linux-kernel - Re: [PATCH] ring_bufer: fix BUF_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: <494CBB6D.9070106@cn.fujitsu.com>
Date:	Sat, 20 Dec 2008 17:31:25 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	Ingo Molnar <mingo@...e.hu>
CC:	Steven Rostedt <rostedt@...dmis.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ring_bufer: fix BUF_PAGE_SIZE

Ingo Molnar wrote:
> * Lai Jiangshan <laijs@...fujitsu.com> wrote:
> 
>> impact: make BUF_PAGE_SIZE changeable.
>>
>> Except allocating/freeing page and the code using PAGE_MASK,
>> all code expect buffer_page's length is BUF_PAGE_SIZE.
>>
>> This patch make this behavior more concordant.
>>
[...]
> 
> hm, why? Non-order-0 allocations are pretty evil - why would we ever want 
> to do them?
> 
> 	Ingo
> 

I think since we introduce BUF_PAGE_SIZE instead of PAGE_SIZE for
buffer_page, we should make it changeable. We can use Non-order-0
allocations, but it doesn't mean we have to use Non-order-0 allocations.

In the old codes, these lines confuse me:
return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE);
addr &= PAGE_MASK;
This patch mostly make the codes concordant.

	Lai


--
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/