I know in theoretically this issue should be equal for sriov or not But since the gpu performance under SRIOV is only one quarter compared with bare-metal (assume 4VF) And the CPU's performance is also limited, so there are chance that the fence is signaled not as quick as bare-metal And lead to the scenario that four different context fence are living in resv, If you do it on bare-metal maybe you need some tricks, at least on my sriov platform I can duplicate this BUG() With 4 repeating loop on VK_EXAMPLE every time /Monk -----Original Message----- From: Koenig, Christian Sent: 2018å¹´2æ??27æ?¥ 16:34 To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org; Chris Wilson <chris at chris-wilson.co.uk> Subject: Re: [PATCH 22/22] drm/amdgpu: fix reservation obj shared count bug Am 27.02.2018 um 04:36 schrieb Liu, Monk: >> Well then there is something else broken and I actually think that this is the root cause here. > What if this VM submits four different jobs on four different rings, > e.g. gfx/compute1/compute2/vce So the fences for those jobs are from > different context, and now you get a mapping on this VM So the shared > count is now 4 Yeah, but each VM submission reserves a shared slot before adding the fence. So even if you have 4 submissions we still have a guaranteed free slot. > I ran VK_example and it always can hit this reservation BUG(), just > repeat running it 4 loops and The BUG() hit, but I did it under SRIOV > case so the CPU&GPU performance is different with bare-metal > > Anyway do you think above scenario exist ? Well you somehow run into this problem, I just don't understand how. It shouldn't matter if you run on bare-metal or SRIOV, the VM handling is the same as far as I know. Going to give it a try today to create some unit tests exercising the problem. Christian. > > > -----Original Message----- > From: Koenig, Christian > Sent: 2018å¹´2æ??26æ?¥ 19:19 > To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org; Chris > Wilson <chris at chris-wilson.co.uk> > Subject: Re: [PATCH 22/22] drm/amdgpu: fix reservation obj shared > count bug > >> What if all those context are not equal ? and accumulated finally to 4 ? > Well then there is something else broken and I actually think that this is the root cause here. > >> You can try VK_EXAMPLE test yourself, see if you can hit that BUG() >> in reservation.c file, > Could you generate a simpler unit test to trigger the problem? > > > Thanks, > Christian. > > Am 26.02.2018 um 11:57 schrieb Liu, Monk: >>> So we call reserve_shared only once and then call reservation_object_add_shared_fence() multiple times, always with the same context. >>> should replace the fence when it has the same context as a previously added fence. >> What if all those context are not equal ? and accumulated finally to 4 ? >> You can try VK_EXAMPLE test yourself, see if you can hit that BUG() >> in reservation.c file, I hit it and it is fixed by this patch, I don't think there is other reason. >> >> -----Original Message----- >> From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On >> Behalf Of Christian K?nig >> Sent: 2018å¹´2æ??26æ?¥ 18:45 >> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org; >> Chris Wilson <chris at chris-wilson.co.uk> >> Subject: Re: [PATCH 22/22] drm/amdgpu: fix reservation obj shared >> count bug >> >>> We must call reserve_shared before amdgpu_bo_fence.... >> Actually that's not correct. See >> reservation_object_add_shared_fence() >> should replace the fence when it has the same context as a previously added fence. >> >> So we call reserve_shared only once and then call >> reservation_object_add_shared_fence() multiple times, always with the same context. >> >> Writing this, Chris actually had patches which may have broken that assumption, but as far as I know those aren't merged yet. >> >> Regards, >> Christian. >> >> Am 26.02.2018 um 11:36 schrieb Liu, Monk: >>> amdgpu_vm_get_pd_bo() should already reserves a shared slot for the fence: >>>> entry->tv.shared = true; >>> That's not related with the bug I fixed! The root cause is there is >>> some sequence that When code path comes to amdgpu_bo_fence of >>> vm_update_directories, no one The shared_cnt is by coincidence >>> already the max value of resv obj, so the BUG() in Reservation.c >>> file will hit, >>> >>> We must call reserve_shared before amdgpu_bo_fence.... >>> >>> >>> >>> -----Original Message----- >>> From: Christian König [mailto:ckoenig.leichtzumerken at gmail.com] >>> Sent: 2018å¹´2æ??26æ?¥ 17:48 >>> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org >>> Subject: Re: [PATCH 22/22] drm/amdgpu: fix reservation obj shared >>> count bug >>> >>> That fix is incorrect. >>> >>> amdgpu_vm_get_pd_bo() should already reserves a shared slot for the fence: >>>>        entry->tv.shared = true; >>> So you must run into this issue because of something else. >>> >>> Regards, >>> Christian. >>> >>> Am 26.02.2018 um 06:35 schrieb Monk Liu: >>>> should call reservation_object_reserve_shared before >>>> amdgpu_bo_fence(), otherwise there are odds kernel hit BUG in >>>> reversation.c >>>> >>>> bug: >>>> [12622.076435] ------------[ cut here ]------------ [12622.076438] >>>> kernel BUG at drivers/dma-buf/reservation.c:233! >>>> [12622.078046] invalid opcode: 0000 [#1] SMP KASAN [12622.078345] >>>> Modules linked in: amdgpu(E) chash(E) gpu_sched(E) ttm(E) drm_kms_helper(E) drm(E) i2c_algo_bit(E) fb_sys_fops(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) amdkfd(E) amd_iommu_v2(E) snd_hda_codec_generic(E) snd_hda_intel(E) snd_hda_codec(E) snd_hda_core(E) snd_hwdep(E) snd_pcm(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) pcbc(E) snd_seq_midi(E) snd_seq_midi_event(E) snd_rawmidi(E) snd_seq(E) aesni_intel(E) snd_seq_device(E) aes_x86_64(E) crypto_simd(E) glue_helper(E) cryptd(E) snd_timer(E) serio_raw(E) snd(E) soundcore(E) i2c_piix4(E) mac_hid(E) binfmt_misc(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) parport_pc(E) ppdev(E) lp(E) parport(E) autofs4(E) 8139too(E) psmouse(E) floppy(E) 8139cp(E) mii(E) pata_acpi(E) >>>> [12622.082664] CPU: 2 PID: 6075 Comm: ShaderImageLoad Tainted: G E 4.13.0-feb15-2018-guest-12 #8 >>>> [12622.083278] Hardware name: QEMU Standard PC (i440FX + PIIX, >>>> 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [12622.083880] task: >>>> ffff8801314f8000 task.stack: ffff8801e6df0000 [12622.084267] RIP: >>>> 0010:reservation_object_add_shared_fence+0x2bc/0x2c0 >>>> [12622.084680] RSP: 0018:ffff8801e6df7ae8 EFLAGS: 00010246 >>>> [12622.085016] RAX: 0000000000000004 RBX: ffff8801f2542a80 RCX: >>>> ffff8801f2542b58 [12622.085471] RDX: ffff880044791428 RSI: >>>> ffff8801e2657d20 RDI: ffff880044791428 [12622.085995] RBP: >>>> ffff8801e6df7b28 R08: 0000000000000000 R09: 0000000000000000 >>>> [12622.086451] R10: 000000009fe2fe07 R11: 0000000000000002 R12: >>>> ffff880044791200 [12622.086905] R13: ffff8801e1da6850 R14: >>>> 0000000000000000 R15: ffff8801e9303000 [12622.087359] FS: >>>> 00007f70109ff700(0000) GS:ffff8801f7500000(0000) >>>> knlGS:0000000000000000 [12622.087874] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [12622.088242] CR2: 00007f6fe1a49000 CR3: 00000001e8377000 CR4: 00000000001406e0 [12622.088698] Call Trace: >>>> [12622.088934] amdgpu_bo_fence+0x25/0x30 [amdgpu] [12622.089271] >>>> amdgpu_vm_update_directories+0x3d7/0x450 [amdgpu] [12622.089721] ? >>>> amdgpu_vm_free_mapping.isra.20+0x30/0x30 [amdgpu] [12622.090184] >>>> amdgpu_gem_va_ioctl+0x409/0x4f0 [amdgpu] [12622.090569] ? >>>> amdgpu_gem_metadata_ioctl+0x1b0/0x1b0 [amdgpu] [12622.090959] >>>> drm_ioctl_kernel+0x6a/0xb0 [drm] [12622.091247] ? >>>> kasan_check_write+0x14/0x20 [12622.091517] drm_ioctl+0x2ea/0x3b0 >>>> [drm] [12622.091805] ? amdgpu_gem_metadata_ioctl+0x1b0/0x1b0 >>>> [amdgpu] [12622.092212] amdgpu_drm_ioctl+0x4b/0x80 [amdgpu] >>>> [12622.092519] >>>> do_vfs_ioctl+0x96/0x5b0 [12622.092754] ? >>>> kvm_sched_clock_read+0x1e/0x30 [12622.093036] ? >>>> kvm_sched_clock_read+0x1e/0x30 [12622.093322] ? >>>> sched_clock+0x9/0x10 [12622.093550] SyS_ioctl+0x79/0x90 [12622.093812] ? >>>> vtime_user_exit+0x29/0x70 [12622.094108] do_syscall_64+0x6e/0x160 >>>> [12622.094350] entry_SYSCALL64_slow_path+0x25/0x25 >>>> [12622.094651] RIP: 0033:0x7f7012ebff07 [12622.094884] RSP: >>>> 002b:00007f70109fdae8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 >>>> [12622.095369] RAX: ffffffffffffffda RBX: 00007f6fe100fe30 RCX: >>>> 00007f7012ebff07 [12622.095827] RDX: 00007f70109fdbb0 RSI: >>>> 00000000c0286448 RDI: 0000000000000004 [12622.096283] RBP: >>>> 00007f70109fdb20 R08: 0000000332000000 R09: 000000000000000e >>>> [12622.096739] R10: 0000000002e2e628 R11: 0000000000000206 R12: >>>> 0000000002ebb8f0 [12622.097195] R13: 00007f6fe100fe30 R14: >>>> 0000000002fe2bf0 R15: 0000000000000000 [12622.097676] Code: 2b e6 >>>> ff ff 41 8b 4f 10 48 8b 75 c8 48 8b 55 d0 e9 06 ff ff ff 49 8d 44 >>>> cf 10 >>>> 45 31 ed 48 89 70 08 41 83 47 10 01 e9 12 ff ff ff <0f> 0b 90 90 0f >>>> 1f >>>> 44 00 00 55 31 c0 48 81 7f 08 00 df a9 ac 48 [12622.098919] RIP: >>>> reservation_object_add_shared_fence+0x2bc/0x2c0 RSP: >>>> ffff8801e6df7ae8 [12622.099527] ---[ end trace 8235addd8e22e444 >>>> ]--- >>>> >>>> Change-Id: I1de84f60c75a0d78b0cad244b8e2bff02aced9fa >>>> Signed-off-by: Monk Liu <Monk.Liu at amd.com> >>>> --- >>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 5 +++++ >>>> 1 file changed, 5 insertions(+) >>>> >>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c >>>> index 0b237e0..e6f159f 100644 >>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c >>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c >>>> @@ -989,6 +989,11 @@ int amdgpu_vm_update_directories(struct amdgpu_device *adev, >>>> amdgpu_ring_pad_ib(ring, params.ib); >>>> amdgpu_sync_resv(adev, &job->sync, root->tbo.resv, >>>> AMDGPU_FENCE_OWNER_VM, false); >>>> + >>>> + r = reservation_object_reserve_shared(root->tbo.resv); >>>> + if (r) >>>> + goto error; >>>> + >>>> WARN_ON(params.ib->length_dw > ndw); >>>> r = amdgpu_job_submit(job, ring, &vm->entity, >>>> AMDGPU_FENCE_OWNER_VM, &fence); >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx at lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
