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Merge branches 'doc.2015.10.06a', 'percpu-rwsem.2015.10.06a' and 'torture.2015.10.06a' into HEAD

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doc.2015.10.06a:  Documentation updates.
percpu-rwsem.2015.10.06a:  Optimization of per-CPU reader-writer semaphores.
torture.2015.10.06a:  Torture-test updates.
This commit is contained in:
Paul E. McKenney
2015-10-07 16:06:25 -07:00
parent d2856b046d ad2ad5d31f 4bace7344d a36a99618b
commit 39cd2dd39a
19 changed files with 569 additions and 103 deletions
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Documentation/RCU/stallwarn.txt
+7
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@@ -205,6 +205,13 @@ o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the
behavior, you might need to replace some of the cond_resched()
calls with calls to cond_resched_rcu_qs().
o Booting Linux using a console connection that is too slow to
keep up with the boot-time console-message rate. For example,
a 115Kbaud serial console can be -way- too slow to keep up
with boot-time message rates, and will frequently result in
RCU CPU stall warning messages. Especially if you have added
debug printk()s.
o Anything that prevents RCU's grace-period kthreads from running.
This can result in the "All QSes seen" console-log message.
This message will include information on when the kthread last
Documentation/RCU/torture.txt
+13 -26
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@@ -166,40 +166,27 @@ test_no_idle_hz Whether or not to test the ability of RCU to operate in
torture_type The type of RCU to test, with string values as follows:
"rcu": rcu_read_lock(), rcu_read_unlock() and call_rcu().
"rcu_sync": rcu_read_lock(), rcu_read_unlock(), and
synchronize_rcu().
"rcu_expedited": rcu_read_lock(), rcu_read_unlock(), and
synchronize_rcu_expedited().
"rcu": rcu_read_lock(), rcu_read_unlock() and call_rcu(),
along with expedited, synchronous, and polling
variants.
"rcu_bh": rcu_read_lock_bh(), rcu_read_unlock_bh(), and
call_rcu_bh().
call_rcu_bh(), along with expedited and synchronous
variants.
"rcu_bh_sync": rcu_read_lock_bh(), rcu_read_unlock_bh(),
and synchronize_rcu_bh().
"rcu_bh_expedited": rcu_read_lock_bh(), rcu_read_unlock_bh(),
and synchronize_rcu_bh_expedited().
"rcu_busted": This tests an intentionally incorrect version
of RCU in order to help test rcutorture itself.
"srcu": srcu_read_lock(), srcu_read_unlock() and
call_srcu().
"srcu_sync": srcu_read_lock(), srcu_read_unlock() and
synchronize_srcu().
"srcu_expedited": srcu_read_lock(), srcu_read_unlock() and
synchronize_srcu_expedited().
call_srcu(), along with expedited and
synchronous variants.
"sched": preempt_disable(), preempt_enable(), and
call_rcu_sched().
call_rcu_sched(), along with expedited,
synchronous, and polling variants.
"sched_sync": preempt_disable(), preempt_enable(), and
synchronize_sched().
"sched_expedited": preempt_disable(), preempt_enable(), and
synchronize_sched_expedited().
"tasks": voluntary context switch and call_rcu_tasks(),
along with expedited and synchronous variants.
Defaults to "rcu".
Documentation/RCU/whatisRCU.txt
+3 -3
View File
@@ -364,7 +364,7 @@ uses of RCU may be found in listRCU.txt, arrayRCU.txt, and NMI-RCU.txt.
};
DEFINE_SPINLOCK(foo_mutex);
struct foo *gbl_foo;
struct foo __rcu *gbl_foo;
/*
* Create a new struct foo that is the same as the one currently
@@ -386,7 +386,7 @@ uses of RCU may be found in listRCU.txt, arrayRCU.txt, and NMI-RCU.txt.
new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
spin_lock(&foo_mutex);
old_fp = gbl_foo;
old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
*new_fp = *old_fp;
new_fp->a = new_a;
rcu_assign_pointer(gbl_foo, new_fp);
@@ -487,7 +487,7 @@ The foo_update_a() function might then be written as follows:
new_fp = kmalloc(sizeof(*new_fp), GFP_KERNEL);
spin_lock(&foo_mutex);
old_fp = gbl_foo;
old_fp = rcu_dereference_protected(gbl_foo, lockdep_is_held(&foo_mutex));
*new_fp = *old_fp;
new_fp->a = new_a;
rcu_assign_pointer(gbl_foo, new_fp);