linux-kernel - Re: [patch 4/4] cpu alloc: Use cpu allocator instead of the builtin modules per cpu allocator

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: <48D3A7EF.5030309@cosmosbay.com>
Date:	Fri, 19 Sep 2008 15:23:59 +0200
From:	Eric Dumazet <dada1@...mosbay.com>
To:	Christoph Lameter <cl@...ux-foundation.org>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	Christoph Lameter <clameter@....com>, linux-mm@...r.kernel.org,
	jeremy@...p.org, ebiederm@...ssion.com, travis@....com,
	herbert@...dor.apana.org.au, xemul@...nvz.org
Subject: Re: [patch 4/4] cpu alloc: Use cpu allocator instead of the builtin
 modules per cpu allocator

Christoph Lameter a écrit :
> Eric Dumazet wrote:
>> Christoph Lameter a écrit :
>>> Remove the builtin per cpu allocator from modules.c and use cpu_alloc
>>> instead.
>>>
>>> Signed-off-by: Christoph Lameter <clameter@....com>
>>> +        percpu_size = sechdrs[pcpuindex].sh_size;
>>> +
>>> +        if (align > PAGE_SIZE) {
>>> +            printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
>>> +                      mod->name, align, PAGE_SIZE);
>>> +            align = PAGE_SIZE;
>>> +        }
>> Minor question : Wy do you have to keep this cap of alignment ?
>>
>> I could not find such a limit in the allocator
> 
> The per cpu areas are allocated on page boundaries and there are multiple of
> those per cpu areas all aligned to page boundary. The alignment can therefore
> only make sense up to a page. Maybe I need to put that into the cpu allocator?

Ah... I missed this page boundaries on the allocator, you are right.

So caping is OK in modules code, in order to mimic previous behavior.

Adding an error case in cpu allocator (for align > PAGE_SIZE) might avoid some errors...




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/