[igt-dev] [Intel-gfx] [PATCH i-g-t 2/5] gem_wsim: Round mmap to page size

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-02-28 14:41:23)
> 
> On 28/02/2019 14:25, Chris Wilson wrote:
> > Quoting Tvrtko Ursulin (2019-02-28 14:18:25)
> >> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >>
> >> mmap(2) mandates size is page aligned.
> >>
> >> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >> ---
> >>   benchmarks/gem_wsim.c | 7 ++++---
> >>   1 file changed, 4 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
> >> index 0a5abc08d8c2..57ceb983cf82 100644
> >> --- a/benchmarks/gem_wsim.c
> >> +++ b/benchmarks/gem_wsim.c
> >> @@ -737,6 +737,7 @@ init_bb(struct w_step *w, unsigned int flags)
> >>   {
> >>          const unsigned int arb_period =
> >>                          get_bb_sz(w->preempt_us) / sizeof(uint32_t);
> >> +       const unsigned int mmap_len = ALIGN(w->bb_sz, 4096);
> >>          unsigned int i;
> >>          uint32_t *ptr;
> > 
> > You only need to do it for
> > 
> > ww->bb_sz = ALIGN(get_bb_sz(), 4096);
> > 
> > All batch lengths are start = ww->bb_sz - get_bb_sz() and so remain
> > correct. Right?
> 
> I think so. I have one more assignment site of w->bb_sz in the upcoming 
> code so it was 2 : 2 and I flipped a coin. Actually I wanted to make it 
> explicit what I am fixing - the mmap size. But now you'll say batch size 
> is also implicitly rounded.. oh well.. I prefer the explicit round up at 
> mmap time.

Ok,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris