Prefaulting for i/o buffers

[Pawel Jakub Dawidek]

On Thu, Mar 01, 2012 at 04:15:53PM +0200, Konstantin Belousov wrote:
> On Thu, Mar 01, 2012 at 03:12:47PM +0100, Pawel Jakub Dawidek wrote:
> > Yes, namecache is already library-like, but I was talking about the
> > buffer cache. I managed to bypass it eventually with suggestions from
> > ups@, but for a long time I was sure it isn't at all possible.
> 
> I am quite curious, in which way buffer layer is mandatory ?

As I said, it is not, but it took me a while to figure it out.
I remember having massive problems when I was working on getting mmaped
reads/writes right and bypassing the buffer cache and talking to the
page cache directly. I don't think there was single example in the tree
that was showing it can be done at that time. Currently tmpfs is using
the same approach as ZFS, AFAIK.

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
FreeBSD committer                         http://www.FreeBSD.org
Am I Evil? Yes, I Am!                     http://tupytaj.pl
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