Re: [RFC 4/9] Atomic reclaim: Save irq flags in vmscan.c

Andi Kleen
2007-08-14T21:39:21Z

On Tue, Aug 14, 2007 at 02:15:12PM -0700, Christoph Lameter wrote:
> On Tue, 14 Aug 2007, Andi Kleen wrote:
>
> > > Hmmmm... The spinlock is its own flag.
> >
> > Yes, but it's not CPU local. Taking the spinlock from another CPU's
> > interrupt handler is perfectly safe, just not from the local CPU.
> > If you use the spinlock as flag you would need to lock out everybody.
>
> So every spinlock would have an array of chars sized to NR_CPUS and set
> the flag when the lock is taken?

I was more thinking of a single per cpu flag for all of page reclaim
That keeps it also cache local.

-Andi