Re: [PATCH 2/2] xfs: add 'discard_sync' mount flag

Eric Sandeen
2018-04-30T22:59:05Z

On 4/30/18 2:58 PM, Jens Axboe wrote:
> On 4/30/18 1:57 PM, Eric Sandeen wrote:
>> On 4/30/18 2:21 PM, Jens Axboe wrote:

...

>> Ok, but I'm not sure how that precludes a block device tunable? You'd tune
>> it for your workload, right?
>
> What kind of tunable are you thinking of? Right now we have one tunable,
> which is the max discard size. Patch #1 actually helps make this do what
> it should for sync discards, instead of just building a bio chain and
> submitting that all at once.
>
>> Or is the concern that it could only be for the entire block device, and
>> perhaps different partitions have different workloads?
>>
>> Sorry, caveman filesystem guy doesn't completely understand block devices.
>
> I just don't know what you are trying to tune :-)

I'm wondering if "make discards synchronous" couldn't just be a block device
tunable, rather than a filesystem mount option tunable.

-Eric