[pnfs] (no subject)

[Benny Halevy]

On Feb. 15, 2008, 19:24 +0200, Fredric Isaman <iisaman at citi.umich.edu> wrote:
> 
> On Fri, 15 Feb 2008, Benny Halevy wrote:
> 
>> On Feb. 14, 2008, 20:21 +0200, Fred Isaman <iisaman at citi.umich.edu> wrote:
<skip>

>>> +	if (!nfss->pnfs_curr_ld->ld_io_ops ||
>>> +	    !nfss->pnfs_curr_ld->ld_io_ops->write_begin) {
>>> +		/* If layout driver doesn't define, just do nothing */
>>> +		goto out;
>> So why bother getting the layout if the method isn't defined?
>> I suggest to do this block first, as we enter the function.
>>
> 
> OK.

It'd be great if you could do a bit of refactoring and put this check and likes
(other LD methods that are likely to be undefined for many LDs) in a static inline
function so we can avoid calling the slow path function all together.  This has
may save a cache row miss on the critical I/O path which has high payoff.

Benny