From 5631bb6c06e5b7dfddd9052afd86ea95fc9726d4 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 9 May 2020 12:52:17 +0100 Subject: [PATCH] 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: 587eefbe9921 ("drm/i915: Pull i915_vma_pin under the vm->mutex") Fixes: 1912e1b11c59 ("drm/i915: Coordinate i915_active with its own mutex") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: # v5.5+ Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20200509115217.26853-1-chris@chris-wilson.co.uk --- 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 0ba7b1e881c08..6501939929d5d 100644 --- a/drivers/gpu/drm/i915/i915_gem_evict.c +++ b/drivers/gpu/drm/i915/i915_gem_evict.c @@ -128,6 +128,13 @@ search_again: 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 @@ search_again: * 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)) -- 2.39.5