Re: [PATCH v2 06/10] mm/vmalloc: Handle non-blocking GFP in __vmalloc_area_node()

[Baoquan He <bhe@redhat.com>]

On 09/15/25 at 03:40pm, Uladzislau Rezki (Sony) wrote:
> Make __vmalloc_area_node() respect non-blocking GFP masks such
> as GFP_ATOMIC and GFP_NOWAIT.
> 
> - Add memalloc_apply_gfp_scope()/memalloc_restore_scope()
>   helpers to apply a proper scope.
> - Apply memalloc_apply_gfp_scope()/memalloc_restore_scope()
>   around vmap_pages_range() for page table setup.
> - Set "nofail" to false if a non-blocking mask is used, as
>   they are mutually exclusive.
> 
> This is particularly important for page table allocations that
> internally use GFP_PGTABLE_KERNEL, which may sleep unless such
> scope restrictions are applied. For example:
> 
> <snip>
> __pte_alloc_kernel()
>   pte_alloc_one_kernel(&init_mm);
>     pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM, 0);
> <snip>
> 
> Note: in most cases, PTE entries are established only up to the
> level required by current vmap space usage, meaning the page tables
> are typically fully populated during the mapping process.
> 
> Acked-by: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
>  include/linux/vmalloc.h |  2 ++
>  mm/vmalloc.c            | 52 +++++++++++++++++++++++++++++++++--------
>  2 files changed, 44 insertions(+), 10 deletions(-)

Reviewed-by: Baoquan He <bhe@redhat.com>