[dpdk-dev] [PATCH] mempool: limit cache_size
Ananyev, Konstantin
konstantin.ananyev at intel.com
Mon May 18 14:41:23 CEST 2015
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Zoltan Kiss
> Sent: Monday, May 18, 2015 1:28 PM
> To: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] mempool: limit cache_size
>
> Hi,
>
> Any opinion on this patch?
>
> Regards,
>
> Zoltan
>
> On 13/05/15 19:59, Zoltan Kiss wrote:
> > Otherwise cache_flushthresh can be bigger than n, and
> > a consumer can starve others by keeping every element
> > either in use or in the cache.
> >
> > Signed-off-by: Zoltan Kiss <zoltan.kiss at linaro.org>
> > ---
> > lib/librte_mempool/rte_mempool.c | 3 ++-
> > lib/librte_mempool/rte_mempool.h | 2 +-
> > 2 files changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
> > index cf7ed76..ca6cd9c 100644
> > --- a/lib/librte_mempool/rte_mempool.c
> > +++ b/lib/librte_mempool/rte_mempool.c
> > @@ -440,7 +440,8 @@ rte_mempool_xmem_create(const char *name, unsigned n, unsigned elt_size,
> > mempool_list = RTE_TAILQ_CAST(rte_mempool_tailq.head, rte_mempool_list);
> >
> > /* asked cache too big */
> > - if (cache_size > RTE_MEMPOOL_CACHE_MAX_SIZE) {
> > + if (cache_size > RTE_MEMPOOL_CACHE_MAX_SIZE ||
> > + (uint32_t) cache_size * CACHE_FLUSHTHRESH_MULTIPLIER > n) {
> > rte_errno = EINVAL;
> > return NULL;
> > }
Why just no 'cache_size > n' then?
Konstantin
> > diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
> > index 9001312..a4a9610 100644
> > --- a/lib/librte_mempool/rte_mempool.h
> > +++ b/lib/librte_mempool/rte_mempool.h
> > @@ -468,7 +468,7 @@ typedef void (rte_mempool_ctor_t)(struct rte_mempool *, void *);
> > * If cache_size is non-zero, the rte_mempool library will try to
> > * limit the accesses to the common lockless pool, by maintaining a
> > * per-lcore object cache. This argument must be lower or equal to
> > - * CONFIG_RTE_MEMPOOL_CACHE_MAX_SIZE. It is advised to choose
> > + * CONFIG_RTE_MEMPOOL_CACHE_MAX_SIZE and n / 1.5. It is advised to choose
> > * cache_size to have "n modulo cache_size == 0": if this is
> > * not the case, some elements will always stay in the pool and will
> > * never be used. The access to the per-lcore table is of course
> >
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