Messages in this thread | | | Subject | Re: [PATCH 1/4] lightnvm: add sync and close block I/O types | From | Matias Bjørling <> | Date | Thu, 5 May 2016 12:08:40 +0200 |
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On 05/05/2016 11:38 AM, Javier González wrote: > >> On 05 May 2016, at 11:21, Matias Bjørling <mb@lightnvm.io> wrote: >> >> On 05/04/2016 05:31 PM, Javier González wrote: >>> Within a target, I/O requests stem from different paths, which might vary >>> in terms of the data structures being allocated, context, etc. This >>> might impact how the request is treated, or how memory is freed once >>> the bio is completed. >>> >>> Add two different types of I/Os: (i) NVM_IOTYPE_SYNC, which indicates >>> that the I/O is synchronous; and (ii) NVM_IOTYPE_CLOSE_BLK, which >>> indicates that the I/O closes the block to which all the ppas on the >>> request belong to. >>> >>> Signed-off-by: Javier González <javier@cnexlabs.com> >>> --- >>> include/linux/lightnvm.h | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h >>> index 29a6890..6c02209 100644 >>> --- a/include/linux/lightnvm.h >>> +++ b/include/linux/lightnvm.h >>> @@ -11,6 +11,8 @@ enum { >>> >>> NVM_IOTYPE_NONE = 0, >>> NVM_IOTYPE_GC = 1, >>> + NVM_IOTYPE_SYNC = 2, >>> + NVM_IOTYPE_CLOSE_BLK = 4, >>> }; >>> >>> #define NVM_BLK_BITS (16) >> >> The sync should not be necessary when the read path is implemented >> using bio_clone. Similarly for NVM_IOTYPE_CLOSE_BLK. The write >> completion can be handled in the bio completion path. > > We need to know where the request comes from; we cannot do it just from > having the bio. This is because we allocate different structures > depending on the type of bio we send. It is not only which bio->end_io > function we have, but which memory needs to be released. Sync is > necessary for the read path when we have a partial bio (data both on > write buffer and disk) that we need to fill up. Also for GC.. In this > case, the bio is to be freed differently. In the case of close the case > is similarly; we do not free memory on the end_io path, but on the caller. > > You can see how these flags are used on pblk. Maybe there is a better > way of doing it that I could not see... >
Use the bio completion path for both. For bio completion, free the data that is specific to the pblk flow and let the nvm_rq->end_io() completion path clean up the nvm_rq specific data. That will clean up the completion paths.
> Javier >
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