| Message ID | 20210318170419.2107512-6-tvrtko.ursulin@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Default request/fence expiry + watchdog | expand |
On Thu, 18 Mar 2021 at 17:04, Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> wrote: > > From: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > > A new Kconfig option CONFIG_DRM_I915_REQUEST_TIMEOUT is added, defaulting > to 20s, and this timeout is applied to all users contexts using the > previously added watchdog facility. > > Result of this is that any user submission will simply fail after this > timeout, either causing a reset (for non-preemptable), or incomplete > results. > > This can have an effect that workloads which used to work fine will > suddenly start failing. Even workloads comprised of short batches but in > long dependency chains can be terminated. > > And becuase of lack of agreement on usefulness and safety of fence error because > propagation this partial execution can be invisible to userspace even if > it is "listening" to returned fence status. > > Another interaction is with hangcheck where care needs to be taken timeout > is not set lower or close to three times the heartbeat interval. Otherwise > a hang in any application can cause complete termination of all > submissions from unrelated clients. Any users modifying the per engine > heartbeat intervals therefore need to be aware of this potential denial of > service to avoid inadvertently enabling it. > > Given all this I am personally not convinced the scheme is a good idea. > Intuitively it feels object importers would be better positioned to > enforce the time they are willing to wait for something to complete. > > v2: > * Improved commit message and Kconfig text. > * Pull in some helper code from patch which got dropped. > > v3: > * Bump timeout to 20s to see if it helps Tigerlake. > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Matthew Auld <matthew.auld@intel.com>
diff --git a/drivers/gpu/drm/i915/Kconfig.profile b/drivers/gpu/drm/i915/Kconfig.profile index 35bbe2b80596..39328567c200 100644 --- a/drivers/gpu/drm/i915/Kconfig.profile +++ b/drivers/gpu/drm/i915/Kconfig.profile @@ -1,3 +1,17 @@ +config DRM_I915_REQUEST_TIMEOUT + int "Default timeout for requests (ms)" + default 20000 # milliseconds + help + Configures the default timeout after which any user submissions will + be forcefully terminated. + + Beware setting this value lower, or close to heartbeat interval + rounded to whole seconds times three, in order to avoid allowing + misbehaving applications causing total rendering failure in unrelated + clients. + + May be 0 to disable the timeout. + config DRM_I915_FENCE_TIMEOUT int "Timeout for unsignaled foreign fences (ms, jiffy granularity)" default 10000 # milliseconds diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index ca37d93ef5e7..be71be21800b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -233,6 +233,8 @@ static void intel_context_set_gem(struct intel_context *ce, if (ctx->sched.priority >= I915_PRIORITY_NORMAL && intel_engine_has_timeslices(ce->engine)) __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags); + + intel_context_set_watchdog_us(ce, ctx->watchdog.timeout_us); } static void __free_engines(struct i915_gem_engines *e, unsigned int count) @@ -852,6 +854,40 @@ static void __assign_timeline(struct i915_gem_context *ctx, context_apply_all(ctx, __apply_timeline, timeline); } +static int __apply_watchdog(struct intel_context *ce, void *timeout_us) +{ + return intel_context_set_watchdog_us(ce, (uintptr_t)timeout_us); +} + +static int +__set_watchdog(struct i915_gem_context *ctx, unsigned long timeout_us) +{ + int ret; + + ret = context_apply_all(ctx, __apply_watchdog, + (void *)(uintptr_t)timeout_us); + if (!ret) + ctx->watchdog.timeout_us = timeout_us; + + return ret; +} + +static void __set_default_fence_expiry(struct i915_gem_context *ctx) +{ + struct drm_i915_private *i915 = ctx->i915; + int ret; + + if (!IS_ACTIVE(CONFIG_DRM_I915_REQUEST_TIMEOUT)) + return; + + /* Default expiry for user fences. */ + ret = __set_watchdog(ctx, CONFIG_DRM_I915_REQUEST_TIMEOUT * 1000); + if (ret) + drm_notice(&i915->drm, + "Failed to configure default fence expiry! (%d)", + ret); +} + static struct i915_gem_context * i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) { @@ -896,6 +932,8 @@ i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) intel_timeline_put(timeline); } + __set_default_fence_expiry(ctx); + trace_i915_context_create(ctx); return ctx; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h index d5bc75508048..f17da7e26c43 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h @@ -150,6 +150,10 @@ struct i915_gem_context { */ atomic_t active_count; + struct { + u64 timeout_us; + } watchdog; + /** * @hang_timestamp: The last time(s) this context caused a GPU hang */ diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.h b/drivers/gpu/drm/i915/gt/intel_context_param.h index f053d8633fe2..3ecacc675f41 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_param.h +++ b/drivers/gpu/drm/i915/gt/intel_context_param.h @@ -6,9 +6,18 @@ #ifndef INTEL_CONTEXT_PARAM_H #define INTEL_CONTEXT_PARAM_H -struct intel_context; +#include <linux/types.h> + +#include "intel_context.h" int intel_context_set_ring_size(struct intel_context *ce, long sz); long intel_context_get_ring_size(struct intel_context *ce); +static inline int +intel_context_set_watchdog_us(struct intel_context *ce, u64 timeout_us) +{ + ce->watchdog.timeout_us = timeout_us; + return 0; +} + #endif /* INTEL_CONTEXT_PARAM_H */