From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH, v2] mempool: avoid memory waste with large pagesize Date: Wed, 9 Mar 2016 13:12:06 -0800 Message-ID: <1457557926-4056-1-git-send-email-stephen@networkplumber.org> To: dev@dpdk.org Return-path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by dpdk.org (Postfix) with ESMTP id 27BCD2BD3 for ; Wed, 9 Mar 2016 22:11:55 +0100 (CET) Received: by mail-pa0-f47.google.com with SMTP id td3so22473393pab.2 for ; Wed, 09 Mar 2016 13:11:55 -0800 (PST) List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" If page size is large (like 64K on ARM) and object size is small then don't waste lots of memory by rounding up to page size. Instead, round up so that 1 or more objects all fit in a page. This preserves the requirement that an object must not a page or virt2phys would break, and makes sure 62K is not wasted per mbuf. Also, fix invalid use of printf (versus log) for error reporting. Signed-off-by: Stephen Hemminger --- v2 - fix trailer_size calculation, and replace printf with log lib/librte_mempool/rte_mempool.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c index f8781e1..ff08a1a 100644 --- a/lib/librte_mempool/rte_mempool.c +++ b/lib/librte_mempool/rte_mempool.c @@ -300,18 +300,23 @@ rte_mempool_calc_obj_size(uint32_t elt_size, uint32_t flags, if (! rte_eal_has_hugepages()) { /* * compute trailer size so that pool elements fit exactly in - * a standard page + * a standard page. If elements are smaller than a page + * then allow multiple elements per page */ - int page_size = getpagesize(); - int new_size = page_size - sz->header_size - sz->elt_size; - if (new_size < 0 || (unsigned int)new_size < sz->trailer_size) { - printf("When hugepages are disabled, pool objects " - "can't exceed PAGE_SIZE: %d + %d + %d > %d\n", - sz->header_size, sz->elt_size, sz->trailer_size, - page_size); + unsigned new_size, orig_size, page_size; + + page_size = getpagesize(); + orig_size = sz->header_size + sz->elt_size; + new_size = rte_align32pow2(orig_size); + if (new_size > page_size) { + RTE_LOG(ERR, MEMPOOL, + "When hugepages are disabled, pool objects " + "can't exceed PAGE_SIZE: %u + %u + %u > %u\n", + sz->header_size, sz->elt_size, sz->trailer_size, + page_size); return 0; } - sz->trailer_size = new_size; + sz->trailer_size = new_size - orig_size; } /* this is the size of an object, including header and trailer */ -- 2.1.4