[PATCH] drm/amdkfd: Use partial migrations/mapping for GPU/CPU page faults in SVM
Chen, Xiaogang
xiaogang.chen at amd.com
Mon Nov 27 16:02:44 UTC 2023
On 11/22/2023 2:12 PM, Felix Kuehling wrote:
>
> On 2023-11-14 16:01, Xiaogang.Chen wrote:
>> From: Xiaogang Chen <xiaogang.chen at amd.com>
>>
>> This patch implements partial migration/mapping for gpu/cpu page
>> faults in SVM
>> according to migration granularity(default 2MB). A svm range may
>> include pages
>> from both system ram and vram of one gpu now. These chagnes are
>> expected to
>> improve migration performance and reduce mmu callback and TLB flush
>> workloads.
>>
>> Signed-off-by: Xiaogang Chen<Xiaogang.Chen at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 152 +++++++++++---------
>> drivers/gpu/drm/amd/amdkfd/kfd_migrate.h | 6 +-
>> drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 176 +++++++++++------------
>> drivers/gpu/drm/amd/amdkfd/kfd_svm.h | 9 +-
>> 4 files changed, 183 insertions(+), 160 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> index 6c25dab051d5..67df1b46f292 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> @@ -442,10 +442,10 @@ svm_migrate_vma_to_vram(struct kfd_node *node,
>> struct svm_range *prange,
>> goto out_free;
>> }
>> if (cpages != npages)
>> - pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
>> + pr_debug("partial migration, 0x%lx/0x%llx pages collected\n",
>> cpages, npages);
>> else
>> - pr_debug("0x%lx pages migrated\n", cpages);
>> + pr_debug("0x%lx pages collected\n", cpages);
>> r = svm_migrate_copy_to_vram(node, prange, &migrate, &mfence,
>> scratch, ttm_res_offset);
>> migrate_vma_pages(&migrate);
>> @@ -479,6 +479,8 @@ svm_migrate_vma_to_vram(struct kfd_node *node,
>> struct svm_range *prange,
>> * svm_migrate_ram_to_vram - migrate svm range from system to device
>> * @prange: range structure
>> * @best_loc: the device to migrate to
>> + * @start_mgr: start page to migrate
>> + * @last_mgr: last page to migrate
>> * @mm: the process mm structure
>> * @trigger: reason of migration
>> *
>> @@ -489,6 +491,7 @@ svm_migrate_vma_to_vram(struct kfd_node *node,
>> struct svm_range *prange,
>> */
>> static int
>> svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
>> + unsigned long start_mgr, unsigned long last_mgr,
>> struct mm_struct *mm, uint32_t trigger)
>> {
>> unsigned long addr, start, end;
>> @@ -498,30 +501,37 @@ svm_migrate_ram_to_vram(struct svm_range
>> *prange, uint32_t best_loc,
>> unsigned long cpages = 0;
>> long r = 0;
>> - if (prange->actual_loc == best_loc) {
>> - pr_debug("svms 0x%p [0x%lx 0x%lx] already on best_loc 0x%x\n",
>> - prange->svms, prange->start, prange->last, best_loc);
>> + if (!best_loc) {
>> + pr_debug("svms 0x%p [0x%lx 0x%lx] migrate to sys ram\n",
>> + prange->svms, start_mgr, last_mgr);
>> return 0;
>> }
>> + if (start_mgr < prange->start || last_mgr > prange->last) {
>> + pr_debug("range [0x%lx 0x%lx] out prange [0x%lx 0x%lx]\n",
>> + start_mgr, last_mgr, prange->start, prange->last);
>> + return -EFAULT;
>> + }
>> +
>> node = svm_range_get_node_by_id(prange, best_loc);
>> if (!node) {
>> pr_debug("failed to get kfd node by id 0x%x\n", best_loc);
>> return -ENODEV;
>> }
>> - pr_debug("svms 0x%p [0x%lx 0x%lx] to gpu 0x%x\n", prange->svms,
>> - prange->start, prange->last, best_loc);
>> + pr_debug("svms 0x%p [0x%lx 0x%lx] in [0x%lx 0x%lx] to gpu 0x%x\n",
>> + prange->svms, start_mgr, last_mgr, prange->start, prange->last,
>> + best_loc);
>> - start = prange->start << PAGE_SHIFT;
>> - end = (prange->last + 1) << PAGE_SHIFT;
>> + start = start_mgr << PAGE_SHIFT;
>> + end = (last_mgr + 1) << PAGE_SHIFT;
>> r = svm_range_vram_node_new(node, prange, true);
>> if (r) {
>> dev_dbg(node->adev->dev, "fail %ld to alloc vram\n", r);
>> return r;
>> }
>> - ttm_res_offset = prange->offset << PAGE_SHIFT;
>> + ttm_res_offset = (start_mgr - prange->start + prange->offset) <<
>> PAGE_SHIFT;
>> for (addr = start; addr < end;) {
>> unsigned long next;
>> @@ -544,8 +554,11 @@ svm_migrate_ram_to_vram(struct svm_range
>> *prange, uint32_t best_loc,
>> if (cpages) {
>> prange->actual_loc = best_loc;
>> - svm_range_dma_unmap(prange);
>> - } else {
>> + prange->vram_pages = prange->vram_pages + cpages;
>> + } else if (!prange->actual_loc) {
>> + /* if no page migrated and all pages from prange are at
>> + * sys ram drop svm_bo got from svm_range_vram_node_new
>> + */
>> svm_range_vram_node_free(prange);
>> }
>> @@ -663,9 +676,8 @@ svm_migrate_copy_to_ram(struct amdgpu_device
>> *adev, struct svm_range *prange,
>> * Context: Process context, caller hold mmap read lock,
>> prange->migrate_mutex
>> *
>> * Return:
>> - * 0 - success with all pages migrated
>> * negative values - indicate error
>> - * positive values - partial migration, number of pages not migrated
>> + * positive values or zero - number of pages got migrated
>> */
>> static long
>> svm_migrate_vma_to_ram(struct kfd_node *node, struct svm_range
>> *prange,
>> @@ -676,6 +688,7 @@ svm_migrate_vma_to_ram(struct kfd_node *node,
>> struct svm_range *prange,
>> uint64_t npages = (end - start) >> PAGE_SHIFT;
>> unsigned long upages = npages;
>> unsigned long cpages = 0;
>> + unsigned long mpages = 0;
>> struct amdgpu_device *adev = node->adev;
>> struct kfd_process_device *pdd;
>> struct dma_fence *mfence = NULL;
>> @@ -725,10 +738,10 @@ svm_migrate_vma_to_ram(struct kfd_node *node,
>> struct svm_range *prange,
>> goto out_free;
>> }
>> if (cpages != npages)
>> - pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
>> + pr_debug("partial migration, 0x%lx/0x%llx pages collected\n",
>> cpages, npages);
>> else
>> - pr_debug("0x%lx pages migrated\n", cpages);
>> + pr_debug("0x%lx pages collected\n", cpages);
>> r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
>> scratch, npages);
>> @@ -751,17 +764,21 @@ svm_migrate_vma_to_ram(struct kfd_node *node,
>> struct svm_range *prange,
>> kvfree(buf);
>> out:
>> if (!r && cpages) {
>> + mpages = cpages - upages;
>> pdd = svm_range_get_pdd_by_node(prange, node);
>> if (pdd)
>> - WRITE_ONCE(pdd->page_out, pdd->page_out + cpages);
>> + WRITE_ONCE(pdd->page_out, pdd->page_out + mpages);
>> }
>> - return r ? r : upages;
>> +
>> + return r ? r : mpages;
>> }
>> /**
>> * svm_migrate_vram_to_ram - migrate svm range from device to system
>> * @prange: range structure
>> * @mm: process mm, use current->mm if NULL
>> + * @start_mgr: start page need be migrated to sys ram
>> + * @last_mgr: last page need be migrated to sys ram
>> * @trigger: reason of migration
>> * @fault_page: is from vmf->page, svm_migrate_to_ram(), this is
>> CPU page fault callback
>> *
>> @@ -771,6 +788,7 @@ svm_migrate_vma_to_ram(struct kfd_node *node,
>> struct svm_range *prange,
>> * 0 - OK, otherwise error code
>> */
>> int svm_migrate_vram_to_ram(struct svm_range *prange, struct
>> mm_struct *mm,
>> + unsigned long start_mgr, unsigned long last_mgr,
>> uint32_t trigger, struct page *fault_page)
>> {
>> struct kfd_node *node;
>> @@ -778,26 +796,33 @@ int svm_migrate_vram_to_ram(struct svm_range
>> *prange, struct mm_struct *mm,
>> unsigned long addr;
>> unsigned long start;
>> unsigned long end;
>> - unsigned long upages = 0;
>> + unsigned long mpages = 0;
>> long r = 0;
>> + /* this pragne has no any vram page to migrate to sys ram */
>> if (!prange->actual_loc) {
>> pr_debug("[0x%lx 0x%lx] already migrated to ram\n",
>> prange->start, prange->last);
>> return 0;
>> }
>> + if (start_mgr < prange->start || last_mgr > prange->last) {
>> + pr_debug("range [0x%lx 0x%lx] out prange [0x%lx 0x%lx]\n",
>> + start_mgr, last_mgr, prange->start, prange->last);
>> + return -EFAULT;
>> + }
>> +
>> node = svm_range_get_node_by_id(prange, prange->actual_loc);
>> if (!node) {
>> pr_debug("failed to get kfd node by id 0x%x\n",
>> prange->actual_loc);
>> return -ENODEV;
>> }
>> pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] from gpu 0x%x to
>> ram\n",
>> - prange->svms, prange, prange->start, prange->last,
>> + prange->svms, prange, start_mgr, last_mgr,
>> prange->actual_loc);
>> - start = prange->start << PAGE_SHIFT;
>> - end = (prange->last + 1) << PAGE_SHIFT;
>> + start = start_mgr << PAGE_SHIFT;
>> + end = (last_mgr + 1) << PAGE_SHIFT;
>> for (addr = start; addr < end;) {
>> unsigned long next;
>> @@ -816,14 +841,21 @@ int svm_migrate_vram_to_ram(struct svm_range
>> *prange, struct mm_struct *mm,
>> pr_debug("failed %ld to migrate prange %p\n", r, prange);
>> break;
>> } else {
>> - upages += r;
>> + mpages += r;
>> }
>> addr = next;
>> }
>> - if (r >= 0 && !upages) {
>> - svm_range_vram_node_free(prange);
>> - prange->actual_loc = 0;
>> + if (r >= 0) {
>> + prange->vram_pages -= mpages;
>> +
>> + /* prange does not have vram page set its actual_loc to system
>> + * and drop its svm_bo ref
>> + */
>> + if (prange->vram_pages == 0 && prange->ttm_res) {
>> + prange->actual_loc = 0;
>> + svm_range_vram_node_free(prange);
>> + }
>> }
>> return r < 0 ? r : 0;
>> @@ -833,17 +865,23 @@ int svm_migrate_vram_to_ram(struct svm_range
>> *prange, struct mm_struct *mm,
>> * svm_migrate_vram_to_vram - migrate svm range from device to device
>> * @prange: range structure
>> * @best_loc: the device to migrate to
>> + * @start: start page need be migrated to sys ram
>> + * @last: last page need be migrated to sys ram
>> * @mm: process mm, use current->mm if NULL
>> * @trigger: reason of migration
>> *
>> * Context: Process context, caller hold mmap read lock, svms lock,
>> prange lock
>> *
>> + * migrate all vram pages in prange to sys ram, then migrate
>> + * [start, last] pages from sys ram to gpu node best_loc.
>> + *
>> * Return:
>> * 0 - OK, otherwise error code
>> */
>> static int
>> svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
>> - struct mm_struct *mm, uint32_t trigger)
>> + unsigned long start, unsigned long last,
>> + struct mm_struct *mm, uint32_t trigger)
>> {
>> int r, retries = 3;
>> @@ -855,7 +893,8 @@ svm_migrate_vram_to_vram(struct svm_range
>> *prange, uint32_t best_loc,
>> pr_debug("from gpu 0x%x to gpu 0x%x\n", prange->actual_loc,
>> best_loc);
>> do {
>> - r = svm_migrate_vram_to_ram(prange, mm, trigger, NULL);
>> + r = svm_migrate_vram_to_ram(prange, mm, prange->start,
>> prange->last,
>> + trigger, NULL);
>> if (r)
>> return r;
>> } while (prange->actual_loc && --retries);
>> @@ -863,17 +902,21 @@ svm_migrate_vram_to_vram(struct svm_range
>> *prange, uint32_t best_loc,
>> if (prange->actual_loc)
>> return -EDEADLK;
>> - return svm_migrate_ram_to_vram(prange, best_loc, mm, trigger);
>> + return svm_migrate_ram_to_vram(prange, best_loc, start, last,
>> mm, trigger);
>> }
>> int
>> svm_migrate_to_vram(struct svm_range *prange, uint32_t best_loc,
>> - struct mm_struct *mm, uint32_t trigger)
>> + unsigned long start, unsigned long last,
>> + struct mm_struct *mm, uint32_t trigger)
>> {
>> - if (!prange->actual_loc)
>> - return svm_migrate_ram_to_vram(prange, best_loc, mm, trigger);
>> + if (!prange->actual_loc || prange->actual_loc == best_loc)
>> + return svm_migrate_ram_to_vram(prange, best_loc, start, last,
>> + mm, trigger);
>> +
>> else
>> - return svm_migrate_vram_to_vram(prange, best_loc, mm, trigger);
>> + return svm_migrate_vram_to_vram(prange, best_loc, start, last,
>> + mm, trigger);
>> }
>> @@ -889,10 +932,9 @@ svm_migrate_to_vram(struct svm_range *prange,
>> uint32_t best_loc,
>> */
>> static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)
>> {
>> + unsigned long start, last, size;
>> unsigned long addr = vmf->address;
>> struct svm_range_bo *svm_bo;
>> - enum svm_work_list_ops op;
>> - struct svm_range *parent;
>> struct svm_range *prange;
>> struct kfd_process *p;
>> struct mm_struct *mm;
>> @@ -929,51 +971,31 @@ static vm_fault_t svm_migrate_to_ram(struct
>> vm_fault *vmf)
>> mutex_lock(&p->svms.lock);
>> - prange = svm_range_from_addr(&p->svms, addr, &parent);
>> + prange = svm_range_from_addr(&p->svms, addr, NULL);
>> if (!prange) {
>> pr_debug("failed get range svms 0x%p addr 0x%lx\n",
>> &p->svms, addr);
>> r = -EFAULT;
>> goto out_unlock_svms;
>> }
>> - mutex_lock(&parent->migrate_mutex);
>> - if (prange != parent)
>> - mutex_lock_nested(&prange->migrate_mutex, 1);
>> + mutex_lock(&prange->migrate_mutex);
>> if (!prange->actual_loc)
>> goto out_unlock_prange;
>> - svm_range_lock(parent);
>> - if (prange != parent)
>> - mutex_lock_nested(&prange->lock, 1);
>> - r = svm_range_split_by_granularity(p, mm, addr, parent, prange);
>> - if (prange != parent)
>> - mutex_unlock(&prange->lock);
>> - svm_range_unlock(parent);
>> - if (r) {
>> - pr_debug("failed %d to split range by granularity\n", r);
>> - goto out_unlock_prange;
>> - }
>> + /* Align migration range start and size to granularity size */
>> + size = 1UL << prange->granularity;
>> + start = max(ALIGN_DOWN(addr, size), prange->start);
>> + last = min(ALIGN(addr + 1, size) - 1, prange->last);
>> - r = svm_migrate_vram_to_ram(prange, vmf->vma->vm_mm,
>> - KFD_MIGRATE_TRIGGER_PAGEFAULT_CPU,
>> - vmf->page);
>> + r = svm_migrate_vram_to_ram(prange, vmf->vma->vm_mm, start, last,
>> + KFD_MIGRATE_TRIGGER_PAGEFAULT_CPU, vmf->page);
>> if (r)
>> pr_debug("failed %d migrate svms 0x%p range 0x%p [0x%lx
>> 0x%lx]\n",
>> - r, prange->svms, prange, prange->start, prange->last);
>> -
>> - /* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
>> - if (p->xnack_enabled && parent == prange)
>> - op = SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP;
>> - else
>> - op = SVM_OP_UPDATE_RANGE_NOTIFIER;
>> - svm_range_add_list_work(&p->svms, parent, mm, op);
>> - schedule_deferred_list_work(&p->svms);
>> + r, prange->svms, prange, start, last);
>> out_unlock_prange:
>> - if (prange != parent)
>> - mutex_unlock(&prange->migrate_mutex);
>> - mutex_unlock(&parent->migrate_mutex);
>> + mutex_unlock(&prange->migrate_mutex);
>> out_unlock_svms:
>> mutex_unlock(&p->svms.lock);
>> out_unref_process:
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
>> b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
>> index 487f26368164..9e48d10e848e 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
>> @@ -41,9 +41,13 @@ enum MIGRATION_COPY_DIR {
>> };
>> int svm_migrate_to_vram(struct svm_range *prange, uint32_t
>> best_loc,
>> + unsigned long start, unsigned long last,
>> struct mm_struct *mm, uint32_t trigger);
>> +
>> int svm_migrate_vram_to_ram(struct svm_range *prange, struct
>> mm_struct *mm,
>> - uint32_t trigger, struct page *fault_page);
>> + unsigned long start, unsigned long last,
>> + uint32_t trigger, struct page *fault_page);
>> +
>> unsigned long
>> svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long
>> addr);
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> index b23ba92a794c..2d9bb364d52c 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> @@ -156,12 +156,13 @@ svm_is_valid_dma_mapping_addr(struct device
>> *dev, dma_addr_t dma_addr)
>> static int
>> svm_range_dma_map_dev(struct amdgpu_device *adev, struct svm_range
>> *prange,
>> unsigned long offset, unsigned long npages,
>> - unsigned long *hmm_pfns, uint32_t gpuidx)
>> + unsigned long *hmm_pfns, uint32_t gpuidx, uint64_t
>> *vram_pages)
>> {
>> enum dma_data_direction dir = DMA_BIDIRECTIONAL;
>> dma_addr_t *addr = prange->dma_addr[gpuidx];
>> struct device *dev = adev->dev;
>> struct page *page;
>> + uint64_t vram_pages_dev;
>> int i, r;
>> if (!addr) {
>> @@ -171,6 +172,7 @@ svm_range_dma_map_dev(struct amdgpu_device *adev,
>> struct svm_range *prange,
>> prange->dma_addr[gpuidx] = addr;
>> }
>> + vram_pages_dev = 0;
>> addr += offset;
>> for (i = 0; i < npages; i++) {
>> if (svm_is_valid_dma_mapping_addr(dev, addr[i]))
>> @@ -180,6 +182,7 @@ svm_range_dma_map_dev(struct amdgpu_device *adev,
>> struct svm_range *prange,
>> if (is_zone_device_page(page)) {
>> struct amdgpu_device *bo_adev =
>> prange->svm_bo->node->adev;
>> + vram_pages_dev++;
>> addr[i] = (hmm_pfns[i] << PAGE_SHIFT) +
>> bo_adev->vm_manager.vram_base_offset -
>> bo_adev->kfd.pgmap.range.start;
>> @@ -196,13 +199,14 @@ svm_range_dma_map_dev(struct amdgpu_device
>> *adev, struct svm_range *prange,
>> pr_debug_ratelimited("dma mapping 0x%llx for page addr
>> 0x%lx\n",
>> addr[i] >> PAGE_SHIFT, page_to_pfn(page));
>> }
>> + *vram_pages = vram_pages_dev;
>> return 0;
>> }
>> static int
>> svm_range_dma_map(struct svm_range *prange, unsigned long *bitmap,
>> unsigned long offset, unsigned long npages,
>> - unsigned long *hmm_pfns)
>> + unsigned long *hmm_pfns, uint64_t *vram_pages)
>> {
>> struct kfd_process *p;
>> uint32_t gpuidx;
>> @@ -221,7 +225,7 @@ svm_range_dma_map(struct svm_range *prange,
>> unsigned long *bitmap,
>> }
>> r = svm_range_dma_map_dev(pdd->dev->adev, prange, offset,
>> npages,
>> - hmm_pfns, gpuidx);
>> + hmm_pfns, gpuidx, vram_pages);
>> if (r)
>> break;
>> }
>> @@ -347,6 +351,7 @@ svm_range *svm_range_new(struct svm_range_list
>> *svms, uint64_t start,
>> INIT_LIST_HEAD(&prange->child_list);
>> atomic_set(&prange->invalid, 0);
>> prange->validate_timestamp = 0;
>> + prange->vram_pages = 0;
>> mutex_init(&prange->migrate_mutex);
>> mutex_init(&prange->lock);
>> @@ -393,6 +398,8 @@ static void svm_range_bo_release(struct kref
>> *kref)
>> prange->start, prange->last);
>> mutex_lock(&prange->lock);
>> prange->svm_bo = NULL;
>> + /* prange should not hold vram page now */
>> + WARN_ON(prange->actual_loc);
>> mutex_unlock(&prange->lock);
>> spin_lock(&svm_bo->list_lock);
>> @@ -973,6 +980,11 @@ svm_range_split_nodes(struct svm_range *new,
>> struct svm_range *old,
>> new->svm_bo = svm_range_bo_ref(old->svm_bo);
>> new->ttm_res = old->ttm_res;
>> + /* set new's vram_pages as old range's now, the acurate
>> vram_pages
>> + * will be updated during mapping
>> + */
>> + new->vram_pages = min(old->vram_pages, new->npages);
>> +
>> spin_lock(&new->svm_bo->list_lock);
>> list_add(&new->svm_bo_list, &new->svm_bo->range_list);
>> spin_unlock(&new->svm_bo->list_lock);
>> @@ -1133,66 +1145,6 @@ svm_range_add_child(struct svm_range *prange,
>> struct mm_struct *mm,
>> list_add_tail(&pchild->child_list, &prange->child_list);
>> }
>> -/**
>> - * svm_range_split_by_granularity - collect ranges within
>> granularity boundary
>> - *
>> - * @p: the process with svms list
>> - * @mm: mm structure
>> - * @addr: the vm fault address in pages, to split the prange
>> - * @parent: parent range if prange is from child list
>> - * @prange: prange to split
>> - *
>> - * Trims @prange to be a single aligned block of prange->granularity if
>> - * possible. The head and tail are added to the child_list in @parent.
>> - *
>> - * Context: caller must hold mmap_read_lock and prange->lock
>> - *
>> - * Return:
>> - * 0 - OK, otherwise error code
>> - */
>> -int
>> -svm_range_split_by_granularity(struct kfd_process *p, struct
>> mm_struct *mm,
>> - unsigned long addr, struct svm_range *parent,
>> - struct svm_range *prange)
>> -{
>> - struct svm_range *head, *tail;
>> - unsigned long start, last, size;
>> - int r;
>> -
>> - /* Align splited range start and size to granularity size, then
>> a single
>> - * PTE will be used for whole range, this reduces the number of PTE
>> - * updated and the L1 TLB space used for translation.
>> - */
>> - size = 1UL << prange->granularity;
>> - start = ALIGN_DOWN(addr, size);
>> - last = ALIGN(addr + 1, size) - 1;
>> -
>> - pr_debug("svms 0x%p split [0x%lx 0x%lx] to [0x%lx 0x%lx] size
>> 0x%lx\n",
>> - prange->svms, prange->start, prange->last, start, last, size);
>> -
>> - if (start > prange->start) {
>> - r = svm_range_split(prange, start, prange->last, &head);
>> - if (r)
>> - return r;
>> - svm_range_add_child(parent, mm, head, SVM_OP_ADD_RANGE);
>> - }
>> -
>> - if (last < prange->last) {
>> - r = svm_range_split(prange, prange->start, last, &tail);
>> - if (r)
>> - return r;
>> - svm_range_add_child(parent, mm, tail, SVM_OP_ADD_RANGE);
>> - }
>> -
>> - /* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
>> - if (p->xnack_enabled && prange->work_item.op == SVM_OP_ADD_RANGE) {
>> - prange->work_item.op = SVM_OP_ADD_RANGE_AND_MAP;
>> - pr_debug("change prange 0x%p [0x%lx 0x%lx] op %d\n",
>> - prange, prange->start, prange->last,
>> - SVM_OP_ADD_RANGE_AND_MAP);
>> - }
>> - return 0;
>> -}
>> static bool
>> svm_nodes_in_same_hive(struct kfd_node *node_a, struct kfd_node
>> *node_b)
>> {
>> @@ -1615,12 +1567,14 @@ static void *kfd_svm_page_owner(struct
>> kfd_process *p, int32_t gpuidx)
>> * 5. Release page table (and SVM BO) reservation
>> */
>> static int svm_range_validate_and_map(struct mm_struct *mm,
>> + unsigned long map_start, unsigned long map_last,
>> struct svm_range *prange, int32_t gpuidx,
>> bool intr, bool wait, bool flush_tlb)
>> {
>> struct svm_validate_context *ctx;
>> unsigned long start, end, addr;
>> struct kfd_process *p;
>> + uint64_t vram_pages;
>> void *owner;
>> int32_t idx;
>> int r = 0;
>> @@ -1689,11 +1643,15 @@ static int svm_range_validate_and_map(struct
>> mm_struct *mm,
>> }
>> }
>> + vram_pages = 0;
>> start = prange->start << PAGE_SHIFT;
>> end = (prange->last + 1) << PAGE_SHIFT;
>> for (addr = start; !r && addr < end; ) {
>> struct hmm_range *hmm_range;
>> + unsigned long map_start_vma;
>> + unsigned long map_last_vma;
>> struct vm_area_struct *vma;
>> + uint64_t vram_pages_vma;
>> unsigned long next = 0;
>> unsigned long offset;
>> unsigned long npages;
>> @@ -1722,9 +1680,11 @@ static int svm_range_validate_and_map(struct
>> mm_struct *mm,
>> if (!r) {
>> offset = (addr - start) >> PAGE_SHIFT;
>> r = svm_range_dma_map(prange, ctx->bitmap, offset, npages,
>> - hmm_range->hmm_pfns);
>> + hmm_range->hmm_pfns, &vram_pages_vma);
>
> This is not ideal. We do a partial mapping below, but we still do
> hmm_range_get_pages and DMA mapping of the entire range. I think that
> will still run into issues with system memory usage when we do partial
> migration of newly allocated ranges in page faults.
There will be a following patch that does partial hmm page walking that
uses hmm_ragne_get_pages on same range as partial migration/mapping
instead of entire range. It is an enhancement to partial
migration/mapping. I plan to submit it after partial migration/mapping.
This patch combines partial migration and mapping in svm. With it I do
not see the system memory issue as when only applied partial migration.
The following partial hmm page walking patch will be an improvement on
performance.
Regards
Xiaogang
>
> Regards,
> Felix
>
>
>> if (r)
>> pr_debug("failed %d to dma map range\n", r);
>> + else
>> + vram_pages += vram_pages_vma;
>> }
>> svm_range_lock(prange);
>> @@ -1738,9 +1698,16 @@ static int svm_range_validate_and_map(struct
>> mm_struct *mm,
>> r = -EAGAIN;
>> }
>> - if (!r)
>> - r = svm_range_map_to_gpus(prange, offset, npages, readonly,
>> - ctx->bitmap, wait, flush_tlb);
>> + if (!r) {
>> + map_start_vma = max(map_start, prange->start + offset);
>> + map_last_vma = min(map_last, prange->start + offset +
>> npages - 1);
>> + if (map_start_vma <= map_last_vma) {
>> + offset = map_start_vma - prange->start;
>> + npages = map_last_vma - map_start_vma + 1;
>> + r = svm_range_map_to_gpus(prange, offset, npages,
>> readonly,
>> + ctx->bitmap, wait, flush_tlb);
>> + }
>> + }
>> if (!r && next == end)
>> prange->mapped_to_gpu = true;
>> @@ -1750,6 +1717,19 @@ static int svm_range_validate_and_map(struct
>> mm_struct *mm,
>> addr = next;
>> }
>> + if (addr == end) {
>> + prange->vram_pages = vram_pages;
>> +
>> + /* if prange does not include any vram page and it
>> + * has not released svm_bo drop its svm_bo reference
>> + * and set its actaul_loc to sys ram
>> + */
>> + if (!vram_pages && prange->ttm_res) {
>> + prange->actual_loc = 0;
>> + svm_range_vram_node_free(prange);
>> + }
>> + }
>> +
>> svm_range_unreserve_bos(ctx);
>> if (!r)
>> prange->validate_timestamp = ktime_get_boottime();
>> @@ -1833,8 +1813,8 @@ static void svm_range_restore_work(struct
>> work_struct *work)
>> */
>> mutex_lock(&prange->migrate_mutex);
>> - r = svm_range_validate_and_map(mm, prange, MAX_GPU_INSTANCE,
>> - false, true, false);
>> + r = svm_range_validate_and_map(mm, prange->start,
>> prange->last, prange,
>> + MAX_GPU_INSTANCE, false, true, false);
>> if (r)
>> pr_debug("failed %d to map 0x%lx to gpus\n", r,
>> prange->start);
>> @@ -2002,6 +1982,7 @@ static struct svm_range *svm_range_clone(struct
>> svm_range *old)
>> new->actual_loc = old->actual_loc;
>> new->granularity = old->granularity;
>> new->mapped_to_gpu = old->mapped_to_gpu;
>> + new->vram_pages = old->vram_pages;
>> bitmap_copy(new->bitmap_access, old->bitmap_access,
>> MAX_GPU_INSTANCE);
>> bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);
>> @@ -2912,6 +2893,7 @@ svm_range_restore_pages(struct amdgpu_device
>> *adev, unsigned int pasid,
>> uint32_t vmid, uint32_t node_id,
>> uint64_t addr, bool write_fault)
>> {
>> + unsigned long start, last, size;
>> struct mm_struct *mm = NULL;
>> struct svm_range_list *svms;
>> struct svm_range *prange;
>> @@ -3047,40 +3029,44 @@ svm_range_restore_pages(struct amdgpu_device
>> *adev, unsigned int pasid,
>> kfd_smi_event_page_fault_start(node, p->lead_thread->pid, addr,
>> write_fault, timestamp);
>> - if (prange->actual_loc != best_loc) {
>> + /* Align migration range start and size to granularity size */
>> + size = 1UL << prange->granularity;
>> + start = max_t(unsigned long, ALIGN_DOWN(addr, size),
>> prange->start);
>> + last = min_t(unsigned long, ALIGN(addr + 1, size) - 1,
>> prange->last);
>> + if (prange->actual_loc != 0 || best_loc != 0) {
>> migration = true;
>> +
>> if (best_loc) {
>> - r = svm_migrate_to_vram(prange, best_loc, mm,
>> - KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU);
>> + r = svm_migrate_to_vram(prange, best_loc, start, last,
>> + mm, KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU);
>> if (r) {
>> pr_debug("svm_migrate_to_vram failed (%d) at %llx,
>> falling back to system memory\n",
>> r, addr);
>> /* Fallback to system memory if migration to
>> * VRAM failed
>> */
>> - if (prange->actual_loc)
>> - r = svm_migrate_vram_to_ram(prange, mm,
>> - KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU,
>> - NULL);
>> + if (prange->actual_loc && prange->actual_loc !=
>> best_loc)
>> + r = svm_migrate_vram_to_ram(prange, mm, start,
>> last,
>> + KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU, NULL);
>> else
>> r = 0;
>> }
>> } else {
>> - r = svm_migrate_vram_to_ram(prange, mm,
>> - KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU,
>> - NULL);
>> + r = svm_migrate_vram_to_ram(prange, mm, start, last,
>> + KFD_MIGRATE_TRIGGER_PAGEFAULT_GPU, NULL);
>> }
>> if (r) {
>> pr_debug("failed %d to migrate svms %p [0x%lx 0x%lx]\n",
>> - r, svms, prange->start, prange->last);
>> + r, svms, start, last);
>> goto out_unlock_range;
>> }
>> }
>> - r = svm_range_validate_and_map(mm, prange, gpuidx, false,
>> false, false);
>> + r = svm_range_validate_and_map(mm, start, last, prange, gpuidx,
>> false,
>> + false, false);
>> if (r)
>> pr_debug("failed %d to map svms 0x%p [0x%lx 0x%lx] to gpus\n",
>> - r, svms, prange->start, prange->last);
>> + r, svms, start, last);
>> kfd_smi_event_page_fault_end(node, p->lead_thread->pid, addr,
>> migration);
>> @@ -3426,18 +3412,24 @@ svm_range_trigger_migration(struct mm_struct
>> *mm, struct svm_range *prange,
>> *migrated = false;
>> best_loc = svm_range_best_prefetch_location(prange);
>> - if (best_loc == KFD_IOCTL_SVM_LOCATION_UNDEFINED ||
>> - best_loc == prange->actual_loc)
>> + /* when best_loc is a gpu node and same as prange->actual_loc
>> + * we still need do migration as prange->actual_loc !=0 does
>> + * not mean all pages in prange are vram. hmm migrate will pick
>> + * up right pages during migration.
>> + */
>> + if ((best_loc == KFD_IOCTL_SVM_LOCATION_UNDEFINED) ||
>> + (best_loc == 0 && prange->actual_loc == 0))
>> return 0;
>> if (!best_loc) {
>> - r = svm_migrate_vram_to_ram(prange, mm,
>> + r = svm_migrate_vram_to_ram(prange, mm, prange->start,
>> prange->last,
>> KFD_MIGRATE_TRIGGER_PREFETCH, NULL);
>> *migrated = !r;
>> return r;
>> }
>> - r = svm_migrate_to_vram(prange, best_loc, mm,
>> KFD_MIGRATE_TRIGGER_PREFETCH);
>> + r = svm_migrate_to_vram(prange, best_loc, prange->start,
>> prange->last,
>> + mm, KFD_MIGRATE_TRIGGER_PREFETCH);
>> *migrated = !r;
>> return r;
>> @@ -3492,7 +3484,11 @@ static void
>> svm_range_evict_svm_bo_worker(struct work_struct *work)
>> mutex_lock(&prange->migrate_mutex);
>> do {
>> + /* migrate all vram pages in this prange to sys ram
>> + * after that prange->actual_loc should be zero
>> + */
>> r = svm_migrate_vram_to_ram(prange, mm,
>> + prange->start, prange->last,
>> KFD_MIGRATE_TRIGGER_TTM_EVICTION, NULL);
>> } while (!r && prange->actual_loc && --retries);
>> @@ -3616,8 +3612,8 @@ svm_range_set_attr(struct kfd_process *p,
>> struct mm_struct *mm,
>> flush_tlb = !migrated && update_mapping &&
>> prange->mapped_to_gpu;
>> - r = svm_range_validate_and_map(mm, prange, MAX_GPU_INSTANCE,
>> - true, true, flush_tlb);
>> + r = svm_range_validate_and_map(mm, prange->start,
>> prange->last, prange,
>> + MAX_GPU_INSTANCE, true, true, flush_tlb);
>> if (r)
>> pr_debug("failed %d to map svm range\n", r);
>> @@ -3631,8 +3627,8 @@ svm_range_set_attr(struct kfd_process *p,
>> struct mm_struct *mm,
>> pr_debug("Remapping prange 0x%p [0x%lx 0x%lx]\n",
>> prange, prange->start, prange->last);
>> mutex_lock(&prange->migrate_mutex);
>> - r = svm_range_validate_and_map(mm, prange, MAX_GPU_INSTANCE,
>> - true, true, prange->mapped_to_gpu);
>> + r = svm_range_validate_and_map(mm, prange->start,
>> prange->last, prange,
>> + MAX_GPU_INSTANCE, true, true,
>> prange->mapped_to_gpu);
>> if (r)
>> pr_debug("failed %d on remap svm range\n", r);
>> mutex_unlock(&prange->migrate_mutex);
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
>> b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
>> index c528df1d0ba2..026863a0abcd 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
>> @@ -78,6 +78,7 @@ struct svm_work_list_item {
>> * @update_list:link list node used to add to update_list
>> * @mapping: bo_va mapping structure to create and update GPU
>> page table
>> * @npages: number of pages
>> + * @vram_pages: vram pages number in this svm_range
>> * @dma_addr: dma mapping address on each GPU for system memory
>> physical page
>> * @ttm_res: vram ttm resource map
>> * @offset: range start offset within mm_nodes
>> @@ -88,7 +89,9 @@ struct svm_work_list_item {
>> * @flags: flags defined as KFD_IOCTL_SVM_FLAG_*
>> * @perferred_loc: perferred location, 0 for CPU, or GPU id
>> * @perfetch_loc: last prefetch location, 0 for CPU, or GPU id
>> - * @actual_loc: the actual location, 0 for CPU, or GPU id
>> + * @actual_loc: this svm_range location. 0: all pages are from sys ram;
>> + * GPU id: this svm_range may include vram pages from
>> GPU with
>> + * id actual_loc.
>> * @granularity:migration granularity, log2 num pages
>> * @invalid: not 0 means cpu page table is invalidated
>> * @validate_timestamp: system timestamp when range is validated
>> @@ -112,6 +115,7 @@ struct svm_range {
>> struct list_head list;
>> struct list_head update_list;
>> uint64_t npages;
>> + uint64_t vram_pages;
>> dma_addr_t *dma_addr[MAX_GPU_INSTANCE];
>> struct ttm_resource *ttm_res;
>> uint64_t offset;
>> @@ -168,9 +172,6 @@ struct kfd_node *svm_range_get_node_by_id(struct
>> svm_range *prange,
>> int svm_range_vram_node_new(struct kfd_node *node, struct svm_range
>> *prange,
>> bool clear);
>> void svm_range_vram_node_free(struct svm_range *prange);
>> -int svm_range_split_by_granularity(struct kfd_process *p, struct
>> mm_struct *mm,
>> - unsigned long addr, struct svm_range *parent,
>> - struct svm_range *prange);
>> int svm_range_restore_pages(struct amdgpu_device *adev, unsigned
>> int pasid,
>> uint32_t vmid, uint32_t node_id, uint64_t addr,
>> bool write_fault);
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