[dpdk-stable] [PATCH 19.11 1/2] mem: exclude unused memory from core dump
luca.boccassi at gmail.com
luca.boccassi at gmail.com
Mon Feb 22 12:58:39 CET 2021
From: Li Feng <fengli at smartx.com>
[ backported from upstream commit d72e4042c5ebda7af81448b387af8218136402d0 ]
Currently, even though memory is mapped with PROT_NONE, this does not
cause it to be excluded from core dumps. This is counter-productive,
because in a lot of cases, this memory will go unused (e.g. when the
memory subsystem preallocates VA space but hasn't yet mapped physical
pages into it).
Use `madvise()` call with MADV_DONTDUMP/MADV_NOCORE to exclude the
unused memory from being dumped.
Signed-off-by: Li Feng <fengli at smartx.com>
Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
As requested by Stephen. This stops coredumps from DPDK applications
from massively inflating in size with unused memory chunks.
lib/librte_eal/common/eal_common_memory.c | 15 +++++++++++++++
lib/librte_eal/linux/eal/eal_memalloc.c | 3 +++
2 files changed, 18 insertions(+)
diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index cc7d54e0c7..9a797a4fa3 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -40,6 +40,14 @@
static void *next_baseaddr;
static uint64_t system_page_sz;
+#ifdef RTE_EXEC_ENV_LINUX
+#define RTE_DONTDUMP MADV_DONTDUMP
+#elif RTE_EXEC_ENV_FREEBSD
+#define RTE_DONTDUMP MADV_NOCORE
+#else
+#error "madvise doesn't support this OS"
+#endif
+
#define MAX_MMAP_WITH_DEFINED_ADDR_TRIES 5
void *
eal_get_virtual_area(void *requested_addr, size_t *size,
@@ -179,6 +187,13 @@ eal_get_virtual_area(void *requested_addr, size_t *size,
munmap(aligned_end, after_len);
}
+ if (!unmap) {
+ /* Exclude these pages from a core dump. */
+ if (madvise(aligned_addr, *size, RTE_DONTDUMP) != 0)
+ RTE_LOG(DEBUG, EAL, "madvise failed: %s\n",
+ strerror(errno));
+ }
+
return aligned_addr;
}
diff --git a/lib/librte_eal/linux/eal/eal_memalloc.c b/lib/librte_eal/linux/eal/eal_memalloc.c
index 51d239de37..22f1ff68eb 100644
--- a/lib/librte_eal/linux/eal/eal_memalloc.c
+++ b/lib/librte_eal/linux/eal/eal_memalloc.c
@@ -710,6 +710,9 @@ free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
return -1;
}
+ if (madvise(ms->addr, ms->len, MADV_DONTDUMP) != 0)
+ RTE_LOG(DEBUG, EAL, "madvise failed: %s\n", strerror(errno));
+
exit_early = false;
/* if we're using anonymous hugepages, nothing to be done */
--
2.29.2
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