summaryrefslogtreecommitdiff
path: root/include/linux/init_task.h
diff options
context:
space:
mode:
authorPeter Zijlstra <peterz@infradead.org>2013-11-07 14:43:43 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-13 13:41:50 +0100
commitfb00aca474405f4fa8a8519c3179fed722eabd83 (patch)
tree8a779629a771dd3340d5a3ba0ba16b732b8de1c8 /include/linux/init_task.h
parentaf6ace764d03900524e9b1ac621a1c520ee49fc6 (diff)
rtmutex: Turn the plist into an rb-tree
Turn the pi-chains from plist to rb-tree, in the rt_mutex code, and provide a proper comparison function for -deadline and -priority tasks. This is done mainly because: - classical prio field of the plist is just an int, which might not be enough for representing a deadline; - manipulating such a list would become O(nr_deadline_tasks), which might be to much, as the number of -deadline task increases. Therefore, an rb-tree is used, and tasks are queued in it according to the following logic: - among two -priority (i.e., SCHED_BATCH/OTHER/RR/FIFO) tasks, the one with the higher (lower, actually!) prio wins; - among a -priority and a -deadline task, the latter always wins; - among two -deadline tasks, the one with the earliest deadline wins. Queueing and dequeueing functions are changed accordingly, for both the list of a task's pi-waiters and the list of tasks blocked on a pi-lock. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Dario Faggioli <raistlin@linux.it> Signed-off-by: Juri Lelli <juri.lelli@gmail.com> Signed-off-again-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1383831828-15501-10-git-send-email-juri.lelli@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/init_task.h')
-rw-r--r--include/linux/init_task.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index b0ed422e4e4a..f0e52383a001 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -11,6 +11,7 @@
#include <linux/user_namespace.h>
#include <linux/securebits.h>
#include <linux/seqlock.h>
+#include <linux/rbtree.h>
#include <net/net_namespace.h>
#include <linux/sched/rt.h>
@@ -154,6 +155,14 @@ extern struct task_group root_task_group;
#define INIT_TASK_COMM "swapper"
+#ifdef CONFIG_RT_MUTEXES
+# define INIT_RT_MUTEXES(tsk) \
+ .pi_waiters = RB_ROOT, \
+ .pi_waiters_leftmost = NULL,
+#else
+# define INIT_RT_MUTEXES(tsk)
+#endif
+
/*
* INIT_TASK is used to set up the first task table, touch at
* your own risk!. Base=0, limit=0x1fffff (=2MB)
@@ -221,6 +230,7 @@ extern struct task_group root_task_group;
INIT_TRACE_RECURSION \
INIT_TASK_RCU_PREEMPT(tsk) \
INIT_CPUSET_SEQ(tsk) \
+ INIT_RT_MUTEXES(tsk) \
INIT_VTIME(tsk) \
}