[igt-dev] [PATCH i-g-t] Return allocated size in gem_create_in_memory_regions() and friends

[Zbigniew Kempczyński]

On Sat, Oct 02, 2021 at 01:32:08PM -0700, Dixit, Ashutosh wrote:
> On Mon, 27 Sep 2021 23:52:41 -0700, Zbigniew Kempczyński wrote:
> >
> > > diff --git a/lib/intel_bufops.c b/lib/intel_bufops.c
> > > index d1395c1605d..52794c1ac10 100644
> > > --- a/lib/intel_bufops.c
> > > +++ b/lib/intel_bufops.c
> > > @@ -819,7 +819,7 @@ static void __intel_buf_init(struct buf_ops *bops,
> > >	if (handle)
> > >		buf->handle = handle;
> > >	else {
> > > -		if (!__gem_create_in_memory_regions(bops->fd, &handle, size, region))
> > > +		if (!__gem_create_in_memory_regions(bops->fd, &handle, &size, region))
> > >			buf->handle = handle;
> > >		else
> > >			buf->handle = gem_create(bops->fd, size);
> >
> > As size can be different we pass we should update buf->size accordingly.
> > Look at few lines above:
> >
> >	/* Store real bo size to avoid mistakes in calculating it again */
> >	buf->size = size;
> >
> > I think these lines can be moved at the bottom of the condition.
> >
> > buf->size is returned as a call to intel_buf_bo_size() and used in
> > intel_bb_add_object(). This can be important for no-reloc mode to avoid
> > overlapping object on softpin and hitting -ENOSPC.
> 
> I have a new patch reverting part of the changes done in 22643ce4014a:
> 
> https://patchwork.freedesktop.org/series/95376/
> 
> In this context I want to check regarding the above change again: should we
> be setting buf->size above to the allocated size or to the requested size,
> in case the two are different? Currently the code (even after the new
> patch) is setting it to the allocated size which might be >= the requested
> size. Thanks.

Keep the requested size, not underlying bo size. I'm going to do quick 
rename from intel_buf_bo_size() to intel_buf_size() to avoid confusion we
got gem bo size instead of raw sze.

--
Zbigniew