Re: CVS commit: src/sys/fs/puffs

[yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi)]

hi,

> YAMAMOTO Takashi <yamt%mwd.biglobe.ne.jp@localhost> wrote:
> 
>> as i told you a few times, ioflush is not a thread to free memory.
>> pagedaemon is. 
> 
> Sure ioflush do not directly free memory, but vnodes' dirty page use
> memory, don't they? If ioflush stops working, is pageadaemon able to
> pageout that kind of memory?

pagedaemon flushes dirty pages by itself, yes.

> 
>> please read ufs_bmaparray and grep "uvm.pagedaemon_lwp"
>> in src/sys/kern/ to see what other filesystems do.  i don't think this
>> approach works for puffs because it's almost impossible to say in which
>> cases an operation needs memory allocation to complete, though.
> 
> It is indeed impossible, as we cannot know what the userland filesystem
> will do.

a possible solution would be local page recycling.  ie. reserve some pages
and put them onto a page queue dedicated for a given set of processes
so that pages can be recycled in the set independently from the global queue.

YAMAMOTO Takashi

> 
> -- 
> Emmanuel Dreyfus
> http://hcpnet.free.fr/pubz
> manu%netbsd.org@localhost