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* [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory
@ 2022-11-17 21:38 James Zhu
  2022-11-17 22:03 ` Felix Kuehling
                   ` (2 more replies)
  0 siblings, 3 replies; 9+ messages in thread
From: James Zhu @ 2022-11-17 21:38 UTC (permalink / raw)
  To: amd-gfx, christian.koenig, Felix.kuehling, philip.yang; +Cc: jamesz

When applications try to allocate large system (more than > 128GB),
"stall cpu" is reported.

for such large system memory, walk_page_range takes more than 20s usually.
The warning message can be removed when splitting hmm range into smaller
ones which is not more 64GB for each walk_page_range.

[  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
[  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
[  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
[  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
[  185.439137] 	(t=21000 jiffies g=6325 q=1215)
[  185.439141] NMI backtrace for cpu 8
[  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
[  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
[  185.439150] Call Trace:
[  185.439153]  <IRQ>
[  185.439157]  dump_stack+0x64/0x7c
[  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
[  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
[  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
[  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
[  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
[  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
[  185.439185]  update_process_times+0x8c/0xc0
[  185.439189]  tick_sched_timer+0x63/0x70
[  185.439192]  __hrtimer_run_queues+0xff/0x250
[  185.439195]  hrtimer_interrupt+0xf4/0x200
[  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
[  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
[  185.439206]  </IRQ>
[  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
[  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
[  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
[  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
[  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
[  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
[  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
[  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
[  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
[  185.439232]  prep_new_page+0x81/0xc0
[  185.439236]  get_page_from_freelist+0x13be/0x16f0
[  185.439240]  ? release_pages+0x16a/0x4a0
[  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
[  185.439247]  alloc_pages_vma+0x74/0x1e0
[  185.439251]  __handle_mm_fault+0xafe/0x1360
[  185.439255]  handle_mm_fault+0xc3/0x280
[  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
[  185.439261]  __walk_page_range+0x692/0x9b0
[  185.439265]  walk_page_range+0x9b/0x120
[  185.439269]  hmm_range_fault+0x4f/0x90
[  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
[  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
[  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
[  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]

Signed-off-by: James Zhu <James.Zhu@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 47 +++++++++++++++++--------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
index a48ea62b12b0..0425fc6a49aa 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
@@ -163,6 +163,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
 			       struct hmm_range **phmm_range)
 {
 	struct hmm_range *hmm_range;
+	unsigned long hmm_range_end;
 	unsigned long timeout;
 	unsigned long i;
 	unsigned long *pfns;
@@ -184,25 +185,41 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
 		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
 	hmm_range->hmm_pfns = pfns;
 	hmm_range->start = start;
-	hmm_range->end = start + npages * PAGE_SIZE;
+	hmm_range_end = start + npages * PAGE_SIZE;
 	hmm_range->dev_private_owner = owner;
 
-	/* Assuming 512MB takes maxmium 1 second to fault page address */
-	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
-	timeout = jiffies + msecs_to_jiffies(timeout);
+#define MAX_WALK_BYTE	(64ULL<<30)
+	do {
+		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, hmm_range_end);
+
+		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
+			hmm_range->start, hmm_range->end);
+
+		/* Assuming 512MB takes maxmium 1 second to fault page address */
+		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
+			HMM_RANGE_DEFAULT_TIMEOUT;
+		timeout = jiffies + msecs_to_jiffies(timeout);
 
 retry:
-	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
-	r = hmm_range_fault(hmm_range);
-	if (unlikely(r)) {
-		/*
-		 * FIXME: This timeout should encompass the retry from
-		 * mmu_interval_read_retry() as well.
-		 */
-		if (r == -EBUSY && !time_after(jiffies, timeout))
-			goto retry;
-		goto out_free_pfns;
-	}
+		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
+		r = hmm_range_fault(hmm_range);
+		if (unlikely(r)) {
+			/*
+			 * FIXME: This timeout should encompass the retry from
+			 * mmu_interval_read_retry() as well.
+			 */
+			if (r == -EBUSY && !time_after(jiffies, timeout))
+				goto retry;
+			goto out_free_pfns;
+		}
+
+		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
+		hmm_range->start = hmm_range->end;
+		schedule();
+	} while (hmm_range->end < hmm_range_end);
+
+	hmm_range->start = start;
+	hmm_range->hmm_pfns = pfns;
 
 	/*
 	 * Due to default_flags, all pages are HMM_PFN_VALID or
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* Re: [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-17 21:38 [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory James Zhu
@ 2022-11-17 22:03 ` Felix Kuehling
  2022-11-18 12:22   ` James Zhu
  2022-11-21 13:13 ` [PATCH v2] " James Zhu
  2022-11-21 14:53 ` [PATCH v3] " James Zhu
  2 siblings, 1 reply; 9+ messages in thread
From: Felix Kuehling @ 2022-11-17 22:03 UTC (permalink / raw)
  To: James Zhu, amd-gfx, christian.koenig, philip.yang; +Cc: jamesz

Am 2022-11-17 um 16:38 schrieb James Zhu:
> When applications try to allocate large system (more than > 128GB),
> "stall cpu" is reported.
>
> for such large system memory, walk_page_range takes more than 20s usually.
> The warning message can be removed when splitting hmm range into smaller
> ones which is not more 64GB for each walk_page_range.
>
> [  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
> [  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
> [  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
> [  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
> [  185.439137] 	(t=21000 jiffies g=6325 q=1215)
> [  185.439141] NMI backtrace for cpu 8
> [  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
> [  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
> [  185.439150] Call Trace:
> [  185.439153]  <IRQ>
> [  185.439157]  dump_stack+0x64/0x7c
> [  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
> [  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
> [  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
> [  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
> [  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
> [  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
> [  185.439185]  update_process_times+0x8c/0xc0
> [  185.439189]  tick_sched_timer+0x63/0x70
> [  185.439192]  __hrtimer_run_queues+0xff/0x250
> [  185.439195]  hrtimer_interrupt+0xf4/0x200
> [  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
> [  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
> [  185.439206]  </IRQ>
> [  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
> [  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
> [  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
> [  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
> [  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
> [  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
> [  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
> [  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
> [  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
> [  185.439232]  prep_new_page+0x81/0xc0
> [  185.439236]  get_page_from_freelist+0x13be/0x16f0
> [  185.439240]  ? release_pages+0x16a/0x4a0
> [  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
> [  185.439247]  alloc_pages_vma+0x74/0x1e0
> [  185.439251]  __handle_mm_fault+0xafe/0x1360
> [  185.439255]  handle_mm_fault+0xc3/0x280
> [  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
> [  185.439261]  __walk_page_range+0x692/0x9b0
> [  185.439265]  walk_page_range+0x9b/0x120
> [  185.439269]  hmm_range_fault+0x4f/0x90
> [  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
> [  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
> [  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
> [  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]
>
> Signed-off-by: James Zhu <James.Zhu@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 47 +++++++++++++++++--------
>   1 file changed, 32 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> index a48ea62b12b0..0425fc6a49aa 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> @@ -163,6 +163,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   			       struct hmm_range **phmm_range)
>   {
>   	struct hmm_range *hmm_range;
> +	unsigned long hmm_range_end;
>   	unsigned long timeout;
>   	unsigned long i;
>   	unsigned long *pfns;
> @@ -184,25 +185,41 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
>   	hmm_range->hmm_pfns = pfns;
>   	hmm_range->start = start;
> -	hmm_range->end = start + npages * PAGE_SIZE;
> +	hmm_range_end = start + npages * PAGE_SIZE;

This variable name is too easy to confuse with hmm_range->end. I would 
suggest calling it "end", analogous to "start".


>   	hmm_range->dev_private_owner = owner;
>   
> -	/* Assuming 512MB takes maxmium 1 second to fault page address */
> -	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
> -	timeout = jiffies + msecs_to_jiffies(timeout);
> +#define MAX_WALK_BYTE	(64ULL<<30)
> +	do {
> +		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, hmm_range_end);
> +
> +		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
> +			hmm_range->start, hmm_range->end);
> +
> +		/* Assuming 512MB takes maxmium 1 second to fault page address */
> +		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
> +			HMM_RANGE_DEFAULT_TIMEOUT;
> +		timeout = jiffies + msecs_to_jiffies(timeout);
>   
>   retry:
> -	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> -	r = hmm_range_fault(hmm_range);
> -	if (unlikely(r)) {
> -		/*
> -		 * FIXME: This timeout should encompass the retry from
> -		 * mmu_interval_read_retry() as well.
> -		 */
> -		if (r == -EBUSY && !time_after(jiffies, timeout))
> -			goto retry;
> -		goto out_free_pfns;
> -	}
> +		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> +		r = hmm_range_fault(hmm_range);
> +		if (unlikely(r)) {
> +			/*
> +			 * FIXME: This timeout should encompass the retry from
> +			 * mmu_interval_read_retry() as well.
> +			 */
> +			if (r == -EBUSY && !time_after(jiffies, timeout))
> +				goto retry;
> +			goto out_free_pfns;
> +		}
> +
> +		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
> +		hmm_range->start = hmm_range->end;
> +		schedule();

We don't need to schedule for ranges < MAX_WALK_BYTES. I guess these 
three lines could be conditional:

+		if (hmm_range->end == end)
+			break;

		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
		hmm_range->start = hmm_range->end;
		schedule();

Regards,
   Felix


> +	} while (hmm_range->end < hmm_range_end);
> +
> +	hmm_range->start = start;
> +	hmm_range->hmm_pfns = pfns;
>   
>   	/*
>   	 * Due to default_flags, all pages are HMM_PFN_VALID or

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-17 22:03 ` Felix Kuehling
@ 2022-11-18 12:22   ` James Zhu
  0 siblings, 0 replies; 9+ messages in thread
From: James Zhu @ 2022-11-18 12:22 UTC (permalink / raw)
  To: Felix Kuehling, James Zhu, amd-gfx, christian.koenig, philip.yang


On 2022-11-17 17:03, Felix Kuehling wrote:
> Am 2022-11-17 um 16:38 schrieb James Zhu:
>> When applications try to allocate large system (more than > 128GB),
>> "stall cpu" is reported.
>>
>> for such large system memory, walk_page_range takes more than 20s 
>> usually.
>> The warning message can be removed when splitting hmm range into smaller
>> ones which is not more 64GB for each walk_page_range.
>>
>> [  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: 
>> amdgpu: create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
>> [  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: 
>> amdgpu: creating userptr BO for user_addr = 7f63c7a00000
>> [  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
>> [  185.439125] rcu:     8-....: (20999 ticks this GP) 
>> idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
>> [  185.439137]     (t=21000 jiffies g=6325 q=1215)
>> [  185.439141] NMI backtrace for cpu 8
>> [  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: 
>> G           O 5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
>> [  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant 
>> XL675d Gen10 Plus, BIOS A47 11/06/2020
>> [  185.439150] Call Trace:
>> [  185.439153]  <IRQ>
>> [  185.439157]  dump_stack+0x64/0x7c
>> [  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
>> [  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
>> [  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
>> [  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
>> [  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
>> [  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
>> [  185.439185]  update_process_times+0x8c/0xc0
>> [  185.439189]  tick_sched_timer+0x63/0x70
>> [  185.439192]  __hrtimer_run_queues+0xff/0x250
>> [  185.439195]  hrtimer_interrupt+0xf4/0x200
>> [  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
>> [  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
>> [  185.439206]  </IRQ>
>> [  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
>> [  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
>> [  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 
>> ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 
>> 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 
>> 84 00 00
>> [  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
>> [  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 
>> 000000000000005c
>> [  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: 
>> ffff88a59e0e5d20
>> [  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: 
>> ffffea0096783940
>> [  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: 
>> ffffea0096783980
>> [  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 
>> 0000000000000000
>> [  185.439232]  prep_new_page+0x81/0xc0
>> [  185.439236]  get_page_from_freelist+0x13be/0x16f0
>> [  185.439240]  ? release_pages+0x16a/0x4a0
>> [  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
>> [  185.439247]  alloc_pages_vma+0x74/0x1e0
>> [  185.439251]  __handle_mm_fault+0xafe/0x1360
>> [  185.439255]  handle_mm_fault+0xc3/0x280
>> [  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
>> [  185.439261]  __walk_page_range+0x692/0x9b0
>> [  185.439265]  walk_page_range+0x9b/0x120
>> [  185.439269]  hmm_range_fault+0x4f/0x90
>> [  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
>> [  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
>> [  185.439603] amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 
>> [amdgpu]
>> [  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]
>>
>> Signed-off-by: James Zhu <James.Zhu@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 47 +++++++++++++++++--------
>>   1 file changed, 32 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> index a48ea62b12b0..0425fc6a49aa 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> @@ -163,6 +163,7 @@ int amdgpu_hmm_range_get_pages(struct 
>> mmu_interval_notifier *notifier,
>>                      struct hmm_range **phmm_range)
>>   {
>>       struct hmm_range *hmm_range;
>> +    unsigned long hmm_range_end;
>>       unsigned long timeout;
>>       unsigned long i;
>>       unsigned long *pfns;
>> @@ -184,25 +185,41 @@ int amdgpu_hmm_range_get_pages(struct 
>> mmu_interval_notifier *notifier,
>>           hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
>>       hmm_range->hmm_pfns = pfns;
>>       hmm_range->start = start;
>> -    hmm_range->end = start + npages * PAGE_SIZE;
>> +    hmm_range_end = start + npages * PAGE_SIZE;
>
> This variable name is too easy to confuse with hmm_range->end. I would 
> suggest calling it "end", analogous to "start".
[JZ] Sure
>
>
>>       hmm_range->dev_private_owner = owner;
>>   -    /* Assuming 512MB takes maxmium 1 second to fault page address */
>> -    timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
>> -    timeout = jiffies + msecs_to_jiffies(timeout);
>> +#define MAX_WALK_BYTE    (64ULL<<30)
>> +    do {
>> +        hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, 
>> hmm_range_end);
>> +
>> +        pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
>> +            hmm_range->start, hmm_range->end);
>> +
>> +        /* Assuming 512MB takes maxmium 1 second to fault page 
>> address */
>> +        timeout = max((hmm_range->end - hmm_range->start) >> 29, 
>> 1ULL) *
>> +            HMM_RANGE_DEFAULT_TIMEOUT;
>> +        timeout = jiffies + msecs_to_jiffies(timeout);
>>     retry:
>> -    hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
>> -    r = hmm_range_fault(hmm_range);
>> -    if (unlikely(r)) {
>> -        /*
>> -         * FIXME: This timeout should encompass the retry from
>> -         * mmu_interval_read_retry() as well.
>> -         */
>> -        if (r == -EBUSY && !time_after(jiffies, timeout))
>> -            goto retry;
>> -        goto out_free_pfns;
>> -    }
>> +        hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
>> +        r = hmm_range_fault(hmm_range);
>> +        if (unlikely(r)) {
>> +            /*
>> +             * FIXME: This timeout should encompass the retry from
>> +             * mmu_interval_read_retry() as well.
>> +             */
>> +            if (r == -EBUSY && !time_after(jiffies, timeout))
>> +                goto retry;
>> +            goto out_free_pfns;
>> +        }
>> +
>> +        hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
>> +        hmm_range->start = hmm_range->end;
>> +        schedule();
>
> We don't need to schedule for ranges < MAX_WALK_BYTES. I guess these 
> three lines could be conditional:
>
> +        if (hmm_range->end == end)
> +            break;
>
>         hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
>         hmm_range->start = hmm_range->end;
>         schedule();
[JZ] Yes, it will be more accurate. I will update it. Thanks!
>
> Regards,
>   Felix
>
>
>> +    } while (hmm_range->end < hmm_range_end);
>> +
>> +    hmm_range->start = start;
>> +    hmm_range->hmm_pfns = pfns;
>>         /*
>>        * Due to default_flags, all pages are HMM_PFN_VALID or

^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH v2] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-17 21:38 [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory James Zhu
  2022-11-17 22:03 ` Felix Kuehling
@ 2022-11-21 13:13 ` James Zhu
  2022-11-21 13:18   ` Christian König
  2022-11-21 14:53 ` [PATCH v3] " James Zhu
  2 siblings, 1 reply; 9+ messages in thread
From: James Zhu @ 2022-11-21 13:13 UTC (permalink / raw)
  To: amd-gfx, christian.koenig, Felix.kuehling, philip.yang; +Cc: jamesz

When applications try to allocate large system (more than > 128GB),
"stall cpu" is reported.

for such large system memory, walk_page_range takes more than 20s usually.
The warning message can be removed when splitting hmm range into smaller
ones which is not more 64GB for each walk_page_range.

[  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
[  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
[  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
[  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
[  185.439137] 	(t=21000 jiffies g=6325 q=1215)
[  185.439141] NMI backtrace for cpu 8
[  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
[  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
[  185.439150] Call Trace:
[  185.439153]  <IRQ>
[  185.439157]  dump_stack+0x64/0x7c
[  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
[  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
[  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
[  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
[  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
[  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
[  185.439185]  update_process_times+0x8c/0xc0
[  185.439189]  tick_sched_timer+0x63/0x70
[  185.439192]  __hrtimer_run_queues+0xff/0x250
[  185.439195]  hrtimer_interrupt+0xf4/0x200
[  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
[  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
[  185.439206]  </IRQ>
[  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
[  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
[  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
[  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
[  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
[  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
[  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
[  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
[  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
[  185.439232]  prep_new_page+0x81/0xc0
[  185.439236]  get_page_from_freelist+0x13be/0x16f0
[  185.439240]  ? release_pages+0x16a/0x4a0
[  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
[  185.439247]  alloc_pages_vma+0x74/0x1e0
[  185.439251]  __handle_mm_fault+0xafe/0x1360
[  185.439255]  handle_mm_fault+0xc3/0x280
[  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
[  185.439261]  __walk_page_range+0x692/0x9b0
[  185.439265]  walk_page_range+0x9b/0x120
[  185.439269]  hmm_range_fault+0x4f/0x90
[  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
[  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
[  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
[  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]

Signed-off-by: James Zhu <James.Zhu@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 49 +++++++++++++++++--------
 1 file changed, 34 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
index a48ea62b12b0..fb51144ab77e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
@@ -163,6 +163,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
 			       struct hmm_range **phmm_range)
 {
 	struct hmm_range *hmm_range;
+	unsigned long end;
 	unsigned long timeout;
 	unsigned long i;
 	unsigned long *pfns;
@@ -184,25 +185,43 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
 		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
 	hmm_range->hmm_pfns = pfns;
 	hmm_range->start = start;
-	hmm_range->end = start + npages * PAGE_SIZE;
+	end = start + npages * PAGE_SIZE;
 	hmm_range->dev_private_owner = owner;
 
-	/* Assuming 512MB takes maxmium 1 second to fault page address */
-	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
-	timeout = jiffies + msecs_to_jiffies(timeout);
+#define MAX_WALK_BYTE	(64ULL<<30)
+	do {
+		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
+
+		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
+			hmm_range->start, hmm_range->end);
+
+		/* Assuming 512MB takes maxmium 1 second to fault page address */
+		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
+			HMM_RANGE_DEFAULT_TIMEOUT;
+		timeout = jiffies + msecs_to_jiffies(timeout);
 
 retry:
-	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
-	r = hmm_range_fault(hmm_range);
-	if (unlikely(r)) {
-		/*
-		 * FIXME: This timeout should encompass the retry from
-		 * mmu_interval_read_retry() as well.
-		 */
-		if (r == -EBUSY && !time_after(jiffies, timeout))
-			goto retry;
-		goto out_free_pfns;
-	}
+		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
+		r = hmm_range_fault(hmm_range);
+		if (unlikely(r)) {
+			/*
+			 * FIXME: This timeout should encompass the retry from
+			 * mmu_interval_read_retry() as well.
+			 */
+			if (r == -EBUSY && !time_after(jiffies, timeout))
+				goto retry;
+			goto out_free_pfns;
+		}
+
+		if (hmm_range->end == end)
+			break;
+		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
+		hmm_range->start = hmm_range->end;
+		schedule();
+	} while (hmm_range->end < end);
+
+	hmm_range->start = start;
+	hmm_range->hmm_pfns = pfns;
 
 	/*
 	 * Due to default_flags, all pages are HMM_PFN_VALID or
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* Re: [PATCH v2] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-21 13:13 ` [PATCH v2] " James Zhu
@ 2022-11-21 13:18   ` Christian König
  2022-11-21 14:46     ` James Zhu
  0 siblings, 1 reply; 9+ messages in thread
From: Christian König @ 2022-11-21 13:18 UTC (permalink / raw)
  To: James Zhu, amd-gfx, Felix.kuehling, philip.yang; +Cc: jamesz



Am 21.11.22 um 14:13 schrieb James Zhu:
> When applications try to allocate large system (more than > 128GB),
> "stall cpu" is reported.
>
> for such large system memory, walk_page_range takes more than 20s usually.
> The warning message can be removed when splitting hmm range into smaller
> ones which is not more 64GB for each walk_page_range.
>
> [  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
> [  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
> [  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
> [  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
> [  185.439137] 	(t=21000 jiffies g=6325 q=1215)
> [  185.439141] NMI backtrace for cpu 8
> [  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
> [  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
> [  185.439150] Call Trace:
> [  185.439153]  <IRQ>
> [  185.439157]  dump_stack+0x64/0x7c
> [  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
> [  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
> [  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
> [  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
> [  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
> [  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
> [  185.439185]  update_process_times+0x8c/0xc0
> [  185.439189]  tick_sched_timer+0x63/0x70
> [  185.439192]  __hrtimer_run_queues+0xff/0x250
> [  185.439195]  hrtimer_interrupt+0xf4/0x200
> [  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
> [  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
> [  185.439206]  </IRQ>
> [  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
> [  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
> [  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
> [  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
> [  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
> [  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
> [  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
> [  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
> [  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
> [  185.439232]  prep_new_page+0x81/0xc0
> [  185.439236]  get_page_from_freelist+0x13be/0x16f0
> [  185.439240]  ? release_pages+0x16a/0x4a0
> [  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
> [  185.439247]  alloc_pages_vma+0x74/0x1e0
> [  185.439251]  __handle_mm_fault+0xafe/0x1360
> [  185.439255]  handle_mm_fault+0xc3/0x280
> [  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
> [  185.439261]  __walk_page_range+0x692/0x9b0
> [  185.439265]  walk_page_range+0x9b/0x120
> [  185.439269]  hmm_range_fault+0x4f/0x90
> [  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
> [  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
> [  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
> [  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]
>
> Signed-off-by: James Zhu <James.Zhu@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 49 +++++++++++++++++--------
>   1 file changed, 34 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> index a48ea62b12b0..fb51144ab77e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> @@ -163,6 +163,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   			       struct hmm_range **phmm_range)
>   {
>   	struct hmm_range *hmm_range;
> +	unsigned long end;
>   	unsigned long timeout;
>   	unsigned long i;
>   	unsigned long *pfns;
> @@ -184,25 +185,43 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
>   	hmm_range->hmm_pfns = pfns;
>   	hmm_range->start = start;
> -	hmm_range->end = start + npages * PAGE_SIZE;
> +	end = start + npages * PAGE_SIZE;
>   	hmm_range->dev_private_owner = owner;
>   
> -	/* Assuming 512MB takes maxmium 1 second to fault page address */
> -	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
> -	timeout = jiffies + msecs_to_jiffies(timeout);
> +#define MAX_WALK_BYTE	(64ULL<<30)

Please don't add any defines in the middle of the code.

> +	do {
> +		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
> +
> +		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
> +			hmm_range->start, hmm_range->end);
> +
> +		/* Assuming 512MB takes maxmium 1 second to fault page address */
> +		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
> +			HMM_RANGE_DEFAULT_TIMEOUT;
> +		timeout = jiffies + msecs_to_jiffies(timeout);
>   
>   retry:
> -	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> -	r = hmm_range_fault(hmm_range);
> -	if (unlikely(r)) {
> -		/*
> -		 * FIXME: This timeout should encompass the retry from
> -		 * mmu_interval_read_retry() as well.
> -		 */
> -		if (r == -EBUSY && !time_after(jiffies, timeout))
> -			goto retry;
> -		goto out_free_pfns;
> -	}
> +		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> +		r = hmm_range_fault(hmm_range);
> +		if (unlikely(r)) {
> +			/*
> +			 * FIXME: This timeout should encompass the retry from
> +			 * mmu_interval_read_retry() as well.
> +			 */
> +			if (r == -EBUSY && !time_after(jiffies, timeout))
> +				goto retry;
> +			goto out_free_pfns;
> +		}
> +
> +		if (hmm_range->end == end)
> +			break;
> +		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
> +		hmm_range->start = hmm_range->end;
> +		schedule();
> +	} while (hmm_range->end < end);
> +
> +	hmm_range->start = start;
> +	hmm_range->hmm_pfns = pfns;
>   
>   	/*
>   	 * Due to default_flags, all pages are HMM_PFN_VALID or


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v2] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-21 13:18   ` Christian König
@ 2022-11-21 14:46     ` James Zhu
  0 siblings, 0 replies; 9+ messages in thread
From: James Zhu @ 2022-11-21 14:46 UTC (permalink / raw)
  To: Christian König, James Zhu, amd-gfx, Felix.kuehling,
	philip.yang


On 2022-11-21 08:18, Christian König wrote:
>
>
> Am 21.11.22 um 14:13 schrieb James Zhu:
>> When applications try to allocate large system (more than > 128GB),
>> "stall cpu" is reported.
>>
>> for such large system memory, walk_page_range takes more than 20s 
>> usually.
>> The warning message can be removed when splitting hmm range into smaller
>> ones which is not more 64GB for each walk_page_range.
>>
>> [  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: 
>> amdgpu: create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
>> [  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: 
>> amdgpu: creating userptr BO for user_addr = 7f63c7a00000
>> [  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
>> [  185.439125] rcu:     8-....: (20999 ticks this GP) 
>> idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
>> [  185.439137]     (t=21000 jiffies g=6325 q=1215)
>> [  185.439141] NMI backtrace for cpu 8
>> [  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: 
>> G           O 5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
>> [  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant 
>> XL675d Gen10 Plus, BIOS A47 11/06/2020
>> [  185.439150] Call Trace:
>> [  185.439153]  <IRQ>
>> [  185.439157]  dump_stack+0x64/0x7c
>> [  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
>> [  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
>> [  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
>> [  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
>> [  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
>> [  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
>> [  185.439185]  update_process_times+0x8c/0xc0
>> [  185.439189]  tick_sched_timer+0x63/0x70
>> [  185.439192]  __hrtimer_run_queues+0xff/0x250
>> [  185.439195]  hrtimer_interrupt+0xf4/0x200
>> [  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
>> [  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
>> [  185.439206]  </IRQ>
>> [  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
>> [  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
>> [  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 
>> ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 
>> 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 
>> 84 00 00
>> [  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
>> [  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 
>> 000000000000005c
>> [  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: 
>> ffff88a59e0e5d20
>> [  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: 
>> ffffea0096783940
>> [  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: 
>> ffffea0096783980
>> [  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 
>> 0000000000000000
>> [  185.439232]  prep_new_page+0x81/0xc0
>> [  185.439236]  get_page_from_freelist+0x13be/0x16f0
>> [  185.439240]  ? release_pages+0x16a/0x4a0
>> [  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
>> [  185.439247]  alloc_pages_vma+0x74/0x1e0
>> [  185.439251]  __handle_mm_fault+0xafe/0x1360
>> [  185.439255]  handle_mm_fault+0xc3/0x280
>> [  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
>> [  185.439261]  __walk_page_range+0x692/0x9b0
>> [  185.439265]  walk_page_range+0x9b/0x120
>> [  185.439269]  hmm_range_fault+0x4f/0x90
>> [  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
>> [  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
>> [  185.439603] amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 
>> [amdgpu]
>> [  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]
>>
>> Signed-off-by: James Zhu <James.Zhu@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 49 +++++++++++++++++--------
>>   1 file changed, 34 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> index a48ea62b12b0..fb51144ab77e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> @@ -163,6 +163,7 @@ int amdgpu_hmm_range_get_pages(struct 
>> mmu_interval_notifier *notifier,
>>                      struct hmm_range **phmm_range)
>>   {
>>       struct hmm_range *hmm_range;
>> +    unsigned long end;
>>       unsigned long timeout;
>>       unsigned long i;
>>       unsigned long *pfns;
>> @@ -184,25 +185,43 @@ int amdgpu_hmm_range_get_pages(struct 
>> mmu_interval_notifier *notifier,
>>           hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
>>       hmm_range->hmm_pfns = pfns;
>>       hmm_range->start = start;
>> -    hmm_range->end = start + npages * PAGE_SIZE;
>> +    end = start + npages * PAGE_SIZE;
>>       hmm_range->dev_private_owner = owner;
>>   -    /* Assuming 512MB takes maxmium 1 second to fault page address */
>> -    timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
>> -    timeout = jiffies + msecs_to_jiffies(timeout);
>> +#define MAX_WALK_BYTE    (64ULL<<30)
>
> Please don't add any defines in the middle of the code.
[JZ] sure. can I have RB on this patch? Thanks!
>
>> +    do {
>> +        hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
>> +
>> +        pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
>> +            hmm_range->start, hmm_range->end);
>> +
>> +        /* Assuming 512MB takes maxmium 1 second to fault page 
>> address */
>> +        timeout = max((hmm_range->end - hmm_range->start) >> 29, 
>> 1ULL) *
>> +            HMM_RANGE_DEFAULT_TIMEOUT;
>> +        timeout = jiffies + msecs_to_jiffies(timeout);
>>     retry:
>> -    hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
>> -    r = hmm_range_fault(hmm_range);
>> -    if (unlikely(r)) {
>> -        /*
>> -         * FIXME: This timeout should encompass the retry from
>> -         * mmu_interval_read_retry() as well.
>> -         */
>> -        if (r == -EBUSY && !time_after(jiffies, timeout))
>> -            goto retry;
>> -        goto out_free_pfns;
>> -    }
>> +        hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
>> +        r = hmm_range_fault(hmm_range);
>> +        if (unlikely(r)) {
>> +            /*
>> +             * FIXME: This timeout should encompass the retry from
>> +             * mmu_interval_read_retry() as well.
>> +             */
>> +            if (r == -EBUSY && !time_after(jiffies, timeout))
>> +                goto retry;
>> +            goto out_free_pfns;
>> +        }
>> +
>> +        if (hmm_range->end == end)
>> +            break;
>> +        hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
>> +        hmm_range->start = hmm_range->end;
>> +        schedule();
>> +    } while (hmm_range->end < end);
>> +
>> +    hmm_range->start = start;
>> +    hmm_range->hmm_pfns = pfns;
>>         /*
>>        * Due to default_flags, all pages are HMM_PFN_VALID or
>

^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH v3] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-17 21:38 [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory James Zhu
  2022-11-17 22:03 ` Felix Kuehling
  2022-11-21 13:13 ` [PATCH v2] " James Zhu
@ 2022-11-21 14:53 ` James Zhu
  2022-11-22 15:12   ` James Zhu
  2022-11-22 16:21   ` Felix Kuehling
  2 siblings, 2 replies; 9+ messages in thread
From: James Zhu @ 2022-11-21 14:53 UTC (permalink / raw)
  To: amd-gfx, christian.koenig, Felix.kuehling, philip.yang; +Cc: jamesz

-v2: 1. rename variable to redue confuse
     2. optimize the code
-v3: move new define out of the middle of the code

When applications try to allocate large system (more than > 128GB),
"stall cpu" is reported.

for such large system memory, walk_page_range takes more than 20s usually.
The warning message can be removed when splitting hmm range into smaller
ones which is not more 64GB for each walk_page_range.

[  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
[  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
[  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
[  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
[  185.439137] 	(t=21000 jiffies g=6325 q=1215)
[  185.439141] NMI backtrace for cpu 8
[  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
[  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
[  185.439150] Call Trace:
[  185.439153]  <IRQ>
[  185.439157]  dump_stack+0x64/0x7c
[  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
[  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
[  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
[  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
[  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
[  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
[  185.439185]  update_process_times+0x8c/0xc0
[  185.439189]  tick_sched_timer+0x63/0x70
[  185.439192]  __hrtimer_run_queues+0xff/0x250
[  185.439195]  hrtimer_interrupt+0xf4/0x200
[  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
[  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
[  185.439206]  </IRQ>
[  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
[  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
[  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
[  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
[  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
[  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
[  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
[  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
[  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
[  185.439232]  prep_new_page+0x81/0xc0
[  185.439236]  get_page_from_freelist+0x13be/0x16f0
[  185.439240]  ? release_pages+0x16a/0x4a0
[  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
[  185.439247]  alloc_pages_vma+0x74/0x1e0
[  185.439251]  __handle_mm_fault+0xafe/0x1360
[  185.439255]  handle_mm_fault+0xc3/0x280
[  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
[  185.439261]  __walk_page_range+0x692/0x9b0
[  185.439265]  walk_page_range+0x9b/0x120
[  185.439269]  hmm_range_fault+0x4f/0x90
[  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
[  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
[  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
[  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]

Signed-off-by: James Zhu <James.Zhu@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 50 +++++++++++++++++--------
 1 file changed, 35 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
index a48ea62b12b0..8a2e5716d8db 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
@@ -51,6 +51,8 @@
 #include "amdgpu_amdkfd.h"
 #include "amdgpu_hmm.h"
 
+#define MAX_WALK_BYTE	(64ULL<<30)
+
 /**
  * amdgpu_hmm_invalidate_gfx - callback to notify about mm change
  *
@@ -163,6 +165,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
 			       struct hmm_range **phmm_range)
 {
 	struct hmm_range *hmm_range;
+	unsigned long end;
 	unsigned long timeout;
 	unsigned long i;
 	unsigned long *pfns;
@@ -184,25 +187,42 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
 		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
 	hmm_range->hmm_pfns = pfns;
 	hmm_range->start = start;
-	hmm_range->end = start + npages * PAGE_SIZE;
+	end = start + npages * PAGE_SIZE;
 	hmm_range->dev_private_owner = owner;
 
-	/* Assuming 512MB takes maxmium 1 second to fault page address */
-	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
-	timeout = jiffies + msecs_to_jiffies(timeout);
+	do {
+		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
+
+		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
+			hmm_range->start, hmm_range->end);
+
+		/* Assuming 512MB takes maxmium 1 second to fault page address */
+		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
+			HMM_RANGE_DEFAULT_TIMEOUT;
+		timeout = jiffies + msecs_to_jiffies(timeout);
 
 retry:
-	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
-	r = hmm_range_fault(hmm_range);
-	if (unlikely(r)) {
-		/*
-		 * FIXME: This timeout should encompass the retry from
-		 * mmu_interval_read_retry() as well.
-		 */
-		if (r == -EBUSY && !time_after(jiffies, timeout))
-			goto retry;
-		goto out_free_pfns;
-	}
+		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
+		r = hmm_range_fault(hmm_range);
+		if (unlikely(r)) {
+			/*
+			 * FIXME: This timeout should encompass the retry from
+			 * mmu_interval_read_retry() as well.
+			 */
+			if (r == -EBUSY && !time_after(jiffies, timeout))
+				goto retry;
+			goto out_free_pfns;
+		}
+
+		if (hmm_range->end == end)
+			break;
+		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
+		hmm_range->start = hmm_range->end;
+		schedule();
+	} while (hmm_range->end < end);
+
+	hmm_range->start = start;
+	hmm_range->hmm_pfns = pfns;
 
 	/*
 	 * Due to default_flags, all pages are HMM_PFN_VALID or
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* Re: [PATCH v3] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-21 14:53 ` [PATCH v3] " James Zhu
@ 2022-11-22 15:12   ` James Zhu
  2022-11-22 16:21   ` Felix Kuehling
  1 sibling, 0 replies; 9+ messages in thread
From: James Zhu @ 2022-11-22 15:12 UTC (permalink / raw)
  To: James Zhu, amd-gfx, christian.koenig, Felix.kuehling, philip.yang

[-- Attachment #1: Type: text/plain, Size: 6519 bytes --]

Ping...

On 2022-11-21 09:53, James Zhu wrote:
> -v2: 1. rename variable to redue confuse
>       2. optimize the code
> -v3: move new define out of the middle of the code
>
> When applications try to allocate large system (more than > 128GB),
> "stall cpu" is reported.
>
> for such large system memory, walk_page_range takes more than 20s usually.
> The warning message can be removed when splitting hmm range into smaller
> ones which is not more 64GB for each walk_page_range.
>
> [  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
> [  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
> [  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
> [  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
> [  185.439137] 	(t=21000 jiffies g=6325 q=1215)
> [  185.439141] NMI backtrace for cpu 8
> [  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
> [  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
> [  185.439150] Call Trace:
> [  185.439153]  <IRQ>
> [  185.439157]  dump_stack+0x64/0x7c
> [  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
> [  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
> [  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
> [  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
> [  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
> [  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
> [  185.439185]  update_process_times+0x8c/0xc0
> [  185.439189]  tick_sched_timer+0x63/0x70
> [  185.439192]  __hrtimer_run_queues+0xff/0x250
> [  185.439195]  hrtimer_interrupt+0xf4/0x200
> [  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
> [  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
> [  185.439206]  </IRQ>
> [  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
> [  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
> [  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
> [  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
> [  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
> [  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
> [  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
> [  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
> [  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
> [  185.439232]  prep_new_page+0x81/0xc0
> [  185.439236]  get_page_from_freelist+0x13be/0x16f0
> [  185.439240]  ? release_pages+0x16a/0x4a0
> [  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
> [  185.439247]  alloc_pages_vma+0x74/0x1e0
> [  185.439251]  __handle_mm_fault+0xafe/0x1360
> [  185.439255]  handle_mm_fault+0xc3/0x280
> [  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
> [  185.439261]  __walk_page_range+0x692/0x9b0
> [  185.439265]  walk_page_range+0x9b/0x120
> [  185.439269]  hmm_range_fault+0x4f/0x90
> [  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
> [  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
> [  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
> [  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]
>
> Signed-off-by: James Zhu<James.Zhu@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 50 +++++++++++++++++--------
>   1 file changed, 35 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> index a48ea62b12b0..8a2e5716d8db 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> @@ -51,6 +51,8 @@
>   #include "amdgpu_amdkfd.h"
>   #include "amdgpu_hmm.h"
>   
> +#define MAX_WALK_BYTE	(64ULL<<30)
> +
>   /**
>    * amdgpu_hmm_invalidate_gfx - callback to notify about mm change
>    *
> @@ -163,6 +165,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   			       struct hmm_range **phmm_range)
>   {
>   	struct hmm_range *hmm_range;
> +	unsigned long end;
>   	unsigned long timeout;
>   	unsigned long i;
>   	unsigned long *pfns;
> @@ -184,25 +187,42 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
>   	hmm_range->hmm_pfns = pfns;
>   	hmm_range->start = start;
> -	hmm_range->end = start + npages * PAGE_SIZE;
> +	end = start + npages * PAGE_SIZE;
>   	hmm_range->dev_private_owner = owner;
>   
> -	/* Assuming 512MB takes maxmium 1 second to fault page address */
> -	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
> -	timeout = jiffies + msecs_to_jiffies(timeout);
> +	do {
> +		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
> +
> +		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
> +			hmm_range->start, hmm_range->end);
> +
> +		/* Assuming 512MB takes maxmium 1 second to fault page address */
> +		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
> +			HMM_RANGE_DEFAULT_TIMEOUT;
> +		timeout = jiffies + msecs_to_jiffies(timeout);
>   
>   retry:
> -	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> -	r = hmm_range_fault(hmm_range);
> -	if (unlikely(r)) {
> -		/*
> -		 * FIXME: This timeout should encompass the retry from
> -		 * mmu_interval_read_retry() as well.
> -		 */
> -		if (r == -EBUSY && !time_after(jiffies, timeout))
> -			goto retry;
> -		goto out_free_pfns;
> -	}
> +		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> +		r = hmm_range_fault(hmm_range);
> +		if (unlikely(r)) {
> +			/*
> +			 * FIXME: This timeout should encompass the retry from
> +			 * mmu_interval_read_retry() as well.
> +			 */
> +			if (r == -EBUSY && !time_after(jiffies, timeout))
> +				goto retry;
> +			goto out_free_pfns;
> +		}
> +
> +		if (hmm_range->end == end)
> +			break;
> +		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
> +		hmm_range->start = hmm_range->end;
> +		schedule();
> +	} while (hmm_range->end < end);
> +
> +	hmm_range->start = start;
> +	hmm_range->hmm_pfns = pfns;
>   
>   	/*
>   	 * Due to default_flags, all pages are HMM_PFN_VALID or

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^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v3] drm/amdgpu: fix stall on CPU when allocate large system memory
  2022-11-21 14:53 ` [PATCH v3] " James Zhu
  2022-11-22 15:12   ` James Zhu
@ 2022-11-22 16:21   ` Felix Kuehling
  1 sibling, 0 replies; 9+ messages in thread
From: Felix Kuehling @ 2022-11-22 16:21 UTC (permalink / raw)
  To: James Zhu, amd-gfx, christian.koenig, philip.yang; +Cc: jamesz

Am 2022-11-21 um 09:53 schrieb James Zhu:
> -v2: 1. rename variable to redue confuse
>       2. optimize the code
> -v3: move new define out of the middle of the code
>
> When applications try to allocate large system (more than > 128GB),
> "stall cpu" is reported.
>
> for such large system memory, walk_page_range takes more than 20s usually.
> The warning message can be removed when splitting hmm range into smaller
> ones which is not more 64GB for each walk_page_range.
>
> [  164.437617] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1753: amdgpu: 	create BO VA 0x7f63c7a00000 size 0x2f16000000 domain CPU
> [  164.488847] amdgpu:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu:1785: amdgpu: creating userptr BO for user_addr = 7f63c7a00000
> [  185.439116] rcu: INFO: rcu_sched self-detected stall on CPU
> [  185.439125] rcu: 	8-....: (20999 ticks this GP) idle=e22/1/0x4000000000000000 softirq=2242/2242 fqs=5249
> [  185.439137] 	(t=21000 jiffies g=6325 q=1215)
> [  185.439141] NMI backtrace for cpu 8
> [  185.439143] CPU: 8 PID: 3470 Comm: kfdtest Kdump: loaded Tainted: G           O      5.12.0-0_fbk5_zion_rc1_5697_g2c723fb88626 #1
> [  185.439147] Hardware name: HPE ProLiant XL675d Gen10 Plus/ProLiant XL675d Gen10 Plus, BIOS A47 11/06/2020
> [  185.439150] Call Trace:
> [  185.439153]  <IRQ>
> [  185.439157]  dump_stack+0x64/0x7c
> [  185.439163]  nmi_cpu_backtrace.cold.7+0x30/0x65
> [  185.439165]  ? lapic_can_unplug_cpu+0x70/0x70
> [  185.439170]  nmi_trigger_cpumask_backtrace+0xf9/0x100
> [  185.439174]  rcu_dump_cpu_stacks+0xc5/0xf5
> [  185.439178]  rcu_sched_clock_irq.cold.97+0x112/0x38c
> [  185.439182]  ? tick_sched_handle.isra.21+0x50/0x50
> [  185.439185]  update_process_times+0x8c/0xc0
> [  185.439189]  tick_sched_timer+0x63/0x70
> [  185.439192]  __hrtimer_run_queues+0xff/0x250
> [  185.439195]  hrtimer_interrupt+0xf4/0x200
> [  185.439199]  __sysvec_apic_timer_interrupt+0x51/0xd0
> [  185.439201]  sysvec_apic_timer_interrupt+0x69/0x90
> [  185.439206]  </IRQ>
> [  185.439207]  asm_sysvec_apic_timer_interrupt+0x12/0x20
> [  185.439211] RIP: 0010:clear_page_rep+0x7/0x10
> [  185.439214] Code: e8 fe 7c 51 00 44 89 e2 48 89 ee 48 89 df e8 60 ff ff ff c6 03 00 5b 5d 41 5c c3 cc cc cc cc cc cc cc cc b9 00 02 00 00 31 c0 <f3> 48 ab c3 0f 1f 44 00 00 31 c0 b9 40 00 00 00 66 0f 1f 84 00 00
> [  185.439218] RSP: 0018:ffffc9000f58f818 EFLAGS: 00000246
> [  185.439220] RAX: 0000000000000000 RBX: 0000000000000881 RCX: 000000000000005c
> [  185.439223] RDX: 0000000000100dca RSI: 0000000000000000 RDI: ffff88a59e0e5d20
> [  185.439225] RBP: ffffea0096783940 R08: ffff888118c35280 R09: ffffea0096783940
> [  185.439227] R10: ffff888000000000 R11: 0000160000000000 R12: ffffea0096783980
> [  185.439228] R13: ffffea0096783940 R14: ffff88b07fdfdd00 R15: 0000000000000000
> [  185.439232]  prep_new_page+0x81/0xc0
> [  185.439236]  get_page_from_freelist+0x13be/0x16f0
> [  185.439240]  ? release_pages+0x16a/0x4a0
> [  185.439244]  __alloc_pages_nodemask+0x1ae/0x340
> [  185.439247]  alloc_pages_vma+0x74/0x1e0
> [  185.439251]  __handle_mm_fault+0xafe/0x1360
> [  185.439255]  handle_mm_fault+0xc3/0x280
> [  185.439257]  hmm_vma_fault.isra.22+0x49/0x90
> [  185.439261]  __walk_page_range+0x692/0x9b0
> [  185.439265]  walk_page_range+0x9b/0x120
> [  185.439269]  hmm_range_fault+0x4f/0x90
> [  185.439274]  amdgpu_hmm_range_get_pages+0x24f/0x260 [amdgpu]
> [  185.439463]  amdgpu_ttm_tt_get_user_pages+0xc2/0x190 [amdgpu]
> [  185.439603]  amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x49f/0x7a0 [amdgpu]
> [  185.439774]  kfd_ioctl_alloc_memory_of_gpu+0xfb/0x410 [amdgpu]
>
> Signed-off-by: James Zhu <James.Zhu@amd.com>

Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>


> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 50 +++++++++++++++++--------
>   1 file changed, 35 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> index a48ea62b12b0..8a2e5716d8db 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
> @@ -51,6 +51,8 @@
>   #include "amdgpu_amdkfd.h"
>   #include "amdgpu_hmm.h"
>   
> +#define MAX_WALK_BYTE	(64ULL<<30)
> +
>   /**
>    * amdgpu_hmm_invalidate_gfx - callback to notify about mm change
>    *
> @@ -163,6 +165,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   			       struct hmm_range **phmm_range)
>   {
>   	struct hmm_range *hmm_range;
> +	unsigned long end;
>   	unsigned long timeout;
>   	unsigned long i;
>   	unsigned long *pfns;
> @@ -184,25 +187,42 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>   		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
>   	hmm_range->hmm_pfns = pfns;
>   	hmm_range->start = start;
> -	hmm_range->end = start + npages * PAGE_SIZE;
> +	end = start + npages * PAGE_SIZE;
>   	hmm_range->dev_private_owner = owner;
>   
> -	/* Assuming 512MB takes maxmium 1 second to fault page address */
> -	timeout = max(npages >> 17, 1ULL) * HMM_RANGE_DEFAULT_TIMEOUT;
> -	timeout = jiffies + msecs_to_jiffies(timeout);
> +	do {
> +		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
> +
> +		pr_debug("hmm range: start = 0x%lx, end = 0x%lx",
> +			hmm_range->start, hmm_range->end);
> +
> +		/* Assuming 512MB takes maxmium 1 second to fault page address */
> +		timeout = max((hmm_range->end - hmm_range->start) >> 29, 1ULL) *
> +			HMM_RANGE_DEFAULT_TIMEOUT;
> +		timeout = jiffies + msecs_to_jiffies(timeout);
>   
>   retry:
> -	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> -	r = hmm_range_fault(hmm_range);
> -	if (unlikely(r)) {
> -		/*
> -		 * FIXME: This timeout should encompass the retry from
> -		 * mmu_interval_read_retry() as well.
> -		 */
> -		if (r == -EBUSY && !time_after(jiffies, timeout))
> -			goto retry;
> -		goto out_free_pfns;
> -	}
> +		hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
> +		r = hmm_range_fault(hmm_range);
> +		if (unlikely(r)) {
> +			/*
> +			 * FIXME: This timeout should encompass the retry from
> +			 * mmu_interval_read_retry() as well.
> +			 */
> +			if (r == -EBUSY && !time_after(jiffies, timeout))
> +				goto retry;
> +			goto out_free_pfns;
> +		}
> +
> +		if (hmm_range->end == end)
> +			break;
> +		hmm_range->hmm_pfns += MAX_WALK_BYTE >> PAGE_SHIFT;
> +		hmm_range->start = hmm_range->end;
> +		schedule();
> +	} while (hmm_range->end < end);
> +
> +	hmm_range->start = start;
> +	hmm_range->hmm_pfns = pfns;
>   
>   	/*
>   	 * Due to default_flags, all pages are HMM_PFN_VALID or

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2022-11-22 16:21 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-11-17 21:38 [PATCH] drm/amdgpu: fix stall on CPU when allocate large system memory James Zhu
2022-11-17 22:03 ` Felix Kuehling
2022-11-18 12:22   ` James Zhu
2022-11-21 13:13 ` [PATCH v2] " James Zhu
2022-11-21 13:18   ` Christian König
2022-11-21 14:46     ` James Zhu
2022-11-21 14:53 ` [PATCH v3] " James Zhu
2022-11-22 15:12   ` James Zhu
2022-11-22 16:21   ` Felix Kuehling

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