From: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
To: dev@dpdk.org, Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Subject: [dpdk-dev] [PATCH 2/2] memalloc: keep in mind a failed MAP_FIXED mmap may still perform an unmap
Date: Fri, 1 Jun 2018 14:51:09 +0200 [thread overview]
Message-ID: <1527857469-159391-2-git-send-email-dariuszx.stojaczyk@intel.com> (raw)
In-Reply-To: <1527857469-159391-1-git-send-email-dariuszx.stojaczyk@intel.com>
This isn't documented in the manuals, but a failed
mmap(..., MAP_FIXED) may still unmap overlapping
regions. In such case, we need to remap these regions
back into our address space to ensure mem contiguity.
We do it unconditionally now on mmap failure just to
be safe.
Verified on Linux 4.9.0-4-amd64. I was getting
ENOMEM when trying to map in hugetlbfs with no space
left, but the previous anonymous mapping was still
being removed.
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
---
lib/librte_eal/linuxapp/eal/eal_memalloc.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
index b959ea5..e59ad6e 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memalloc.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
@@ -527,7 +527,13 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
if (va == MAP_FAILED) {
RTE_LOG(DEBUG, EAL, "%s(): mmap() failed: %s\n", __func__,
strerror(errno));
- goto resized;
+ if (errno == ENOMEM) {
+ /* mmap failed, but the previous region might have
+ * been unmapped anyway; try to remap it */
+ goto unmapped;
+ } else {
+ goto resized;
+ }
}
if (va != addr) {
RTE_LOG(DEBUG, EAL, "%s(): wrong mmap() address\n", __func__);
@@ -588,6 +594,7 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
mapped:
munmap(addr, alloc_sz);
+unmapped:
flags = MAP_FIXED;
#ifdef RTE_ARCH_PPC_64
flags |= MAP_HUGETLB;
--
2.7.4
next prev parent reply other threads:[~2018-06-01 9:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-01 12:51 [dpdk-dev] [PATCH 1/2] memalloc: do not leave unmapped holes in EAL virtual memory area Dariusz Stojaczyk
2018-06-01 11:00 ` Burakov, Anatoly
2018-06-01 12:22 ` Stojaczyk, DariuszX
2018-06-01 14:59 ` Burakov, Anatoly
2018-06-01 12:51 ` Dariusz Stojaczyk [this message]
2018-06-01 11:08 ` [dpdk-dev] [PATCH 2/2] memalloc: keep in mind a failed MAP_FIXED mmap may still perform an unmap Burakov, Anatoly
2018-06-01 12:41 ` Stojaczyk, DariuszX
2018-06-01 13:37 ` [dpdk-dev] [PATCH 1/2] memalloc: do not leave unmapped holes in EAL virtual memory area Dariusz Stojaczyk
2018-06-01 13:39 ` [dpdk-dev] [PATCH v2 " Dariusz Stojaczyk
2018-06-01 10:24 ` Stojaczyk, DariuszX
2018-06-01 11:14 ` Burakov, Anatoly
2018-06-01 12:59 ` [dpdk-dev] [PATCH v3 " Dariusz Stojaczyk
2018-06-01 12:59 ` [dpdk-dev] [PATCH v3 2/2] memalloc: keep in mind a failed MAP_FIXED mmap may still perform an unmap Dariusz Stojaczyk
2018-06-01 15:07 ` Burakov, Anatoly
2018-06-01 15:06 ` [dpdk-dev] [PATCH v3 1/2] memalloc: do not leave unmapped holes in EAL virtual memory area Burakov, Anatoly
2018-07-12 21:42 ` [dpdk-dev] [dpdk-stable] " Thomas Monjalon
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