dm_crypt / kworker占用IO并导致系统冻结

Question

我不知道如何调试它，但是我注意到，如果我执行的任务需要大量磁盘读/写(例如更新一个大型postgres表)，定期实际读取和写入将降到0，而dm_crypt在iotop中显示99.9%的IO使用率。

最重要的是，随着多个kworker线程的产生，整个DE会经常冻结。鼠标继续工作，可以移动，但在30-60年代左右没有其他窗口响应。

CPU在整个时间处于低利用率，冻结过程与iotop中显示的多个kworker线程一致。

以下是冻结期的syslog输出

Oct 22 11:09:47 pop-os /usr/lib/gdm3/gdm-x-session[3348]: (EE) client bug: timer event5 debounce: scheduled expiry is in the past (-6ms), your system is too slow
Oct 22 11:09:47 pop-os /usr/lib/gdm3/gdm-x-session[3348]: (EE) client bug: timer event5 debounce short: scheduled expiry is in the past (-19ms), your system is too slow
Oct 22 11:10:12 pop-os gjs[184224]: JS ERROR: Gio.IOErrorEnum: Timeout was reached
                                    _proxyInvoker@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:139:46
                                    _makeProxyMethod/<@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:164:30
                                    makeAreaScreenshot@/home/anthony/.local/share/gnome-shell/extensions/gnome-shell-screenshot@ttll.de/auxhelper.js:78:33
                                    main/<@/home/anthony/.local/share/gnome-shell/extensions/gnome-shell-screenshot@ttll.de/auxhelper.js:190:21
                                    main@/home/anthony/.local/share/gnome-shell/extensions/gnome-shell-screenshot@ttll.de/auxhelper.js:204:30
                                    @/home/anthony/.local/share/gnome-shell/extensions/gnome-shell-screenshot@ttll.de/auxhelper.js:216:3
Oct 22 11:10:36 pop-os gnome-shell[3610]: JS ERROR: Error: cmd: gjs /home/anthony/.local/share/gnome-shell/extensions/gnome-shell-screenshot@ttll.de/auxhelper.js --filename /tmp/gnome-shell-screenshot-ZPGAT0.png --area 3640,809,948,419 exitCode=256
                                          callHelper/<@/home/anthony/.local/share/gnome-shell/extensions/gnome-shell-screenshot@ttll.de/selection.js:87:16
Oct 22 11:10:50 pop-os gnome-shell[3610]: ../clutter/clutter/clutter-actor.c:10558: The clutter_actor_set_allocation() function can only be called from within the implementation of the ClutterActor::allocate() virtual function.

postgres数据库存储在一个与操作系统分离的磁盘上，所以在写到它时，我的DE不应该冻结吗？有人对我如何进一步调试这个问题并找出问题的原因有什么建议吗？

pop-os 20.04

5.4.0-7634-generic

Answer 1

要解决这个问题，我必须编辑vm.dirty_ratio和vm.dirty_background_ratio。问题是，我写到磁盘的速度超过了磁盘所能处理的速度，而且每当缓存被填满时，系统就会冻结。