java - native 内存分配 (mmap) 映射失败

Question

我开始面临 native 内存分配问题。我想可能与 -Xmx 和 -Xms 设置有关。设置此值的推荐方法是什么？

目前我有:-Xmx13G -Xms6G

我读到建议设置相同的值，但没有解释原因。

我得到的错误是:

    # There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 746061824 bytes for committing reserved memory.
# Possible reasons:
#   The system is out of physical RAM or swap space
#   In 32 bit mode, the process size limit was hit
#   Decrease number of Java threads
#   Decrease Java thread stack sizes (-Xss)
#   Set larger code cache with -XX:ReservedCodeCacheSize=
# This output file may be truncated or incomplete.
#
#  Out of Memory Error (os_linux.cpp:2627), pid=13528, tid=0x00007f2b0b5f5700
#
# JRE version: Java(TM) SE Runtime Environment (8.0_101-b13) (build 1.8.0_101-b13)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.101-b13 mixed mode linux-amd64 compressed oops)
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#

/proc/meminfo:
MemTotal:       16433112 kB
MemFree:          166336 kB
Buffers:          114324 kB
Cached:           398396 kB
SwapCached:            0 kB
Active:         15151496 kB
Inactive:         254348 kB
Active(anon):   14893020 kB
Inactive(anon):      604 kB
Active(file):     258476 kB
Inactive(file):   253744 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                12 kB
Writeback:             0 kB
AnonPages:      14892976 kB
Mapped:            24024 kB
Shmem:               696 kB
Slab:             349384 kB
SReclaimable:     187700 kB
SUnreclaim:       161684 kB
KernelStack:       43520 kB
PageTables:       276768 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     8216556 kB
Committed_AS:   33089080 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       31404 kB
VmallocChunk:   34359652884 kB
HardwareCorrupted:     0 kB
AnonHugePages:  13486080 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       28672 kB
DirectMap2M:    16879616 kB

Memory: 4k page, physical 16433112k(166336k free), swap 0k(0k free)

vm_info: Java HotSpot(TM) 64-Bit Server VM (25.101-b13) for linux-amd64 JRE (1.8.0_101-b13), built on Jun 22 2016 02:59:44 by "java_re" with gcc 4.3.0 20080428 (Red Hat 4.3.0-8)

Answer 1

您显然要求的远远超过您系统上实际可用的数量。您总共有 16GB，但已使用 90%，并且您没有任何交换空间，因此您无法获得 -Xms6G，更不用说更多 (-Xmx13G).

您需要找出哪些其他进程正在使用内存，例如 top 并按驻留内存排序(大写字母 O，然后是 q)，并在运行 JVM 之前停止足够的它们以释放至少 6GB。

那个，或者将你的物理内存加倍到 32GB，或者添加 16GB 的交换空间(但如果系统负载过重，这可能会导致抖动)。