linux-kernel

问题 I run a SPECJbb benchmark in my KVM virtual machine. It shows a drastic drop on throughput between Warehouse 2 and Warehouse 3(The different between them is just addding on cocurrent task) Then I use perf in my guest virtual machine. It shows that _spin_unlock_irqrestore has very high sampling rate. Events: 31K cycles 74.89% [kernel] [k] _spin_unlock_irqrestore 7.36% perf-1968.map [.] 0x7f84b913e064 6.82% [kernel] [k] __do_softirq 6.39% [kernel] [k] handle_IRQ_event ... It seems that only 7

问题 I run a SPECJbb benchmark in my KVM virtual machine. It shows a drastic drop on throughput between Warehouse 2 and Warehouse 3(The different between them is just addding on cocurrent task) Then I use perf in my guest virtual machine. It shows that _spin_unlock_irqrestore has very high sampling rate. Events: 31K cycles 74.89% [kernel] [k] _spin_unlock_irqrestore 7.36% perf-1968.map [.] 0x7f84b913e064 6.82% [kernel] [k] __do_softirq 6.39% [kernel] [k] handle_IRQ_event ... It seems that only 7

问题 I'm trying to add a simple helloworld System Call to kernel 3.13.0-37-generic on 64 bit system. I'll try to show what I did so far step by step : 1- I've downloaded kernel source by : sudo apt-get source linux-image-3.13.0-37-generic After that, kernel source files extracted to /usr/src/ 2- Define a new system call sys_hello() : I've created a directory with hello name in the kernel source directory in /usr/src/linux-3.13/ And I created a hello.c file in hello directory with below content :

问题 I'm trying to add a simple helloworld System Call to kernel 3.13.0-37-generic on 64 bit system. I'll try to show what I did so far step by step : 1- I've downloaded kernel source by : sudo apt-get source linux-image-3.13.0-37-generic After that, kernel source files extracted to /usr/src/ 2- Define a new system call sys_hello() : I've created a directory with hello name in the kernel source directory in /usr/src/linux-3.13/ And I created a hello.c file in hello directory with below content :

问题 I need to disable a CONFIG_STRICT_DEVMEM option in my Linux kernel and recompile it. Why? I was told to do so. I know I can disable it by simply commenting it out in the .config file, but I need to see how it is done through make menuconfig or make nconfig . Why? This is for a demo and I need to be able to show it. Does anyone know how to do it? Any help is appreciated. 回答1: If you don't know your way around menuconfig, hit / to search (à la vim and friends), and type in enough of the config

问题 I'm working on sensor data acquisition in Android (Jelly Bean on Samsung Galaxy S3). I'm new to Android/Linux internals. I'm trying to read Android sources on how the sensor samples rise from the drivers to userspace. As a reference take a look here. I can go all the way from the SensorManager down to the SensorService. I can see the kernel module loading infrastructure, the registration of the event input device and the input_report_rel() function calls in the drivers (e.g. the open-sourced

问题 I'm working on sensor data acquisition in Android (Jelly Bean on Samsung Galaxy S3). I'm new to Android/Linux internals. I'm trying to read Android sources on how the sensor samples rise from the drivers to userspace. As a reference take a look here. I can go all the way from the SensorManager down to the SensorService. I can see the kernel module loading infrastructure, the registration of the event input device and the input_report_rel() function calls in the drivers (e.g. the open-sourced

问题 I am trying to write a netfilter module and want to access the fields of the IPHeader that denotes the DF and MF fields. I can access most other fields as desired but I think I have to extract the DF and MF fields from the ipheader in the struct and manipulate them say for example I want to set or unset the DF bit depending on the type of packet I receive. The below structure has 'frag_off' how do I access/rewrite IP_DF and IP_MF from this? struct iphdr { #if defined(__LITTLE_ENDIAN_BITFIELD)

问题 I am trying to write a netfilter module and want to access the fields of the IPHeader that denotes the DF and MF fields. I can access most other fields as desired but I think I have to extract the DF and MF fields from the ipheader in the struct and manipulate them say for example I want to set or unset the DF bit depending on the type of packet I receive. The below structure has 'frag_off' how do I access/rewrite IP_DF and IP_MF from this? struct iphdr { #if defined(__LITTLE_ENDIAN_BITFIELD)

问题 I am pretty desperate searching for a solution to this. I am running a Kubernetes Cluster (v1.16.7) on AWS. Node specs are : It is an Amazon EC2 t3.medium instance with 4GB RAM and AMI: k8s-1.11-debian-stretch-amd64-hvm-ebs-2018-08-17 with kernel: 4.9.0-7-amd64 My main problem is that I see increased memory usage in the kernel, which leads to faster memory starvation issues in my node. More specifically: free -m : total used free shared buff/cache available Mem: 3895 3470 130 3 294 204 Swap: