Quoting Tvrtko Ursulin (2018-09-12 14:34:16) > > On 12/09/2018 12:11, Chris Wilson wrote: > > If we try and fail to allocate a i915_request, we apply some > > backpressure on the clients to throttle the memory allocations coming > > from i915.ko. Currently, we wait until completely idle, but this is far > > too heavy and leads to some situations where the only escape is to > > declare a client hung and reset the GPU. The intent is to only ratelimit > > the allocation requests, so we need only wait for a jiffie before using > > the normal direct reclaim. > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106680 > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/i915/i915_request.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c > > index 09ed48833b54..588bc5a4d18b 100644 > > --- a/drivers/gpu/drm/i915/i915_request.c > > +++ b/drivers/gpu/drm/i915/i915_request.c > > @@ -736,7 +736,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx) > > ret = i915_gem_wait_for_idle(i915, > > I915_WAIT_LOCKED | > > I915_WAIT_INTERRUPTIBLE, > > - MAX_SCHEDULE_TIMEOUT); > > + 1); > > if (ret) > > goto err_unreserve; > > > > > > What is the remaining value of even trying to wait for idle, instead of > maybe just i915_request_retire and sleep for a jiffie? The intention > would potentially read clearer since it is questionable there is any > relationship with idle and rate limiting clients. In fact, now that I > think of it, waiting for idle is a nice way to starve an unlucky client > forever. Better to starve the unlucky client, than to allow the entire system to grind to a halt. One caveat to using RCU is that it is our responsibility to apply backpressure as none is applied by the vm. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
