Hi Oded,
it looks sane to me and is Reviewed-by: Christian König
<christian.koenig at amd.com>.
Christian.
Am 11.05.2018 um 09:38 schrieb Oded Gabbay:
> Hi Felix,
> Same as patch 2. ACK but I want an extra review from amdgpu people.
> Thanks,
> Oded
>
> On Fri, Mar 23, 2018 at 10:32 PM, Felix Kuehling <Felix.Kuehling at amd.com> wrote:
>> When an MMU notifier runs in memory reclaim context, it can deadlock
>> trying to take locks that are already held in the thread causing the
>> memory reclaim. The solution is to avoid memory reclaim while holding
>> locks that are taken in MMU notifiers.
>>
>> This commit fixes kmalloc while holding rmn->lock by moving the call
>> outside the lock. The GFX MMU notifier also locks reservation objects.
>> I have no good solution for avoiding reclaim while holding reservation
>> objects. The HSA MMU notifier will not lock any reservation objects.
>>
>> v2: Moved allocation outside lock instead of using GFP_NOIO
>>
>> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 17 +++++++++--------
>> 1 file changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> index f2ed18e..83e344f 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> @@ -380,7 +380,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
>> enum amdgpu_mn_type type =
>> bo->kfd_bo ? AMDGPU_MN_TYPE_HSA : AMDGPU_MN_TYPE_GFX;
>> struct amdgpu_mn *rmn;
>> - struct amdgpu_mn_node *node = NULL;
>> + struct amdgpu_mn_node *node = NULL, *new_node;
>> struct list_head bos;
>> struct interval_tree_node *it;
>>
>> @@ -388,6 +388,10 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
>> if (IS_ERR(rmn))
>> return PTR_ERR(rmn);
>>
>> + new_node = kmalloc(sizeof(*new_node), GFP_KERNEL);
>> + if (!new_node)
>> + return -ENOMEM;
>> +
>> INIT_LIST_HEAD(&bos);
>>
>> down_write(&rmn->lock);
>> @@ -401,13 +405,10 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
>> list_splice(&node->bos, &bos);
>> }
>>
>> - if (!node) {
>> - node = kmalloc(sizeof(struct amdgpu_mn_node), GFP_KERNEL);
>> - if (!node) {
>> - up_write(&rmn->lock);
>> - return -ENOMEM;
>> - }
>> - }
>> + if (!node)
>> + node = new_node;
>> + else
>> + kfree(new_node);
>>
>> bo->mn = rmn;
>>
>> --
>> 2.7.4
>>
