Re: reduce double caching in mfs

2016-09-11 Thread Ted Unangst
Bob Beck wrote: > I really dislike "CHEAP". > > and it almost seems like these should actually be NOCACHE.. why the heck > can't they be? So i looked at NOCACHE, but it seemed like that option may destroy the buffer too soon. Anyway, I tested it and it does go boom. With just NOCACHE in mfs,

Re: reduce double caching in mfs

2016-09-10 Thread Theo de Raadt
> Isn't the solution to this problem a working dynamic buffer cache? I'm > not sure adding a hack for mfs, and the complexity that comes with it, > is the way to go. Did somebody analyzed what broke when the buffer > cache was cranked to 90%? My digging suggested that something on "write side"

Re: reduce double caching in mfs

2016-09-09 Thread Bob Beck
I really dislike "CHEAP". and it almost seems like these should actually be NOCACHE.. why the heck can't they be? On Thu, Sep 8, 2016 at 7:49 PM, Ted Unangst wrote: > Currently, the bufcache doesn't know that mfs is backed by memory. All i/o > to > mfs ends up being

Re: reduce double caching in mfs

2016-09-09 Thread Martin Pieuchot
On 08/09/16(Thu) 14:49, Ted Unangst wrote: > Currently, the bufcache doesn't know that mfs is backed by memory. All i/o to > mfs ends up being double cached, once in the userland process and again in the > kernel bufcache. This is wasteful. In particular, it means one can't use mfs > to increase

reduce double caching in mfs

2016-09-08 Thread Ted Unangst
Currently, the bufcache doesn't know that mfs is backed by memory. All i/o to mfs ends up being double cached, once in the userland process and again in the kernel bufcache. This is wasteful. In particular, it means one can't use mfs to increase the effective size of the buffer cache. Reading or