Re: [PATCH] mm/vmalloc: add vm_struct for vm_map_ram area

[zijun_hu]

On 07/19/2017 06:44 PM, Zhaoyang Huang wrote:
> /proc/vmallocinfo will not show the area allocated by vm_map_ram, which
> will make confusion when debug. Add vm_struct for them and show them in
> proc.
> 
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxxxxxx>
> ---
another patch titled "vmalloc: show lazy-purged vma info in vmallocinfo" was phased-in to linux-next branch
to resolve this problem.
>  mm/vmalloc.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 34a1c3e..4a2e93c 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -46,6 +46,9 @@ struct vfree_deferred {
>  
>  static void __vunmap(const void *, int);
>  
> +static void setup_vmap_ram_vm(struct vm_struct *vm, struct vmap_area *va,
> +				unsigned long flags, const void *caller);
> +
>  static void free_work(struct work_struct *w)
>  {
>  	struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
> @@ -315,6 +318,7 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
>  /*** Global kva allocator ***/
>  
>  #define VM_VM_AREA	0x04
> +#define VM_VM_RAM	0x08
>  
>  static DEFINE_SPINLOCK(vmap_area_lock);
>  /* Export for kexec only */
> @@ -1141,6 +1145,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
>  
>  	va = find_vmap_area(addr);
>  	BUG_ON(!va);
> +	kfree(va->vm);
>  	free_unmap_vmap_area(va);
>  }
>  EXPORT_SYMBOL(vm_unmap_ram);
> @@ -1173,6 +1178,12 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>  		addr = (unsigned long)mem;
>  	} else {
>  		struct vmap_area *va;
> +		struct vm_struct *area;
> +
> +		area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
> +		if (unlikely(!area))
> +			return NULL;
> +
>  		va = alloc_vmap_area(size, PAGE_SIZE,
>  				VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
>  		if (IS_ERR(va))
> @@ -1180,6 +1191,7 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t pro
>  
>  		addr = va->va_start;
>  		mem = (void *)addr;
> +		setup_vmap_ram_vm(area, va, 0, __builtin_return_address(0));
>  	}
>  	if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
>  		vm_unmap_ram(mem, count);
> @@ -1362,6 +1374,19 @@ static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
>  	spin_unlock(&vmap_area_lock);
>  }
>  
> +static void setup_vmap_ram_vm(struct vm_struct *vm, struct vmap_area *va,
> +			      unsigned long flags, const void *caller)
> +{
> +	spin_lock(&vmap_area_lock);
> +	vm->flags = flags;
> +	vm->addr = (void *)va->va_start;
> +	vm->size = va->va_end - va->va_start;
> +	vm->caller = caller;
> +	va->vm = vm;
> +	va->flags |= VM_VM_RAM;
> +	spin_unlock(&vmap_area_lock);
> +}
> +
>  static void clear_vm_uninitialized_flag(struct vm_struct *vm)
>  {
>  	/*
> @@ -2698,7 +2723,7 @@ static int s_show(struct seq_file *m, void *p)
>  	 * s_show can encounter race with remove_vm_area, !VM_VM_AREA on
>  	 * behalf of vmap area is being tear down or vm_map_ram allocation.
>  	 */
> -	if (!(va->flags & VM_VM_AREA))
> +	if (!(va->flags & (VM_VM_AREA | VM_VM_RAM)))
>  		return 0;
>  
>  	v = va->vm;
>