Messages in this thread | | | Subject | Re: [PATCH 3/3] lightnvm: pblk: take write semaphore on metadata | From | Matias Bjørling <> | Date | Wed, 29 Aug 2018 15:40:26 +0200 |
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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.
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