Re: [PATCH v5 8/9] mm: memory: flatten alloc_anon_folio() retry loop

[Dev Jain <dev.jain@arm.com>]

On 28/05/26 2:15 am, Johannes Weiner wrote:
> alloc_anon_folio() uses a top-level if (folio) that buries the success
> path four levels deep. This makes for awkward long lines and wrapping.
> The next patch will add more code here, so flatten this now to keep
> things clean and simple.
> 
> The next label is already there, use it for !folio.
> 
> No functional change intended.
> 
> Suggested-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> Acked-by: Usama Arif <usama.arif@linux.dev>
> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
> ---

Reviewed-by: Dev Jain <dev.jain@arm.com>


>  mm/memory.c | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 7c020995eafc..135f5c0f57bd 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -5215,24 +5215,24 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
>  	while (orders) {
>  		addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order);
>  		folio = vma_alloc_folio(gfp, order, vma, addr);
> -		if (folio) {
> -			if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
> -				count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
> -				folio_put(folio);
> -				goto next;
> -			}
> -			folio_throttle_swaprate(folio, gfp);
> -			/*
> -			 * When a folio is not zeroed during allocation
> -			 * (__GFP_ZERO not used) or user folios require special
> -			 * handling, folio_zero_user() is used to make sure
> -			 * that the page corresponding to the faulting address
> -			 * will be hot in the cache after zeroing.
> -			 */
> -			if (user_alloc_needs_zeroing())
> -				folio_zero_user(folio, vmf->address);
> -			return folio;
> +		if (!folio)
> +			goto next;
> +		if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
> +			count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
> +			folio_put(folio);
> +			goto next;
>  		}
> +		folio_throttle_swaprate(folio, gfp);
> +		/*
> +		 * When a folio is not zeroed during allocation
> +		 * (__GFP_ZERO not used) or user folios require special
> +		 * handling, folio_zero_user() is used to make sure
> +		 * that the page corresponding to the faulting address
> +		 * will be hot in the cache after zeroing.
> +		 */
> +		if (user_alloc_needs_zeroing())
> +			folio_zero_user(folio, vmf->address);
> +		return folio;
>  next:
>  		count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK);
>  		order = next_order(&orders, order);