Re: [PATCHv2 3/8] mm: Accept memory in __alloc_pages_bulk().

[Tom Lendacky <thomas.lendacky@amd.com>]

On 8/9/24 06:48, Kirill A. Shutemov wrote:
> Currently, the kernel only accepts memory in get_page_from_freelist(),
> but there is another path that directly takes pages from free lists -
> __alloc_page_bulk(). This function can consume all accepted memory and
> will resort to __alloc_pages_noprof() if necessary.
> 
> Conditionally accepted in __alloc_pages_bulk().
> 
> The same issue may arise due to deferred page initialization. Kick the
> deferred initialization machinery before abandoning the zone, as the
> kernel does in get_page_from_freelist().

Is the deferred page init issue an existing problem? In other words,
should it be a separate patch with a Fixes: tag so it can go back to
stable kernels?

Thanks,
Tom

> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Acked-by: David Hildenbrand <david@redhat.com>
> ---
>  mm/page_alloc.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index f7bb885aab07..ed62ecd6775f 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4613,12 +4613,23 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
>  			goto failed;
>  		}
>  
> +		cond_accept_memory(zone, 0);
> +retry_this_zone:
>  		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages;
>  		if (zone_watermark_fast(zone, 0,  mark,
>  				zonelist_zone_idx(ac.preferred_zoneref),
>  				alloc_flags, gfp)) {
>  			break;
>  		}
> +
> +		if (cond_accept_memory(zone, 0))
> +			goto retry_this_zone;
> +
> +		/* Try again if zone has deferred pages */
> +		if (deferred_pages_enabled()) {
> +			if (_deferred_grow_zone(zone, 0))
> +				goto retry_this_zone;
> +		}
>  	}
>  
>  	/*