summaryrefslogtreecommitdiffstats
path: root/include/uapi
diff options
context:
space:
mode:
authorDavid S. Miller2013-11-04 19:48:30 +0100
committerDavid S. Miller2013-11-04 19:48:30 +0100
commit394efd19d5fcae936261bd48e5b33b21897aacf8 (patch)
treec48cf3ddbb07fd87309f1abdf31a27c71330e587 /include/uapi
parentnet/hsr: Add support for the High-availability Seamless Redundancy protocol (... (diff)
parentMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net (diff)
downloadkernel-qcow2-linux-394efd19d5fcae936261bd48e5b33b21897aacf8.tar.gz
kernel-qcow2-linux-394efd19d5fcae936261bd48e5b33b21897aacf8.tar.xz
kernel-qcow2-linux-394efd19d5fcae936261bd48e5b33b21897aacf8.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: drivers/net/ethernet/emulex/benet/be.h drivers/net/netconsole.c net/bridge/br_private.h Three mostly trivial conflicts. The net/bridge/br_private.h conflict was a function signature (argument addition) change overlapping with the extern removals from Joe Perches. In drivers/net/netconsole.c we had one change adjusting a printk message whilst another changed "printk(KERN_INFO" into "pr_info(". Lastly, the emulex change was a new inline function addition overlapping with Joe Perches's extern removals. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi')
-rw-r--r--include/uapi/linux/perf_event.h12
1 files changed, 7 insertions, 5 deletions
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 009a655a5d35..2fc1602e23bb 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -456,13 +456,15 @@ struct perf_event_mmap_page {
/*
* Control data for the mmap() data buffer.
*
- * User-space reading the @data_head value should issue an rmb(), on
- * SMP capable platforms, after reading this value -- see
- * perf_event_wakeup().
+ * User-space reading the @data_head value should issue an smp_rmb(),
+ * after reading this value.
*
* When the mapping is PROT_WRITE the @data_tail value should be
- * written by userspace to reflect the last read data. In this case
- * the kernel will not over-write unread data.
+ * written by userspace to reflect the last read data, after issueing
+ * an smp_mb() to separate the data read from the ->data_tail store.
+ * In this case the kernel will not over-write unread data.
+ *
+ * See perf_output_put_handle() for the data ordering.
*/
__u64 data_head; /* head in the data section */
__u64 data_tail; /* user-space written tail */