在Linux下,如何发现哪个进程使用交换空间更多?


当前回答

与@lolotux相同的答案,但有排序输出:

printf 'Computing swap usage...\n';
swap_usages="$(
    SUM=0
    OVERALL=0

    for DIR in `find /proc/ -maxdepth 1 -type d -regex "^/proc/[0-9]+"`
    do
        PID="$(printf '%s' "$DIR" | cut -d / -f 3)"
        PROGNAME=`ps -p $PID -o comm --no-headers`
        for SWAP in `grep VmSwap $DIR/status 2>/dev/null | awk '{ print $2 }'`
        do
            let SUM=$SUM+$SWAP
        done
        if (( $SUM > 0 )); then
            printf "$SUM KB ($PROGNAME) swapped PID=$PID\\n"
        fi
        let OVERALL=$OVERALL+$SUM
        SUM=0
        break
    done
    printf '9999999999 Overall swap used: %s KB\n' "$OVERALL"
)"

printf '%s' "$swap_usages" | sort -nk1

示例输出:

Computing swap usage...
2064 KB (systemd) swapped PID=1
59620 KB (xfdesktop) swapped PID=21405
64484 KB (nemo) swapped PID=763627
66740 KB (teamviewerd) swapped PID=1618
68244 KB (flameshot) swapped PID=84209
763136 KB (plugin_host) swapped PID=1881345
1412480 KB (java) swapped PID=43402
3864548 KB (sublime_text) swapped PID=1881327
9999999999 Overall swap used: 2064 KB

其他回答

另一种在shell中避免循环的脚本变体:

#!/bin/bash
grep VmSwap /proc/[0-9]*/status | awk -F':' -v sort="$1" '
  {
    split($1,pid,"/") # Split first field on /
    split($3,swp," ") # Split third field on space
    cmdlinefile = "/proc/"pid[3]"/cmdline" # Build the cmdline filepath
    getline pname[pid[3]] < cmdlinefile # Get the command line from pid
    swap[pid[3]] = sprintf("%6i %s",swp[1],swp[2]) # Store the swap used (with unit to avoid rebuilding at print)
    sum+=swp[1] # Sum the swap
  }
  END {
    OFS="\t" # Change the output separator to tabulation
    print "Pid","Swap used","Command line" # Print header
    if(sort) {
      getline max_pid < "/proc/sys/kernel/pid_max"
      for(p=1;p<=max_pid;p++) {
        if(p in pname) print p,swap[p],pname[p] # print the values
      }
    } else {
      for(p in pname) { # Loop over all pids found
        print p,swap[p],pname[p] # print the values
      }
    }
    print "Total swap used:",sum # print the sum
  }'

标准用法是script.sh以随机顺序获取每个程序的使用情况(直到awk如何存储其哈希值)或script.sh 1以pid对输出进行排序。

我希望我已经对代码进行了足够的注释,以说明它的功能。

运行top,然后按OpEnter。现在进程应该根据它们的交换使用情况进行排序。

这是一个更新,因为我原来的答案没有提供一个确切的答案,在评论中指出的问题。从htop常见问题:

It is not possible to get the exact size of used swap space of a process. Top fakes this information by making SWAP = VIRT - RES, but that is not a good metric, because other stuff such as video memory counts on VIRT as well (for example: top says my X process is using 81M of swap, but it also reports my system as a whole is using only 2M of swap. Therefore, I will not add a similar Swap column to htop because I don't know a reliable way to get this information (actually, I don't think it's possible to get an exact number, because of shared pages).

这是我的一句话:

cat /proc/*/status | grep -E 'VmSwap:|Name:' | grep VmSwap -B1 | cut -d':' -f2 | grep -v '\-\-' | grep -o -E '[a-zA-Z0-9]+.*$' | cut -d' ' -f1 | xargs -n2 echo | sort -k2 -n

这一行的步骤是:

Get all the data in /proc/process/status for all processes Select the fields VmSwap and Name for each Remove the processes that don't have the VmSwap field Remove the names of the fields (VmSwap: and Name:) Remove lines with -- that were added by the previous step Remove the spaces at the start of the lines Remove the second part of each process name and " kB" after the swap usage number Take name and number (process name and swap usage) and put them in one line, one after the other Sort the lines by the swap usage

自2015年内核补丁添加SwapPss (https://lore.kernel.org/patchwork/patch/570506/)以来,人们终于可以得到成比例的交换计数,这意味着如果一个进程交换了很多,然后它分叉,两个分叉的进程将分别报告交换50%。如果其中一个发生分叉,每个进程被计算为交换页面的33%,所以如果你把所有的交换使用量计算在一起,你得到的是真实的交换使用量,而不是数值乘以进程数。

简而言之:

(cd /proc; for pid in [0-9]*; do printf "%5s %6s %s\n" "$pid" "$(awk 'BEGIN{sum=0} /SwapPss:/{sum+=$2} END{print sum}' $pid/smaps)" "$(cat $pid/comm)"; done | sort -k2n,2 -k1n,1)

第一列是pid,第二列是KiB中的交换使用情况,其余一行是正在执行的命令。相同的交换计数按pid排序。

上面可能会发出这样的行

awk: cmd. line:1: fatal: cannot open file `15407/smaps' for reading (No such file or directory)

这仅仅意味着pid为15407的进程在/proc/的列表中看到它和读取进程smaps文件之间结束。如果这对您来说很重要,只需在末尾添加2>/dev/null即可。请注意,您可能还会丢失任何其他可能的诊断。

在现实世界的示例案例中,这改变了其他报告在一台服务器上运行的每个apache子服务器使用约40 MB交换空间的工具,而每个子服务器实际使用7-3630 KB交换空间。

您可以使用Procpath(作者在这里),以简化从/proc/$PID/status解析vmswwap。

$ procpath record -f stat,cmdline,status -r 1 -d db.sqlite
$ sqlite3 -column db.sqlite \
  'SELECT status_name, status_vmswap FROM record ORDER BY status_vmswap DESC LIMIT 5'
Web Content  192136       
okular       186872       
thunderbird  183692       
Web Content  143404       
MainThread   86300

您还可以像这样绘制感兴趣的进程的vmswwap。在这里,我正在记录Firefox进程树,同时打开几十个选项卡,并启动一个占用大量内存的应用程序,试图导致它进行交换(这对Firefox来说并不令人信服,但您的情况可能不同)。

$ procpath record -f stat,cmdline,status -i 1 -d db2.sqlite \
  '$..children[?(@.stat.pid == 6029)]'
# interrupt by Ctrl+C
$ procpath plot -d db2.sqlite -q cpu --custom-value-expr status_vmswap \
  --title "CPU usage, % vs Swap, kB"