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Upgrade CentOS 7 to latest kernel (4.19.1)

· One min read

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org \ rpm -Uvh https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm \ yum --disablerepo="*" --enablerepo="elrepo-kernel" list available \ yum --enablerepo=elrepo-kernel install -y kernel-ml \

Temporarily boot to new kernel 4.19 # grub2-reboot 0 # reboot

Permanently boot to new kernel 4.19 vi /etc/default/grub Change or Add: GRUB_DEFAULT=0 grub2-mkconfig -o /boot/grub2/grub.cfg reboot

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org && \ rpm -Uvh https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm && \ yum --enablerepo=elrepo-kernel install -y kernel-ml && \ sed -i "s|GRUB_DEFAULT=saved|# GRUB_DEFAULT=saved\nGRUB_DEFAULT=0|" /etc/default/grub && \ grub2-mkconfig -o /boot/grub2/grub.cfg && \ reboot

echo "" >> /etc/yum.conf && \ echo "proxy=http://172.16.126.20:8090" >> /etc/yum.conf && \ rpm --httpproxy http://172.16.126.20:8090 --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org && \ rpm --httpproxy http://172.16.126.20:8090 -Uvh https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm && \ yum --enablerepo=elrepo-kernel install -y kernel-ml && \ sed -i "s|GRUB_DEFAULT=saved|# GRUB_DEFAULT=saved\nGRUB_DEFAULT=0|" /etc/default/grub && \ grub2-mkconfig -o /boot/grub2/grub.cfg && \ reboot

refers: http://ask.xmodulo.com/change-default-boot-kernel-centos.html https://www.tecmint.com/install-upgrade-kernel-version-in-centos-7/ https://www.kernel.org/ https://www.elrepo.org/

Dynamically create generic C# object using reflection | 动态创建C#泛型实例

· One min read

Classes referenced by generic type:

public class Cat
{
    ...
}
public class Dog
{
    ...
}

Generic class:

public class Animals<T>
{
    public Animals(int id, T body)
    {
        Id = id;
        Body = body;
    }

    public int Id { get; set; }

    public T Body { get; set; }
}

Create instance for generic class dynamically:

using System;
using Newtonsoft.Json;

namespace RtxService.Api
{
    public class Program
    {
        public static void Main(string[] args)
        {
                var cat = new Cat()
                {
                    ...
                };

                var type = typeof(Cat);
                var genericType = typeof(Animals<>).MakeGenericType(type);
                var animal = Activator.CreateInstance(
                    genericType,
                    1,
                    JsonConvert.DeserializeObject(cat, type));
        }
    }
}

refs: https://stackoverflow.com/questions/1151464/how-to-dynamically-create-generic-c-sharp-object-using-reflection

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