[Haiku-commits] r26671 - haiku/trunk/src/add-ons/kernel/file_systems/bfs

[Axel Dörfler]

Ingo Weinhold <ingo_weinhold at gmx.de> wrote:
> On 2008-07-29 at 09:39:38 [+0200], Axel Dörfler <axeld at pinc-software.de> 
> > wrote:
> > bonefish at mail.berlios.de wrote:
> > > +    return bfs_get_file_map(volume_for_vnode(node), node, 
> > > offset, size,
> > > vecs,
> > > +        _count);
> > Any reason why you are calling bfs_get_file_map() directly instead 
> > of
> > using the file map that each Inode (with a file cache) has?
> No, I just wasn't really thinking. Both methods have problems though, 
> since 
> they allocate memory/blocks, which might be very undesirable in the 
> page 
> writer.

Indeed, even though bfs_get_file_map() is guaranteed to need memory 
each time :-)
We could lock the range of disk offsets in the file map for pages 
mapped in, but in any case, only the swap file is problematic for 
obvious reasons. For that, I wanted to have an additional file map call 
that allows to lock the whole map into memory.

Bye,
   Axel.