Andi Kleen <ak@suse.de> wrote:
>
> > +
> > +struct bgl_lock {
> > + spinlock_t lock;
> > +} ____cacheline_aligned_in_smp;
> > +
> > +struct blockgroup_lock {
> > + struct bgl_lock locks[NR_BG_LOCKS];
> > +};
>
> Why don't you use per_cpu data for this ? It can be indexed as well
> with per_cpu() and it would safe a lot of space because the padding
> would not be all wasted. If you want more than NR_CPUS locks it could be
> done using a simple two level index scheme.
per_cpu data is statically allocated, at compile-time. And it doesn't work
for modules.
These hashed locks need to be dynamically allocated (one per filesystem) and
they need to work from modules.
And this hashed lock is not a per-cpu thing. (No locks are!) It just uses
NR_CPUS to decide how big the hash should be.
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This archive was generated by hypermail 2b29 : Tue Apr 15 2003 - 22:00:33 EST