Hi Chao, On Tue, Jun 30, 2015 at 06:42:09PM +0800, Chao Yu wrote: > For now, in extent cache, we have a global lru list which links all extent > node in the cache, and the list is protected by a global spinlock. > > If we want to shrink extent cache, we will: > 1. delete all target extent node from global lru list under spinlock; > 2. traverse all per-inode extent tree in global radix tree; > 2.a. traverse all extent node in per-inode extent tree, try to free > extent > node if it is not in global lru list already. > > This method is inefficient when there is huge number of inode extent tree in > global extent tree. > > In this patch we introduce a new method for extent cache shrinking: > When we attach a new extent node, we record extent tree pointer in extent > node. > In shrink flow, we can try to find and lock extent tree of inode directly by > this backward pointer, and then detach the extent node from extent tree. > > This can help to shrink extent cache more efficiently.
Yes, but as we discussed before, this way will consume 4 bytes per each extent_node. Can it be acceptable? Instead, IMO, we need to focus on how to increase its hit ratio first. Actually, I wrote a patch for that. Could you check that first? Thanks, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
