On Mon, Oct 22, 2001 at 03:50:29PM +0530, C. Mohanasundaram wrote:
> } ____cacheline_aligned;
>
> in the above structure what is ___cacheline_aligned
> is it just a variable of type struct udp_mib
> if so why doesnt the compiler throw an error saying declaration of
> ___cacheline_aligned as it is seen in every structure defined in the file
> net/snmp.h
> if i try to copy and paste the structures in a userland program it throws
> redeclaration of ___cacheline_aligned error.
cacheline_aligned is a define expanding to a gcc __attribute__; the atrtibute
align is used to align the structure to a cache line (e.g. 32 bytes).
> 2. if i use sizeof(struct ip_mib) from a kernel module it shows 96
> but if i cut and paste the same data structure in a userland program the size
> is shown as 68.I dont understand why.
I assume you removed the "__cacheline_aligned" bit in user space ?
john
--
"I'm frightened of figurines."
- Pulp
-
Kernelnewbies: Help each other learn about the Linux kernel.
Archive: http://mail.nl.linux.org/kernelnewbies/
IRC Channel: irc.openprojects.net / #kernelnewbies
Web Page: http://www.kernelnewbies.org/
