On Tue, Mar 9, 2021 at 1:41 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > - A driver writer may want to choose between posted and > nonposted mmio based on performance considerations: > if writes are never serialized, posted writes should always > be faster. However, if the driver uses a spinlock to serialize > writes, then a nonposted write is likely faster than a posted > write followed by a read that serializes the spin_unlock. > In this case we want the driver to explicitly pick one over > the other, and not have rely on bus specific magic. OK then I am all for having drivers explicitly choose access method. Openness to speed optimization is a well established Linux kernel design principle. Yours, Linus Walleij
