Re: Update shared mappings

Andrea Arcangeli
1998-12-02T18:45:52Z

On Wed, 2 Dec 1998, Stephen C. Tweedie wrote:

>else's mm semaphore. If you have two processes doing that to each other
>(ie. two processes mapping the same file r/w and doing msyncs), then you
>can most certainly still deadlock.

The thing would be trivially fixable if it would exists a down_trylock()
that returns 0 if the semaphore was just held. I rejected now the
update_shared_mappings from my tree in the meantime though.

I have a question. Please consider only the UP case (as if linux would not
support SMP at all). Is it possible that while we are running inside
sys_msync() and another process has the mmap semaphore held?

Stephen I read some emails about a PG_dirty flag. Could you tell me some
more about that flag?

Andrea Arcangeli