Commit 955da9d7 authored by Chris Wilson's avatar Chris Wilson Committed by Rodrigo Vivi

drm/i915: Handle idling during i915_gem_evict_something busy loops

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
Fixes: 2850748e ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Fixes: b1e3177b ("drm/i915: Coordinate i915_active with its own mutex")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200509115217.26853-1-chris@chris-wilson.co.uk
(cherry picked from commit 73e28cc4)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
parent 475e8423
......@@ -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).
......@@ -143,22 +150,13 @@ 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 != ERR_PTR(-EAGAIN) && i915_vma_is_active(vma)) {
if (!active)
active = vma;
list_move_tail(&vma->vm_link, &vm->bound_list);
continue;
}
}
if (mark_free(&scan, vma, flags, &eviction_list))
goto found;
......
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