Andrea Arcangeli wrote: > > On Thu, Oct 19, 2000 at 05:16:14PM -0400, Jeff Garzik wrote: > > solution is really elegant. Excluding all the debug code and assertions > > I stick in there, the guts of via audio mmap support went from ~50 lines > > to ~10. > > Was it 50 lines with remap_page_range? Yeah. Via audio is scatter-gather, so I had a function via_mmap_chan which had to walk the scatter-gather list, calling remap_page_range for each PAGE_SIZE'd dma buffer. Now with nopage(), the need to walk the scatter-gather list is completely avoided. The scatter-gather info is stored as an array, so finding the physical address for a virtual page is a direct lookup. > Which is the advantage of introducing pagefaults that we can avoid? (and > that we are also used to avoid) Well, I don't know the VM well so I can't say how bad the lack of VM_LOCK will affect latency, if at all. I prefer this way because it seems the most clean -- let the system pagefault if it wants to, we're not really losing the buffer, only a reference to it. Jeff -- Jeff Garzik | The difference between laziness and Building 1024 | prioritization is the end result. MandrakeSoft | - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Linus Torvalds
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Andrea Arcangeli
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Linus Torvalds
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Andrea Arcangeli
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Jeff Garzik
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Andrea Arcangeli
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Jeff Garzik
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Linus Torvalds
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Andrea Arcangeli
- Re: VM_RESERVED [was Re: mapping user space buffer to ker... Jeff Garzik
- Re: mapping user space buffer to kernel address space Jeff Garzik
- Re: mapping user space buffer to kernel address space Linus Torvalds
- Re: mapping user space buffer to kernel address space faith
- Re: mapping user space buffer to kernel address space Stephen Tweedie
- Re: mapping user space buffer to kernel address space Linus Torvalds
- Re: mapping user space buffer to kernel address space Andrea Arcangeli
- Re: mapping user space buffer to kernel address space Linus Torvalds
- Re: mapping user space buffer to kernel address space Andrea Arcangeli
- Re: mapping user space buffer to kernel address space Stephen Tweedie
- Re: mapping user space buffer to kernel address space Andrea Arcangeli
- Re: mapping user space buffer to kernel address space Stephen Tweedie