From: Chris Wilson Date: Tue, 7 May 2019 12:11:08 +0000 (+0100) Subject: drm/i915: Stop spinning for DROP_IDLE (debugfs/i915_drop_caches) X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3970564940ba0322bcefce7fd8fd35c2b85846bf;p=linux.git drm/i915: Stop spinning for DROP_IDLE (debugfs/i915_drop_caches) If the user is racing a call to debugfs/i915_drop_caches with ongoing submission from another thread/process, we may never end up idling the GPU and be uninterruptibly spinning in debugfs/i915_drop_caches trying to catch an idle moment. Just flush the work once, that should be enough to park the system under correct conditions. Outside of those we either have a driver bug or the user is racing themselves. Sadly, because the user may be provoking the unwanted situation we can't put a warn here to attract attention to a probable bug. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20190507121108.18377-4-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index fc6e60d82477e..b6094063be9b3 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -3947,9 +3947,7 @@ i915_drop_caches_set(void *data, u64 val) fs_reclaim_release(GFP_KERNEL); if (val & DROP_IDLE) { - do { - flush_delayed_work(&i915->gem.retire_work); - } while (READ_ONCE(i915->gt.awake)); + flush_delayed_work(&i915->gem.retire_work); flush_work(&i915->gem.idle_work); }