Messages in this thread | | | Date | Mon, 13 Aug 2007 11:13:49 +0200 | From | Jens Axboe <> | Subject | Re: Distributed storage. |
| |
On Mon, Aug 13 2007, Daniel Phillips wrote: > On Monday 13 August 2007 00:45, Jens Axboe wrote: > > On Mon, Aug 13 2007, Jens Axboe wrote: > > > > 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
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |