Re: Pls apply this spinlock patch to the kernel

[Alan Cox]

> and occupies the full cacheline. The five hottest spinlocks for this 
> work load are set to that type (kmap_lock, lru_list_lock, 
> pagecache_lock, kernel_flag, pagemap_lru_lock)  The change is done in 
> the common code, except for the kernel_flag. 

That seems overkill. What you are saying is that static spinlocks need
to be declared in some cases to be followed by padding.

> +static spinlock_cacheline_t lru_list_lock_cacheline = {SPIN_LOCK_UNLOCKED};
> +#define lru_list_lock  lru_list_lock_cacheline.lock

So why not just add a macro for aligning then do

spinlock_t pagecache_lock ____cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
cache_line_pad;

where cache_line_pad is an asm(".align") - I would assume that is
sufficient - Linus ?

Alan