关于 zram 和 swapfile 的疑问

ifnk · 2021-12-01 10:04:32

我电脑是16g内存 , 500g 的 ssd
之前按照 archwiki 开的是 16g 的 swapfile

$ sudo dd if=/dev/nvme0n1p3 of=/swapfile bs=1G count=16

平时都不关机，然后开的ide 就放那边也不关(webstorm ,idea , rider ,pycharm ……) 所以内存和 swapfile 都占的快满了……

今早浏览网页的时候鼠标卡的很，然后开网页 tab 也慢，free -h 发现 swap 和内存都占满了……

然后就关机重启了，想着把 swapfile 拉大拉到了50g

但是百度了都说 swapfile 给你内存的 1倍就行了，还有说开了 swap 对硬盘读写有影响，影响ssd寿命 ……

然后又百度到了一个叫 zram 的东西，但是这个资料比较少，我只在 wiki 上面看到了这个

# modprobe zram
# echo lz4 > /sys/block/zram0/comp_algorithm
# echo 32G > /sys/block/zram0/disksize
# mkswap --label zram0 /dev/zram0
# swapon --priority 100 /dev/zram0

然后按照这个弄下来以后，我按 free -h 发现我有 81g 的交换空间了哈哈

$ free -h
total used free shared buff/cache available
内存： 14Gi 13Gi 238Mi 166Mi 1.2Gi 939Mi
交换： 81Gi 6.0Gi 76Gi

我就多开了好多网页来测试，发现一点也不卡 (也有可能是我刚关机，内存占用后面会慢慢变大的)

我平时的笔记本使用场景就是拿 jetbrains 的 ide 写代码，开 node 跑前端项目，开chrome 查资料或者看视频，偶尔用 docker ,不玩游戏 , 16g内存不开交换不够用

原来我本来想换一台 32g 的笔记本，现在我突然就不想换了，有这个交换内存技术，那我岂不是 16g 也够用了？

但是这个也是有副作用的吧？

百度说 zram 是消耗 cpu 来压缩内存的技术 ,也就是说会让 cpu 占用高

然后 swap 又会影响 ssd寿命

想问下我这么搞对电脑影响（副作用）大么？不大的话我就不换电脑了

还有开 zram 和 swapfile 同时开可以么？还是只开 zram 就可以了，zram 是不是越大越好？

我看 github 有个 zram-generator https://github.com/systemd/zram-generat … or.conf.md 项目是配置 zram config 的，我是按照 archwiki 配置 zram的，

这两种方式有什么区别么？

JerryXiao · 2021-12-01 10:50:03

你的物理内存16G zram你已经开了32G了，而且 priority 设置成了 100 ，我觉得你的swapfile应该很难被用到了。
同时开当然可以但是 priority 高的zram会先用，除非你已经用掉了32G的zram swap，(lz4 压缩的 zram 一般期望的压缩比是 2:1 左右，就是说你的16G物理内存已经基本用完了)，才会用到你的swapfile，但是如果真的到了那个时候，你的kernel肯定在疯狂回收内存，多半你这时候已经感觉系统"卡死"了。
所以如果你要用32G zram，swapfile就不是非常必要的了。而且zram自己有backing_dev可以把数据写入非易失性储存中(ssd)，这个和zram的配合远好于priority调节的swapfile。

JerryXiao · 2021-12-01 10:52:04

另外archlinux的kernel默认开启zswap，详情请看zswap的wiki页面，所以你以为你在用zram，实际上很可能是在在用zswap，包括你的swapfile也不一定就是写到ssd上了，很可能是zswap压缩一下又放回内存了

ifnk · 2021-12-02 09:30:45

JerryXiao 说：

另外archlinux的kernel默认开启zswap，详情请看zswap的wiki页面，所以你以为你在用zram，实际上很可能是在在用zswap，包括你的swapfile也不一定就是写到ssd上了，很可能是zswap压缩一下又放回内存了

大佬，我昨天用了一天 zram ,没关机，今早我的 webstorm 崩了 …… 然后我又开开，过一会又崩了 …… 会不会是 zram 引起的？我现在把 zram 禁用了，只用 swapfile ，看看 ide 会不会崩……

下面是 webstorm 的崩溃日志

#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGILL (0x4) at pc=0x00007efc73d08005, pid=1266841, tid=1331668
#
# JRE version: OpenJDK Runtime Environment JBR-11.0.13.7-1751.19-jcef (11.0.13+7) (build 11.0.13+7-b1751.19)
# Java VM: OpenJDK 64-Bit Server VM JBR-11.0.13.7-1751.19-jcef (11.0.13+7-b1751.19, mixed mode, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# J 51749 c1 com.intellij.codeInsight.daemon.impl.Divider.divideInsideAndOutsideInOneRoot(Lcom/intellij/psi/PsiFile;JJLjava/util/List;Lit/unimi/dsi/fastutil/longs/LongList;Ljava/util/List;Lit/unimi/dsi/fastutil/longs/LongList;Ljava/util/List;Lit/unimi/dsi/fastutil/longs/LongList;Z)V (706 bytes) @ 0x00007efc73d08005 [0x00007efc73d02bc0+0x0000000000005445]
#
# Core dump will be written. Default location: Core dumps may be processed with "/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h" (or dumping to /home/ifnk/core.1266841)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

--------------- S U M M A R Y ------------

Command Line: -Xms128m -Xmx750m -XX:ReservedCodeCacheSize=512m -XX:+IgnoreUnrecognizedVMOptions -XX:+UseG1GC -XX:SoftRefLRUPolicyMSPerMB=50 -XX:CICompilerCount=2 -XX:+HeapDumpOnOutOfMemoryError -XX:-OmitStackTraceInFastThrow -ea -Dsun.io.useCanonCaches=false -Djdk.http.auth.tunneling.disabledSchemes="" -Djdk.attach.allowAttachSelf=true -Djdk.module.illegalAccess.silent=true -Dkotlinx.coroutines.debug=off -Dsun.tools.attach.tmp.only=true -Xmx1859m -XX:ErrorFile=/home/ifnk/java_error_in_webstorm_%p.log -XX:HeapDumpPath=/home/ifnk/java_error_in_webstorm_.hprof -Djb.vmOptionsFile=/home/ifnk/.config/JetBrains/WebStorm2021.3/webstorm64.vmoptions -Djava.system.class.loader=com.intellij.util.lang.PathClassLoader -Didea.vendor.name=JetBrains -Didea.paths.selector=WebStorm2021.3 -Didea.platform.prefix=WebStorm -Dsplash=true com.intellij.idea.Main

Host: AMD Ryzen 5 5500U with Radeon Graphics, 12 cores, 14G, Arch Linux
Time: Thu Dec 2 09:16:46 2021 CST elapsed time: 1627.024258 seconds (0d 0h 27m 7s)

--------------- T H R E A D ---------------

Current thread (0x00007efb9427a000): JavaThread "JobScheduler FJ pool 8/11" daemon [_thread_in_Java, id=1331668, stack(0x00007efb5408e000,0x00007efb5418f000)]

Stack: [0x00007efb5408e000,0x00007efb5418f000], sp=0x00007efb5418d030, free space=1020k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
J 51749 c1 com.intellij.codeInsight.daemon.impl.Divider.divideInsideAndOutsideInOneRoot(Lcom/intellij/psi/PsiFile;JJLjava/util/List;Lit/unimi/dsi/fastutil/longs/LongList;Ljava/util/List;Lit/unimi/dsi/fastutil/longs/LongList;Ljava/util/List;Lit/unimi/dsi/fastutil/longs/LongList;Z)V (706 bytes) @ 0x00007efc73d08005 [0x00007efc73d02bc0+0x0000000000005445]
J 53225 c1 com.intellij.codeInsight.daemon.impl.Divider.divideInsideAndOutsideInOneRoot(Lcom/intellij/psi/PsiFile;JJLcom/intellij/util/Processor;)V (170 bytes) @ 0x00007efc7345b544 [0x00007efc7345ab60+0x00000000000009e4]
j com.intellij.codeInsight.daemon.impl.LineMarkersPass.doCollectInformation(Lcom/intellij/openapi/progress/ProgressIndicator;)V+120
J 54735 c2 com.intellij.codeHighlighting.TextEditorHighlightingPass.collectInformation(Lcom/intellij/openapi/progress/ProgressIndicator;)V (39 bytes) @ 0x00007efc81e746f8 [0x00007efc81e743e0+0x0000000000000318]
J 52612 c2 com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$$Lambda$3391.run()V (8 bytes) @ 0x00007efc810fd630 [0x00007efc810fd420+0x0000000000000210]
J 46333 c2 com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(Ljava/lang/Runnable;)Z (68 bytes) @ 0x00007efc818d2688 [0x00007efc818d2540+0x0000000000000148]
J 52611 c2 com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$$Lambda$3388.run()V (8 bytes) @ 0x00007efc80de2ff0 [0x00007efc80de2ec0+0x0000000000000130]
J 57991 c2 com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(Lcom/intellij/openapi/progress/ProgressIndicator;Ljava/lang/Thread;Lcom/intellij/openapi/progress/ProgressIndicator;Lcom/intellij/openapi/util/ThrowableComputable;)Ljava/lang/Object; (607 bytes) @ 0x00007efc820fa4f0 [0x00007efc820fa2a0+0x0000000000000250]
J 52502 c2 com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$$Lambda$3386.run()V (8 bytes) @ 0x00007efc811b5a18 [0x00007efc811b5140+0x00000000000008d8]
J 55918 c2 com.intellij.concurrency.JobLauncherImpl$VoidForkJoinTask$1.exec()Z (153 bytes) @ 0x00007efc813e7e70 [0x00007efc813e7c60+0x0000000000000210]
J 58375 c2 java.util.concurrent.ForkJoinTask.doExec()I java.base@11.0.13 (37 bytes) @ 0x00007efc8215580c [0x00007efc821557c0+0x000000000000004c]
J 31993 c2 java.util.concurrent.ForkJoinPool.scan(Ljava/util/concurrent/ForkJoinPool$WorkQueue;I)Z java.base@11.0.13 (209 bytes) @ 0x00007efc81091f28 [0x00007efc81091c80+0x00000000000002a8]
j java.util.concurrent.ForkJoinPool.runWorker(Ljava/util/concurrent/ForkJoinPool$WorkQueue;)V+25 java.base@11.0.13
j java.util.concurrent.ForkJoinWorkerThread.run()V+24 java.base@11.0.13
v ~StubRoutines::call_stub
V [libjvm.so+0x8766c3] JavaCalls::call_helper(JavaValue*, methodHandle const&, JavaCallArguments*, Thread*)+0x313
V [libjvm.so+0x874960] JavaCalls::call_virtual(JavaValue*, Klass*, Symbol*, Symbol*, JavaCallArguments*, Thread*)+0x160
V [libjvm.so+0x874a31] JavaCalls::call_virtual(JavaValue*, Handle, Klass*, Symbol*, Symbol*, Thread*)+0x81
V [libjvm.so+0x914f4c] thread_entry(JavaThread*, Thread*)+0x6c
V [libjvm.so+0xe05260] JavaThread::thread_main_inner()+0xd0
V [libjvm.so+0xe01369] Thread::call_run()+0x149
V [libjvm.so+0xbc580e] thread_native_entry(Thread*)+0xee

siginfo: si_signo: 4 (SIGILL), si_code: 2 (ILL_ILLOPN), si_addr: 0x00007efc73d08005

Register to memory mapping:

RAX=0x0000000095353468 is an oop: com.intellij.psi.impl.source.tree.PsiWhiteSpaceImpl
{0x0000000095353468} - klass: 'com/intellij/psi/impl/source/tree/PsiWhiteSpaceImpl'
RBX=0x00000000b41d2d30 is an oop: [Ljava.lang.Object;
{0x00000000b41d2d30} - klass: 'java/lang/Object'[]
- length: 10
RCX=0x0 is NULL
RDX=0x00000000b41d2d10 is pointing into object: [Ljava.lang.Object;
{0x00000000b41d2ce0} - klass: 'java/lang/Object'[]
- length: 10
RSP=0x00007efb5418d030 is pointing into the stack for thread: 0x00007efb9427a000
RBP=0x00007efb5418d428 is pointing into the stack for thread: 0x00007efb9427a000
RSI=0x0000000000000212 is an unknown value
RDI=0x00000000b41d2d18 is an oop: com.intellij.util.containers.Stack
{0x00000000b41d2d18} - klass: 'com/intellij/util/containers/Stack'
R8 =0x0000000000000030 is an unknown value
R9 =0x0000000000000001 is an unknown value
R10=0x0000000095353468 is an oop: com.intellij.psi.impl.source.tree.PsiWhiteSpaceImpl
{0x0000000095353468} - klass: 'com/intellij/psi/impl/source/tree/PsiWhiteSpaceImpl'
R11=0x00000000000006b8 is an unknown value
R12=0x0 is NULL
R13=0x00000000901de8b8 is an oop: java.lang.ThreadLocal
{0x00000000901de8b8} - klass: 'java/lang/ThreadLocal'
R14=0x000000000000002d is an unknown value
R15=0x00007efb9427a000 is a thread

Registers:
RAX=0x0000000095353468, RBX=0x00000000b41d2d30, RCX=0x0000000000000000, RDX=0x00000000b41d2d10
RSP=0x00007efb5418d030, RBP=0x00007efb5418d428, RSI=0x0000000000000212, RDI=0x00000000b41d2d18
R8 =0x0000000000000030, R9 =0x0000000000000001, R10=0x0000000095353468, R11=0x00000000000006b8
R12=0x0000000000000000, R13=0x00000000901de8b8, R14=0x000000000000002d, R15=0x00007efb9427a000
RIP=0x00007efc73d08005, EFLAGS=0x0000000000010213, CSGSFS=0x002b000000000033, ERR=0x0000000000000000
TRAPNO=0x0000000000000006

Top of Stack: (sp=0x00007efb5418d030)
0x00007efb5418d030: 000000000000db05 00007efc80f406c4
0x00007efb5418d040: 0000000095682e50 0000000094789e30
0x00007efb5418d050: 000000009127e7e8 0000000094789e30
0x00007efb5418d060: 0000000300000002 00000000b41d2b10

Instructions: (pc=0x00007efc73d08005)
0x00007efc73d07f05: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f15: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f25: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f35: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f45: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f55: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f65: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f75: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f85: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07f95: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07fa5: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07fb5: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07fc5: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07fd5: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07fe5: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d07ff5: 00 00 00 00 00 00 00 00 00 00 00 00 c2 26 00 c2
0x00007efc73d08005: 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x00007efc73d08015: 00 01 00 c2 28 00 01 80 e5 01 e6 02 00 ea 02 03
0x00007efc73d08025: 03 d8 01 00 00 19 00 c2 21 00 00 00 00 01 00 00
0x00007efc73d08035: c4 22 00 c2 1d 00 c2 1e 00 c2 1f 00 c2 47 00 c2
0x00007efc73d08045: 48 00 c2 49 00 c1 4a 00 c1 23 00 e1 23 00 c2 25
0x00007efc73d08055: 00 c2 26 00 c2 27 00 c2 28 00 c2 29 00 c2 2c 00
0x00007efc73d08065: c1 2a 00 00 00 00 00 00 00 00 00 01 90 fa 02 00
0x00007efc73d08075: 00 ff 03 04 0a ac 00 00 19 00 c2 21 00 00 00 00
0x00007efc73d08085: 01 00 00 c4 22 00 c2 1d 00 c2 1e 00 c2 1f 00 c2
0x00007efc73d08095: 47 00 c2 48 00 c2 49 00 c1 4a 00 c1 23 00 e1 23
0x00007efc73d080a5: 00 c2 25 00 c2 26 00 c2 27 00 c2 28 00 c2 29 00
0x00007efc73d080b5: c2 2c 00 c1 2a 00 c2 25 00 c1 2d 00 e1 2a 00 00
0x00007efc73d080c5: 00 01 b1 cd 04 00 00 19 00 c2 21 00 00 00 00 01
0x00007efc73d080d5: 00 00 c4 22 00 c2 1d 00 c2 1e 00 c2 1f 00 c2 47
0x00007efc73d080e5: 00 c2 48 00 c2 49 00 c1 4a 00 c1 23 00 e1 23 00
0x00007efc73d080f5: c2 25 00 c2 26 00 c2 27 00 c2 28 00 c2 29 00 c2

Stack slot to memory mapping:
stack at sp + 0 slots: 0x000000000000db05 is an unknown value
stack at sp + 1 slots: 0x00007efc80f406c4 is at entry_point+100 in (nmethod*)0x00007efc80f40490
stack at sp + 2 slots: 0x0000000095682e50 is an oop: java.util.HashMap$Node
{0x0000000095682e50} - klass: 'java/util/HashMap$Node'
stack at sp + 3 slots: 0x0000000094789e30 is an oop: com.intellij.openapi.vfs.newvfs.impl.VirtualFileImpl
{0x0000000094789e30} - klass: 'com/intellij/openapi/vfs/newvfs/impl/VirtualFileImpl'
stack at sp + 4 slots: 0x000000009127e7e8 is an oop: com.intellij.openapi.project.impl.ProjectExImpl
{0x000000009127e7e8} - klass: 'com/intellij/openapi/project/impl/ProjectExImpl'
stack at sp + 5 slots: 0x0000000094789e30 is an oop: com.intellij.openapi.vfs.newvfs.impl.VirtualFileImpl
{0x0000000094789e30} - klass: 'com/intellij/openapi/vfs/newvfs/impl/VirtualFileImpl'
stack at sp + 6 slots: 0x0000000300000002 is an unknown value
stack at sp + 7 slots: 0x00000000b41d2b10 is an oop: [Lcom.intellij.openapi.roots.GeneratedSourcesFilter;
{0x00000000b41d2b10} - klass: 'com/intellij/openapi/roots/GeneratedSourcesFilter'[]
- length: 3

com.intellij.diagnostic.JBRCrash

SamLukeYes · 2021-12-02 10:32:18

zram 不宜和 zswap 同时使用，但 Arch 的内核是默认开启 zswap 的，如果要使用 zram 的话应该加上内核参数 zswap.enabled=0

Arch Linux

#1 2021-12-01 10:04:32

关于 zram 和 swapfile 的疑问

#2 2021-12-01 10:50:03

Re: 关于 zram 和 swapfile 的疑问

#3 2021-12-01 10:52:04

Re: 关于 zram 和 swapfile 的疑问

#4 2021-12-02 09:30:45

Re: 关于 zram 和 swapfile 的疑问

#5 2021-12-02 10:32:18

Re: 关于 zram 和 swapfile 的疑问

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