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

2018-11-11 Thread Xishi Qiu



On 2018/11/8 19:14, Zhaoyang Huang wrote:
> From: Zhaoyang Huang 
> 
> There is no caller and pages information etc for the area which is
> created by vm_map_ram as well as the page count > VMAP_MAX_ALLOC.
> Add them on in this commit.
> 
> Signed-off-by: Zhaoyang Huang 
> ---
>  mm/vmalloc.c | 30 --
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index cfea25b..819b690 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -45,7 +45,8 @@ struct vfree_deferred {
>  static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
>  
>  static void __vunmap(const void *, int);
> -
> +static void setup_vmalloc_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);
> @@ -1138,6 +1139,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
>   BUG_ON(!va);
>   debug_check_no_locks_freed((void *)va->va_start,
>   (va->va_end - va->va_start));
> + kfree(va->vm);
>   free_unmap_vmap_area(va);
>  }
>  EXPORT_SYMBOL(vm_unmap_ram);
> @@ -1170,6 +1172,8 @@ 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;
> +
>   va = alloc_vmap_area(size, PAGE_SIZE,
>   VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
>   if (IS_ERR(va))
> @@ -1177,11 +1181,17 @@ void *vm_map_ram(struct page **pages, unsigned int 
> count, int node, pgprot_t pro
>  
>   addr = va->va_start;
>   mem = (void *)addr;
> + area = kzalloc_node(sizeof(*area), GFP_KERNEL, node);
> + if (likely(area)) {
> + setup_vmalloc_vm(area, va, 0, 
> __builtin_return_address(0));
> + va->flags &= ~VM_VM_AREA;
> + }
Hi Zhaoyang,

I think if we set the flag VM_VM_AREA, that means we have some info,
so how about do not clear the flag after setup_vmalloc_vm, and just
update the print in s_show.

...
if (v->flags & VM_ALLOC)
seq_puts(m, " vmalloc");
+   if (v->flags & VM_MAP_RAM)  // add a new flag for vm_map_ram?
+   seq_puts(m, " vm_map_ram");
...

Thanks,
Xishi QIu
>   }
>   if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
>   vm_unmap_ram(mem, count);
>   return NULL;
>   }
> +
>   return mem;
>  }
>  EXPORT_SYMBOL(vm_map_ram);
> @@ -2688,19 +2698,19 @@ 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)) {
> - seq_printf(m, "0x%pK-0x%pK %7ld %s\n",
> - (void *)va->va_start, (void *)va->va_end,
> - va->va_end - va->va_start,
> - va->flags & VM_LAZY_FREE ? "unpurged vm_area" : 
> "vm_map_ram");
> -
> + if (!(va->flags & VM_VM_AREA) && !va->vm)
>   return 0;
> - }
>  
>   v = va->vm;
>  
> - seq_printf(m, "0x%pK-0x%pK %7ld",
> - v->addr, v->addr + v->size, v->size);
> + if (!(va->flags & VM_VM_AREA))
> + seq_printf(m, "0x%pK-0x%pK %7ld %s\n",
> + (void *)va->va_start, (void *)va->va_end,
> + va->va_end - va->va_start,
> + va->flags & VM_LAZY_FREE ? "unpurged vm_area" : 
> "vm_map_ram");
> + else
> + seq_printf(m, "0x%pK-0x%pK %7ld",
> + v->addr, v->addr + v->size, v->size);
>  
>   if (v->caller)
>   seq_printf(m, " %pS", v->caller);
> 


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

2018-11-08 Thread Andrew Morton
On Thu,  8 Nov 2018 19:14:49 +0800 Zhaoyang Huang  
wrote:

> There is no caller and pages information etc for the area which is
> created by vm_map_ram as well as the page count > VMAP_MAX_ALLOC.
> Add them on in this commit.

Well I can kind of see what this is doing - it increases the amount of
info in /proc/vmallocinfo for regions which were created by
vm_map_area(), yes?

But I'd like to hear it in your words, please.  What problem are we
trying to solve?  Why is it actually a problem?  Why is the additional
information considered useful, etc?

It would help a lot if the changelog were to include before-and-after
examples from the /proc/vmallocinfo output.

Thanks.