> -----Original Message----- > From: Chris Wilson [mailto:chris@xxxxxxxxxxxxxxxxxx] > Sent: Thursday, November 20, 2014 11:41 AM > To: Daniel, Thomas > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; akash goel (akash.goels@xxxxxxxxx) > Subject: Re: [PATCH] drm/i915: Don't pin LRC in GGTT when > dumping in debugfs > > On Thu, Nov 20, 2014 at 11:25:57AM +0000, Daniel, Thomas wrote: > > > -----Original Message----- > > > From: Chris Wilson [mailto:chris@xxxxxxxxxxxxxxxxxx] > > > Sent: Thursday, November 20, 2014 11:16 AM > > > To: Daniel, Thomas > > > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; akash-goels@xxxxxxxxx > > > Subject: Re: [PATCH] drm/i915: Don't pin LRC in GGTT > > > when dumping in debugfs > > > > > > On Thu, Nov 20, 2014 at 11:12:05AM +0000, Thomas Daniel wrote: > > > > LRC object does not need to be mapped into the GGTT when dumping. > > > > Just use pin_pages. A side-effect of this patch is that a compiler > > > > warning goes away (not checking return value of > i915_gem_obj_ggtt_pin). > > > > > > Please explain why you need to pin the pages. > > I suppose I don't as this is protected by the struct mutex and unpin is called > before returning. > > The question is: do we need protection against kmalloc and a potential call > into the shrinker who may steal the pages from underneath us. Here, we > only do a seq_printf() under the lock after get_pages() and that uses a > preallocated buffer. I don't think so... If a context is in the context_list then the ctx_obj will have a nonzero refcount. The struct mutex prevents the refcount from changing. Can you identify any situation where the pages may go away? Thomas. > -Chris > > -- > Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
