Messages in this thread |  | | Date | Thu, 08 Feb 2007 12:19:45 -0800 (PST) | Subject | Re: Size of 2.6.20 task_struct on x86_64 machines | From | David Miller <> |
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From: William Cohen <wcohen@redhat.com> Date: Thu, 08 Feb 2007 11:14:13 -0500
> This past week I was playing around with that pahole tool > (http://oops.ghostprotocols.net:81/acme/dwarves/) and looking at the > size of various struct in the kernel. I was surprised by the size of > the task_struct on x86_64, approaching 4K. I looked through the > fields in task_struct and found that a number of them were declared as > "unsigned long" rather than "unsigned int" despite them appearing okay > as 32-bit sized fields. On x86_64 "unsigned long" ends up being 8 > bytes in size and forces 8 byte alignment. Is there a reason there > a reason they are "unsigned long"?
I think at one point we used the atomic bit operations to operate on things like tsk->flags, and those interfaces require unsigned long as the type.
That doesn't appear to be the case any longer, so at a minimum your tsk->flags conversion to unsigned int should be ok. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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