Subject: Re: that VM/fs cache coherency problem
To: None <tech-kern@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
Date: 08/03/1995 07:10:33
>> So vi is using mmap? This is probably the same problem that David
>> Greenman sent me mail about at one time. vnode_pager_setsize
>> doesn't properly deal with files whose length is not a multiple of
>> the page size (either shrinking or growing). [...]
> This may need some small changes before it will drop into NetBSD.
> The 4.4-lite code doesn't have a "vm_pager_map_page", but does have a
> "vm_pager_map_pages" routine that I think should work okay for this.
I did change it to use vm_pager_map_pages() and vm_pager_unmap_pages()
and it built and runs. But I've been unable to detect any difference
with the patch in or out. (I did tweak it slightly, on reading
vm_object_page_remove, to make sure it got the right pages.) The real
problem I was seeing was the nullfs one I just reported.