[haiku-development] Re: Fixate blocks in cache block

  • From: Janito Ferreira Filho <jvffprog@xxxxxxxxxxx>
  • To: Haiku Development <haiku-development@xxxxxxxxxxxxx>
  • Date: Tue, 13 Apr 2010 19:18:00 +0000


is it a reasonable implementation to use the block cache to store altered 
blocks notified in the journal without actually writing them? I'm thinking 
about getting write access to the overwritten blocks when the journal replays 
the log in read only mode, and then discard everything when the file system is 
unmounted. I guess it would be easier to ignore block transactions right now, 
unless it's impossible to give external read access while I maintain write 
access. How many blocks does the block cache normally store? I assume it would 
be a nice idea to warn when more than a certain threshold of the cache is used?

It would probably be more efficient if there were a block remapping scheme. 
Does the block cache support any kind of block triggers? Would it be possible 
to implement something like that (maybe in the future)?



> Date: Tue, 13 Apr 2010 00:14:16 +0200
> From: axeld@xxxxxxxxxxxxxxxx
> To: haiku-development@xxxxxxxxxxxxx
> Subject: [haiku-development] Re: Fixate blocks in cache block
> On 04/12/2010 10:36 PM, Janito Ferreira Filho wrote:
> > is there a way to create an empty block, write a value to it and prevent
> > it from being flushed to disk? Thanks in advance,
> As long as you have referenced it, it won't be written back.
> If you are using transaction support, it won't be written back as long
> as its part of an open transaction.
> Bye,
>    Axel.
Hotmail: Powerful Free email with security by Microsoft.

Other related posts: