On Thu, Jul 22, 2021, 11:20 PM Michal Hocko <mhocko@suse.com> wrote:

> On Thu 22-07-21 21:47:56, Suren Baghdasaryan wrote:
> > On Thu, Jul 22, 2021, 7:04 PM Shakeel Butt <shakeelb@google.com> wrote:
> >
> > > On Thu, Jul 22, 2021 at 6:14 PM Suren Baghdasaryan <surenb@google.com>
> > > wrote:
> > > >
> > > [...]
> > > > +
> > > > +       mmap_read_lock(mm);
> > >
> > > How about mmap_read_trylock(mm) and return -EAGAIN on failure?
> > >
> >
> > That sounds like a good idea. Thanks! I'll add that in the next respin.
>
> Why is that a good idea? Can you do anything meaningful about the
> failure other than immediately retry the syscall and hope for the best?
>

I was thinking if this syscall implements "best effort without blocking"
approach then for a more strict usage user can simply retry. However
retrying means issuing another syscall, so additional overhead...
I guess such "best effort" approach would be unusual for a syscall, so
maybe we can keep it as it is now and if such "do not block" mode is needed
we can use flags to implement it later?



> --
> Michal Hocko
> SUSE Labs
>