当usbnet打印 kevent * may have been dropped(转)
http://patchwork.ozlabs.org/patch/815639/
Every once in a while when my system is under a bit of stress I see
some spammy messages show up in my logs that say: kevent X may have been dropped As far as I can tell these messages aren't terribly useful. The
comments around the messages make me think that either workqueues used
to work differently or that the original author of the code missed a
sublety related to them. The error message appears to predate the git
conversion of the kernel so it's somewhat hard to tell. Specifically, workqueues should work like this: A) If a workqueue hasn't been scheduled then schedule_work() schedules
it and returns true. B) If a workqueue has been scheduled (but hasn't started) then
schedule_work() will do nothing and return false. C) If a workqueue has been scheduled (and has started) then
schedule_work() will put it on the queue to run again and return
true. Said another way: if you call schedule_work() you can guarantee that
at least one full runthrough of the work will happen again. That
should mean that the work will get processed and I don't see any
reason to think something should be dropped. Reading the comments in in usbnet_defer_kevent() made me think that B)
and C) would be treated the same. That is: even if we've started the
work and are 99% of the way through then schedule_work() would return
false and the work wouldn't be queued again. If schedule_work()
really did behave that way then, truly, some amount of work would be
lost. ...but it doesn't. NOTE: if somehow these warnings are useful to mean something then
perhaps we should change them to make it more obvious. If it's
interesting to know when the work is backlogged then we should change
the spam to say "warning: usbnet is backlogged". ALSO NOTE: If somehow some of the types of work need to be repeated if
usbnet_defer_kevent() is called multiple times then that should be
quite easy to accomplish without dropping any work on the floor. We
can just keep an atomic count for that type of work and add a loop
into usbnet_deferred_kevent().
当usbnet打印 kevent * may have been dropped(转)的更多相关文章
- USB_ModeSwitch for Android 7
USB_ModeSwitch官网: USB_ModeSwitch - Handling Mode-Switching USB Devices on Linux USB_ModeSwitch for A ...
- usbnet驱动深入分析-usb虚拟网卡host端【转】
转自:http://blog.csdn.net/zh98jm/article/details/6339320 1.驱动流程: 2.明确probe函数的功能: probe有usb core 经枚举过 ...
- Snort里如何将一个tcpdump格式的二进制文件读取打印到屏幕上(图文详解)
不多说,直接上干货! 关于tcpdump二进制格式,这个基本概念不说. 支持tcpdump二进制格式的嗅探器工具,这里我说两个:tcpdump或者ethereal. [root@datatest Se ...
- ASP.NET MVC5+EF6+EasyUI 后台管理系统(55)-Web打印
系列目录 前言 1.本次主要弥补工作流,用户表单数据的打印 2.使用JQprint做为web打印插件 3.兼容:FireFox,Chrome,IE. 4.没有依赖也没有配置,使用简单 代码下载:htt ...
- C#中5步完成word文档打印的方法
在日常工作中,我们可能常常需要打印各种文件资料,比如word文档.对于编程员,应用程序中文档的打印是一项非常重要的功能,也一直是一个非常复杂的工作.特别是提到Web打印,这的确会很棘手.一般如果要想选 ...
- 开源免费且稳定实用的.NET PDF打印组件itextSharp(.NET组件介绍之八)
在这个.NET组件的介绍系列中,受到了很多园友的支持,一些园友(如:数据之巅. [秦时明月]等等这些大神 )也给我提出了对应的建议,我正在努力去改正,有不足之处还望大家多多包涵.在传播一些简单的知识的 ...
- Ajax使用WCF实现小票pos机打印源码
通过ajax跨域方式调用WCF服务,实现小票pos机的打印,源码提供web方式,客户端方式测试,服务驻留右侧底部任务栏,可控制服务开启暂停,用户可自定义小票打印模板,配合零售录入. qq 22945 ...
- Jqprint实现页面打印
好些项目需要实现页面打印,特别是一些后台管理类系统,下面介绍一款轻量级的打印插件: 1.实现页面打印要引入jQuery和Jqprint.点击下载Jqprint插件 <script languag ...
- Android连接网络打印机进行打印
首先这是网络打印工具类,通过Socket实现,多说一句,网络打印机端口号一般默认的是9100 package com.Ieasy.Tool; import android.annotation.Sup ...
随机推荐
- 【微信小程序】mpvue中页面之间传值(全网唯一真正可行的方法,中指推了一下隐形眼镜)
摘要: mpvue中页面之间传值(注意:是页面之间,不是组件之间) 场景:A页面跳转B页面,在B页面选择商品,将商品名带回A页面并显示 使用api: getCurrentPages step1: A页 ...
- 手把手教你如何用 OpenCV + Python 实现人脸检测
配好了OpenCV的Python环境,OpenCV的Python环境搭建.于是迫不及待的想体验一下opencv的人脸识别,如下文. 必备知识 Haar-like Haar-like百科释义.通俗的来讲 ...
- yii2自定义验证规则
- CSP-S 爆零记
抱歉,这么晚才更. 事实是:我都没有去 所以爆零了 QwQ
- WPF的DataGrid的某个列绑定数据的三种方法(Binding、Converter、DataTrigger)
最近在使用WPF的时候,遇到某个列的值需要根据内容不同进行转换显示的需求.尝试了一下,大概有三种方式可以实现: 1.传统的Binding方法,后台构造好数据,绑定就行. 2.转换器方法(Convert ...
- 解决真机编译出现System.DllNotFoundException: 'libmono-native.so'错误都方法
1.去掉勾选:使用共享运行时 2 检查android SDK是否安装了NDK 3.使用真机运行编译APK
- DB2 catalog 编目
(步骤)ap用户: (1)进入db2 db2 (2)catalog database 命令 catalog db list (3)查看本地节点目录.IP.节点名.服务名称.目录条目类型 list no ...
- 为Dynamics CRM注释的图片附件做个预览功能
关注本人微信和易信公众号: 微软动态CRM专家罗勇 ,回复163或者20151017可方便获取本文,同时可以在第一时间得到我发布的最新的博文信息,follow me! Dynamics CRM中注释可 ...
- Windows下的DNS命令用法
- ipconfig 查看DNS缓存内容: ipconfig /displaydns 将显示所有缓存的DNS解析结果. 清空DNS缓存内容: ipconfig /flushdns 将清空缓存的DNS解 ...
- Python上下文管理器的使用
上下文管理器可以控制代码块执行前的准备动作,以及执行后的清理动作. 创建一个上下文管理器类的步骤:(1)一个__init__方法,来完成初始化(可选)(2)一个__enter__方法,来完成所有建立工 ...