From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] [PATCH i-g-t v2] i915/gem_ctx_persistence: Race context closure with replace-engines
Date: Tue, 11 Feb 2020 20:13:37 +0000 [thread overview]
Message-ID: <20200211201337.1121177-1-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20200211192253.1120964-1-chris@chris-wilson.co.uk>
Tvrtko spotted a race condition between replacing a set of hanging
engines and closing the context. So exercise it.
5s is not much time to hit the small window, but a little bit of testing
several times a day is better than nothing.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
tests/i915/gem_ctx_persistence.c | 84 ++++++++++++++++++++++++++++++++
1 file changed, 84 insertions(+)
diff --git a/tests/i915/gem_ctx_persistence.c b/tests/i915/gem_ctx_persistence.c
index 22f29d25e..389b300f0 100644
--- a/tests/i915/gem_ctx_persistence.c
+++ b/tests/i915/gem_ctx_persistence.c
@@ -33,6 +33,7 @@
#include "i915/gem_engine_topology.h"
#include "i915/gem_ring.h"
#include "i915/gem_submission.h"
+#include "igt_aux.h"
#include "igt_debugfs.h"
#include "igt_dummyload.h"
#include "igt_gt.h"
@@ -803,6 +804,86 @@ static void replace_engines(int i915, const struct intel_execution_engine2 *e)
gem_quiescent_gpu(i915);
}
+static void race_set_engines(int i915, int fd)
+{
+ I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, 1) = {
+ .engines = {}
+ };
+ struct drm_i915_gem_context_param param = {
+ .param = I915_CONTEXT_PARAM_ENGINES,
+ .value = to_user_pointer(&engines),
+ .size = sizeof(engines),
+ };
+
+ while (read(fd, ¶m.ctx_id, sizeof(param.ctx_id)) > 0) {
+ if (!param.ctx_id)
+ break;
+ __gem_context_set_param(i915, ¶m);
+ }
+}
+
+static void close_replace_race(int i915)
+{
+ const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+ int fence = -1;
+ int fd[2];
+
+ /*
+ * Tvrtko being the evil genius noticed that if we could successfully
+ * replace a set of engines after the context had been closed, those
+ * engines could escape oversight.
+ */
+
+ igt_assert(pipe(fd) == 0);
+ igt_fork(child, ncpus) {
+ close(fd[1]);
+ race_set_engines(i915, fd[0]);
+ }
+ for (int i = 0; i < ncpus; i++)
+ close(fd[0]);
+
+ igt_until_timeout(5) {
+ igt_spin_t *spin;
+ uint32_t ctx;
+
+ ctx = gem_context_clone_with_engines(i915, 0);
+ gem_context_set_persistence(i915, ctx, false);
+
+ spin = igt_spin_new(i915, ctx, .flags = IGT_SPIN_FENCE_OUT);
+ for (int i = 0; i < ncpus; i++)
+ write(fd[1], &ctx, sizeof(ctx));
+
+ if (fence < 0) {
+ fence = spin->out_fence;
+ } else {
+ int tmp;
+
+ tmp = sync_fence_merge(fence, spin->out_fence);
+ close(fence);
+ close(spin->out_fence);
+
+ fence = tmp;
+ }
+ spin->out_fence = -1;
+
+ gem_context_destroy(i915, ctx);
+ }
+
+ for (int i = 0; i < ncpus; i++) {
+ uint32_t end = 0;
+
+ write(fd[1], &end, sizeof(end));
+ }
+ close(fd[1]);
+
+ igt_debugfs_dump(i915, "i915_engine_info");
+ igt_assert(sync_fence_wait(fence, MSEC_PER_SEC / 2) == 0);
+ close(fence);
+
+ igt_waitchildren();
+ gem_quiescent_gpu(i915);
+}
+
static void replace_engines_hostile(int i915,
const struct intel_execution_engine2 *e)
{
@@ -961,6 +1042,9 @@ igt_main
replace_engines_hostile(i915, e);
}
}
+
+ igt_subtest("close-replace-race")
+ close_replace_race(i915);
}
igt_fixture {
--
2.25.0
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next prev parent reply other threads:[~2020-02-11 20:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 19:22 [Intel-gfx] [PATCH i-g-t] i915/gem_ctx_persistence: Race context closure with replace-engines Chris Wilson
2020-02-11 20:13 ` Chris Wilson [this message]
2020-02-12 11:11 ` [Intel-gfx] ✗ GitLab.Pipeline: failure for " Patchwork
2020-02-12 11:23 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-02-13 9:07 ` [Intel-gfx] [igt-dev] [PATCH i-g-t] " Tvrtko Ursulin
2020-02-13 9:51 ` Chris Wilson
2020-02-13 11:02 ` Tvrtko Ursulin
2020-02-14 3:27 ` [Intel-gfx] ✓ Fi.CI.IGT: success for " Patchwork
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