[PATCH 3/3] drm/xe: Force wedged state and block GT reset upon any GPU hang

Wed Mar 13 21:44:00 UTC 2024

On Wed, Mar 13, 2024 at 03:49:56PM -0500, Lucas De Marchi wrote:
> On Wed, Mar 13, 2024 at 03:54:59PM -0400, Rodrigo Vivi wrote:
> > In many validation situations when debugging GPU Hangs,
> > it is useful to preserve the GT situation from the moment
> > that the timeout occurred.
> > 
> > This patch introduces a module parameter that could be used
> > on situations like this.
> > 
> > If xe.wedged module parameter is set to 2, Xe will be declared
> > wedged on every single execution timeout (a.k.a. GPU hang) right
> > after devcoredump snapshot capture and without attempting any
> > kind of GT reset and blocking entirely any kind of execution.
> > 
> > Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
> > Cc: Himanshu Somaiya <himanshu.somaiya at intel.com>
> > Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > ---
> > drivers/gpu/drm/xe/xe_device.c     | 22 ++++++++++++++++++++++
> > drivers/gpu/drm/xe/xe_device.h     |  6 +-----
> > drivers/gpu/drm/xe/xe_guc_submit.c |  4 ++++
> > drivers/gpu/drm/xe/xe_module.c     |  5 +++++
> > drivers/gpu/drm/xe/xe_module.h     |  1 +
> > 5 files changed, 33 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> > index 5f0a2bdb7c24..296bc75a55f7 100644
> > --- a/drivers/gpu/drm/xe/xe_device.c
> > +++ b/drivers/gpu/drm/xe/xe_device.c
> > @@ -774,3 +774,25 @@ u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64 address)
> > {
> > 	return address & GENMASK_ULL(xe->info.va_bits - 1, 0);
> > }
> > +
> > +/**
> > + * xe_device_declare_wedged - Declare device wedged
> > + * @xe: xe device instance
> > + *
> > + * This is a final state that can only be cleared with a module reload.
> 
> same thing I mentioned about module reload elsewhere.
> 
> > + * In this state every IOCTL will be blocked so the GT cannot be used.
> > + * In general it will be called upon any critical error such as gt reset
> > + * failure or guc loading failure.
> > + * If xe.wedged module parameter is set to 2, this function will be called
> > + * on every single execution timeout (a.k.a. GPU hang) right after devcoredump
> > + * snapshot capture. In this mode, GT reset won't be attempted so the state of
> > + * the issue is preserved for further debugging.
> 
> Maybe make it a little bit more drastic so people don't use it when they
> shouldn't. I really hate the amount of reset=0 I see on machines being
> used with i915 with the additional patches to achieve a similar goal.
> IMO it should be a very targeted tool in a toolbox, not the hammer it
> became.
> 
> "In this mode, GT reset won't be attempted so there will be no recovery.
> Any GPU hang will completely kill the GPU so an autopsy may be
> attempted.  Use with care, if you know what you're doing."
> 
> > + */
> > +void xe_device_declare_wedged(struct xe_device *xe)
> > +{
> > +	if (xe_modparam.wedged == 0)
> > +		return;
> > +
> > +	atomic_set(&xe->wedged, 1);
> > +	drm_err(&xe->drm, "CRITICAL: Xe has been declared wedged. A module reload is required.\n");
> > +}
> > diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
> > index d10664d32f7f..de3149baf82f 100644
> > --- a/drivers/gpu/drm/xe/xe_device.h
> > +++ b/drivers/gpu/drm/xe/xe_device.h
> > @@ -181,10 +181,6 @@ static inline bool xe_device_wedged(struct xe_device *xe)
> > 	return atomic_read(&xe->wedged);
> > }
> > 
> > -static inline void xe_device_declare_wedged(struct xe_device *xe)
> > -{
> > -	atomic_set(&xe->wedged, 1);
> > -	drm_err(&xe->drm, "CRITICAL: Xe has been declared wedged. A module reload is required.\n");
> > -}
> > +void xe_device_declare_wedged(struct xe_device *xe);
> > 
> > #endif
> > diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> > index 19efdb2f881f..987a57205fc4 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> > +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> > @@ -34,6 +34,7 @@
> > #include "xe_macros.h"
> > #include "xe_map.h"
> > #include "xe_mocs.h"
> > +#include "xe_module.h"
> > #include "xe_ring_ops_types.h"
> > #include "xe_sched_job.h"
> > #include "xe_trace.h"
> > @@ -949,6 +950,9 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
> > 	simple_error_capture(q);
> > 	xe_devcoredump(job);
> > 
> > +	if (xe_modparam.wedged == 2)
> > +		xe_device_declare_wedged(xe);
> > +
> > 	trace_xe_sched_job_timedout(job);
> > 
> > 	/* Kill the run_job entry point */
> > diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
> > index 110b69864656..61272553f40f 100644
> > --- a/drivers/gpu/drm/xe/xe_module.c
> > +++ b/drivers/gpu/drm/xe/xe_module.c
> > @@ -17,6 +17,7 @@ struct xe_modparam xe_modparam = {
> > 	.enable_display = true,
> > 	.guc_log_level = 5,
> > 	.force_probe = CONFIG_DRM_XE_FORCE_PROBE,
> > +	.wedged = 1,
> > 	/* the rest are 0 by default */
> > };
> > 
> > @@ -48,6 +49,10 @@ module_param_named_unsafe(force_probe, xe_modparam.force_probe, charp, 0400);
> > MODULE_PARM_DESC(force_probe,
> > 		 "Force probe options for specified devices. See CONFIG_DRM_XE_FORCE_PROBE for details.");
> > 
> > +module_param_named_unsafe(wedged, xe_modparam.wedged, int, 0600);
> > +MODULE_PARM_DESC(wedged,
> > +		 "Wedged mode - 0=never, 1=upon-critical-errors[default], 2=upon-any-hang");
> 
> as we chatted earlier today, I think there's one thing missing. If an
> engine hangs, we won't notice as GuC will reset the engine by itself.
> We still need to pass GLOBAL_POLICY_DISABLE_ENGINE_RESET as a policy to
> GuC in the ADS structure. This is what I was attempting earlier today.
> 
> I was wondering if we could even update that in runtime with
> INTEL_GUC_ACTION_GLOBAL_SCHED_POLICY_CHANGE so we can target the debug
> only to when we are ready to reproduce the issues and only on the
> specific device.

I like that... Perhaps instead of the module parameter we have a debugfs
entry where we switch the state?

So, on a debugfs write to switch to this mode that gets 'busted'/'wedged'/'dead'
on every timeout/hang, then at that time we send this sched policy change?

> 
> Lucas De Marchi
> 
> > +
> > struct init_funcs {
> > 	int (*init)(void);
> > 	void (*exit)(void);
> > diff --git a/drivers/gpu/drm/xe/xe_module.h b/drivers/gpu/drm/xe/xe_module.h
> > index 88ef0e8b2bfd..0f95dcd8942f 100644
> > --- a/drivers/gpu/drm/xe/xe_module.h
> > +++ b/drivers/gpu/drm/xe/xe_module.h
> > @@ -18,6 +18,7 @@ struct xe_modparam {
> > 	char *huc_firmware_path;
> > 	char *gsc_firmware_path;
> > 	char *force_probe;
> > +	int wedged;
> > };
> > 
> > extern struct xe_modparam xe_modparam;
> > -- 
> > 2.44.0
> > 