From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH, v2] mempool: avoid memory waste with large pagesize
Date: Wed, 9 Mar 2016 13:12:06 -0800 [thread overview]
Message-ID: <1457557926-4056-1-git-send-email-stephen@networkplumber.org> (raw)
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 <stephen@networkplumber.org>
---
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
next reply other threads:[~2016-03-09 21:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 21:12 Stephen Hemminger [this message]
2016-03-10 8:37 ` Olivier MATZ
2016-03-10 10:48 ` Ferruh Yigit
2016-03-10 11:12 ` Olivier MATZ
2016-03-11 4:09 ` Stephen Hemminger
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