From mboxrd@z Thu Jan  1 00:00:00 1970
From: Frank Rowand <frank.rowand@am.sony.com>
Subject: spin locks and migrate_disable()
Date: Fri, 30 Mar 2012 14:57:45 -0700
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To: Thomas Gleixner <tglx@linutronix.de>
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Hi Thomas,

Two questions about spin_lock() in include/linux/spinlock_rt.h.

(1) spin_lock() and related functions invoke migrate_disable() and
migrate_enable().  These functions are created by your patch,
sched-migrate-disable.patch, and are EXPORT_SYMBOL_GPL().  Would
you be willing to change these to EXPORT_SYMBOL()?

(2) What is the purpose of the migrate_disable() in the spin lock?
Is it a correctness issue, or a performance issue, or something else?

Thanks!

-Frank