linux-kernel - Re: [PATCH 2/8] mm: Accept memory in __alloc_pages

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Message-ID: <ZrHWQ/+EC5CApJ3M@kernel.org>
Date: Tue, 6 Aug 2024 10:52:35 +0300
From: Mike Rapoport <rppt@...nel.org>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	"Borislav Petkov (AMD)" <bp@...en8.de>,
	Mel Gorman <mgorman@...e.de>, Vlastimil Babka <vbabka@...e.cz>,
	Tom Lendacky <thomas.lendacky@....com>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	David Hildenbrand <david@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/8] mm: Accept memory in __alloc_pages_bulk().

On Mon, Aug 05, 2024 at 05:59:34PM +0300, 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().
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

Acked-by: Mike Rapoport (Microsoft) <rppt@...nel.org>

> ---
>  mm/page_alloc.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index aa9b1eaa638c..90a1f01d5996 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4576,12 +4576,25 @@ 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;
> +
> +#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
> +		/* Try again if zone has deferred pages */
> +		if (deferred_pages_enabled()) {
> +			if (_deferred_grow_zone(zone, 0))
> +				goto retry_this_zone;
> +		}
> +#endif
>  	}
>  
>  	/*
> -- 
> 2.43.0
>