* Archie Cobbs: > On Thu, Oct 30, 2025 at 4:39 PM Florian Weimer <[email protected]> wrote: > >> I'm trying to image in a way to get rid of the double buffering in >> FileInputStream/FileOutputStream: have the kernel access the heap >> directly, instead of a copy. > > Wasn't that one of the goals of the NIO Channel API and direct > ByteBuffers?
Code that allocates ByteBuffers cannot always determine whether they should be direct or not. > You've probably already considered that approach - if so I'm curious > why it doesn't work. It works, but if I recall there is lots of thorny code for the direct buffer used for bouncing, to enable FileChannel etc. for heap buffers. That could go away on platforms where the kernel can directly access heap arrays. But maybe that's not true on all platforms, so that code will have to be maintained indefinitely. Thanks, Florian
