From: Philip Yang Date: Fri, 19 Nov 2021 22:02:50 +0000 (-0500) Subject: drm/amdkfd: simplify drain retry fault X-Git-Tag: block-5.17-2022-01-21~94^2~17^2~7 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=2e4477282c8cff9fd2155710ed9168f38faa0b4f;p=linux-2.6-block.git drm/amdkfd: simplify drain retry fault unmap range always increase atomic svms->drain_pagefaults to simplify both parent range and child range unmap, page fault handle ignores the retry fault if svms->drain_pagefaults is set to speed up interrupt handling. svm_range_drain_retry_fault restart draining if another range unmap from cpu. Signed-off-by: Philip Yang Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h index 836ec8860c1b..7ea528941951 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h @@ -767,7 +767,7 @@ struct svm_range_list { struct list_head deferred_range_list; spinlock_t deferred_list_lock; atomic_t evicted_ranges; - bool drain_pagefaults; + atomic_t drain_pagefaults; struct delayed_work restore_work; DECLARE_BITMAP(bitmap_supported, MAX_GPU_INSTANCE); struct task_struct *faulting_task; diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index ae3e8b907221..10868d5b549f 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -1957,10 +1957,16 @@ static void svm_range_drain_retry_fault(struct svm_range_list *svms) { struct kfd_process_device *pdd; struct kfd_process *p; + int drain; uint32_t i; p = container_of(svms, struct kfd_process, svms); +restart: + drain = atomic_read(&svms->drain_pagefaults); + if (!drain) + return; + for_each_set_bit(i, svms->bitmap_supported, p->n_pdds) { pdd = p->pdds[i]; if (!pdd) @@ -1972,6 +1978,8 @@ static void svm_range_drain_retry_fault(struct svm_range_list *svms) &pdd->dev->adev->irq.ih1); pr_debug("drain retry fault gpu %d svms 0x%p done\n", i, svms); } + if (atomic_cmpxchg(&svms->drain_pagefaults, drain, 0) != drain) + goto restart; } static void svm_range_deferred_list_work(struct work_struct *work) @@ -1997,8 +2005,7 @@ retry: /* Checking for the need to drain retry faults must be inside * mmap write lock to serialize with munmap notifiers. */ - if (unlikely(READ_ONCE(svms->drain_pagefaults))) { - WRITE_ONCE(svms->drain_pagefaults, false); + if (unlikely(atomic_read(&svms->drain_pagefaults))) { mmap_write_unlock(mm); svm_range_drain_retry_fault(svms); goto retry; @@ -2045,12 +2052,6 @@ svm_range_add_list_work(struct svm_range_list *svms, struct svm_range *prange, struct mm_struct *mm, enum svm_work_list_ops op) { spin_lock(&svms->deferred_list_lock); - /* Make sure pending page faults are drained in the deferred worker - * before the range is freed to avoid straggler interrupts on - * unmapped memory causing "phantom faults". - */ - if (op == SVM_OP_UNMAP_RANGE) - svms->drain_pagefaults = true; /* if prange is on the deferred list */ if (!list_empty(&prange->deferred_list)) { pr_debug("update exist prange 0x%p work op %d\n", prange, op); @@ -2129,6 +2130,12 @@ svm_range_unmap_from_cpu(struct mm_struct *mm, struct svm_range *prange, pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] [0x%lx 0x%lx]\n", svms, prange, prange->start, prange->last, start, last); + /* Make sure pending page faults are drained in the deferred worker + * before the range is freed to avoid straggler interrupts on + * unmapped memory causing "phantom faults". + */ + atomic_inc(&svms->drain_pagefaults); + unmap_parent = start <= prange->start && last >= prange->last; list_for_each_entry(pchild, &prange->child_list, child_list) { @@ -2594,6 +2601,11 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid, pr_debug("restoring svms 0x%p fault address 0x%llx\n", svms, addr); + if (atomic_read(&svms->drain_pagefaults)) { + pr_debug("draining retry fault, drop fault 0x%llx\n", addr); + goto out; + } + /* p->lead_thread is available as kfd_process_wq_release flush the work * before releasing task ref. */ @@ -2740,6 +2752,7 @@ void svm_range_list_fini(struct kfd_process *p) * Ensure no retry fault comes in afterwards, as page fault handler will * not find kfd process and take mm lock to recover fault. */ + atomic_inc(&p->svms.drain_pagefaults); svm_range_drain_retry_fault(&p->svms); @@ -2763,6 +2776,7 @@ int svm_range_list_init(struct kfd_process *p) mutex_init(&svms->lock); INIT_LIST_HEAD(&svms->list); atomic_set(&svms->evicted_ranges, 0); + atomic_set(&svms->drain_pagefaults, 0); INIT_DELAYED_WORK(&svms->restore_work, svm_range_restore_work); INIT_WORK(&svms->deferred_list_work, svm_range_deferred_list_work); INIT_LIST_HEAD(&svms->deferred_range_list);