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-rw-r--r--Documentation/cgroups/cpuacct.txt18
-rw-r--r--Documentation/infiniband/ipoib.txt45
-rw-r--r--Documentation/trace/ftrace.txt (renamed from Documentation/ftrace.txt)0
-rw-r--r--Documentation/trace/kmemtrace.txt (renamed from Documentation/vm/kmemtrace.txt)0
-rw-r--r--Documentation/trace/mmiotrace.txt (renamed from Documentation/tracers/mmiotrace.txt)0
-rw-r--r--Documentation/trace/tracepoints.txt (renamed from Documentation/tracepoints.txt)0
6 files changed, 63 insertions, 0 deletions
diff --git a/Documentation/cgroups/cpuacct.txt b/Documentation/cgroups/cpuacct.txt
index bb775fbe43d..8b930946c52 100644
--- a/Documentation/cgroups/cpuacct.txt
+++ b/Documentation/cgroups/cpuacct.txt
@@ -30,3 +30,21 @@ The above steps create a new group g1 and move the current shell
process (bash) into it. CPU time consumed by this bash and its children
can be obtained from g1/cpuacct.usage and the same is accumulated in
/cgroups/cpuacct.usage also.
+
+cpuacct.stat file lists a few statistics which further divide the
+CPU time obtained by the cgroup into user and system times. Currently
+the following statistics are supported:
+
+user: Time spent by tasks of the cgroup in user mode.
+system: Time spent by tasks of the cgroup in kernel mode.
+
+user and system are in USER_HZ unit.
+
+cpuacct controller uses percpu_counter interface to collect user and
+system times. This has two side effects:
+
+- It is theoretically possible to see wrong values for user and system times.
+ This is because percpu_counter_read() on 32bit systems isn't safe
+ against concurrent writes.
+- It is possible to see slightly outdated values for user and system times
+ due to the batch processing nature of percpu_counter.
diff --git a/Documentation/infiniband/ipoib.txt b/Documentation/infiniband/ipoib.txt
index 864ff328378..6d40f00b358 100644
--- a/Documentation/infiniband/ipoib.txt
+++ b/Documentation/infiniband/ipoib.txt
@@ -24,6 +24,49 @@ Partitions and P_Keys
The P_Key for any interface is given by the "pkey" file, and the
main interface for a subinterface is in "parent."
+Datagram vs Connected modes
+
+ The IPoIB driver supports two modes of operation: datagram and
+ connected. The mode is set and read through an interface's
+ /sys/class/net/<intf name>/mode file.
+
+ In datagram mode, the IB UD (Unreliable Datagram) transport is used
+ and so the interface MTU has is equal to the IB L2 MTU minus the
+ IPoIB encapsulation header (4 bytes). For example, in a typical IB
+ fabric with a 2K MTU, the IPoIB MTU will be 2048 - 4 = 2044 bytes.
+
+ In connected mode, the IB RC (Reliable Connected) transport is used.
+ Connected mode is to takes advantage of the connected nature of the
+ IB transport and allows an MTU up to the maximal IP packet size of
+ 64K, which reduces the number of IP packets needed for handling
+ large UDP datagrams, TCP segments, etc and increases the performance
+ for large messages.
+
+ In connected mode, the interface's UD QP is still used for multicast
+ and communication with peers that don't support connected mode. In
+ this case, RX emulation of ICMP PMTU packets is used to cause the
+ networking stack to use the smaller UD MTU for these neighbours.
+
+Stateless offloads
+
+ If the IB HW supports IPoIB stateless offloads, IPoIB advertises
+ TCP/IP checksum and/or Large Send (LSO) offloading capability to the
+ network stack.
+
+ Large Receive (LRO) offloading is also implemented and may be turned
+ on/off using ethtool calls. Currently LRO is supported only for
+ checksum offload capable devices.
+
+ Stateless offloads are supported only in datagram mode.
+
+Interrupt moderation
+
+ If the underlying IB device supports CQ event moderation, one can
+ use ethtool to set interrupt mitigation parameters and thus reduce
+ the overhead incurred by handling interrupts. The main code path of
+ IPoIB doesn't use events for TX completion signaling so only RX
+ moderation is supported.
+
Debugging Information
By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set
@@ -55,3 +98,5 @@ References
http://ietf.org/rfc/rfc4391.txt
IP over InfiniBand (IPoIB) Architecture (RFC 4392)
http://ietf.org/rfc/rfc4392.txt
+ IP over InfiniBand: Connected Mode (RFC 4755)
+ http://ietf.org/rfc/rfc4755.txt
diff --git a/Documentation/ftrace.txt b/Documentation/trace/ftrace.txt
index fd9a3e69381..fd9a3e69381 100644
--- a/Documentation/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
diff --git a/Documentation/vm/kmemtrace.txt b/Documentation/trace/kmemtrace.txt
index a956d9b7f94..a956d9b7f94 100644
--- a/Documentation/vm/kmemtrace.txt
+++ b/Documentation/trace/kmemtrace.txt
diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/trace/mmiotrace.txt
index 5731c67abc5..5731c67abc5 100644
--- a/Documentation/tracers/mmiotrace.txt
+++ b/Documentation/trace/mmiotrace.txt
diff --git a/Documentation/tracepoints.txt b/Documentation/trace/tracepoints.txt
index c0e1ceed75a..c0e1ceed75a 100644
--- a/Documentation/tracepoints.txt
+++ b/Documentation/trace/tracepoints.txt