Re: [dpdk-dev] [PATCH] mempool: fix search of maximum contiguous pages

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> 
> > > > diff --git a/lib/librte_mempool/rte_mempool.c
> > > > b/lib/librte_mempool/rte_mempool.c
> > > > index 71017e1..e3e254a 100644
> > > > --- a/lib/librte_mempool/rte_mempool.c
> > > > +++ b/lib/librte_mempool/rte_mempool.c
> > > > @@ -426,9 +426,12 @@ rte_mempool_populate_phys_tab(struct
> > > > rte_mempool *mp, char *vaddr,
> > > >
> > > >  	for (i = 0; i < pg_num && mp->populated_size < mp->size; i += n) {
> > > >
> > > > +		phys_addr_t paddr_next;
> > > > +		paddr_next = paddr[i] + pg_sz;
> > > > +
> > > >  		/* populate with the largest group of contiguous pages */
> > > >  		for (n = 1; (i + n) < pg_num &&
> > > > -			     paddr[i] + pg_sz == paddr[i+n]; n++)
> > > > +			     paddr_next == paddr[i+n]; n++, paddr_next += pg_sz)
> > > >  			;
> > >
> > > Good catch.
> > > Why not just paddr[i + n - 1] != paddr[i + n]?
> >
> > Sorry, I meant 'paddr[i + n - 1] + pg_sz == paddr[i+n]' off course.
> >
> > > Then you don't need extra variable (paddr_next) here.
> > > Konstantin
> 
> Thank you, Konstantin
> 'paddr[i + n - 1] + pg_sz = paddr[i + n]' also can fix it and have straight meaning.
> But I assume that my revision with paddr_next += pg_sz may have a bit better performance.

I don't think there would be any real difference, again it is not performance critical code-path.

> By the way, paddr[i] + n * pg_sz = paddr[i + n] can also resolve it.

Yes, that's one seems even better for me - make things more clear.
Konstantin

> 
> /Wei
> 
> > >
> > > >
> > > >  		ret = rte_mempool_populate_phys(mp, vaddr + i * pg_sz,
> > > > --
> > > > 2.7.4