Yes, some fields only used for special ops. But union may increase the
complexity of stuct.
And the extra memory may not a problem because "Ops" in one
transaction should be within ten.
On Thu, Jul 2, 2015 at 10:05 PM, Dałek, Piotr
<Piotr.Dalek@xxxxxxxxxxxxxx> wrote:
> Hello,
>
> In ObjectStore.h we have the following stuct:
>
> struct Op {
> __le32 op;
> __le32 cid;
> __le32 oid;
> __le64 off;
> __le64 len;
> __le32 dest_cid;
> __le32 dest_oid; //OP_CLONE, OP_CLONERANGE
> __le64 dest_off; //OP_CLONERANGE
> __le32 hint_type; //OP_COLL_HINT
> __le64 expected_object_size; //OP_SETALLOCHINT
> __le64 expected_write_size; //OP_SETALLOCHINT
> __le32 split_bits; //OP_SPLIT_COLLECTION2
> __le32 split_rem; //OP_SPLIT_COLLECTION2
> } __attribute__ ((packed)) ;
>
> Some of the fields (like hint_type and split_rem) are totally unused in certain ops, and they eat up space anyway. Maybe we should use unions here, and re-use some of the fields for other purposes? Right now the structure is 72 bytes in size, and for most ops, at least 32 bytes are always wasted.
>
>
> With best regards / Pozdrawiam
> Piotr Dałek
>
>
--
Best Regards,
Wheat
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