nouveau/hmm: map pages after migration
Subsystems (5)
v3 cover nouveau/hmm: map pages after migration
Originally patch 4 was targeted for Jason's rdma tree since other HMM related changes were queued there. Now that those have been merged, these patches just contain changes to nouveau so they could go through any tree. I guess Ben Skeggs' tree would be appropriate.
Changes since v2:
Added patches 1-3 to fix some minor issues.
Eliminated nouveau_find_svmm() since it is easily found. Applied Jason Gunthorpe's suggestions for nouveau_pfns_to_args().
Changes since v1:
Rebase to linux-5.6.0-rc4
Address Christoph Hellwig's comments
Ralph Campbell (4):
nouveau/hmm: fix vma range check for migration nouveau/hmm: check for SVM initialized before migrating
nouveau: remove useless SVM range check nouveau/hmm: map pages after migration
drivers/gpu/drm/nouveau/nouveau_dmem.c | 46 +++++++++++------ drivers/gpu/drm/nouveau/nouveau_dmem.h | 2 + drivers/gpu/drm/nouveau/nouveau_svm.c | 69 ++++++++++++++++++++++++-- drivers/gpu/drm/nouveau/nouveau_svm.h | 5 ++ 4 files changed, 102 insertions(+), 20 deletions(-)
Signature · 1 line
2.20.1
PATCH v3 1/4 nouveau/hmm: fix vma range check for migration
find_vma_intersection(mm, start, end) only guarantees that end is greater than or equal to vma->vm_start but doesn't guarantee that start is greater than or equal to vma->vm_start. The calculation for the intersecting range in nouveau_svmm_bind() isn't accounting for this and can call migrate_vma_setup() with a starting address less than vma->vm_start. This results in migrate_vma_setup() returning -EINVAL for the range instead of nouveau skipping that part of the range and migrating the rest.
--- drivers/gpu/drm/nouveau/nouveau_svm.c | 1 + 1 file changed, 1 insertion(+)
drivers/gpu/drm/nouveau/nouveau_svm.c +1 -0
@@ -179,6 +179,7 @@ nouveau_svmm_bind(struct drm_device *dev, void *data,if (!vma)break ; + addr =max (addr, vma->vm_start); next =min (vma->vm_end, end);/* This is a best effort so we ignore errors */ nouveau_dmem_migrate_vma (cli->drm, vma, addr, next);
Signature · 1 line
2.20.1
Re: [Nouveau] [PATCH v3 1/4] nouveau/hmm: fix vma range check for migration
I've taken all 4 patches in my tree.
Thanks Ralph,
Ben.
Quoted 34 lines · Ralph Campbell
find_vma_intersection(mm, start, end)only guarantees that end is greater than or equal tovma->vm_startbut doesn't guarantee that start is greater than or equal tovma->vm_start. The calculation for the intersecting range innouveau_svmm_bind()isn't accounting for this and can callmigrate_vma_setup()with a starting address less thanvma->vm_start. This results inmigrate_vma_setup()returning-EINVALfor the range instead of nouveau skipping that part of the range and migrating the rest.Signed-off-by Ralph Campbell <[email protected]>--- drivers/gpu/drm/nouveau/nouveau_svm.c | 1 + 1 file changed, 1 insertion(+)drivers/gpu/drm/nouveau/nouveau_svm.c +1
-1@@ -179,6 +179,7 @@ nouveau_svmm_bind(struct drm_device *dev, void *data,if (!vma)break ; + addr =max (addr, vma->vm_start); next =min (vma->vm_end, end);/* This is a best effort so we ignore errors */ nouveau_dmem_migrate_vma (cli->drm, vma, addr, next); --2.20.1
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PATCH v3 2/4 nouveau/hmm: check for SVM initialized before migrating
In reply to Ralph CampbellWhen migrating system memory to GPU memory, check that SVM has been enabled. Even though most errors can be ignored since migration is a performance optimization, return an error because this is a violation of the API.
--- drivers/gpu/drm/nouveau/nouveau_svm.c | 5 +++++ 1 file changed, 5 insertions(+)
drivers/gpu/drm/nouveau/nouveau_svm.c +5 -0
@@ -171,6 +171,11 @@ nouveau_svmm_bind(struct drm_device *dev, void *data, mm =get_task_mm (current);down_read (&mm->mmap_sem); +if (!cli->svm.svmm) { +up_read (&mm->mmap_sem); +return -EINVAL ; + } +for (addr = args->va_start, end = args->va_start + size; addr < end;) {struct vm_area_struct *vma;unsigned long next;
Signature · 1 line
2.20.1
PATCH v3 3/4 nouveau: remove useless SVM range check
In reply to Ralph CampbellWhen nouveau processes GPU faults, it checks to see if the fault address falls within the "unmanaged" range which is reserved for fixed allocations instead of addresses chosen by the core mm code. If start is greater than or equal to svmm->unmanaged.limit, then limit will also be greater than svmm->unmanaged.limit which is greater than svmm->unmanaged.start and the start = max_t(u64, start, svmm->unmanaged.limit) will change nothing. Just remove the useless lines of code.
--- drivers/gpu/drm/nouveau/nouveau_svm.c | 3 --- 1 file changed, 3 deletions(-)
drivers/gpu/drm/nouveau/nouveau_svm.c +0 -3
@@ -663,9 +663,6 @@ nouveau_svm_fault(struct nvif_notify *notify) limit = start + (ARRAY_SIZE (args.phys) <<PAGE_SHIFT );if (start < svmm->unmanaged.limit) limit =min_t (u64, limit, svmm->unmanaged.start); -else -if (limit > svmm->unmanaged.start) - start =max_t (u64, start, svmm->unmanaged.limit);SVMM_DBG (svmm,"wndw %016llx-%016llx" , start, limit); mm = svmm->notifier.mm;
Signature · 1 line
2.20.1
PATCH v3 4/4 nouveau/hmm: map pages after migration
In reply to Ralph CampbellWhen memory is migrated to the GPU, it is likely to be accessed by GPU code soon afterwards. Instead of waiting for a GPU fault, map the migrated memory into the GPU page tables with the same access permissions as the source CPU page table entries. This preserves copy on write semantics.
--- drivers/gpu/drm/nouveau/nouveau_dmem.c | 46 +++++++++++++------- drivers/gpu/drm/nouveau/nouveau_dmem.h | 2 + drivers/gpu/drm/nouveau/nouveau_svm.c | 59 +++++++++++++++++++++++++- drivers/gpu/drm/nouveau/nouveau_svm.h | 5 +++ 4 files changed, 95 insertions(+), 17 deletions(-)
drivers/gpu/drm/nouveau/nouveau_dmem.c +30 -16
@@ -25,11 +25,13 @@#include "nouveau_dma.h" #include "nouveau_mem.h" #include "nouveau_bo.h" +#include "nouveau_svm.h" #include <nvif/class.h> #include <nvif/object.h> #include <nvif/if500b.h> #include <nvif/if900b.h> +#include <nvif/if000c.h> #include <linux/sched/mm.h> #include <linux/hmm.h>
@@ -558,10 +560,11 @@ nouveau_dmem_init(struct nouveau_drm *drm) }static unsigned long nouveau_dmem_migrate_copy_one (struct nouveau_drm *drm, -unsigned long src,dma_addr_t *dma_addr) +unsigned long src,dma_addr_t *dma_addr,u64 *pfn) {struct device *dev = drm->dev->dev;struct page *dpage, *spage; +unsigned long paddr; spage =migrate_pfn_to_page (src);if (!spage || !(src &MIGRATE_PFN_MIGRATE ))
@@ -569,17 +572,21 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm, dpage =nouveau_dmem_page_alloc_locked (drm);if (!dpage) -return 0 ; + goto out; *dma_addr =dma_map_page (dev, spage,0 ,PAGE_SIZE ,DMA_BIDIRECTIONAL );if (dma_mapping_error (dev, *dma_addr)) goto out_free_page; + paddr =nouveau_dmem_page_addr (dpage);if (drm->dmem->migrate.copy_func (drm,1 ,NOUVEAU_APER_VRAM , -nouveau_dmem_page_addr (dpage),NOUVEAU_APER_HOST , - *dma_addr)) + paddr,NOUVEAU_APER_HOST , *dma_addr)) goto out_dma_unmap; + *pfn =NVIF_VMM_PFNMAP_V0_V |NVIF_VMM_PFNMAP_V0_VRAM | + ((paddr >>PAGE_SHIFT ) <<NVIF_VMM_PFNMAP_V0_ADDR_SHIFT ); +if (src &MIGRATE_PFN_WRITE ) + *pfn |=NVIF_VMM_PFNMAP_V0_W ;return migrate_pfn (page_to_pfn (dpage)) |MIGRATE_PFN_LOCKED ; out_dma_unmap:
@@ -587,18 +594,20 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm, out_free_page:nouveau_dmem_page_free_locked (drm, dpage); out: + *pfn =NVIF_VMM_PFNMAP_V0_NONE ;return 0 ; }static void nouveau_dmem_migrate_chunk (struct nouveau_drm *drm, -struct migrate_vma *args,dma_addr_t *dma_addrs) +struct nouveau_svmm *svmm,struct migrate_vma *args, +dma_addr_t *dma_addrs,u64 *pfns) {struct nouveau_fence *fence;unsigned long addr = args->start, nr_dma =0 , i;for (i =0 ; addr < args->end; i++) { args->dst[i] =nouveau_dmem_migrate_copy_one (drm, args->src[i], - dma_addrs + nr_dma); + dma_addrs + nr_dma, pfns + i);if (args->dst[i]) nr_dma++; addr +=PAGE_SIZE ;
@@ -607,20 +616,18 @@ static void nouveau_dmem_migrate_chunk(struct nouveau_drm *drm,nouveau_fence_new (drm->dmem->migrate.chan, false, &fence);migrate_vma_pages (args);nouveau_dmem_fence_done (&fence); +nouveau_pfns_map (svmm, args->vma->vm_mm, args->start, pfns, i);while (nr_dma--) {dma_unmap_page (drm->dev->dev, dma_addrs[nr_dma],PAGE_SIZE ,DMA_BIDIRECTIONAL ); } -/* -* FIXME optimization: update GPU page table to point to newly migrated -* memory. -*/ migrate_vma_finalize (args); }int nouveau_dmem_migrate_vma (struct nouveau_drm *drm, +struct nouveau_svmm *svmm,struct vm_area_struct *vma,unsigned long start,unsigned long end)
@@ -632,7 +639,8 @@ nouveau_dmem_migrate_vma(struct nouveau_drm *drm, .vma = vma, .start = start, }; -unsigned long c, i; +unsigned long i; +u64 *pfns;int ret = -ENOMEM ; args.src =kcalloc (max,sizeof (*args.src),GFP_KERNEL );
@@ -646,19 +654,25 @@ nouveau_dmem_migrate_vma(struct nouveau_drm *drm,if (!dma_addrs) goto out_free_dst; -for (i =0 ; i < npages; i += c) { - c =min (SG_MAX_SINGLE_ALLOC , npages); - args.end = start + (c <<PAGE_SHIFT ); + pfns =nouveau_pfns_alloc (max); +if (!pfns) + goto out_free_dma; + +for (i =0 ; i < npages; i += max) { + args.end = start + (max <<PAGE_SHIFT ); ret =migrate_vma_setup (&args);if (ret) - goto out_free_dma; + goto out_free_pfns;if (args.cpages) -nouveau_dmem_migrate_chunk (drm, &args, dma_addrs); +nouveau_dmem_migrate_chunk (drm, svmm, &args, dma_addrs, + pfns); args.start = args.end; } ret =0 ; +out_free_pfns: +nouveau_pfns_free (pfns); out_free_dma:kfree (dma_addrs); out_free_dst:
drivers/gpu/drm/nouveau/nouveau_dmem.h +2 -0
@@ -25,6 +25,7 @@struct drm_device ;struct drm_file ;struct nouveau_drm ; +struct nouveau_svmm ;struct hmm_range ;#if IS_ENABLED (CONFIG_DRM_NOUVEAU_SVM )
@@ -34,6 +35,7 @@ void nouveau_dmem_suspend(struct nouveau_drm *);void nouveau_dmem_resume (struct nouveau_drm *);int nouveau_dmem_migrate_vma (struct nouveau_drm *drm, +struct nouveau_svmm *svmm,struct vm_area_struct *vma,unsigned long start,unsigned long end);
drivers/gpu/drm/nouveau/nouveau_svm.c +58 -1
77 lines not on this page · raw message
drivers/gpu/drm/nouveau/nouveau_svm.h +5 -0
@@ -18,6 +18,11 @@ void nouveau_svmm_fini(struct nouveau_svmm **);int nouveau_svmm_join (struct nouveau_svmm *,u64 inst);void nouveau_svmm_part (struct nouveau_svmm *,u64 inst);int nouveau_svmm_bind (struct drm_device *,void *,struct drm_file *); + +u64 *nouveau_pfns_alloc (unsigned long npages); +void nouveau_pfns_free (u64 *pfns); +void nouveau_pfns_map (struct nouveau_svmm *svmm,struct mm_struct *mm, +unsigned long addr,u64 *pfns,unsigned long npages);#else /* IS_ENABLED(CONFIG_DRM_NOUVEAU_SVM) */ static inline void nouveau_svm_init (struct nouveau_drm *drm) {}static inline void nouveau_svm_fini (struct nouveau_drm *drm) {}
Signature · 1 line
2.20.1