Re: [PATCH v3 4/7] mm/vmalloc: explicitly identify vm_map_ram area when shown in /proc/vmcoreinfo

Lorenzo Stoakes
2023-01-16T12:24:17Z

On Fri, Jan 13, 2023 at 11:19:18AM +0800, Baoquan He wrote:
> Now, by marking VMAP_RAM in vmap_area->flags for vm_map_ram, we can
> clearly differentiate it with other vmalloc areas. So identify
> vm_map_area area by checking VMAP_RAM of vmap_area->flags when shown
> in /proc/vmcoreinfo.
>
> Meanwhile, the code comment above vm_map_ram area checking in s_show()
> is not needed any more, remove it here.
>
> Signed-off-by: Baoquan He <bhe@redhat.com>
> ---
> mm/vmalloc.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 13875bc41e27..4a10b3b692fa 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -4225,11 +4225,7 @@ static int s_show(struct seq_file *m, void *p)
>
> va = list_entry(p, struct vmap_area, list);
>
> - /*
> - * s_show can encounter race with remove_vm_area, !vm on behalf
> - * of vmap area is being tear down or vm_map_ram allocation.
> - */
> - if (!va->vm) {
> + if (!va->vm && (va->flags & VMAP_RAM)) {
> seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
> (void *)va->va_start, (void *)va->va_end,
> va->va_end - va->va_start);
> --
> 2.34.1
>

Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>