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 1/2] memalloc: do not leave unmapped holes in EAL virtual memory area
Date: Fri, 1 Jun 2018 14:51:08 +0200 [thread overview]
Message-ID: <1527857469-159391-1-git-send-email-dariuszx.stojaczyk@intel.com> (raw)
EAL reserves a huge area in virtual address space
to provide virtual address contiguity for e.g.
future memory extensions (memory hotplug). During
memory hotplug, if the hugepage mmap succeeds but
doesn't suffice EAL's requiriments, the EAL would
unmap this mapping straight away, leaving a hole in
its virtual memory area and making it available
to everyone. As EAL still thinks it owns the entire
region, it may try to mmap it later with MAP_FIXED,
possibly overriding a user's mapping that was made
in the meantime.
This patch ensures each hole is mapped back by EAL,
so that it won't be available to anyone else.
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
---
lib/librte_eal/linuxapp/eal/eal_memalloc.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
index 8c11f98..b959ea5 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memalloc.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
@@ -39,6 +39,7 @@
#include "eal_filesystem.h"
#include "eal_internal_cfg.h"
#include "eal_memalloc.h"
+#include "eal_private.h"
/*
* not all kernel version support fallocate on hugetlbfs, so fall back to
@@ -490,6 +491,8 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
int ret = 0;
int fd;
size_t alloc_sz;
+ int flags;
+ void *new_addr;
/* takes out a read lock on segment or segment list */
fd = get_seg_fd(path, sizeof(path), hi, list_idx, seg_idx);
@@ -585,6 +588,20 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
mapped:
munmap(addr, alloc_sz);
+ flags = MAP_FIXED;
+#ifdef RTE_ARCH_PPC_64
+ flags |= MAP_HUGETLB;
+#endif
+ new_addr = eal_get_virtual_area(addr, &alloc_sz, alloc_sz, 0, flags);
+ if (new_addr != addr) {
+ if (new_addr != NULL) {
+ munmap(new_addr, alloc_sz);
+ }
+ /* We're leaving a hole in our virtual address space. If
+ * somebody else maps this hole now, we might accidentally
+ * override it in the future. */
+ rte_panic("can't mmap holes in our virtual address space");
+ }
resized:
if (internal_config.single_file_segments) {
resize_hugefile(fd, path, list_idx, seg_idx, map_offset,
--
2.7.4
next 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 Dariusz Stojaczyk [this message]
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 ` [dpdk-dev] [PATCH 2/2] memalloc: keep in mind a failed MAP_FIXED mmap may still perform an unmap Dariusz Stojaczyk
2018-06-01 11:08 ` 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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