[PATCH 3/3] drm/i915/gvt: [small locks] use scheduler lock
Zhang, Pei
pei.zhang at intel.com
Thu Jan 25 07:52:15 UTC 2018
> -----Original Message-----
> From: intel-gvt-dev
> [mailto:intel-gvt-dev-bounces at lists.freedesktop.org]
> On Behalf Of Zhenyu Wang
> Sent: Thursday, January 25, 2018 3:23 PM
> To: Zhang, Pei <pei.zhang at intel.com>
> Cc: intel-gvt-dev at lists.freedesktop.org; Wang, Zhi A
> <zhi.a.wang at intel.com>; zhenyuw at linux.intel.com
> Subject: Re: [PATCH 3/3] drm/i915/gvt: [small locks] use scheduler
> lock
>
> On 2018.01.25 15:09:27 +0800, pei.zhang at intel.com wrote:
> > From: Pei Zhang <pei.zhang at intel.com>
> >
> > The scheduler lock(gvt->sched_lock) is used to protect gvt scheduler
> > logic, including the gvt scheduler structure(gvt->scheduler and per
> > vgpu schedule data(vgpu->sched_data, vgpu->sched_ctl).
> >
> > Signed-off-by: Pei Zhang <pei.zhang at intel.com>
> > ---
> > drivers/gpu/drm/i915/gvt/display.c | 3 ---
> > drivers/gpu/drm/i915/gvt/gvt.c | 1 +
> > drivers/gpu/drm/i915/gvt/gvt.h | 7 ++++++
> > drivers/gpu/drm/i915/gvt/sched_policy.c | 41
> ++++++++++++++++++++++++++++-----
> > drivers/gpu/drm/i915/gvt/scheduler.c | 8 +++----
> > 5 files changed, 47 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gvt/display.c
> > b/drivers/gpu/drm/i915/gvt/display.c
> > index 84197d3..8042fc1 100644
> > --- a/drivers/gpu/drm/i915/gvt/display.c
> > +++ b/drivers/gpu/drm/i915/gvt/display.c
> > @@ -328,9 +328,6 @@ void intel_gvt_check_vblank_emulation(struct
> intel_gvt *gvt)
> > struct intel_vgpu *vgpu;
> > int pipe, id;
> >
> > - if (WARN_ON(!mutex_is_locked(&gvt->lock)))
> > - return;
> > -
> > for_each_active_vgpu(gvt, vgpu, id) {
> > for (pipe = 0; pipe < I915_MAX_PIPES; pipe++) {
> > if (pipe_is_enabled(vgpu, pipe))
>
> This is not for sched lock, looks should be in last patch, and as we
> check all active vgpu here, still requires gvt lock for that purpose.
[Pei] you are right. I will add the gvt lock.
>
> > diff --git a/drivers/gpu/drm/i915/gvt/gvt.c
> > b/drivers/gpu/drm/i915/gvt/gvt.c index d8d5e6c..b119c53 100644
> > --- a/drivers/gpu/drm/i915/gvt/gvt.c
> > +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> > @@ -377,6 +377,7 @@ int intel_gvt_init_device(struct
> > drm_i915_private
> *dev_priv)
> > spin_lock_init(&gvt->scheduler.mmio_context_lock);
> > mutex_init(&gvt->lock);
> > mutex_init(&gvt->gtt_lock);
> > + mutex_init(&gvt->sched_lock);
> > gvt->dev_priv = dev_priv;
> >
> > init_device_info(gvt);
> > diff --git a/drivers/gpu/drm/i915/gvt/gvt.h
> > b/drivers/gpu/drm/i915/gvt/gvt.h index 76f6c24..1997419 100644
> > --- a/drivers/gpu/drm/i915/gvt/gvt.h
> > +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> > @@ -181,6 +181,11 @@ struct intel_vgpu {
> > bool pv_notified;
> > bool failsafe;
> > unsigned int resetting_eng;
> > +
> > + /* both sched_data and sched_ctl can be seen a part of the global
> gvt
> > + * scheduler structure. So these 2 vgpu data are protected by gvt-
> >sched_lock,
> > + * not vgpu->vgpu_lock.
> > + * */
> > void *sched_data;
> >
> > struct vgpu_sched_ctl sched_ctl;
> > @@ -295,6 +300,8 @@ struct intel_gvt {
> > */
> > struct mutex lock;
> > struct mutex gtt_lock;
> > + /* scheduler scope lock, protect gvt and vgpu schedule related
> > +data
> */
> > + struct mutex sched_lock;
> >
> > struct drm_i915_private *dev_priv;
> > struct idr vgpu_idr; /* vGPU IDR pool */
> > diff --git a/drivers/gpu/drm/i915/gvt/sched_policy.c
> > b/drivers/gpu/drm/i915/gvt/sched_policy.c
> > index d031f64..f78fa21 100644
> > --- a/drivers/gpu/drm/i915/gvt/sched_policy.c
> > +++ b/drivers/gpu/drm/i915/gvt/sched_policy.c
> > @@ -228,8 +228,9 @@ void intel_gvt_schedule(struct intel_gvt *gvt)
> > struct gvt_sched_data *sched_data = gvt->scheduler.sched_data;
> > static uint64_t timer_check;
> >
> > - mutex_lock(&gvt->lock);
> > -
> > + /* Don't use external lock to protect service_request.
> > + * Instead, always use atomic bit ops on it.
> > + */
> > if (test_and_clear_bit(INTEL_GVT_REQUEST_SCHED,
> > (void *)&gvt->service_request)) {
> > if (!(timer_check++ % GVT_TS_BALANCE_PERIOD_MS)) @@ -237,9
> +238,9
> > @@ void intel_gvt_schedule(struct intel_gvt *gvt)
> > }
> > clear_bit(INTEL_GVT_REQUEST_EVENT_SCHED, (void
> > *)&gvt->service_request);
> >
> > + mutex_lock(&gvt->sched_lock);
> > tbs_sched_func(sched_data);
> > -
> > - mutex_unlock(&gvt->lock);
> > + mutex_unlock(&gvt->sched_lock);
> > }
> >
> > static enum hrtimer_restart tbs_timer_fn(struct hrtimer
> > *timer_data) @@ -352,36 +353,62 @@ static struct
> > intel_gvt_sched_policy_ops tbs_schedule_ops = {
> >
> > int intel_gvt_init_sched_policy(struct intel_gvt *gvt) {
> > + int ret;
> > +
> > + mutex_lock(&gvt->sched_lock);
> > gvt->scheduler.sched_ops = &tbs_schedule_ops;
> > + ret = gvt->scheduler.sched_ops->init(gvt);
> > + mutex_unlock(&gvt->sched_lock);
> >
> > - return gvt->scheduler.sched_ops->init(gvt);
> > + return ret;
> > }
> >
> > void intel_gvt_clean_sched_policy(struct intel_gvt *gvt) {
> > + mutex_lock(&gvt->sched_lock);
> > gvt->scheduler.sched_ops->clean(gvt);
> > + mutex_unlock(&gvt->sched_lock);
> > }
> >
> > +/* for per-vgpu scheduler policy, there are 2 per-vgpu data:
> > + * sched_data, and sched_ctl. We see these 2 data as part of
> > + * the global scheduler which are proteced by gvt->sched_lock.
> > + * Caller should make their decision if the vgpu_lock should
> > + * be hold outside.
> > + */
> > +
> > int intel_vgpu_init_sched_policy(struct intel_vgpu *vgpu) {
> > - return vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
> > + int ret;
> > +
> > + mutex_lock(&vgpu->gvt->sched_lock);
> > + ret = vgpu->gvt->scheduler.sched_ops->init_vgpu(vgpu);
> > + mutex_unlock(&vgpu->gvt->sched_lock);
> > +
> > + return ret;
> > }
> >
> > void intel_vgpu_clean_sched_policy(struct intel_vgpu *vgpu) {
> > + mutex_lock(&vgpu->gvt->sched_lock);
> > vgpu->gvt->scheduler.sched_ops->clean_vgpu(vgpu);
> > + mutex_unlock(&vgpu->gvt->sched_lock);
> > }
> >
> > void intel_vgpu_start_schedule(struct intel_vgpu *vgpu) {
> > gvt_dbg_core("vgpu%d: start schedule\n", vgpu->id);
> >
> > + mutex_lock(&vgpu->gvt->sched_lock);
> > vgpu->gvt->scheduler.sched_ops->start_schedule(vgpu);
> > + mutex_unlock(&vgpu->gvt->sched_lock);
> > }
> >
> > void intel_gvt_kick_schedule(struct intel_gvt *gvt) {
> > + mutex_lock(&gvt->sched_lock);
> > intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);
> > + mutex_unlock(&gvt->sched_lock);
> > }
> >
> > void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu) @@ -392,6
> > +419,7 @@ void intel_vgpu_stop_schedule(struct intel_vgpu *vgpu)
> >
> > gvt_dbg_core("vgpu%d: stop schedule\n", vgpu->id);
> >
> > + mutex_lock(&vgpu->gvt->sched_lock);
> > scheduler->sched_ops->stop_schedule(vgpu);
> >
> > if (scheduler->next_vgpu == vgpu)
> > @@ -411,4 +439,5 @@ void intel_vgpu_stop_schedule(struct intel_vgpu
> *vgpu)
> > }
> > }
> > spin_unlock_bh(&scheduler->mmio_context_lock);
> > + mutex_unlock(&vgpu->gvt->sched_lock);
> > }
> > diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c
> > b/drivers/gpu/drm/i915/gvt/scheduler.c
> > index 907195a..f1b191d 100644
> > --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> > +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> > @@ -602,7 +602,7 @@ static struct intel_vgpu_workload
> *pick_next_workload(
> > struct intel_gvt_workload_scheduler *scheduler = &gvt->scheduler;
> > struct intel_vgpu_workload *workload = NULL;
> >
> > - mutex_lock(&gvt->lock);
> > + mutex_lock(&gvt->sched_lock);
> >
> > /*
> > * no current vgpu / will be scheduled out / no workload @@ -648,7
> > +648,7 @@ static struct intel_vgpu_workload *pick_next_workload(
> >
> > atomic_inc(&workload->vgpu->submission.running_workload_num);
> > out:
> > - mutex_unlock(&gvt->lock);
> > + mutex_unlock(&gvt->sched_lock);
> > return workload;
> > }
> >
> > @@ -749,8 +749,8 @@ static void complete_current_workload(struct
> intel_gvt *gvt, int ring_id)
> > struct intel_vgpu_submission *s = &vgpu->submission;
> > int event;
> >
> > - mutex_lock(&gvt->lock);
> > mutex_lock(&vgpu->vgpu_lock);
> > + mutex_lock(&gvt->sched_lock);
> >
> > /* For the workload w/ request, needs to wait for the context
> > * switch to make sure request is completed.
> > @@ -828,8 +828,8 @@ static void complete_current_workload(struct
> intel_gvt *gvt, int ring_id)
> > if (gvt->scheduler.need_reschedule)
> > intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);
> >
> > + mutex_unlock(&gvt->sched_lock);
> > mutex_unlock(&vgpu->vgpu_lock);
> > - mutex_unlock(&gvt->lock);
> > }
> >
> > struct workload_thread_param {
> > --
> > 2.7.4
> >
>
> --
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>
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