[Dprobes] Re: [ANNOUNCE] DProbes 1.1

[Andi K. <ak...@su...>]

Hallo, 

On Tue, Oct 24, 2000 at 07:37:08PM +0530, bsu...@in... wrote:
> For (a), your suggestion of a two pass approach is I guess feasible, but I
> wish there were a simpler way to do it.
> Actually I don't even really like the idea of forcing the swapped out page
> back in, which we are having to do right now -   it would have been nicer
> if there were a swapin() routine in the vma ops that we could have used for
> on-demand probe insertion, just the way we use inode address space
> readpage() right now for discardable pages, but maybe that's asking for too
> much :-)  [Could vma type based swapin() logic be a useful abstraction in
> general, aside from dprobes ?].

I think it would be. You could propose it on the linux-mm mailing list and
ask Linus what he thinks. 

I agree that it would be much nicer to do it this way. 

> We don't quite understand (b), though. There is indeed a race due to our
> not holding the page given to us by handle_mm_fault, while we try to access
> it, and we need to fix that of course, but that doesn't sound exactly like
> what you mention here. We do have handle_mm_fault being called under the mm
> semaphore. Could you explain the deadlock situation that you have in mind ?

It does not exist sorry. I was misremembering the lock hierarchy at that
place when I wrote the mail and should have double checked it.


-Andi