On Fri, Sep 12, 2008 at 8:16 PM, Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx> wrote: > This patch enables request-based dm. > > o Request-based dm and bio-based dm coexist, since there are > some target drivers which are more fitting to bio-based dm. > Also, there are other bio-based devices in the kernel > (e.g. md, loop). > Since bio-based device can't receive struct request, > there are some limitations on device stacking between > bio-based and request-based. > > type of underlying device > bio-based requeset-based > ---------------------------------------------- > bio-based OK OK > request-based NG OK > So will some configurations would become impossible, if a target is made request-based and bio-based one is removed. Hope both types of targets would co-exist and would be selectable for sometime. > The device type is recognized by the queue flag in the kernel, > so dm follows that. > > o The type of a dm device is decided at the first table loading time. > Until then, mempool creations are deferred, since mempools for > request-based dm are different from those for bio-based dm. > Once the type of a dm device is decided, the type can't be changed. > > o Currently, request-based dm supports only tables that have a single > target. Barrier support should be straight forward? Thanks Nikanth Karthikesan -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
