| Summary: | [CI] igt@perf_pmu@rc6 - dmesg-warn - BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1034 -> BUG: scheduling while atomic: perf_pmu/1513/0x00000004 -> DEBUG_LOCKS_WARN_ON(val > preempt_count()) | ||
|---|---|---|---|
| Product: | DRI | Reporter: | Marta Löfstedt <marta.lofstedt> |
| Component: | DRM/Intel | Assignee: | Marta Löfstedt <marta.lofstedt> |
| Status: | CLOSED FIXED | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> |
| Severity: | normal | ||
| Priority: | medium | CC: | intel-gfx-bugs |
| Version: | DRI git | ||
| Hardware: | Other | ||
| OS: | All | ||
| Whiteboard: | ReadyForDev | ||
| i915 platform: | BXT | i915 features: | Perf/OA |
|
Description
Marta Löfstedt
2018-02-05 07:10:31 UTC
commit b2f78cda260bc6a1a2d382b1d85a29e69b5b3724 Author: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Date: Mon Feb 5 09:34:48 2018 +0000 drm/i915/pmu: Fix PMU enable vs execlists tasklet race Commit 99e48bf98dd0 ("drm/i915: Lock out execlist tasklet while peeking inside for busy-stats") added a tasklet_disable call in busy stats enabling, but we failed to understand that the PMU enable callback runs as an hard IRQ (IPI). Consequence of this is that the PMU enable callback can interrupt the execlists tasklet, and will then deadlock when it calls intel_engine_stats_enable->tasklet_disable. To fix this, I realized it is possible to move the engine stats enablement and disablement to PMU event init and destroy hooks. This allows for much simpler implementation since those hooks run in normal context (can sleep). v2: Extract engine_event_destroy. (Chris Wilson) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Fixes: 99e48bf98dd0 ("drm/i915: Lock out execlist tasklet while peeking inside for busy-stats") Testcase: igt/perf_pmu/enable-race-* Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: intel-gfx@lists.freedesktop.org Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20180205093448.13877-1-tvrtko.ursulin@linux.intel.com Wrong bug, sorry. commit 1fe699e30113ed6f6e853ff44710d256072ea627 Author: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Date: Tue Feb 6 18:33:11 2018 +0000 drm/i915/pmu: Fix sleep under atomic in RC6 readout We are not allowed to call intel_runtime_pm_get from the PMU counter read callback since the former can sleep, and the latter is running under IRQ context. To workaround this, we record the last known RC6 and while runtime suspended estimate its increase by querying the runtime PM core timestamps. Downside of this approach is that we can temporarily lose a chunk of RC6 time, from the last PMU read-out to runtime suspend entry, but that will eventually catch up, once device comes back online and in the presence of PMU queries. Also, we have to be careful not to overshoot the RC6 estimate, so once resumed after a period of approximation, we only update the counter once it catches up. With the observation that RC6 is increasing while the device is suspended, this should not pose a problem and can only cause slight inaccuracies due clock base differences. v2: Simplify by estimating on top of PM core counters. (Imre) Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104943 Fixes: 6060b6aec03c ("drm/i915/pmu: Add RC6 residency metrics") Testcase: igt/perf_pmu/rc6-runtime-pm Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Imre Deak <imre.deak@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20180206183311.17924-1-tvrtko.ursulin@linux.intel.com Fix included in CI_DRM_3735 I will monitor and close if applicable. |
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