Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- promote level for the document title;
- mark literal blocks.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
---
Documentation/futex-requeue-pi.txt | 83 +++++++++++++++++++-------------------
1 file changed, 42 insertions(+), 41 deletions(-)
diff --git a/Documentation/futex-requeue-pi.txt b/Documentation/futex-requeue-pi.txt
index 77b36f59d16b..14ab5787b9a7 100644
--- a/Documentation/futex-requeue-pi.txt
+++ b/Documentation/futex-requeue-pi.txt
@@ -1,5 +1,6 @@
+================
Futex Requeue PI
-----------------
+================
Requeueing of tasks from a non-PI futex to a PI futex requires
special handling in order to ensure the underlying rt_mutex is never
@@ -20,28 +21,28 @@ implementation would wake the highest-priority waiter, and leave the
rest to the natural wakeup inherent in unlocking the mutex
associated with the condvar.
-Consider the simplified glibc calls:
+Consider the simplified glibc calls::
-/* caller must lock mutex */
-pthread_cond_wait(cond, mutex)
-{
- lock(cond->__data.__lock);
- unlock(mutex);
- do {
- unlock(cond->__data.__lock);
- futex_wait(cond->__data.__futex);
- lock(cond->__data.__lock);
- } while(...)
- unlock(cond->__data.__lock);
- lock(mutex);
-}
+ /* caller must lock mutex */
+ pthread_cond_wait(cond, mutex)
+ {
+ lock(cond->__data.__lock);
+ unlock(mutex);
+ do {
+ unlock(cond->__data.__lock);
+ futex_wait(cond->__data.__futex);
+ lock(cond->__data.__lock);
+ } while(...)
+ unlock(cond->__data.__lock);
+ lock(mutex);
+ }
-pthread_cond_broadcast(cond)
-{
- lock(cond->__data.__lock);
- unlock(cond->__data.__lock);
- futex_requeue(cond->data.__futex, cond->mutex);
-}
+ pthread_cond_broadcast(cond)
+ {
+ lock(cond->__data.__lock);
+ unlock(cond->__data.__lock);
+ futex_requeue(cond->data.__futex, cond->mutex);
+ }
Once pthread_cond_broadcast() requeues the tasks, the cond->mutex
has waiters. Note that pthread_cond_wait() attempts to lock the
@@ -53,29 +54,29 @@ In order to support PI-aware pthread_condvar's, the kernel needs to
be able to requeue tasks to PI futexes. This support implies that
upon a successful futex_wait system call, the caller would return to
user space already holding the PI futex. The glibc implementation
-would be modified as follows:
+would be modified as follows::
-/* caller must lock mutex */
-pthread_cond_wait_pi(cond, mutex)
-{
- lock(cond->__data.__lock);
- unlock(mutex);
- do {
- unlock(cond->__data.__lock);
- futex_wait_requeue_pi(cond->__data.__futex);
- lock(cond->__data.__lock);
- } while(...)
- unlock(cond->__data.__lock);
- /* the kernel acquired the mutex for us */
-}
+ /* caller must lock mutex */
+ pthread_cond_wait_pi(cond, mutex)
+ {
+ lock(cond->__data.__lock);
+ unlock(mutex);
+ do {
+ unlock(cond->__data.__lock);
+ futex_wait_requeue_pi(cond->__data.__futex);
+ lock(cond->__data.__lock);
+ } while(...)
+ unlock(cond->__data.__lock);
+ /* the kernel acquired the mutex for us */
+ }
-pthread_cond_broadcast_pi(cond)
-{
- lock(cond->__data.__lock);
- unlock(cond->__data.__lock);
- futex_requeue_pi(cond->data.__futex, cond->mutex);
-}
+ pthread_cond_broadcast_pi(cond)
+ {
+ lock(cond->__data.__lock);
+ unlock(cond->__data.__lock);
+ futex_requeue_pi(cond->data.__futex, cond->mutex);
+ }
The actual glibc implementation will likely test for PI and make the
necessary changes inside the existing calls rather than creating new
--
2.9.4
--
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