adreno源码系列全局内存申请

Posted 2022-12-15 bubbleben

1. kgsl_allocate_global

struct kgsl_memdesc *kgsl_allocate_global(struct kgsl_device *device,
		u64 size, u32 padding, u64 flags, u32 priv, const char *name)

	int ret;
    // 全局内存描述符[见1.1节]
	struct kgsl_global_memdesc *md;

	if (flags & KGSL_MEMFLAGS_SECURE)
		return kgsl_allocate_secure_global(device, size, flags, priv,
			name);

    // 分配kgsl_global_memdesc
	md = kzalloc(sizeof(*md), GFP_KERNEL);
	if (!md)
		return ERR_PTR(-ENOMEM);

	/*
	 * Make sure that we get global memory from system memory to keep from
	 * taking up pool memory for the life of the driver
	 */
    // 设置私有标志位
	priv |= KGSL_MEMDESC_GLOBAL | KGSL_MEMDESC_SYSMEM;

    // 申请物理内存[见第2节]
	ret = kgsl_allocate_kernel(device, &md->memdesc, size, flags, priv);
	if (ret) 
		kfree(md);
		return ERR_PTR(ret);
	

    // 设置全局内存描述符的名称
	md->name = name;

	/*
	 * No lock here, because this function is only called during probe/init
	 * while the caller is holding the mute
	 */
    // 将其添加到kgsl_device->globals链表尾部
	list_add_tail(&md->node, &device->globals);

    // 分配GPU虚拟地址并映射到GPU页表[见第3节]
	kgsl_mmu_map_global(device, &md->memdesc, padding);
	kgsl_trace_gpu_mem_total(device, md->memdesc.size);

    // 返回全局内存描述符的kgsl_memdesc成员
	return &md->memdesc;

1.1 kgsl_global_memdesc

/**
 * struct kgsl_global_memdesc  - wrapper for global memory objects
 */
// 全局内存描述符：主要是对kgsl_memdesc的封装
struct kgsl_global_memdesc 
	/** @memdesc: Container for the GPU memory descriptor for the object */
	struct kgsl_memdesc memdesc;
	/** @name: Name of the object for the debugfs list */
	const char *name;
	/** @node: List node for the list of global objects */
	struct list_head node;
;

2. kgsl_allocate_kernel

int kgsl_allocate_kernel(struct kgsl_device *device,
		struct kgsl_memdesc *memdesc, u64 size, u64 flags, u32 priv)

	int ret;

    // kgsl_allocate_user[见2.1节]
	ret = kgsl_allocate_user(device, memdesc, size, flags, priv);
	if (ret)
		return ret;

    // 调用在kgsl_system_ops中定义的kgsl_paged_map_kernel[见2.4节]
	if (memdesc->ops->map_kernel) 
		ret = memdesc->ops->map_kernel(memdesc);
		if (ret) 
			kgsl_sharedmem_free(memdesc);
			return ret;
		
	

	return 0;

2.1 kgsl_allocate_user

int kgsl_allocate_user(struct kgsl_device *device, struct kgsl_memdesc *memdesc,
		u64 size, u64 flags, u32 priv)

	if (device->mmu.type == KGSL_MMU_TYPE_NONE)
		return kgsl_alloc_contiguous(device, memdesc, size, flags,
			priv);
	else if (flags & KGSL_MEMFLAGS_SECURE)
		return kgsl_allocate_secure(device, memdesc, size, flags, priv);

    // 分配物理页面[见2.2节]
	return kgsl_alloc_pages(device, memdesc, size, flags, priv);

2.2 kgsl_alloc_pages

static int kgsl_alloc_pages(struct kgsl_device *device,
		struct kgsl_memdesc *memdesc, u64 size, u64 flags, u32 priv)

	struct page **pages;
	int count;

	size = PAGE_ALIGN(size);

	if (!size || size > UINT_MAX)
		return -EINVAL;

	kgsl_memdesc_init(device, memdesc, flags);
	memdesc->priv |= priv;

    // 标志位包含KGSL_MEMDESC_SYSMEM
	if (priv & KGSL_MEMDESC_SYSMEM) 
        // kgsl_memdesc的操作函数
		memdesc->ops = &kgsl_system_ops;
        // 从系统而非kgsl内存池分配页面[见2.3节]
		count = kgsl_system_alloc_pages(size, &pages, device->dev);
	 else 
		memdesc->ops = &kgsl_pool_ops;
		count = kgsl_pool_alloc_pages(size, &pages, device->dev);
	

	if (count < 0)
		return count;

    // 分配的物理页面
	memdesc->pages = pages;
    // 分配的物理内存大小
	memdesc->size = size;
    // 分配的物理页面数量
	memdesc->page_count = count;

	KGSL_STATS_ADD(size, &kgsl_driver.stats.page_alloc,
		&kgsl_driver.stats.page_alloc_max);

	return 0;

2.3 kgsl_system_alloc_pages

static int kgsl_system_alloc_pages(u64 size, struct page ***pages,
		struct device *dev)

	struct scatterlist sg;
	struct page **local;
    // 将内存大小转换为页面数量
	int i, npages = size >> PAGE_SHIFT;
	int order = get_order(PAGE_SIZE);

	local = kvcalloc(npages, sizeof(*pages), GFP_KERNEL);
	if (!local)
		return -ENOMEM;

	for (i = 0; i < npages; i++) 
        // 分配掩码
		gfp_t gfp = __GFP_ZERO | __GFP_HIGHMEM |
			GFP_KERNEL | __GFP_NORETRY;

        // 从伙伴系统申请物理页面
		local[i] = alloc_pages(gfp, get_order(PAGE_SIZE));
		if (!local[i]) 
			for (i = i - 1; i >= 0; i--) 
#ifdef CONFIG_MM_STAT_UNRECLAIMABLE_PAGES
				mod_node_page_state(page_pgdat(local[i]),
					NR_UNRECLAIMABLE_PAGES, -(1 << order));
#endif
				__free_pages(local[i], order);
			
			kvfree(local);
			return -ENOMEM;
		

		/* Make sure the cache is clean */
		sg_init_table(&sg, 1);
		sg_set_page(&sg, local[i], PAGE_SIZE, 0);
		sg_dma_address(&sg) = page_to_phys(local[i]);

		dma_sync_sg_for_device(dev, &sg, 1, DMA_BIDIRECTIONAL);
#ifdef CONFIG_MM_STAT_UNRECLAIMABLE_PAGES
		mod_node_page_state(page_pgdat(local[i]), NR_UNRECLAIMABLE_PAGES,
				(1 << order));
#endif
	

    // 返回page数组
	*pages = local;
	return npages;

2.4 kgsl_paged_map_kernel

static int kgsl_paged_map_kernel(struct kgsl_memdesc *memdesc)

	int ret = 0;

	/* Sanity check - don't map more than we could possibly chew */
	if (memdesc->size > ULONG_MAX)
		return -ENOMEM;

	mutex_lock(&kernel_map_global_lock);
	if ((!memdesc->hostptr) && (memdesc->pages != NULL)) 
		pgprot_t page_prot = pgprot_writecombine(PAGE_KERNEL);

        // kgsl_memdesc->hostptr用于表示内核空间虚拟地址：可以被所有进程共享
        // 这里通过vmap在内核虚拟地址空间中映射一块page_count个页面的连续空间
		memdesc->hostptr = vmap(memdesc->pages, memdesc->page_count,
					VM_IOREMAP, page_prot);
        // 映射成功：更新内存数据统计
		if (memdesc->hostptr)
			KGSL_STATS_ADD(memdesc->size,
				&kgsl_driver.stats.vmalloc,
				&kgsl_driver.stats.vmalloc_max);
		else
			ret = -ENOMEM;
	
    // 使用此内核虚拟地址的线程数量加1
	if (memdesc->hostptr)
		memdesc->hostptr_count++;

	mutex_unlock(&kernel_map_global_lock);

	return ret;

3. kgsl_mmu_map_global

void kgsl_mmu_map_global(struct kgsl_device *device,
		struct kgsl_memdesc *memdesc, u32 padding)

	struct kgsl_mmu *mmu = &(device->mmu);

    // 支持IOMMU: 调用在kgsl_iommu_ops中定义的kgsl_iommu_map_global[见3.1节]
	if (MMU_OP_VALID(mmu, mmu_map_global))
		mmu->mmu_ops->mmu_map_global(mmu, memdesc, padding);

3.1 kgsl_iommu_map_global

// 32位系统GPU虚拟地址基地址
#define KGSL_IOMMU_GLOBAL_MEM_BASE32	0xf8000000
// 64位系统GPU虚拟地址基地址
#define KGSL_IOMMU_GLOBAL_MEM_BASE64	0xfc000000

#define KGSL_IOMMU_GLOBAL_MEM_BASE(__mmu)	\\
	(test_bit(KGSL_MMU_64BIT, &(__mmu)->features) ? \\
		KGSL_IOMMU_GLOBAL_MEM_BASE64 : KGSL_IOMMU_GLOBAL_MEM_BASE32)

static void kgsl_iommu_map_global(struct kgsl_mmu *mmu,
		struct kgsl_memdesc *memdesc, u32 padding)

	struct kgsl_device *device = KGSL_MMU_DEVICE(mmu);
	struct kgsl_iommu *iommu = _IOMMU_PRIV(mmu);

	if (memdesc->flags & KGSL_MEMFLAGS_SECURE) 
		kgsl_iommu_map_secure_global(mmu, memdesc);
		return;
	

    // kgsl_memdesc->gpuaddr用于表示GPU虚拟地址
	if (!memdesc->gpuaddr) 
		u64 offset;
		u64 base;

		/* Find room for the memdesc plus any padding */
        // 根据物理内存大小以及priv标志位(KGSL_MEMDESC_RANDOM：随机地址)计算偏移量
		offset = global_get_offset(device, memdesc->size + padding,
			memdesc->priv);

		if (IS_ERR_VALUE(offset))
			return;

		if (kgsl_iommu_split_tables_enabled(mmu))
			base = KGSL_IOMMU_SPLIT_TABLE_BASE;
		else
            // 64位GPU虚拟地址基地址 = 0xfc000000
			base = KGSL_IOMMU_GLOBAL_MEM_BASE(mmu);

        // GPU虚拟地址 = 全局内存基地址 + 偏移量 = 0xfc000000 + 偏移量
		memdesc->gpuaddr = base + offset;
	

	/*
	 * Warn if a global is added after first per-process pagetables have
	 * been created since we do not go back and retroactively add the
	 * globals to existing pages
	 */
	WARN_ON(!kgsl_iommu_split_tables_enabled(mmu) && iommu->ppt_active);

    // 将GPU虚拟地址添加到默认页表中[见1.7节]
	kgsl_iommu_map_global_to_pt(mmu, memdesc, mmu->defaultpagetable);
	kgsl_iommu_map_global_to_pt(mmu, memdesc, mmu->lpac_pagetable);

3.2 kgsl_iommu_map_global_to_pt

static void kgsl_iommu_map_global_to_pt(struct kgsl_mmu *mmu,
		struct kgsl_memdesc *memdesc, struct kgsl_pagetable *pt)

	/* If the pagetable hasn't been created yet, do nothing */
	if (IS_ERR_OR_NULL(pt))
		return;

	kgsl_mmu_map(pt, memdesc);

3.3 kgsl_mmu_map

int
kgsl_mmu_map(struct kgsl_pagetable *pagetable,
				struct kgsl_memdesc *memdesc)

	int size;
	struct kgsl_device *device = KGSL_MMU_DEVICE(pagetable->mmu);

	if (!memdesc->gpuaddr)
		return -EINVAL;
	/* Only global mappings should be mapped multiple times */
    // 只有全局的内存才能够映射多次
	if (!kgsl_memdesc_is_global(memdesc) &&
			(KGSL_MEMDESC_MAPPED & memdesc->priv))
		return -EINVAL;

    // 计算该块内存描述符的大小
	size = kgsl_memdesc_footprint(memdesc);

	if (PT_OP_VALID(pagetable, mmu_map)) 
		int ret;

        // 支持IOMMU: 调用在iommu_pt_ops中定义的kgsl_iommu_map将该块内存添加到页表中
		ret = pagetable->pt_ops->mmu_map(pagetable, memdesc);
		if (ret)
			return ret;

        // 更新内存数据统计
		atomic_inc(&pagetable->stats.entries);
		KGSL_STATS_ADD(size, &pagetable->stats.mapped,
				&pagetable->stats.max_mapped);
		kgsl_mmu_trace_gpu_mem_pagetable(pagetable);

		if (!kgsl_memdesc_is_global(memdesc)
				&& !(memdesc->flags & KGSL_MEMFLAGS_USERMEM_ION)) 
			kgsl_trace_gpu_mem_total(device, size);
		

        // KGSL_MEMDESC_MAPPED标记该内存描述符已被映射到页表
		memdesc->priv |= KGSL_MEMDESC_MAPPED;
	

	return 0;