On Mon, Sep 30, 2013 at 4:34 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: >> My other worry is about interruptibility/restartability. Ideas? >> >> What happens on splice(from, to, 4G) and it's a non-reflink copy? >> Can the page cache copy be made restartable? Or should splice() be >> allowed to return a short count? What happens on (non-reflink) remote >> copies and huge request sizes? > > If I were writing an application that required copies to be restartable, > I'd probably use the largest possible range in the reflink case but > break the copy into smaller chunks in the splice case. > The app really doesn't want to care about that. And it doesn't want to care about restartability, etc.. It's something the *kernel* has to care about. You just can't have uninterruptible syscalls that sleep for a "long" time, otherwise first you'll just have annoyed users pressing ^C in vain; then, if the sleep is even longer, warnings about task sleeping too long. One idea is letting splice() return a short count, and so the app can safely issue SIZE_MAX requests and the kernel can decide if it can copy the whole file in one go or if it wants to do it in smaller chunks. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
