RE: [git pull] ia64 changes

Linus Torvalds
2009-09-29T18:07:40Z

On Tue, 29 Sep 2009, Luck, Tony wrote:
>
> What will be the big areas of growth? dentry? inode? Something off
> in networking?

I'd pick dentry, but I'm biased (I happen to think the dcache is one of
the most important data structures we have). Right now, in x86-64, we lay
out the spinlock along with the other int-sized things, and we've tried to
pack things over the years (ie put the commonly accessed ones together).

See for example commit c2452f32786159ed85f0e4b21fec09258f822fc8.

I do agree that none of the static spinlocks care about size, obviously.
The only time the size of a spinlock matters is when it's embedded in one
of the critical common data structures. And in _many_ cases you'll have
pointers there that end up forcing it to 64-bit, but 'struct dentry' is an
example of something where things can be (and are) more densely packed,
and people have spent some time on it.

Linus