[PATCH v3] drm/amdkfd: Use partial hmm page walk during buffer validation in SVM
Chen, Xiaogang
xiaogang.chen at amd.com
Mon Dec 11 20:00:01 UTC 2023
On 12/11/2023 8:42 AM, Philip Yang wrote:
>
>
> On 2023-12-06 10:24, Xiaogang.Chen wrote:
>> From: Xiaogang Chen<xiaogang.chen at amd.com>
>>
>> v2:
>> -not need calculate vram page number for new registered svm range, only
>> do it for split vram pages.
>>
>> v3:
>> -use dma address to calculate vram page number of split svm range;
>> use migrate_vma from hmm to calculate page number that migrate to vram.
>>
>> SVM uses hmm page walk to valid buffer before map to gpu vm. After have partial
>> migration/mapping do validation on same vm range as migration/map do instead of
>> whole svm range that can be very large. This change is expected to improve svm
>> code performance.
>
> This looks better, but it is redundant to loop through prange->npages
> to find vram pages after splitting.
>
To cal split vram page number of prange we always has to loop through
prange->npages to check each page by its dma addr.
I can put that into svm_range_split_pages when (old->actual_loc &&
old->ttm_res) is true to cal vram page number, still need loop through
new->npages. Basically we do not save cpu cycle, so not sure where it is
redundant.
Regards
Xiaogang
> Could add new function svm_range_split_vram_pages to split dma_addr
> array and count vram_pages in the same prange->npages loop...
>
> svm_range_split_adjust(struct svm_range *new, struct svm_range *old,
> {
>
> .............
>
> if (old->actual_loc && old->ttm_res) {
> r = svm_range_split_nodes(new, old, start, last);
> if (r)
> return r;
>
> r = svm_range_split_vram_pages(....);
>
> } else {
>
> r = svm_range_split_pages(new, old, start, last);
> }
>
> Regards,
>
> Philip
>
>> Signed-off-by: Xiaogang Chen<Xiaogang.Chen at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 35 ++++--------
>> drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 72 ++++++++++++------------
>> 2 files changed, 48 insertions(+), 59 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> index b854cbf06dce..34376184c37c 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
>> @@ -260,19 +260,6 @@ static void svm_migrate_put_sys_page(unsigned long addr)
>> put_page(page);
>> }
>>
>> -static unsigned long svm_migrate_successful_pages(struct migrate_vma *migrate)
>> -{
>> - unsigned long cpages = 0;
>> - unsigned long i;
>> -
>> - for (i = 0; i < migrate->npages; i++) {
>> - if (migrate->src[i] & MIGRATE_PFN_VALID &&
>> - migrate->src[i] & MIGRATE_PFN_MIGRATE)
>> - cpages++;
>> - }
>> - return cpages;
>> -}
>> -
>> static unsigned long svm_migrate_unsuccessful_pages(struct migrate_vma *migrate)
>> {
>> unsigned long upages = 0;
>> @@ -402,6 +389,7 @@ svm_migrate_vma_to_vram(struct kfd_node *node, struct svm_range *prange,
>> struct dma_fence *mfence = NULL;
>> struct migrate_vma migrate = { 0 };
>> unsigned long cpages = 0;
>> + unsigned long mpages = 0;
>> dma_addr_t *scratch;
>> void *buf;
>> int r = -ENOMEM;
>> @@ -450,12 +438,13 @@ svm_migrate_vma_to_vram(struct kfd_node *node, struct svm_range *prange,
>> r = svm_migrate_copy_to_vram(node, prange, &migrate, &mfence, scratch, ttm_res_offset);
>> migrate_vma_pages(&migrate);
>>
>> - pr_debug("successful/cpages/npages 0x%lx/0x%lx/0x%lx\n",
>> - svm_migrate_successful_pages(&migrate), cpages, migrate.npages);
>> -
>> svm_migrate_copy_done(adev, mfence);
>> migrate_vma_finalize(&migrate);
>>
>> + mpages = cpages - svm_migrate_unsuccessful_pages(&migrate);
>> + pr_debug("successful/cpages/npages 0x%lx/0x%lx/0x%lx\n",
>> + mpages, cpages, migrate.npages);
>> +
>> kfd_smi_event_migration_end(node, p->lead_thread->pid,
>> start >> PAGE_SHIFT, end >> PAGE_SHIFT,
>> 0, node->id, trigger);
>> @@ -465,12 +454,12 @@ svm_migrate_vma_to_vram(struct kfd_node *node, struct svm_range *prange,
>> out_free:
>> kvfree(buf);
>> out:
>> - if (!r && cpages) {
>> + if (!r && mpages) {
>> pdd = svm_range_get_pdd_by_node(prange, node);
>> if (pdd)
>> - WRITE_ONCE(pdd->page_in, pdd->page_in + cpages);
>> + WRITE_ONCE(pdd->page_in, pdd->page_in + mpages);
>>
>> - return cpages;
>> + return mpages;
>> }
>> return r;
>> }
>> @@ -498,7 +487,7 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
>> struct vm_area_struct *vma;
>> uint64_t ttm_res_offset;
>> struct kfd_node *node;
>> - unsigned long cpages = 0;
>> + unsigned long mpages = 0;
>> long r = 0;
>>
>> if (start_mgr < prange->start || last_mgr > prange->last) {
>> @@ -540,15 +529,15 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
>> pr_debug("failed %ld to migrate\n", r);
>> break;
>> } else {
>> - cpages += r;
>> + mpages += r;
>> }
>> ttm_res_offset += next - addr;
>> addr = next;
>> }
>>
>> - if (cpages) {
>> + if (mpages) {
>> prange->actual_loc = best_loc;
>> - prange->vram_pages = prange->vram_pages + cpages;
>> + prange->vram_pages = prange->vram_pages + mpages;
>> } 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
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> index 2834fb351818..8d012ca82cd6 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> @@ -158,13 +158,12 @@ 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, uint64_t *vram_pages)
>> + unsigned long *hmm_pfns, uint32_t gpuidx)
>> {
>> 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) {
>> @@ -174,7 +173,6 @@ 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]))
>> @@ -184,7 +182,6 @@ 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;
>> @@ -201,14 +198,14 @@ 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, uint64_t *vram_pages)
>> + unsigned long *hmm_pfns)
>> {
>> struct kfd_process *p;
>> uint32_t gpuidx;
>> @@ -227,7 +224,7 @@ 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, vram_pages);
>> + hmm_pfns, gpuidx);
>> if (r)
>> break;
>> }
>> @@ -982,11 +979,6 @@ 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);
>> @@ -1049,6 +1041,28 @@ svm_range_split_adjust(struct svm_range *new, struct svm_range *old,
>> return 0;
>> }
>>
>> +static int
>> +svm_range_vram_pages(struct svm_range *prange)
>> +{
>> + int i, j;
>> + dma_addr_t *addr;
>> + uint64_t vram_pages = 0;
>> +
>> + for (i = 0; i < MAX_GPU_INSTANCE; i++) {
>> + vram_pages = 0;
>> + if (!prange->dma_addr[i])
>> + continue;
>> +
>> + addr = prange->dma_addr[i];
>> + for (j = 0; j < prange->npages; j++) {
>> + if (addr[j]&SVM_RANGE_VRAM_DOMAIN)
>> + vram_pages++;
>> + }
>> + }
>> +
>> + return vram_pages;
>> +}
>> +
>> /**
>> * svm_range_split - split a range in 2 ranges
>> *
>> @@ -1100,6 +1114,10 @@ svm_range_split(struct svm_range *prange, uint64_t start, uint64_t last,
>> r, old_start, old_last, start, last);
>> svm_range_free(*new, false);
>> *new = NULL;
>> + } else if (prange->actual_loc && prange->ttm_res && *new) {
>> + /* calculate *new vram_pages and reduce from prange vram_pages */
>> + (*new)->vram_pages = svm_range_vram_pages(*new);
>> + prange->vram_pages -= (*new)->vram_pages;
>> }
>>
>> return r;
>> @@ -1109,7 +1127,7 @@ static int
>> svm_range_split_tail(struct svm_range *prange, uint64_t new_last,
>> struct list_head *insert_list, struct list_head *remap_list)
>> {
>> - struct svm_range *tail;
>> + struct svm_range *tail = NULL;
>> int r = svm_range_split(prange, prange->start, new_last, &tail);
>>
>> if (!r) {
>> @@ -1124,7 +1142,7 @@ static int
>> svm_range_split_head(struct svm_range *prange, uint64_t new_start,
>> struct list_head *insert_list, struct list_head *remap_list)
>> {
>> - struct svm_range *head;
>> + struct svm_range *head = NULL;
>> int r = svm_range_split(prange, new_start, prange->last, &head);
>>
>> if (!r) {
>> @@ -1573,7 +1591,6 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
>> 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;
>> @@ -1642,15 +1659,13 @@ 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;
>> + start = map_start << PAGE_SHIFT;
>> + end = (map_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;
>> @@ -1677,13 +1692,11 @@ static int svm_range_validate_and_map(struct mm_struct *mm,
>> }
>>
>> if (!r) {
>> - offset = (addr - start) >> PAGE_SHIFT;
>> + offset = (addr - (prange->start << PAGE_SHIFT)) >> PAGE_SHIFT;
>> r = svm_range_dma_map(prange, ctx->bitmap, offset, npages,
>> - hmm_range->hmm_pfns, &vram_pages_vma);
>> + hmm_range->hmm_pfns);
>> if (r)
>> pr_debug("failed %d to dma map range\n", r);
>> - else
>> - vram_pages += vram_pages_vma;
>> }
>>
>> svm_range_lock(prange);
>> @@ -1716,19 +1729,6 @@ 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();
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