linux-kernel - Re: [PATCHv2 3/8] mm: Accept memory in __alloc_pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8640d12f-e4b4-5bd1-b772-6aae5e5ef972@amd.com>
Date: Fri, 9 Aug 2024 10:31:03 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, Mel Gorman <mgorman@...e.de>,
 Vlastimil Babka <vbabka@...e.cz>
Cc: Mike Rapoport <rppt@...nel.org>,
 "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: [PATCHv2 3/8] mm: Accept memory in __alloc_pages_bulk().

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@...ux.intel.com>
> Acked-by: David Hildenbrand <david@...hat.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;
> +		}
>  	}
>  
>  	/*