-Xms5g
-Xmx5g

## JVM configuration
################################################################
## IMPORTANT: JVM heap size
################################################################
##
## You should always set the min and max JVM heap
## size to the same value. For example, to set
## the heap to 4 GB, set:
##
## -Xms4g
## -Xmx4g
##
## See https://www.elastic.co/guide/en/elasticsearch/reference/current/heap-size.html
## for more information
##
################################################################
# Xms represents the initial size of total heap space
# Xmx represents the maximum size of total heap space
-Xms5g
-Xmx5g
################################################################
## Expert settings
################################################################
##
## All settings below this section are considered
## expert settings. Don't tamper with them unless
## you understand what you are doing
##
################################################################
## GC configuration
-XX:+UseConcMarkSweepGC
-XX:CMSInitiatingOccupancyFraction=75
-XX:+UseCMSInitiatingOccupancyOnly
## optimizations
# pre-touch memory pages used by the JVM during initialization
-XX:+AlwaysPreTouch
## basic
# force the server VM (remove on 32-bit client JVMs)
-server
# explicitly set the stack size (reduce to 320k on 32-bit client JVMs)
-Xss1m
# set to headless, just in case
-Djava.awt.headless=true
# ensure UTF-8 encoding by default (e.g. filenames)
-Dfile.encoding=UTF-8
# use our provided JNA always versus the system one
-Djna.nosys=true
# use old-style file permissions on JDK9
-Djdk.io.permissionsUseCanonicalPath=true
# flags to configure Netty
-Dio.netty.noUnsafe=true
-Dio.netty.noKeySetOptimization=true
-Dio.netty.recycler.maxCapacityPerThread=0
# log4j 2
-Dlog4j.shutdownHookEnabled=false
-Dlog4j2.disable.jmx=true
-Dlog4j.skipJansi=true
## heap dumps
# generate a heap dump when an allocation from the Java heap fails
# heap dumps are created in the working directory of the JVM
-XX:+HeapDumpOnOutOfMemoryError
# specify an alternative path for heap dumps
# ensure the directory exists and has sufficient space
#-XX:HeapDumpPath=${heap.dump.path}
## GC logging
#-XX:+PrintGCDetails
#-XX:+PrintGCTimeStamps
#-XX:+PrintGCDateStamps
#-XX:+PrintClassHistogram
#-XX:+PrintTenuringDistribution
#-XX:+PrintGCApplicationStoppedTime
# log GC status to a file with time stamps
# ensure the directory exists
#-Xloggc:${loggc}
# By default, the GC log file will not rotate.
# By uncommenting the lines below, the GC log file
# will be rotated every 128MB at most 32 times.
#-XX:+UseGCLogFileRotation
#-XX:NumberOfGCLogFiles=32
#-XX:GCLogFileSize=128M
# Elasticsearch 5.0.0 will throw an exception on unquoted field names in JSON.
# If documents were already indexed with unquoted fields in a previous version
# of Elasticsearch, some operations may throw errors.
#
# WARNING: This option will be removed in Elasticsearch 6.0.0 and is provided
# only for migration purposes.
#-Delasticsearch.json.allow_unquoted_field_names=true

docker run -d -i -t -m 256M --memory-swap 512M --name centos2.12 centos /bin/bash

-m, --memory 
# 內存限制大小，單位可以為 b,k,M,g；最小為4M
--memory-swap
# 內存+交換分區大小總限制
--memory-reservation # 預留內存大小；容器在宿主機最小占用內存；
--oom-kill-disable
# out-of-memory 內存溢出；限制kill容器進程，默認沒設置
--oom-score-adj
# 容器被 OOM killer 殺死的優先級，范圍是[-1000, 1000]，默認為 0
--memory-swappiness
# 用于設置容器的虛擬內存控制行為。值為 0~100 之間的整數
--kernel-memory
核心內存限制,最小為 4M。

--memory-swap 不是交換分區，而是 memory + swap 的大小；
容器的交換分區 swap = memory-swap - memory

memory-swap 不設置 或者設置為 0 ；
容器的交換分區 swap 大小就是 memory 的小大；
容器的進程使用最大內存 = memory + swap

當 memory-swap 設置為 -1 時；
容器內存大小為 memory 設置的大小；
交換分區大小為宿主機 swap 大小；
容器進程能使用的最大內存 = memory + 宿主機 swap 大小；

--oom-kill-disable
限制 kill 容器進程; （必須設置在 memory 之后才有限；）
docker run -d -i -t -m 256M --oom-kill-disable --name Centos-1 centos /bin/bash

核心內存包括：
stack pages（棧頁面）
slab pages
socket memory pressure
tcp memory pressure

docker run -d -i -t -m 500M --kernel-memory 128M --name Centos-2 centos /bin/bash
限制容器內存 256M；限制核心內存 128M 。
docker run -d -i -t --kernel-memory 128M --name Centos-3 centos /bin/bash
內存為宿主機memory大小， 限制核心內存 128M

--memory-swappiness就是用來設置這個比例的。
--memory-swappiness可以設置為從 0 到 100。
# 0 表示關閉匿名頁面交換。
# 100 表示所有的匿名頁都可以交換。默認情況下，如果不適用--memory-swappiness，則該值從父進程繼承而來。
docker run -d -i -t --memory-swappiness=0 --name Centos-4 centos /bin/bash
將--memory-swappiness設置為 0 可以保持容器的工作集，避免交換代理的性能損失。

sysctl vm.swappiness = 100 
# cat /proc/sys/vm/swappiness