What’s virtual address limit of 32bit/64bit Linux kernel?

RHEL 5 code 32bit: include/asm-i386/processor.h /* * User space process size: 3GB (default). */ #define TASK_SIZE (PAGE_OFFSET) 64bit: include/asm-x86_64/processor.h /* * User space process size. 47bits minus one guard page. */ #define TASK_SIZE64 (0x800000000000UL - 4096) /* This decides where the kernel will search for a free chunk of vm * space during mmap's. */… Continue reading What’s virtual address limit of 32bit/64bit Linux kernel?

vmware-tools installation failure in Fedora 18?

If you are failing installing vmware-tools in Fedora 18 with the following message, it might be caused of the changes in Fedora 18 kernel-revel package. The path "" is not a valid path to the .... Here's the simple command that will resolve the issue. It also works for latest Fedora 17 issue. $ cp… Continue reading vmware-tools installation failure in Fedora 18?

Jump into a vmcore analysis – Step 1

If you have a vmcore needs to be analysed, you should have to download related kernel-debuginfo package unless your kernel does have all the debug information in the live kernel. You might easily check the kernel version of the vmcore by run 'uname -r', but safest way would be checking vmcore itself. You can use… Continue reading Jump into a vmcore analysis – Step 1

How to check which applications are using hugepages

You can find how much is allocated and how much is actually used by HugePages by run the following command. $ grep -i huge /proc/meminfo AnonHugePages: 776192 kB HugePages_Total: 241 HugePages_Free: 113 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB But, there's a time you also want to know which applications are actually used HugePages. You… Continue reading How to check which applications are using hugepages

How to build a module with source codes in separate directories.

If you want to use separate directories for source files and target modules, you can use below scheme. mod_main.c #include #include MODULE_LICENSE("GPL"); static int __init mod_entry(void) { return 0; } static void __exit mod_exit(void) { return; } module_init(mod_entry); module_exit(mod_exit); sub_mod.c #include #include int sub_func(int i) { printk("Hello %d", i); return 0; } EXPORT_SYMBOL(sub_func); http://pagead2.googlesyndication.com/pagead/show_ads.js Makefile… Continue reading How to build a module with source codes in separate directories.

How to debug an application

If you want to debug an application that is shipped with the fedora, you can use the following command. [root@localhost ~]# debuginfo-install gedit-3.4.2-1.fc17.x86_64 Loaded plugins: langpacks, presto, refresh-packagekit enabling fedora-debuginfo enabling updates-debuginfo --> Running transaction check ---> Package atk-debuginfo.x86_64 0:2.4.0-1.fc17 will be installed ---> Package cairo-debuginfo.x86_64 0:1.10.2-7.fc17 will be installed ---> Package enchant-debuginfo.x86_64 1:1.6.0-4.fc17 will… Continue reading How to debug an application