Re: [POLL] SLAB : Are the 32 and 192 bytes caches really usefull on x86_64 machines ?

Dave Jones
2006-01-04T05:26:57Z

On Thu, Dec 29, 2005 at 12:50:10PM +1100, Keith Owens wrote:
> Dave Jones (on Wed, 28 Dec 2005 20:29:15 -0500) wrote:
> >
> > > Something like this:
> > >
> > > http://lwn.net/Articles/124374/
> >
> >One thing that really sticks out like a sore thumb is soft_cursor()
> >That thing gets called a *lot*, and every time it does a kmalloc/free
> >pair that 99.9% of the time is going to be the same size alloc as
> >it was the last time. This patch makes that alloc persistent
> >(and does a realloc if the size changes).
> >The only time it should change is if the font/resolution changes I think.
>
> Can soft_cursor() be called from multiple processes at the same time,
> in particular with dual head systems? If so then a static variable is
> not going to work.

I looked at this a little closer. If my understanding of the console/fb layers
is correct, soft_cursor() is serialised by the console_sem in
drivers/video/console/fbcon.c::fb_flashcursor()

Dave