Re: 回复: [PATCH v2] drm/amdgpu: Put drm_dev_enter/exit outside hot codepath
Andrey Grodzovsky
andrey.grodzovsky at amd.com
Wed Sep 15 14:04:09 UTC 2021
On 2021-09-15 9:57 a.m., Christian König wrote:
> Am 15.09.21 um 15:52 schrieb Andrey Grodzovsky:
>> On 2021-09-15 2:42 a.m., Pan, Xinhui wrote:
>>> [AMD Official Use Only]
>>>
>>> Andrey
>>> I hit panic with this plug/unplug test without this patch.
>>
>>
>> Can you please tell which ASIC you are using and which kernel branch
>> and what is the tip commit ?
>>
>>
>>> But as we add enter/exit in all its callers. maybe it would not
>>> impact plug/unplug.
>>
>>
>> If you add enter/exit in all callers then why this solves the problem
>> ? Is it because in one or more callers
>> amdgpu_gmc_set_pte_pde is called many times and so calling enter/exit
>> many times creates the problematic
>> contention from multiple threads ?
>
> The most likely cause of this is cache line bouncing I think and yes
> moving the enter/exit a level up should fix this.
>
> But I strongly suggest to test this with lockdep enabled and
> hotplug/GPU reset a couple of times.
Xinhui already tried testing with Hotplug and there is a regression
crash as you can see bellow. That
why I wanted to know which kernel and which ASIC to see if I can
reproduce and fix the regression quickly.
I will try on my side with latest kernel and vega 10 anyway since i see
vega 10 functions from the trace.
Andrey
>
> Christian.
>
>>
>> Andrey
>>
>>>
>>> [ 1109.041095] BUG: unable to handle page fault for address:
>>> 00000000000010e1
>>> [ 1109.086353] RIP: 0010:vega10_power_gate_vce+0x15/0x40 [amdgpu]
>>> [ 1109.196706] Call Trace:
>>> [ 1109.199374] ? pp_set_powergating_by_smu+0x1f9/0x4a0 [amdgpu]
>>> [ 1109.205843] amdgpu_dpm_set_powergating_by_smu+0xa6/0x150 [amdgpu]
>>> [ 1109.212776] amdgpu_dpm_enable_vce+0x36/0x100 [amdgpu]
>>> [ 1109.218563] vce_v4_0_hw_fini+0xe1/0xf0 [amdgpu]
>>> [ 1109.223747] amdgpu_device_fini_hw+0x333/0x483 [amdgpu]
>>> [ 1109.229650] amdgpu_driver_unload_kms+0x80/0xe0 [amdgpu]
>>> [ 1109.235577] amdgpu_pci_remove+0x37/0x70 [amdgpu]
>>> [ 1109.240853] pci_device_remove+0x3b/0xb0
>>> [ 1109.245127] device_release_driver_internal+0x100/0x1d0
>>> [ 1109.250857] device_release_driver+0x12/0x20
>>> [ 1109.255535] pci_stop_bus_device+0x79/0xa0
>>> [ 1109.260016] pci_stop_and_remove_bus_device_locked+0x1b/0x30
>>> [ 1109.266197] remove_store+0x7b/0x90
>>> [ 1109.269990] dev_attr_store+0x14/0x30
>>> [ 1109.274002] sysfs_kf_write+0x48/0x60
>>> [ 1109.277998] kernfs_fop_write_iter+0x14e/0x1e0
>>>
>>> ________________________________________
>>> 发件人: Pan, Xinhui <Xinhui.Pan at amd.com>
>>> 发送时间: 2021年9月15日 14:37
>>> 收件人: amd-gfx at lists.freedesktop.org
>>> 抄送: Deucher, Alexander; Koenig, Christian; Grodzovsky, Andrey; Pan,
>>> Xinhui
>>> 主题: [PATCH v2] drm/amdgpu: Put drm_dev_enter/exit outside hot
>>> codepath
>>>
>>> We hit soft hang while doing memory pressure test on one numa system.
>>> After a qucik look, this is because kfd invalid/valid userptr memory
>>> frequently with process_info lock hold.
>>> Looks like update page table mapping use too much cpu time.
>>>
>>> perf top says below,
>>> 75.81% [kernel] [k] __srcu_read_unlock
>>> 6.19% [amdgpu] [k] amdgpu_gmc_set_pte_pde
>>> 3.56% [kernel] [k] __srcu_read_lock
>>> 2.20% [amdgpu] [k] amdgpu_vm_cpu_update
>>> 2.20% [kernel] [k] __sg_page_iter_dma_next
>>> 2.15% [drm] [k] drm_dev_enter
>>> 1.70% [drm] [k] drm_prime_sg_to_dma_addr_array
>>> 1.18% [kernel] [k] __sg_alloc_table_from_pages
>>> 1.09% [drm] [k] drm_dev_exit
>>>
>>> So move drm_dev_enter/exit outside gmc code, instead let caller do it.
>>> They are gart_unbind, gart_map, vm_clear_bo, vm_update_pdes and
>>> gmc_init_pdb0. vm_bo_update_mapping already calls it.
>>>
>>> Signed-off-by: xinhui pan <xinhui.pan at amd.com>
>>> ---
>>> change from v1:
>>> add enter/exit in more gmc_set_pte_pde callers
>>> ---
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 11 ++++++++++
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 11 +++++-----
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 28
>>> +++++++++++++++++-------
>>> 3 files changed, 36 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
>>> index 76efd5f8950f..d7e4f4660acf 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
>>> @@ -34,6 +34,7 @@
>>> #include <asm/set_memory.h>
>>> #endif
>>> #include "amdgpu.h"
>>> +#include <drm/drm_drv.h>
>>>
>>> /*
>>> * GART
>>> @@ -230,12 +231,16 @@ int amdgpu_gart_unbind(struct amdgpu_device
>>> *adev, uint64_t offset,
>>> u64 page_base;
>>> /* Starting from VEGA10, system bit must be 0 to mean
>>> invalid. */
>>> uint64_t flags = 0;
>>> + int idx;
>>>
>>> if (!adev->gart.ready) {
>>> WARN(1, "trying to unbind memory from uninitialized
>>> GART !\n");
>>> return -EINVAL;
>>> }
>>>
>>> + if (!drm_dev_enter(&adev->ddev, &idx))
>>> + return 0;
>>> +
>>> t = offset / AMDGPU_GPU_PAGE_SIZE;
>>> p = t / AMDGPU_GPU_PAGES_IN_CPU_PAGE;
>>> for (i = 0; i < pages; i++, p++) {
>>> @@ -254,6 +259,7 @@ int amdgpu_gart_unbind(struct amdgpu_device
>>> *adev, uint64_t offset,
>>> for (i = 0; i < adev->num_vmhubs; i++)
>>> amdgpu_gmc_flush_gpu_tlb(adev, 0, i, 0);
>>>
>>> + drm_dev_exit(idx);
>>> return 0;
>>> }
>>>
>>> @@ -276,12 +282,16 @@ int amdgpu_gart_map(struct amdgpu_device
>>> *adev, uint64_t offset,
>>> {
>>> uint64_t page_base;
>>> unsigned i, j, t;
>>> + int idx;
>>>
>>> if (!adev->gart.ready) {
>>> WARN(1, "trying to bind memory to uninitialized
>>> GART !\n");
>>> return -EINVAL;
>>> }
>>>
>>> + if (!drm_dev_enter(&adev->ddev, &idx))
>>> + return 0;
>>> +
>>> t = offset / AMDGPU_GPU_PAGE_SIZE;
>>>
>>> for (i = 0; i < pages; i++) {
>>> @@ -291,6 +301,7 @@ int amdgpu_gart_map(struct amdgpu_device *adev,
>>> uint64_t offset,
>>> page_base += AMDGPU_GPU_PAGE_SIZE;
>>> }
>>> }
>>> + drm_dev_exit(idx);
>>> return 0;
>>> }
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>>> index 54f059501a33..1427fd70310c 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
>>> @@ -153,10 +153,6 @@ int amdgpu_gmc_set_pte_pde(struct amdgpu_device
>>> *adev, void *cpu_pt_addr,
>>> {
>>> void __iomem *ptr = (void *)cpu_pt_addr;
>>> uint64_t value;
>>> - int idx;
>>> -
>>> - if (!drm_dev_enter(&adev->ddev, &idx))
>>> - return 0;
>>>
>>> /*
>>> * The following is for PTE only. GART does not have PDEs.
>>> @@ -165,8 +161,6 @@ int amdgpu_gmc_set_pte_pde(struct amdgpu_device
>>> *adev, void *cpu_pt_addr,
>>> value |= flags;
>>> writeq(value, ptr + (gpu_page_idx * 8));
>>>
>>> - drm_dev_exit(idx);
>>> -
>>> return 0;
>>> }
>>>
>>> @@ -752,6 +746,10 @@ void amdgpu_gmc_init_pdb0(struct amdgpu_device
>>> *adev)
>>> adev->gmc.xgmi.physical_node_id *
>>> adev->gmc.xgmi.node_segment_size;
>>> u64 vram_end = vram_addr + vram_size;
>>> u64 gart_ptb_gpu_pa = amdgpu_gmc_vram_pa(adev, adev->gart.bo);
>>> + int idx;
>>> +
>>> + if (!drm_dev_enter(&adev->ddev, &idx))
>>> + return;
>>>
>>> flags |= AMDGPU_PTE_VALID | AMDGPU_PTE_READABLE;
>>> flags |= AMDGPU_PTE_WRITEABLE;
>>> @@ -773,6 +771,7 @@ void amdgpu_gmc_init_pdb0(struct amdgpu_device
>>> *adev)
>>> flags |= AMDGPU_PDE_BFS(0) | AMDGPU_PTE_SNOOPED;
>>> /* Requires gart_ptb_gpu_pa to be 4K aligned */
>>> amdgpu_gmc_set_pte_pde(adev, adev->gmc.ptr_pdb0, i,
>>> gart_ptb_gpu_pa, flags);
>>> + drm_dev_exit(idx);
>>> }
>>>
>>> /**
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> index 0126ece898da..daa16d2f89da 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> @@ -800,7 +800,7 @@ static int amdgpu_vm_clear_bo(struct
>>> amdgpu_device *adev,
>>> struct amdgpu_bo *bo = &vmbo->bo;
>>> unsigned entries, ats_entries;
>>> uint64_t addr;
>>> - int r;
>>> + int r, idx;
>>>
>>> /* Figure out our place in the hierarchy */
>>> if (ancestor->parent) {
>>> @@ -845,9 +845,12 @@ static int amdgpu_vm_clear_bo(struct
>>> amdgpu_device *adev,
>>> return r;
>>> }
>>>
>>> + if (!drm_dev_enter(&adev->ddev, &idx))
>>> + return -ENODEV;
>>> +
>>> r = vm->update_funcs->map_table(vmbo);
>>> if (r)
>>> - return r;
>>> + goto exit;
>>>
>>> memset(¶ms, 0, sizeof(params));
>>> params.adev = adev;
>>> @@ -856,7 +859,7 @@ static int amdgpu_vm_clear_bo(struct
>>> amdgpu_device *adev,
>>>
>>> r = vm->update_funcs->prepare(¶ms, NULL,
>>> AMDGPU_SYNC_EXPLICIT);
>>> if (r)
>>> - return r;
>>> + goto exit;
>>>
>>> addr = 0;
>>> if (ats_entries) {
>>> @@ -872,7 +875,7 @@ static int amdgpu_vm_clear_bo(struct
>>> amdgpu_device *adev,
>>> r = vm->update_funcs->update(¶ms, vmbo, addr,
>>> 0, ats_entries,
>>> value, flags);
>>> if (r)
>>> - return r;
>>> + goto exit;
>>>
>>> addr += ats_entries * 8;
>>> }
>>> @@ -895,10 +898,13 @@ static int amdgpu_vm_clear_bo(struct
>>> amdgpu_device *adev,
>>> r = vm->update_funcs->update(¶ms, vmbo, addr,
>>> 0, entries,
>>> value, flags);
>>> if (r)
>>> - return r;
>>> + goto exit;
>>> }
>>>
>>> - return vm->update_funcs->commit(¶ms, NULL);
>>> + r = vm->update_funcs->commit(¶ms, NULL);
>>> +exit:
>>> + drm_dev_exit(idx);
>>> + return r;
>>> }
>>>
>>> /**
>>> @@ -1384,11 +1390,14 @@ int amdgpu_vm_update_pdes(struct
>>> amdgpu_device *adev,
>>> struct amdgpu_vm *vm, bool immediate)
>>> {
>>> struct amdgpu_vm_update_params params;
>>> - int r;
>>> + int r, idx;
>>>
>>> if (list_empty(&vm->relocated))
>>> return 0;
>>>
>>> + if (!drm_dev_enter(&adev->ddev, &idx))
>>> + return -ENODEV;
>>> +
>>> memset(¶ms, 0, sizeof(params));
>>> params.adev = adev;
>>> params.vm = vm;
>>> @@ -1396,7 +1405,7 @@ int amdgpu_vm_update_pdes(struct amdgpu_device
>>> *adev,
>>>
>>> r = vm->update_funcs->prepare(¶ms, NULL,
>>> AMDGPU_SYNC_EXPLICIT);
>>> if (r)
>>> - return r;
>>> + goto exit;
>>>
>>> while (!list_empty(&vm->relocated)) {
>>> struct amdgpu_vm_bo_base *entry;
>>> @@ -1414,10 +1423,13 @@ int amdgpu_vm_update_pdes(struct
>>> amdgpu_device *adev,
>>> r = vm->update_funcs->commit(¶ms, &vm->last_update);
>>> if (r)
>>> goto error;
>>> + drm_dev_exit(idx);
>>> return 0;
>>>
>>> error:
>>> amdgpu_vm_invalidate_pds(adev, vm);
>>> +exit:
>>> + drm_dev_exit(idx);
>>> return r;
>>> }
>>>
>>> --
>>> 2.25.1
>>>
>
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