Re: [dpdk-dev] [PATCH] malloc: respect SIZE_HINT_ONLY when looking for the biggest free elem

[Thomas Monjalon <thomas@monjalon.net>]

08/10/2018 11:02, Burakov, Anatoly:
> On 07-Oct-18 8:31 PM, Darek Stojaczyk wrote:
> > RTE_MEMZONE_SIZE_HINT_ONLY wasn't checked in any way,
> > causing size hints to be parsed as hard requirements.
> > This resulted in some allocations being failed prematurely.
> > 
> > Fixes: 68b6092bd3c7 ("malloc: allow reserving biggest element")
> > Cc: anatoly.burakov@intel.com
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
> > ---
> >   lib/librte_eal/common/malloc_heap.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
> > index ac7bbb3ba..d2a8bd8dc 100644
> > --- a/lib/librte_eal/common/malloc_heap.c
> > +++ b/lib/librte_eal/common/malloc_heap.c
> > @@ -165,7 +165,9 @@ find_biggest_element(struct malloc_heap *heap, size_t *size,
> >   		for (elem = LIST_FIRST(&heap->free_head[idx]);
> >   				!!elem; elem = LIST_NEXT(elem, free_list)) {
> >   			size_t cur_size;
> > -			if (!check_hugepage_sz(flags, elem->msl->page_sz))
> > +			if ((flags & RTE_MEMZONE_SIZE_HINT_ONLY) == 0 &&
> > +					!check_hugepage_sz(flags,
> > +						elem->msl->page_sz))
> >   				continue;
> 
> Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
> 
> Although to be frank, the whole concept of "reserving biggest available 
> memzone" is currently broken because of dynamic memory allocation. There 
> is currently no way to allocate "as many hugepages as you can", so we're 
> only looking at memory already allocated, which in the general case is 
> less than page size long (unless you use legacy mode or memory 
> preallocation switches).

Applied anyway, thanks