drm/i915: Add an rcu_barrier option to i915_drop_caches (54895010) · Commits · 戴 / test

Sometimes a test has to wait for RCU to complete a grace period and perform its callbacks, for example waiting for a close(fd) to actually perform the fput(filp) and so trigger all the callbacks such as closing GEM contexts. There is no trivial means of triggering an RCU barrier from userspace, so add one for our convenience in debugfs/i915_drop_caches Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Cc: Matthew Auld <matthew.william.auld@gmail.com> Reviewed-by:

Matthew Auld <matthew.william.auld@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191011173823.20432-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_debugfs.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -3599,6 +3599,7 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_wedged_fops,
		#define DROP_IDLE BIT(6)
		#define DROP_RESET_ACTIVE BIT(7)
		#define DROP_RESET_SEQNO BIT(8)
		#define DROP_RCU BIT(9)
		#define DROP_ALL (DROP_UNBOUND \| \
		DROP_BOUND \| \
		DROP_RETIRE \| \
		@@ -3607,7 +3608,8 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_wedged_fops,
		DROP_SHRINK_ALL \|\
		DROP_IDLE \| \
		DROP_RESET_ACTIVE \| \
		DROP_RESET_SEQNO)
		DROP_RESET_SEQNO \| \
		DROP_RCU)
		static int
		i915_drop_caches_get(void data, u64 val)
		{
		@@ -3659,6 +3661,9 @@ i915_drop_caches_set(void *data, u64 val)
		i915_gem_shrink_all(i915);
		fs_reclaim_release(GFP_KERNEL);

		if (val & DROP_RCU)
		rcu_barrier();

		if (val & DROP_FREED)
		i915_gem_drain_freed_objects(i915);

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