Re: [PATCH 3/3] SQUASHME: pnfs: filelayout: print_ds should use dprintk

[Benny Halevy <bhalevy@panasas.com>]

On 2010-10-27 23:42, Benny Halevy wrote:
> On 2010-10-27 23:32, Trond Myklebust wrote:
>> On Wed, 2010-10-27 at 23:29 +0200, Benny Halevy wrote:
>>> On 2010-10-27 23:23, Trond Myklebust wrote:
>>>> On Wed, 2010-10-27 at 23:00 +0200, Benny Halevy wrote:
>>>>> On 2010-10-27 22:17, Fred Isaman wrote:
>>>>>> On Wed, Oct 27, 2010 at 4:06 PM, Benny Halevy <bhalevy@panasas.com> wrote:
>>>>>>> On 2010-10-27 21:49, Fred Isaman wrote:
>>>>>>>> The change to printk was in response to Trond's complaint about
>>>>>>>> successive dprintks.
>>>>>>>>
>>>>>>>> Instead, the following would work:
>>>>>>>>
>>>>>>>>
>>>>>>>> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
>>>>>>>> index 5f52e6f..2ce393c 100644
>>>>>>>> --- a/fs/nfs/nfs4filelayout.c
>>>>>>>> +++ b/fs/nfs/nfs4filelayout.c
>>>>>>>> @@ -585,7 +585,8 @@ filelayout_commit(struct nfs_write_data *data, int sync)
>>>>>>>>               }
>>>>>>>
>>>>>>> If we're going this way, the ifdebug could cover the following
>>>>>>> printout as well...
>>>>>>>
>>>>>>
>>>>>> Did you mean preceding printout?  By the way - the complaint about
>>>>>
>>>>> Yeah, preceding the call to print_ds (following my comment :)
>>>>>
>>>>>> successive dprintks was regarding
>>>>>> print_ds_list repeatedly calling print_ds, which at the time used dprintk.
>>>>>
>>>>> Why do we care to optimize the debug case so much?
>>>>> print_ds_list is already calling print_ds inside ifdebug(FACILITY)
>>>>> so the common, non-debug case is optimized correctly. I.e. we don't
>>>>> repeatedly check the debug flag normally.
>>>>
>>>> It's not about optimizing the debug case. It's about avoiding having to
>>>> check ifdebug(FACILITY) all the time when we're _not_ debugging.
>>>
>>> Right, and so we do, as the whole loop in print_ds_list is enclosed
>>> in ifdebug(FACILITY).
>>
>> In that case, I agree: the whole thing can be converted to use ordinary
>> printks...
> 
> The point is it has a singular caller outside of this loop for which
> the caller needs to check ifdebug(FACILITY) before calling print_ds.
> Not a big deal, but I think it'd be cleaner if print_ds will do a dprintk
> to simplify its singular usage, while the cost of that will be extra tests
> when called, possibly many times, in debug mode from print_ds_list.

Nevermind, I just merged Fred's patch instead.
No need to spend that much energy on cosmetics in this case :)

Benny

> 
> Benny
> 
>>
>> Trond
>>
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