[Intel-xe] [PATCH 1/3] drm/xe: Disable interruptable wait on xe_bo_move()

[Thomas Hellström]

On Mon, 2023-05-29 at 10:59 +0200, Thomas Hellström wrote:
> On Fri, 2023-05-26 at 12:06 -0700, José Roberto de Souza wrote:
> > All the Xe users of dma_resv_wait_timeout() also disable the
> > interruptable wait.
> > And doing so this avoids DRM_IOCTL_XE_EXEC fails when under memory
> > pressure.
> 
> Interruptible waits are crucial for signal delivery latency and for
> user experience (being able to ctrl-c away from somtething that is
> stuck).
> 
> Uninterruptible waits should only ever be used in situations where
> it's
> impossible to recover from an error, like in error or possibly
> destruction paths.
> 
> In this case execbuf should be able to handle the -EINTR returned
> from
> the ioctl and restart. If it doesn't there's an error elsewhere.
> 
> But Maarten had a patch to return the real error code rather than
> rewriting it to -ETIME.
> 
> /Thomas

Upon closer inspection of the code, that bool now set to true should
really be ctx->interruptible. Still Maarten's patch would be needed to
avoid the -ETIME rewrite, though.

/Thomas


> 
> 
> 
> > 
> > Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/239
> > Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_bo.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_bo.c
> > b/drivers/gpu/drm/xe/xe_bo.c
> > index 0db9c05097d07..6ed7e08269e82 100644
> > --- a/drivers/gpu/drm/xe/xe_bo.c
> > +++ b/drivers/gpu/drm/xe/xe_bo.c
> > @@ -609,7 +609,7 @@ static int xe_bo_move(struct ttm_buffer_object
> > *ttm_bo, bool evict,
> >             new_mem->mem_type == XE_PL_SYSTEM) {
> >                 long timeout = dma_resv_wait_timeout(ttm_bo-
> > > base.resv,
> >                                                     
> > DMA_RESV_USAGE_BOOKKEEP,
> > -                                                    true,
> > +                                                    false,
> >                                                     
> > MAX_SCHEDULE_TIMEOUT);
> >                 if (timeout <= 0) {
> >                         ret = -ETIME;
>