linux-kernel - Re: Should a swapped out page be deleted from swap cache?

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]

Date:	Wed, 20 Feb 2013 08:43:30 +0800
From:	Will Huck <will.huckk@...il.com>
To:	Hugh Dickins <hughd@...gle.com>
CC:	Li Haifeng <omycle@...il.com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: Re: Should a swapped out page be deleted from swap cache?

On 02/20/2013 03:06 AM, Hugh Dickins wrote:
> On Tue, 19 Feb 2013, Will Huck wrote:
>> Another question:
> I don't see the connection to deleting a swapped out page from swap cache.
>
>> Why kernel memory mapping use direct mapping instead of kmalloc/vmalloc which
>> will setup mapping on demand?
> I may misunderstand you, and "kernel memory mapping".
>
> kmalloc does not set up a mapping, it uses the direct mapping already set up.
>
> It would be circular if the basic page allocation primitives used kmalloc,
> since kmalloc relies on the basic page allocation primitives.
>
> vmalloc is less efficient than using the direct mapping (repeated setup
> and teardown, no use of hugepages), but necessary when you want a larger

Is there tlb flush in setup and teardown process? and they also expensive?

> virtual array than you're likely to find from the buddy allocator.
>
> Hugh

--
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/