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

From: zijun_hu
Date: Wed Jul 19 2017 - 22:37:25 EST


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;
>