On Wed, Feb 20, 2008 at 01:52:06AM +0100, Andrea Arcangeli wrote: > On Wed, Feb 20, 2008 at 12:04:27AM +0100, Nick Piggin wrote: > > OK (thanks to Robin as well). Now I understand why you are using it, > > but I don't understand why you don't defer new TLBs after the point > > where the linux pte changes. If you can do that, then you look and > > act much more like a TLB from the point of view of the Linux vm. > > Christoph was forced to put the invalidate_range callback _after_ > dropping the PT lock because xpmem has to wait I/O there. But > invalidate_range is called after freeing the VM reference on the pages > so then GRU needed a _range_begin too because GRU has to flush the tlb > before the VM reference on the page is released (xpmem and KVM pin the > pages mapped by the secondary mmu, GRU doesn't). So then > invalidate_range was renamed to invalidate_range_end.
Currently, xpmem blocks faults for the range specified at the _begin callout, then shoots down remote TLBs and does the put_page for all the pages in the specified range. The _end callout merely removes the block. We do not do any wait for I/O. By the time we return from the _begin callout, all activity by the remotes is stopped, pages are dereferenced, and future faults are blocked until released by the _end callout. Thanks, Robin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
