| Message ID | 20200124204149.550337-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] drm/amdgpu: Reduce global locking around filp release | expand |
On Fri, Jan 24, 2020 at 08:41:48PM +0000, Chris Wilson wrote: > For largely legacy reasons, a global mutex (drm_global_mutex) is taken > around open/close of the drm_device, including serialising the filp > release. For drivers with their own fine grained locking, such global > coordination is a hindrance, albeit off the common hot paths. > > References: 7a2c65dd32b1 ("drm: Release filp before global lock") > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Alex Deucher <alexdeucher@gmail.com> > Cc: Christian König <christian.koenig@amd.com> At least on the open side the global mutex also prevents against the backwards sequence of the ->load callback. Since it's all a huge mess I'm kinda leaning towards one set of rules for optimized drm_global_mutex locking, and not a shotgun approach. It's already one of the nastiest locks we have :-/ -Daniel > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c > index 94e2fd758e01..9bce9cfa982e 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c > @@ -1351,7 +1351,7 @@ static const struct file_operations amdgpu_driver_kms_fops = { > .owner = THIS_MODULE, > .open = drm_open, > .flush = amdgpu_flush, > - .release = drm_release, > + .release = drm_release_noglobal, > .unlocked_ioctl = amdgpu_drm_ioctl, > .mmap = amdgpu_mmap, > .poll = drm_poll, > -- > 2.25.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c index 94e2fd758e01..9bce9cfa982e 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -1351,7 +1351,7 @@ static const struct file_operations amdgpu_driver_kms_fops = { .owner = THIS_MODULE, .open = drm_open, .flush = amdgpu_flush, - .release = drm_release, + .release = drm_release_noglobal, .unlocked_ioctl = amdgpu_drm_ioctl, .mmap = amdgpu_mmap, .poll = drm_poll,
For largely legacy reasons, a global mutex (drm_global_mutex) is taken around open/close of the drm_device, including serialising the filp release. For drivers with their own fine grained locking, such global coordination is a hindrance, albeit off the common hot paths. References: 7a2c65dd32b1 ("drm: Release filp before global lock") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Alex Deucher <alexdeucher@gmail.com> Cc: Christian König <christian.koenig@amd.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)