[PATCH] drm/amdkfd: Fix dmabuf's redundant eviction when unmapping
Eric Huang
jinhuieric.huang at amd.com
Mon Apr 10 18:28:17 UTC 2023
Hi Felix,
Thanks for your review and suggestion, but unfortunately the
AMDGPU_GEM_DOMAIN_PREEMPTIBLE is not defined in amdgpu_drm.h. I
understand we need the memory eviction on either kfd_mem_dmamap_dmabuf()
or kfd_mem_dmaunmap_dmabuf() to update DMA address, so I am thinking to
do it as simply as userptr memory does.
The purpose for this change is for non-MES HW scheduler we are using
userptr/paged memory, but since GFX11 we will be using MES scheduler and
it needs the memory to be allocated as GTT/non-paged memory, so we want
all GPUs using GTT/non-paged memory, but there is performance drop,
because of eviction in kfd_mem_dmaunmap_dmabuf.
Currently userptr memory is evicted in kfd_mem_dmamap_userptr as
changing domain to GTT before calling ttm_bo_validate, and not evicted
in kfd_mem_dmamap_userptr, so I think we can do the similar way for
GTT/non-paged memory that setting domain to CPU in
kfd_mem_dmamap_dmabuf, which will evict memory to update DMA address,
and setting domain to GTT in kfd_mem_dmaunmap_dmabuf, which will not
evict memory. The performance should be the same as userptr/paged memory.
Regards,
Eric
On 2023-04-04 16:40, Felix Kuehling wrote:
> [+Christian]
>
> OK, this comes from the ttm_bo_wait_ctx call in this section of
> amdgpu_bo_move:
>
> if ((old_mem->mem_type == TTM_PL_TT ||
> old_mem->mem_type == AMDGPU_PL_PREEMPT) &&
> new_mem->mem_type == TTM_PL_SYSTEM) {
> r = ttm_bo_wait_ctx(bo, ctx);
> if (r)
> return r;
>
> amdgpu_ttm_backend_unbind(bo->bdev, bo->ttm);
> ttm_resource_free(bo, &bo->resource);
> ttm_bo_assign_mem(bo, new_mem);
> goto out;
> }
>
> We can't just remove this wait. It's not even specific to KFD or
> DMABuf imports. We also can't just change it to avoid waiting for
> eviction fences because it's also used for GTT BOs (e.g. before a BO
> gets swapped under extreme memory pressure). So we also need to
> trigger the eviction fence in general case.
>
> In the specific case of DMABuf imports, they share the reservation
> object with the original BO. So waiting on the reservation triggers
> the eviction fence on the original BO. I think we want to avoid the
> waiting on eviction fences for all BOs where the underlying memory is
> managed by some other BO, and at the same time also avoid ever
> evicting the DMABuf import BO. That's what AMDGPU_PL_PREEMPT is for.
> So I think a combination of two changes should to the trick:
>
> 1. Change kfd_mem_dmamap_dmabuf to use AMDGPU_GEM_DOMAIN_PREEMPTIBLE
> 2. Add a special case in the above if-block for old_mem->mem_type ==
> AMDGPU_PL_PREEMPT: use amdgpu_bo_sync_wait with
> owner=AMDGPU_FENCE_OWNER_KFD so that it doesn't wait for eviction
> fences
>
> Regards,
> Felix
>
>
> Am 2023-04-04 um 10:36 schrieb Eric Huang:
>> Here is the backtrace from Jira:
>>
>> Thu Nov 10 13:10:23 2022] Scheduling eviction of pid 97784 in 0 jiffies
>> [Thu Nov 10 13:10:23 2022] WARNING: CPU: 173 PID: 97784 at
>> /var/lib/dkms/amdgpu/5.16.9.22.20-1438746~20.04/build/amd/amdgpu/../amdkfd/kfd_device.c:878
>> kgd2kfd_schedule_evict_and_restore_process+0x104/0x120 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] Modules linked in: veth amdgpu(OE)
>> amddrm_ttm_helper(OE) amdttm(OE) iommu_v2 amd_sched(OE) amdkcl(OE)
>> xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user
>> xfrm_algo xt_addrtype iptable_filter iptable_nat nf_nat nf_conntrack
>> nf_defrag_ipv6 nf_defrag_ipv4 bpfilter br_netfilter bridge stp llc
>> aufs overlay binfmt_misc nls_iso8859_1 dm_multipath scsi_dh_rdac
>> scsi_dh_emc scsi_dh_alua intel_rapl_msr intel_rapl_common amd64_edac
>> edac_mce_amd kvm_amd kvm efi_pstore rapl ipmi_ssif ccp acpi_ipmi
>> k10temp ipmi_si ipmi_devintf ipmi_msghandler mac_hid sch_fq_codel msr
>> ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10
>> raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx
>> xor raid6_pq libcrc32c raid1 raid0 multipath linear mlx5_ib ib_uverbs
>> ib_core crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel
>> crypto_simd cryptd ast drm_vram_helper drm_ttm_helper ttm mlx5_core
>> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
>> [Thu Nov 10 13:10:23 2022] pci_hyperv_intf cec psample igb mlxfw
>> rc_core dca ahci xhci_pci tls drm i2c_algo_bit libahci
>> xhci_pci_renesas i2c_piix4
>> [Thu Nov 10 13:10:23 2022] CPU: 173 PID: 97784 Comm: onnxruntime_tes
>> Tainted: G W OE 5.13.0-30-generic #33~20.04.1-Ubuntu
>> [Thu Nov 10 13:10:23 2022] Hardware name: GIGABYTE
>> G482-Z53-YF/MZ52-G40-00, BIOS R12 05/13/2020
>> [Thu Nov 10 13:10:23 2022] RIP:
>> 0010:kgd2kfd_schedule_evict_and_restore_process+0x104/0x120 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] Code: 5e 5d c3 4c 89 e7 e8 cb c6 44 df eb
>> e7 49 8b 45 60 48 89 ca 48 c7 c7 38 8b d7 c1 48 89 4d e0 8b b0 20 09
>> 00 00 e8 87 ee 7e df <0f> 0b 48 8b 4d e0 eb 9f 41 be ea ff ff ff eb
>> ba 41 be ed ff ff ff
>> [Thu Nov 10 13:10:23 2022] RSP: 0018:ffffb25f2a173978 EFLAGS: 00010086
>> [Thu Nov 10 13:10:23 2022] RAX: 0000000000000000 RBX:
>> 0000000000000001 RCX: 0000000000000027
>> [Thu Nov 10 13:10:23 2022] RDX: 0000000000000027 RSI:
>> 00000000fffeffff RDI: ffff95d06e4a09c8
>> [Thu Nov 10 13:10:23 2022] RBP: ffffb25f2a173998 R08:
>> ffff95d06e4a09c0 R09: ffffb25f2a173750
>> [Thu Nov 10 13:10:23 2022] R10: 0000000000000001 R11:
>> 0000000000000001 R12: ffff95c371d74580
>> [Thu Nov 10 13:10:23 2022] R13: ffff95b1cd3f2000 R14:
>> 0000000000000000 R15: ffff95c371d74580
>> [Thu Nov 10 13:10:23 2022] FS: 00007fcaff268b00(0000)
>> GS:ffff95d06e480000(0000) knlGS:0000000000000000
>> [Thu Nov 10 13:10:23 2022] CS: 0010 DS: 0000 ES: 0000 CR0:
>> 0000000080050033
>> [Thu Nov 10 13:10:23 2022] CR2: 00007fc643980000 CR3:
>> 00000003e9492000 CR4: 0000000000350ee0
>> [Thu Nov 10 13:10:23 2022] Call Trace:
>> [Thu Nov 10 13:10:23 2022] <TASK>
>> [Thu Nov 10 13:10:23 2022] amdkfd_fence_enable_signaling+0x46/0x50
>> [amdgpu]
>> [Thu Nov 10 13:10:23 2022] __dma_fence_enable_signaling+0x52/0xb0
>> [Thu Nov 10 13:10:23 2022] dma_fence_default_wait+0xa9/0x200
>> [Thu Nov 10 13:10:23 2022] dma_fence_wait_timeout+0xbd/0xe0
>> [Thu Nov 10 13:10:23 2022] amddma_resv_wait_timeout+0x6f/0xd0 [amdkcl]
>> [Thu Nov 10 13:10:23 2022] amdttm_bo_wait+0x39/0x50 [amdttm]
>> [Thu Nov 10 13:10:23 2022] amdgpu_bo_move+0x41e/0x7b0 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] ? down_write+0x13/0x50
>> [Thu Nov 10 13:10:23 2022] ? unmap_mapping_pages+0x68/0x130
>> [Thu Nov 10 13:10:23 2022] ttm_bo_handle_move_mem+0x7f/0x120 [amdttm]
>> [Thu Nov 10 13:10:23 2022] amdttm_bo_validate+0xbf/0x100 [amdttm]
>> [Thu Nov 10 13:10:23 2022] kfd_mem_dmaunmap_attachment+0x131/0x140
>> [amdgpu]
>> [Thu Nov 10 13:10:23 2022] unmap_bo_from_gpuvm+0x67/0x80 [amdgpu]
>> [Thu Nov 10 13:10:23 2022]
>> amdgpu_amdkfd_gpuvm_unmap_memory_from_gpu+0x114/0x220 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] ? __mod_memcg_lruvec_state+0x22/0xe0
>> [Thu Nov 10 13:10:23 2022]
>> kfd_ioctl_unmap_memory_from_gpu+0xe8/0x270 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] kfd_ioctl+0x23c/0x590 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] ?
>> kfd_ioctl_get_process_apertures_new+0x330/0x330 [amdgpu]
>> [Thu Nov 10 13:10:23 2022] ? exit_to_user_mode_prepare+0x3d/0x1c0
>> [Thu Nov 10 13:10:23 2022] ? __fget_files+0xa7/0xd0
>> [Thu Nov 10 13:10:23 2022] __x64_sys_ioctl+0x91/0xc0
>> [Thu Nov 10 13:10:23 2022] do_syscall_64+0x61/0xb0
>> [Thu Nov 10 13:10:23 2022] ? do_syscall_64+0x6e/0xb0
>> [Thu Nov 10 13:10:23 2022] ? do_syscall_64+0x6e/0xb0
>> [Thu Nov 10 13:10:23 2022] ? do_syscall_64+0x6e/0xb0
>> [Thu Nov 10 13:10:23 2022] ? do_syscall_64+0x6e/0xb0
>> [Thu Nov 10 13:10:23 2022] ? asm_sysvec_apic_timer_interrupt+0xa/0x20
>> [Thu Nov 10 13:10:23 2022] entry_SYSCALL_64_after_hwframe+0x44/0xae
>> [Thu Nov 10 13:10:23 2022] RIP: 0033:0x7fcaff57b3ab
>> [Thu Nov 10 13:10:23 2022] Code: 0f 1e fa 48 8b 05 e5 7a 0d 00 64 c7
>> 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa
>> b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b5 7a 0d
>> 00 f7 d8 64 89 01 48
>> [Thu Nov 10 13:10:23 2022] RSP: 002b:00007fffe41e0098 EFLAGS:
>> 00000206 ORIG_RAX: 0000000000000010
>> [Thu Nov 10 13:10:23 2022] RAX: ffffffffffffffda RBX:
>> 00007fcacc7f7f80 RCX: 00007fcaff57b3ab
>> [Thu Nov 10 13:10:23 2022] RDX: 00007fffe41e0120 RSI:
>> 00000000c0184b19 RDI: 0000000000000003
>> [Thu Nov 10 13:10:23 2022] RBP: 00007fffe41e00d0 R08:
>> 0000562e2d5730d0 R09: 0000000000000000
>> [Thu Nov 10 13:10:23 2022] R10: 0000562e2c928ec0 R11:
>> 0000000000000206 R12: 0000000000000001
>> [Thu Nov 10 13:10:23 2022] R13: 00007fffe41e04b0 R14:
>> 0000000000000000 R15: 0000562e2d3f5b20
>> [Thu Nov 10 13:10:23 2022] </TASK>
>> [Thu Nov 10 13:10:23 2022] ---[ end trace 1464f08f6be60b30 ]---
>>
>> Regards,
>> Eric
>>
>> On 2023-04-04 10:11, Felix Kuehling wrote:
>>> If we keep the BO in the GTT domain, it means it will not be updated
>>> if we validate it again later in kfd_mem_dmamap_dmabuf. This means
>>> we'll use stale DMA addresses when we update the page tables after
>>> evictions.
>>>
>>> I think we'll need to find a different way to avoid triggering the
>>> eviction fence on the original BO when changing the placement of the
>>> DMABuf import here. If you need help brainstorming here, please
>>> share a backtrace from the eviction generated with the
>>> debug_evictions module param.
>>>
>>> Regards,
>>> Felix
>>>
>>>
>>> Am 2023-04-03 um 13:59 schrieb Eric Huang:
>>>> dmabuf is allocated/mapped as GTT domain, when dma-unmapping dmabuf
>>>> changing placement to CPU will trigger memory eviction after calling
>>>> ttm_bo_validate, and the eviction will cause performance drop.
>>>> Keeping the correct domain will solve the issue.
>>>>
>>>> Signed-off-by: Eric Huang <jinhuieric.huang at amd.com>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> index a3b09edfd1bf..17b708acb447 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>>>> @@ -642,7 +642,7 @@ kfd_mem_dmaunmap_dmabuf(struct
>>>> kfd_mem_attachment *attachment)
>>>> struct ttm_operation_ctx ctx = {.interruptible = true};
>>>> struct amdgpu_bo *bo = attachment->bo_va->base.bo;
>>>> - amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_CPU);
>>>> + amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
>>>> ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>>>> }
>>
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