wired memory - again!

Wojciech Puchar wojtek at wojtek.tensor.gdynia.pl
Sat Jun 9 20:47:45 UTC 2012


>
> First, all memory allocated by UMA and consequently malloc(9) is
> wired. In other words, almost all memory used by kernel is accounted
> as wired.
>
yes i understand this. still i found no way how to find out what allocated 
that much.


> Second, the buffer cache wires the pages which are inserted into VMIO
> buffers. So your observation is basically right, cached buffers means

what are exactly "VMIO" buffers. i understand that page must be wired WHEN 
doing I/O.
But i have too much wired memory even when doing no I/O at all.

> that corresponding memory is removed from queues and put into wired
> state. When buffers are dissolved, pages are unwired and deactivated.
>
> This behaviour is in fact required by VFS, since you do expect to access
> buffer data when you get the buffer.
>


More information about the freebsd-hackers mailing list