) > > Will be very little and swap-prefetch at least in its current form needs > more than very little to start doing anything: > > http://ck.kolivas.org/patches/swap-prefetch/2.6.21-swap_prefetch-38.patch > > | /* > | * Set max number of entries to 2/3 the size of physical ram as we > | * only ever prefetch to consume 2/3 of the ram. > | */ > > However, okay, let's just ignore that and pretend it kicks in even with the > little free memory updatedb itself left behind when it finished: Hm. I didn't read the patch, so I'm only going on what you quoted. >From that, all I see is a limit on how much will be used total, and 2/3 of physical ram is a bunch. This quote doesn't say free ram, it says physical ram. If it really does use only free ram, that indeed sounds pretty pointless. I believe the users who say their apps really do get paged back in though, so suspect that's not the case. Anyway, I only offered a simple explanation of how swap-prefetching can indeed help (and possibly hurt) with something like updatedb, not an analysis of it's current implementation ;-) I'd have to read it, and test it myself to do that, but my world doesn't have a need for it, so... -Mike - 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/
