Re: [LSF/MM] schedule suggestion

[Jerome Glisse <jglisse@redhat.com>]

On Thu, Apr 19, 2018 at 07:43:56AM -0700, Matthew Wilcox wrote:
> On Thu, Apr 19, 2018 at 10:38:25AM -0400, Jerome Glisse wrote:
> > Oh can i get one more small slot for fs ? I want to ask if they are
> > any people against having a callback everytime a struct file is added
> > to a task_struct and also having a secondary array so that special
> > file like device file can store something opaque per task_struct per
> > struct file.
> 
> Do you really want something per _thread_, and not per _mm_?

Well per mm would be fine but i do not see how to make that happen with
reasonable structure. So issue is that you can have multiple task with
same mm but different file descriptors (or am i wrong here ?) thus there
would be no easy way given a struct file to lookup the per mm struct.

So as a not perfect solution i see a new array in filedes which would
allow device driver to store a pointer to their per mm data structure.
To be fair usualy you will only have a single fd in a single task for
a given device.

If you see an easy way to get a per mm per inode pointer store somewhere
with easy lookup i am all ears :)

Cheers,
J�r�me