Merge branch 'v28-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'v28-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (36 commits)
  fix documentation of sysrq-q really
  Fix documentation of sysrq-q
  timer_list: add base address to clock base
  timer_list: print cpu number of clockevents device
  timer_list: print real timer address
  NOHZ: restart tick device from irq_enter()
  NOHZ: split tick_nohz_restart_sched_tick()
  NOHZ: unify the nohz function calls in irq_enter()
  timers: fix itimer/many thread hang, fix
  timers: fix itimer/many thread hang, v3
  ntp: improve adjtimex frequency rounding
  timekeeping: fix rounding problem during clock update
  ntp: let update_persistent_clock() sleep
  hrtimer: reorder struct hrtimer to save 8 bytes on 64bit builds
  posix-timers: lock_timer: make it readable
  posix-timers: lock_timer: kill the bogus ->it_id check
  posix-timers: kill ->it_sigev_signo and ->it_sigev_value
  posix-timers: sys_timer_create: cleanup the error handling
  posix-timers: move the initialization of timer->sigq from send to create path
  posix-timers: sys_timer_create: simplify and s/tasklist/rcu/
  ...

Fix trivial conflicts due to sysrq-q description clahes in
Documentation/sysrq.txt and drivers/char/sysrq.c

1 files changed, 71 insertions, 13 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index f52dbd3587a7..5c38db536e07 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -434,6 +434,39 @@ struct pacct_struct {
         unsigned long           ac_minflt, ac_majflt;
 };
 
+/**
+ * struct task_cputime - collected CPU time counts
+ * @utime:              time spent in user mode, in &cputime_t units
+ * @stime:              time spent in kernel mode, in &cputime_t units
+ * @sum_exec_runtime:   total time spent on the CPU, in nanoseconds
+ *
+ * This structure groups together three kinds of CPU time that are
+ * tracked for threads and thread groups.  Most things considering
+ * CPU time want to group these counts together and treat all three
+ * of them in parallel.
+ */
+struct task_cputime {
+        cputime_t utime;
+        cputime_t stime;
+        unsigned long long sum_exec_runtime;
+};
+/* Alternate field names when used to cache expirations. */
+#define prof_exp        stime
+#define virt_exp        utime
+#define sched_exp       sum_exec_runtime
+
+/**
+ * struct thread_group_cputime - thread group interval timer counts
+ * @totals:             thread group interval timers; substructure for
+ *                      uniprocessor kernel, per-cpu for SMP kernel.
+ *
+ * This structure contains the version of task_cputime, above, that is
+ * used for thread group CPU clock calculations.
+ */
+struct thread_group_cputime {
+        struct task_cputime *totals;
+};
+
 /*
  * NOTE! "signal_struct" does not have it's own
  * locking, because a shared signal_struct always
@@ -479,6 +512,17 @@ struct signal_struct {
         cputime_t it_prof_expires, it_virt_expires;
         cputime_t it_prof_incr, it_virt_incr;
 
+        /*
+         * Thread group totals for process CPU clocks.
+         * See thread_group_cputime(), et al, for details.
+         */
+        struct thread_group_cputime cputime;
+
+        /* Earliest-expiration cache. */
+        struct task_cputime cputime_expires;
+
+        struct list_head cpu_timers[3];
+
         /* job control IDs */
 
         /*
@@ -509,7 +553,7 @@ struct signal_struct {
          * Live threads maintain their own counters and add to these
          * in __exit_signal, except for the group leader.
          */
-        cputime_t utime, stime, cutime, cstime;
+        cputime_t cutime, cstime;
         cputime_t gtime;
         cputime_t cgtime;
         unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;
@@ -518,14 +562,6 @@ struct signal_struct {
         struct task_io_accounting ioac;
 
         /*
-         * Cumulative ns of scheduled CPU time for dead threads in the
-         * group, not including a zombie group leader.  (This only differs
-         * from jiffies_to_ns(utime + stime) if sched_clock uses something
-         * other than jiffies.)
-         */
-        unsigned long long sum_sched_runtime;
-
-        /*
          * We don't bother to synchronize most readers of this at all,
          * because there is no reader checking a limit that actually needs
          * to get both rlim_cur and rlim_max atomically, and either one
@@ -536,8 +572,6 @@ struct signal_struct {
          */
         struct rlimit rlim[RLIM_NLIMITS];
 
-        struct list_head cpu_timers[3];
-
         /* keep the process-shared keyrings here so that they do the right
          * thing in threads created with CLONE_THREAD */
 #ifdef CONFIG_KEYS
@@ -1146,8 +1180,7 @@ struct task_struct {
 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
         unsigned long min_flt, maj_flt;
 
-        cputime_t it_prof_expires, it_virt_expires;
-        unsigned long long it_sched_expires;
+        struct task_cputime cputime_expires;
         struct list_head cpu_timers[3];
 
 /* process credentials */
@@ -1597,6 +1630,7 @@ extern unsigned long long cpu_clock(int cpu);
 
 extern unsigned long long
 task_sched_runtime(struct task_struct *task);
+extern unsigned long long thread_group_sched_runtime(struct task_struct *task);
 
 /* sched_exec is called by processes performing an exec */
 #ifdef CONFIG_SMP
@@ -2094,6 +2128,30 @@ static inline int spin_needbreak(spinlock_t *lock)
 }
 
 /*
+ * Thread group CPU time accounting.
+ */
+
+extern int thread_group_cputime_alloc(struct task_struct *);
+extern void thread_group_cputime(struct task_struct *, struct task_cputime *);
+
+static inline void thread_group_cputime_init(struct signal_struct *sig)
+{
+        sig->cputime.totals = NULL;
+}
+
+static inline int thread_group_cputime_clone_thread(struct task_struct *curr)
+{
+        if (curr->signal->cputime.totals)
+                return 0;
+        return thread_group_cputime_alloc(curr);
+}
+
+static inline void thread_group_cputime_free(struct signal_struct *sig)
+{
+        free_percpu(sig->cputime.totals);
+}
+
+/*
  * Reevaluate whether the task has signals pending delivery.
  * Wake the task if so.
  * This is required every time the blocked sigset_t changes.