From 462321b44a801493ce2eb67bd73564e509a82f45 Mon Sep 17 00:00:00 2001 From: Zoltan Kiss Date: Mon, 18 May 2015 16:35:14 +0100 Subject: [PATCH] mempool: limit cache size 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 Acked-by: Konstantin Ananyev Acked-by: Olivier Matz --- lib/librte_mempool/rte_mempool.c | 8 +++++--- lib/librte_mempool/rte_mempool.h | 2 +- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c index cf7ed761ed..01972ba010 100644 --- a/lib/librte_mempool/rte_mempool.c +++ b/lib/librte_mempool/rte_mempool.c @@ -68,6 +68,8 @@ static struct rte_tailq_elem rte_mempool_tailq = { EAL_REGISTER_TAILQ(rte_mempool_tailq) #define CACHE_FLUSHTHRESH_MULTIPLIER 1.5 +#define CALC_CACHE_FLUSHTHRESH(c) \ + ((typeof(c))((c) * CACHE_FLUSHTHRESH_MULTIPLIER)) /* * return the greatest common divisor between a and b (fast algorithm) @@ -440,7 +442,8 @@ 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 || + CALC_CACHE_FLUSHTHRESH(cache_size) > n) { rte_errno = EINVAL; return NULL; } @@ -565,8 +568,7 @@ rte_mempool_xmem_create(const char *name, unsigned n, unsigned elt_size, mp->header_size = objsz.header_size; mp->trailer_size = objsz.trailer_size; mp->cache_size = cache_size; - mp->cache_flushthresh = (uint32_t) - (cache_size * CACHE_FLUSHTHRESH_MULTIPLIER); + mp->cache_flushthresh = CALC_CACHE_FLUSHTHRESH(cache_size); mp->private_data_size = private_data_size; /* calculate address of the first element for continuous mempool. */ diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h index 90013128ce..a4a9610423 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 -- 2.20.1