sched/preempt, mm/fault: Count pagefault_disable() levels in pagefault_disabled

Until now, pagefault_disable()/pagefault_enabled() used the preempt
count to track whether in an environment with pagefaults disabled (can
be queried via in_atomic()).

This patch introduces a separate counter in task_struct to count the
level of pagefault_disable() calls. We'll keep manipulating the preempt
count to retain compatibility to existing pagefault handlers.

It is now possible to verify whether in a pagefault_disable() envionment
by calling pagefault_disabled(). In contrast to in_atomic() it will not
be influenced by preempt_enable()/preempt_disable().

This patch is based on a patch from Ingo Molnar.

Reviewed-and-tested-by: Thomas Gleixner <[email protected]>
Signed-off-by: David Hildenbrand <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions