On 2019-01-07 11:51 a.m., Grodzovsky, Andrey wrote: > > > On 01/07/2019 11:36 AM, StDenis, Tom wrote: >> On 2019-01-07 11:33 a.m., Grodzovsky, Andrey wrote: >>> >>> On 01/07/2019 11:16 AM, Liu, Shaoyun wrote: >>>> I think it's reasonable to use the hive specific lock for hive specific >>>> functions. >>>> The changes is acked-by Shaoyun.liu < shaoyun....@amd.com> >>>> >>>> -----Original Message----- >>>> From: amd-gfx <amd-gfx-boun...@lists.freedesktop.org> On Behalf Of >>>> StDenis, Tom >>>> Sent: Monday, January 7, 2019 10:16 AM >>>> To: amd-gfx@lists.freedesktop.org >>>> Cc: StDenis, Tom <tom.stde...@amd.com> >>>> Subject: [PATCH] add missing mutex lock to amdgpu_get_xgmi_hive() (v2) >>>> >>>> v2: Move locks around in other functions so that this function can stand >>>> on its own. Also only hold the hive specific lock for add/remove device >>>> instead of the driver global lock so you can't add/remove devices in >>>> parallel from one hive. >>>> >>>> Signed-off-by: Tom St Denis <tom.stde...@amd.com> >>>> --- >>>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +- >>>> drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c | 36 ++++++++++++++-------- >>>> drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.h | 2 +- >>>> 3 files changed, 25 insertions(+), 15 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >>>> index 39d5d058b2c7..13d8e2ad2f7a 100644 >>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >>>> @@ -3525,7 +3525,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device >>>> *adev, >>>> * by different nodes. No point also since the one node already >>>> executing >>>> * reset will also reset all the other nodes in the hive. >>>> */ >>>> - hive = amdgpu_get_xgmi_hive(adev); >>>> + hive = amdgpu_get_xgmi_hive(adev, 0); >>>> if (hive && adev->gmc.xgmi.num_physical_nodes > 1 && >>>> !mutex_trylock(&hive->hive_lock)) >>>> return 0; >>> Let's say i have device 0 in hive A and it just got a gpu reset and at >>> the same time device 1 is being added to same have though >>> amdgpu_xgmi_add_device, hive->hive_lock is acquired by this new device >>> being added and so gpu reset for device 0 bails out on >>> '!mutex_trylock(&hive->hive_lock))' without completing the reset. >>> Also in general i feel a bit uncomfortable about the confusing >>> acquisition scheme in the function and the fact that you take the >>> hive->hive_lock inside amdgpu_get_xgmi_hive but release is still outside >>> of the function. >> Is adding a device while resetting a device even a valid operation >> anyways? > > In theory it's valid if you have hot pluggable devices >> >> I think this means more so that the reset logic is broken. Instead >> there should be a per-hive reset lock that is taken and that is tested >> instead. >> >> Tom > > The hive->hive_lock was added exactly for this purpose and used only for > that purpose. Maybe the naming i gave it wasn't reflective of it's > purpose :)
But the add/remove should use per-hive locks not the global lock... :-) (I'm honestly not trying to bike shed I just thought the get_hive function looked wrong :-)). Tom _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
