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@xxxxxxx>
---
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
