Re: block cache replacement strategy?

[dave b]

On 14 September 2010 01:21, Johannes Stezenbach <js@xxxxxxxxx> wrote:
> On Fri, Sep 10, 2010 at 06:02:48PM +0200, Johannes Stezenbach wrote:
>>
>> Linear read heuristic might be a good guess, but it would
>> be nice to hear a comment from a vm/fs expert which
>> confirms this works as intended.
>
> Apparently I'm unworthy to get a response from someone knowledgable :-(
>
> Anyway I found lmdd (from lmbench) can do random reads,
> and indeed causes the data to enter the block (page?) cache,
> replacing the previous data.


I am no expert, but what did you think would happen if you did dd
twice from /dev/zero?
but... Honestly what do you think will be cached?
If you want 'COW', use btrfs.

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