[Intel-gfx] [PATCH v2 11/15] drm/i915: Port of Added scheduler support to __wait_request() calls

[Chris Wilson]

On Fri, Jun 17, 2016 at 08:09:11AM +0100, Arun Siluvery wrote:
> This is a partial port of the following patch from John Harrison's GPU
> scheduler patch series: (patch sent to Intel-GFX with the subject line
> "[Intel-gfx] [RFC 19/39] drm/i915: Added scheduler support to __wait_request()
> calls" on Fri 17 July 2015)
> 
> 	Author: John Harrison <John.C.Harrison at Intel.com>
> 	Date:   Thu Apr 10 10:48:55 2014 +0100
> 	Subject: drm/i915: Added scheduler support to __wait_request() calls
> 
> Removed all scheduler references and backported it to this baseline. The reason
> we need this is because Chris Wilson has pointed out that threads that don't
> hold the struct_mutex should not be thrown out of __i915_wait_request during
> TDR hang recovery. Therefore we need a way to determine which threads are
> holding the mutex and which are not.
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Signed-off-by: Tomas Elf <tomas.elf at intel.com>
> Signed-off-by: John Harrison <john.c.harrison at intel.com>
> Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h         |  7 ++++++-
>  drivers/gpu/drm/i915/i915_gem.c         | 34 ++++++++++++++++++++++-----------
>  drivers/gpu/drm/i915/intel_display.c    |  5 +++--
>  drivers/gpu/drm/i915/intel_ringbuffer.c |  8 +++++---
>  4 files changed, 37 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index b2105bb..3e02b41 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3350,8 +3350,13 @@ void __i915_add_request(struct drm_i915_gem_request *req,
>  	__i915_add_request(req, NULL, true)
>  #define i915_add_request_no_flush(req) \
>  	__i915_add_request(req, NULL, false)
> +
> +/* flags used by users of __i915_wait_request */
> +#define I915_WAIT_REQUEST_INTERRUPTIBLE  (1 << 0)
> +#define I915_WAIT_REQUEST_LOCKED         (1 << 1)
> +
>  int __i915_wait_request(struct drm_i915_gem_request *req,
> -			bool interruptible,
> +			u32 flags,
>  			s64 *timeout,
>  			struct intel_rps_client *rps);
>  int __must_check i915_wait_request(struct drm_i915_gem_request *req);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index bc404da..b0c2263 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1455,7 +1455,9 @@ static int __i915_spin_request(struct drm_i915_gem_request *req, int state)
>  /**
>   * __i915_wait_request - wait until execution of request has finished
>   * @req: duh!
> - * @interruptible: do an interruptible wait (normally yes)
> + * @flags: flags to define the nature of wait
> + *    I915_WAIT_INTERRUPTIBLE - do an interruptible wait (normally yes)
> + *    I915_WAIT_LOCKED - caller is holding struct_mutex
>   * @timeout: in - how long to wait (NULL forever); out - how much time remaining
>   * @rps: RPS client
>   *
> @@ -1470,7 +1472,7 @@ static int __i915_spin_request(struct drm_i915_gem_request *req, int state)
>   * errno with remaining time filled in timeout argument.
>   */
>  int __i915_wait_request(struct drm_i915_gem_request *req,
> -			bool interruptible,
> +			u32 flags,
>  			s64 *timeout,
>  			struct intel_rps_client *rps)
>  {
> @@ -1478,6 +1480,7 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
>  	struct drm_i915_private *dev_priv = req->i915;
>  	const bool irq_test_in_progress =
>  		ACCESS_ONCE(dev_priv->gpu_error.test_irq_rings) & intel_engine_flag(engine);
> +	bool interruptible = flags & I915_WAIT_REQUEST_INTERRUPTIBLE;
>  	int state = interruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
>  	DEFINE_WAIT(wait);
>  	unsigned long timeout_expire;
> @@ -1526,6 +1529,7 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
>  	for (;;) {
>  		struct timer_list timer;
>  		int reset_pending;
> +		bool locked = flags & I915_WAIT_REQUEST_LOCKED;
>  
>  		prepare_to_wait(&engine->irq_queue, &wait, state);
>  
> @@ -1543,7 +1547,7 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
>  
>  		reset_pending = i915_engine_reset_pending(&dev_priv->gpu_error,
>  							  NULL);
> -		if (reset_pending) {
> +		if (reset_pending || locked) {

Very funny!
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre