I've added to the buffer_head structure a b_prot flag. When it
is set, it cannot change lists (apparently), and the buffer cannot be
removed - which makes the buffer-cache ramdisk fully usable for the first
time. Even if buffers do get deleted, it can be tracable right when it
happens if klogd is shut off and alt-scrolllock is called often...
(My tests on the version posted indicate that protected buffers
do not even get on the LRU list...)
(I have a feeling using b_prot can be useful when b_count and
b_lock are not options, but the fs/driver does not want the buffer
deleted at any cost.)
The next step will be to get the loaded rootdisks into buffer
cache, which should make memory usage much more efficent for rootdisks
(some parts of rootdisks are stored twice in memory when they're used
using the current ramdisk scheme.) Right now, that part works just like
Ted's original driver, except for the fact that it will load gzipped
rootdisks as well :)
If that step works, I'll put it on as ramdisk-1.3.4+.tar.gz
possibly without announcement.
As usual, it's at ftp.best.com:/pub/cpage/ramdisk... I plan to
maintain it and enhance it with each new release...
- Chad