Re: [PATCH v2 01/12] f2fs: cache: implement metadata cache

[Wenjie Qi]

Hi Chao,

> next:
> 	spin_lock_irqsave(&cache->tree_lock, flags);
> 	nr = radix_tree_gang_lookup(&cache->root, (void **)entries, index,
> 		min((unsigned long)F2FS_ONSTACK_CACHES, end - index));
> 	...
> 	spin_unlock_irqrestore(&cache->tree_lock, flags);
> 	...
> 	if (index < end)
> 		goto next;

`nr` bounds each gang lookup, while the outer loop continues until `index`
reaches `end`.  Dropping `tree_lock` between batches is not itself a
scheduling point.

Is there a scheduling point or another bound on the number of entries that
this range invalidation can process in one invocation?