linux-kernel - Re: [PATCH] slub: Clear __GFP_COMP flag when allocating 0 order page

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <5482360c-0a0b-e5f5-b88e-4a6ec4d43f7d@linux.com>
Date: Thu, 11 Apr 2024 09:51:13 -0700 (PDT)
From: "Christoph Lameter (Ampere)" <cl@...ux.com>
To: Haifeng Xu <haifeng.xu@...pee.com>
cc: vbabka@...e.cz, penberg@...nel.org, rientjes@...gle.com, 
    iamjoonsoo.kim@....com, akpm@...ux-foundation.org, 
    roman.gushchin@...ux.dev, 42.hyeyoo@...il.com, linux-mm@...ck.org, 
    linux-kernel@...r.kernel.org
Subject: Re: [PATCH] slub: Clear __GFP_COMP flag when allocating 0 order
 page

On Thu, 11 Apr 2024, Haifeng Xu wrote:

> @@ -1875,6 +1875,13 @@ static inline struct slab *alloc_slab_page(gfp_t flags, int node,
> 	struct slab *slab;
> 	unsigned int order = oo_order(oo);
>
> +	/*
> +	 * If fallback to the minimum order allocation and the order is 0,
> +	 * clear the __GFP_COMP flag.
> +	 */
> +	if (order == 0)
> +		flags = flags & ~__GFP_COMP;


This would be better placed in allocate_slab() when the need for a
fallback to a lower order is detected after the first call to alloc_slab_page().