Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > i915_gem_evict_something() is charged with finding a slot within the GTT > that we may reuse. Since our goal is not to stall, we first look for a > slot that only overlaps idle vma. To this end, on the first pass we move > any active vma to the end of the search list. However, we only stopped > moving active vma after we see the first active vma twice. If during the > search, that first active vma completed, we would not notice and keep on > extending the search list. > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1746 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> # v5.5+ Only thing I would change is tune up the subject line. It fixes a possible busy loop in eviction so I feel 'watch out' is not strong enough for my liking. Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_gem_evict.c | 26 ++++++++++++-------------- > 1 file changed, 12 insertions(+), 14 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c > index 0ba7b1e881c0..6501939929d5 100644 > --- a/drivers/gpu/drm/i915/i915_gem_evict.c > +++ b/drivers/gpu/drm/i915/i915_gem_evict.c > @@ -128,6 +128,13 @@ i915_gem_evict_something(struct i915_address_space *vm, > active = NULL; > INIT_LIST_HEAD(&eviction_list); > list_for_each_entry_safe(vma, next, &vm->bound_list, vm_link) { > + if (vma == active) { /* now seen this vma twice */ > + if (flags & PIN_NONBLOCK) > + break; > + > + active = ERR_PTR(-EAGAIN); > + } > + > /* > * We keep this list in a rough least-recently scanned order > * of active elements (inactive elements are cheap to reap). > @@ -143,21 +150,12 @@ i915_gem_evict_something(struct i915_address_space *vm, > * To notice when we complete one full cycle, we record the > * first active element seen, before moving it to the tail. > */ > - if (i915_vma_is_active(vma)) { > - if (vma == active) { > - if (flags & PIN_NONBLOCK) > - break; > - > - active = ERR_PTR(-EAGAIN); > - } > - > - if (active != ERR_PTR(-EAGAIN)) { > - if (!active) > - active = vma; > + if (active != ERR_PTR(-EAGAIN) && i915_vma_is_active(vma)) { > + if (!active) > + active = vma; > > - list_move_tail(&vma->vm_link, &vm->bound_list); > - continue; > - } > + list_move_tail(&vma->vm_link, &vm->bound_list); > + continue; > } > > if (mark_free(&scan, vma, flags, &eviction_list)) > -- > 2.20.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
