On 25/02/2025 04:42, Matthew Brost wrote:
This patch introduces support for GPU Shared Virtual Memory (SVM) in the
Direct Rendering Manager (DRM) subsystem. SVM allows for seamless
sharing of memory between the CPU and GPU, enhancing performance and
flexibility in GPU computing tasks.
The patch adds the necessary infrastructure for SVM, including data
structures and functions for managing SVM ranges and notifiers. It also
provides mechanisms for allocating, deallocating, and migrating memory
regions between system RAM and GPU VRAM.
This is largely inspired by GPUVM.
v2:
- Take order into account in check pages
- Clear range->pages in get pages error
- Drop setting dirty or accessed bit in get pages (Vetter)
- Remove mmap assert for cpu faults
- Drop mmap write lock abuse (Vetter, Christian)
- Decouple zdd from range (Vetter, Oak)
- Add drm_gpusvm_range_evict, make it work with coherent pages
- Export drm_gpusvm_evict_to_sram, only use in BO evict path (Vetter)
- mmget/put in drm_gpusvm_evict_to_sram
- Drop range->vram_alloation variable
- Don't return in drm_gpusvm_evict_to_sram until all pages detached
- Don't warn on mixing sram and device pages
- Update kernel doc
- Add coherent page support to get pages
- Use DMA_FROM_DEVICE rather than DMA_BIDIRECTIONAL
- Add struct drm_gpusvm_vram and ops (Thomas)
- Update the range's seqno if the range is valid (Thomas)
- Remove the is_unmapped check before hmm_range_fault (Thomas)
- Use drm_pagemap (Thomas)
- Drop kfree_mapping (Thomas)
- dma mapp pages under notifier lock (Thomas)
- Remove ctx.prefault
- Remove ctx.mmap_locked
- Add ctx.check_pages
- s/vram/devmem (Thomas)
v3:
- Fix memory leak drm_gpusvm_range_get_pages
- Only migrate pages with same zdd on CPU fault
- Loop over al VMAs in drm_gpusvm_range_evict
- Make GPUSVM a drm level module
- GPL or MIT license
- Update main kernel doc (Thomas)
- Prefer foo() vs foo for functions in kernel doc (Thomas)
- Prefer functions over macros (Thomas)
- Use unsigned long vs u64 for addresses (Thomas)
- Use standard interval_tree (Thomas)
- s/drm_gpusvm_migration_put_page/drm_gpusvm_migration_unlock_put_page (Thomas)
- Drop err_out label in drm_gpusvm_range_find_or_insert (Thomas)
- Fix kernel doc in drm_gpusvm_range_free_pages (Thomas)
- Newlines between functions defs in header file (Thomas)
- Drop shall language in driver vfunc kernel doc (Thomas)
- Move some static inlines from head to C file (Thomas)
- Don't allocate pages under page lock in drm_gpusvm_migrate_populate_ram_pfn (Thomas)
- Change check_pages to a threshold
v4:
- Fix NULL ptr deref in drm_gpusvm_migrate_populate_ram_pfn (Thomas, Himal)
- Fix check pages threshold
- Check for range being unmapped under notifier lock in get pages (Testing)
- Fix characters per line
- Drop WRITE_ONCE for zdd->devmem_allocation assignment (Thomas)
- Use completion for devmem_allocation->detached (Thomas)
- Make GPU SVM depend on ZONE_DEVICE (CI)
- Use hmm_range_fault for eviction (Thomas)
- Drop zdd worker (Thomas)
v5:
- Select Kconfig deps (CI)
- Set device to NULL in __drm_gpusvm_migrate_to_ram (Matt Auld, G.G.)
- Drop Thomas's SoB (Thomas)
- Add drm_gpusvm_range_start/end/size helpers (Thomas)
- Add drm_gpusvm_notifier_start/end/size helpers (Thomas)
- Absorb drm_pagemap name changes (Thomas)
- Fix driver lockdep assert (Thomas)
- Move driver lockdep assert to static function (Thomas)
- Assert mmap lock held in drm_gpusvm_migrate_to_devmem (Thomas)
- Do not retry forever on eviction (Thomas)
v6:
- Fix drm_gpusvm_get_devmem_page alignment (Checkpatch)
- Modify Kconfig (CI)
- Compile out lockdep asserts (CI)
Cc: Simona Vetter <simona.vetter@xxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: <dri-devel@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/Kconfig | 9 +
drivers/gpu/drm/Makefile | 1 +
drivers/gpu/drm/drm_gpusvm.c | 2236 ++++++++++++++++++++++++++++++++++
include/drm/drm_gpusvm.h | 507 ++++++++
4 files changed, 2753 insertions(+)
create mode 100644 drivers/gpu/drm/drm_gpusvm.c
create mode 100644 include/drm/drm_gpusvm.h
<snip>
+/**
+ * struct drm_gpusvm_notifier - Structure representing a GPU SVM notifier
+ *
+ * @gpusvm: Pointer to the GPU SVM structure
+ * @notifier: MMU interval notifier
+ * @itree: Interval tree node for the notifier (inserted in GPU SVM)
+ * @entry: List entry to fast interval tree traversal
+ * @root: Cached root node of the RB tree containing ranges
+ * @range_list: List head containing of ranges in the same order they appear in
+ * interval tree. This is useful to keep iterating ranges while
+ * doing modifications to RB tree.
Build is failing here. I think just missing:
+ * @flags: ....
+ * @flags.removed: Flag indicating whether the MMU interval notifier has been
+ * removed
+ *
+ * This structure represents a GPU SVM notifier.
+ */
+struct drm_gpusvm_notifier {
+ struct drm_gpusvm *gpusvm;
+ struct mmu_interval_notifier notifier;
+ struct interval_tree_node itree;
+ struct list_head entry;
+ struct rb_root_cached root;
+ struct list_head range_list;
+ struct {
+ u32 removed : 1;
+ } flags;
+};
+
+/**
+ * struct drm_gpusvm_range - Structure representing a GPU SVM range
+ *
+ * @gpusvm: Pointer to the GPU SVM structure
+ * @notifier: Pointer to the GPU SVM notifier
+ * @refcount: Reference count for the range
+ * @itree: Interval tree node for the range (inserted in GPU SVM notifier)
+ * @entry: List entry to fast interval tree traversal
+ * @notifier_seq: Notifier sequence number of the range's pages
+ * @dma_addr: Device address array
+ * @dpagemap: The struct drm_pagemap of the device pages we're dma-mapping.
+ * Note this is assuming only one drm_pagemap per range is allowed.
Same here:
+ * @flags: ....
+ * @flags.migrate_devmem: Flag indicating whether the range can be migrated to device memory
+ * @flags.unmapped: Flag indicating if the range has been unmapped
+ * @flags.partial_unmap: Flag indicating if the range has been partially unmapped
+ * @flags.has_devmem_pages: Flag indicating if the range has devmem pages
+ * @flags.has_dma_mapping: Flag indicating if the range has a DMA mapping
+ *
+ * This structure represents a GPU SVM range used for tracking memory ranges
+ * mapped in a DRM device.
+ */
