Re: [PATCH 09/13] lightnvm: pblk: Kick writer for flush requests

Igor Konopko
2019-03-04T12:52:57Z

On 04.03.2019 10:39, Hans Holmberg wrote:
> On Mon, Mar 4, 2019 at 9:08 AM Javier González <javier@javigon.com> wrote:
>>
>>
>>> On 27 Feb 2019, at 18.14, Igor Konopko <igor.j.konopko@intel.com> wrote:
>>>
>>> In case when there is no enough sector available in rwb
>>> and there is flush request send we should kick write thread
>>> which is not a case in current implementation. This patch
>>> fixes that issue.
>>>
>>> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
>>> ---
>>> drivers/lightnvm/pblk-core.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>>> index 78b1eea4ab67..f48f2e77f770 100644
>>> --- a/drivers/lightnvm/pblk-core.c
>>> +++ b/drivers/lightnvm/pblk-core.c
>>> @@ -375,8 +375,9 @@ void pblk_write_timer_fn(struct timer_list *t)
>>> void pblk_write_should_kick(struct pblk *pblk)
>>> {
>>> unsigned int secs_avail = pblk_rb_read_count(&pblk->rwb);
>>> + unsigned int secs_to_flush = pblk_rb_flush_point_count(&pblk->rwb);
>>>
>>> - if (secs_avail >= pblk->min_write_pgs_data)
>>> + if (secs_avail >= pblk->min_write_pgs_data || secs_to_flush)
>>> pblk_write_kick(pblk);
>>> }
>>>
>>> --
>>> 2.17.1
>>
>> We already kick the write thread in case of REQ_PREFLUSH in
>> pblk_write_cache(), so no need to kick again.
>
> Yeah, I thought i fixed this issue in:
>
> cc9c9a00b10e ("lightnvm: pblk: kick writer on new flush points")
>
> That commit brought down the test time of some of the xfs sync tests
> with a factor of 20 or so.
>
> Igor: Have you seen any case of delayed syncs?

I didn't noticed that in the code. My mistake. So definitely my commit
does not make a sense and we can just forget about that one.

>
>>
>> Javier