[lkml]   [2008]   [Aug]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 5/7] FUSE: implement ioctl support
    On Thu, 28 Aug 2008, Tejun Heo wrote:
    > Miklos Szeredi wrote:
    > >> If you're worried about the double copying due to performance reasons,
    > >> what we can do is implementing userspace to userspace copying. I just
    > >> took easier path of copying twice as u-u copy can't be done using the
    > >> existing FUSE mechanics.
    > >
    > > How about not copying anything in the kernel, just passing the virtual
    > > address to the filesystem? It can get/modify the data of the calling
    > > task by mapping /proc/pid/mem. Ugly, yes, but ioctls are inherently
    > > ugly.
    > Hmmm... I was trying to stay within similar operation mechanics as other
    > ops. Directly accessing the caller's memory has performance benefits
    > but that benefit can also be used by reads and writes. So, if we're
    > gonna do direct memory access, maybe doing it in more generic way is a
    > better idea?

    On the contrary: playing VM games is going to be slow. I think this
    approach is best suited for generic ioctl support because it
    simplifies the kernel part. I'd hate to add all that complexity to
    the kernel if not absolutely necessary.


     \ /
      Last update: 2008-08-28 20:39    [W:0.020 / U:9.948 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site