The patch titled
markers: update preempt_disable. call_rcu, rcu_barrier comments
has been added to the -mm tree. Its filename is
markers-update-preempt_disable-call_rcu-rcu_barrier-comments.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: markers: update preempt_disable. call_rcu, rcu_barrier comments
From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
Add comments requested by Andrew.
Updated comments about synchronize_sched(). Since we use call_rcu and
rcu_barrier now, these comments were out of sync with the code.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Mike Mason <mmlnx@xxxxxxxxxx>
Cc: Dipankar Sarma <dipankar@xxxxxxxxxx>
Cc: David Smith <dsmith@xxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Adrian Bunk <adrian.bunk@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/marker.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff -puN kernel/marker.c~markers-update-preempt_disable-call_rcu-rcu_barrier-comments kernel/marker.c
--- a/kernel/marker.c~markers-update-preempt_disable-call_rcu-rcu_barrier-comments
+++ a/kernel/marker.c
@@ -104,9 +104,9 @@ void marker_probe_cb(const struct marker
char ptype;
/*
- * disabling preemption to make sure the teardown of the callbacks can
- * be done correctly when they are in modules and they insure RCU read
- * coherency.
+ * preempt_disable does two things : disabling preemption to make sure
+ * the teardown of the callbacks can be done correctly when they are in
+ * modules and they insure RCU read coherency.
*/
preempt_disable();
ptype = ACCESS_ONCE(mdata->ptype);
@@ -551,9 +551,9 @@ static int set_marker(struct marker_entr
/*
* Disable a marker and its probe callback.
- * Note: only after a synchronize_sched() issued after setting elem->call to the
- * empty function insures that the original callback is not used anymore. This
- * insured by preemption disabling around the call site.
+ * Note: only waiting an RCU period after setting elem->call to the empty
+ * function insures that the original callback is not used anymore. This insured
+ * by preempt_disable around the call site.
*/
static void disable_marker(struct marker *elem)
{
@@ -565,8 +565,8 @@ static void disable_marker(struct marker
elem->ptype = 0; /* single probe */
/*
* Leave the private data and id there, because removal is racy and
- * should be done only after a synchronize_sched(). These are never used
- * until the next initialization anyway.
+ * should be done only after an RCU period. These are never used until
+ * the next initialization anyway.
*/
}
@@ -601,9 +601,6 @@ void marker_update_probe_range(struct ma
/*
* Update probes, removing the faulty probes.
- * Issues a synchronize_sched() when no reference to the module passed
- * as parameter is found in the probes so the probe module can be
- * safely unloaded from now on.
*
* Internal callback only changed before the first probe is connected to it.
* Single probe private data can only be changed on 0 -> 1 and 2 -> 1
_
Patches currently in -mm which might be from mathieu.desnoyers@xxxxxxxxxx are
origin.patch
markers-update-preempt_disable-call_rcu-rcu_barrier-comments.patch
markers-remove-access_once.patch
make-marker_debug-static.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
