lkml.org 
[lkml]   [2018]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 3/3] lightnvm: pblk: take write semaphore on metadata
Date

> On 29 Aug 2018, at 15.40, Matias Bjørling <mb@lightnvm.io> wrote:
>
> On 08/29/2018 03:21 PM, Javier Gonzalez wrote:
>>> On 29 Aug 2018, at 15.08, Matias Bjørling <mb@lightnvm.io> wrote:
>>>
>>> On 08/29/2018 10:56 AM, Javier González wrote:
>>>> pblk guarantees write ordering at a chunk level through a per open chunk
>>>> semaphore. At this point, since we only have an open I/O stream for both
>>>> user and GC data, the semaphore is per parallel unit.
>>>> For the metadata I/O that is synchronous, the semaphore is not needed as
>>>> ordering is guaranteed. However, if the metadata scheme changes or
>>>> multiple streams are open, this guarantee might not be preserved.
>>>> This patch makes sure that all writes go through the semaphore, even for
>>>> synchronous I/O. This is consistent with pblk's write I/O model. It also
>>>> simplifies maintenance since changes in the metadata scheme could cause
>>>> ordering issues.
>>>> Signed-off-by: Javier González <javier@cnexlabs.com>
>>>> ---
>>>> drivers/lightnvm/pblk-core.c | 16 +++++++++++++++-
>>>> drivers/lightnvm/pblk.h | 1 +
>>>> 2 files changed, 16 insertions(+), 1 deletion(-)
>>>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>>>> index 767178185f19..1e4dc0c1ed88 100644
>>>> --- a/drivers/lightnvm/pblk-core.c
>>>> +++ b/drivers/lightnvm/pblk-core.c
>>>> @@ -558,6 +558,20 @@ int pblk_submit_io_sync(struct pblk *pblk, struct nvm_rq *rqd)
>>>> return ret;
>>>> }
>>>> +int pblk_submit_io_sync_sem(struct pblk *pblk, struct nvm_rq *rqd)
>>>> +{
>>>> + struct ppa_addr *ppa_list;
>>>> + int ret;
>>>> +
>>>> + ppa_list = (rqd->nr_ppas > 1) ? rqd->ppa_list : &rqd->ppa_addr;
>>>> +
>>>> + pblk_down_page(pblk, ppa_list, rqd->nr_ppas);
>>>
>>> If the debug stuff is killed inside __pblk_down_page, then ppa_list
>>> and rqd->nr_ppas does not need to be passed, and this function can be
>>> inlined in its caller. Can we kill it? I'll make the patch if you
>>> like.
>> Sounds good. Sure, please send - should I wait to resend this series?
>
> Will do. Yes, wait a bit. I'll post asap.

No hurry. Thanks!
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-08-29 15:43    [W:1.495 / U:0.432 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site