How to get linux kernel page size programmatically

memory-management linux-device-driver dma
Freddy picture Freddy · Feb 3, 2011 · Viewed 51.4k times · Source

I am working on a Linux module for IA64. My current problem is that the driver uses the PAGE_SIZE and PAGE_SHIFT macros for dma page allocation. The problem I am having is that the machine compiling the driver is not the ones that needed to run the driver. So, if the PAGE_SIZE on the compiling machine is 2^14K and the destination machine is 2^16K then the driver fails.

I don't want to turn this question into a 'best practice' issue about compiling modules on machines which are not the ones running the modules. I understand the issues about that. What I found is that people mostly uses getpagesize() or sysconf(_SC_PAGE_SIZE). These two options are out of the ia64 kernel headers so I can't use them. Is there another way that I could get the runtime PAGE_SIZE?

Options I am looking at:

  • Reading some file in /proc?
  • syscall?
  • Other function that let me calculate the PAGE_SIZE by inference (e.g ORDER, getpageshift, etc)?
  • Other?

Answer

vetri picture vetri · Oct 1, 2012

Try using the getconf utility, which will allow you to retrieve the page size easily.

getconf PAGESIZE

Related questions

What is the use of __iomem in linux while writing device drivers?

I have seen that __iomem is used to store the return type of ioremap(), but I have used u32 in ARM architecture for it and it works well. So what difference does __iomem make here? And in which circumstances should …

Read More
How to work with reserved CMA memory?

I would like to allocate piece of physically contiguous reserved memory (in predefined physical addresses) for my device with DMA support. As I see CMA has three options: 1. To reserve memory via kernel config file. 2. To reserve memory via kernel …

Read More
What are the -Xms and -Xmx parameters when starting JVM?

Please explain the use of Xms and Xmx parameters in JVMs. What are the default values for them?

Read More