On Mon, Aug 13 2007, Daniel Phillips wrote:

On Monday 13 August 2007 00:45, Jens Axboe wrote:

quoted

On Mon, Aug 13 2007, Jens Axboe wrote:

quoted

quoted

You did not comment on the one about putting the bio destructor
in the ->endio handler, which looks dead simple.  The majority of
cases just use the default endio handler and the default
destructor.  Of the remaining cases, where a specialized
destructor is needed, typically a specialized endio handler is
too, so combining is free.  There are few if any cases where a
new specialized endio handler would need to be written.

We could do that without too much work, I agree.

But that idea fails as well, since reference counts and IO completion
are two completely seperate entities. So unless end IO just happens
to be the last user holding a reference to the bio, you cannot free
it.

That is not a problem.  When bio_put hits zero it calls ->endio instead 
of the destructor.  The ->endio sees that the count is zero and 
destroys the bio.

You can't be serious? You'd stall end io completion notification because
someone holds a reference to a bio. Surely you jest.

Needless to say, that will never go in.

-- 
Jens Axboe