| Message ID | 20181010165533.23345-4-lionel.g.landwerlin@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/perf: Add OA buffer size uAPI parameter | expand |
On Wed, 10 Oct 2018 at 19:55, Lionel Landwerlin <lionel.g.landwerlin@intel.com> wrote: > > If 2 processes race to open the perf stream, it's possible that one of them > will see that OA buffer has already been allocated, while a previous process > is still finishing to reprogram the hardware (on gen8+). > > The opening sequence has been reworked a few times and we probably lost > track of the order in which things are supposed to happen. > > Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Accidental resend, or did the locking actually change recently?
On 10/10/2018 20:24, Matthew Auld wrote: > On Wed, 10 Oct 2018 at 19:55, Lionel Landwerlin > <lionel.g.landwerlin@intel.com> wrote: >> If 2 processes race to open the perf stream, it's possible that one of them >> will see that OA buffer has already been allocated, while a previous process >> is still finishing to reprogram the hardware (on gen8+). >> >> The opening sequence has been reworked a few times and we probably lost >> track of the order in which things are supposed to happen. >> >> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> > Accidental resend, or did the locking actually change recently? > Indeed.... Sorry for that, dropping for good! - Lionel
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index 88f3f9b6a353..a648ded97969 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -1494,13 +1494,15 @@ static int alloc_oa_buffer(struct drm_i915_private *dev_priv) struct i915_vma *vma; int ret; - if (WARN_ON(dev_priv->perf.oa.oa_buffer.vma)) - return -ENODEV; - ret = i915_mutex_lock_interruptible(&dev_priv->drm); if (ret) return ret; + if (dev_priv->perf.oa.oa_buffer.vma) { + ret = -EBUSY; + goto unlock; + } + BUILD_BUG_ON_NOT_POWER_OF_2(OA_BUFFER_SIZE); BUILD_BUG_ON(OA_BUFFER_SIZE < SZ_128K || OA_BUFFER_SIZE > SZ_16M);
If 2 processes race to open the perf stream, it's possible that one of them will see that OA buffer has already been allocated, while a previous process is still finishing to reprogram the hardware (on gen8+). The opening sequence has been reworked a few times and we probably lost track of the order in which things are supposed to happen. Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> --- drivers/gpu/drm/i915/i915_perf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)