Add PREEMPT_RT 4.4.9-rt17 patch series
Add the PREEMPT_RT 4.4.9-rt17 patch series as a set of .patch files in
the rt-patches subdir of the kernel. The intention is to apply these
at build time to RT kernels.
IGNORE_GVS
Change-Id: I7e0d9282c0e17540aa98c18a15e88634c57a3a23
Signed-off-by: Allen Martin <amartin@nvidia.com>
Reviewed-on: http://git-master/r/1193842
Reviewed-by: Samuel Payne <spayne@nvidia.com>
diff --git a/rt-patches/0219-net-Use-cpu_chill-instead-of-cpu_relax.patch b/rt-patches/0219-net-Use-cpu_chill-instead-of-cpu_relax.patch
new file mode 100644
index 0000000..dbcf6db
--- /dev/null
+++ b/rt-patches/0219-net-Use-cpu_chill-instead-of-cpu_relax.patch
@@ -0,0 +1,71 @@
+From 4399914b86960e945f4cffa99d3d09cfd263c9d0 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 7 Mar 2012 21:10:04 +0100
+Subject: [PATCH 219/317] net: Use cpu_chill() instead of cpu_relax()
+X-NVConfidentiality: public
+
+Retry loops on RT might loop forever when the modifying side was
+preempted. Use cpu_chill() instead of cpu_relax() to let the system
+make progress.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Allen Martin <amartin@nvidia.com>
+---
+ net/packet/af_packet.c | 5 +++--
+ net/rds/ib_rdma.c | 3 ++-
+ 2 files changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
+index da1ae0e13cb5..a1899dce1a70 100644
+--- a/net/packet/af_packet.c
++++ b/net/packet/af_packet.c
+@@ -63,6 +63,7 @@
+ #include <linux/if_packet.h>
+ #include <linux/wireless.h>
+ #include <linux/kernel.h>
++#include <linux/delay.h>
+ #include <linux/kmod.h>
+ #include <linux/slab.h>
+ #include <linux/vmalloc.h>
+@@ -695,7 +696,7 @@ static void prb_retire_rx_blk_timer_expired(unsigned long data)
+ if (BLOCK_NUM_PKTS(pbd)) {
+ while (atomic_read(&pkc->blk_fill_in_prog)) {
+ /* Waiting for skb_copy_bits to finish... */
+- cpu_relax();
++ cpu_chill();
+ }
+ }
+
+@@ -957,7 +958,7 @@ static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
+ if (!(status & TP_STATUS_BLK_TMO)) {
+ while (atomic_read(&pkc->blk_fill_in_prog)) {
+ /* Waiting for skb_copy_bits to finish... */
+- cpu_relax();
++ cpu_chill();
+ }
+ }
+ prb_close_block(pkc, pbd, po, status);
+diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
+index a2340748ec86..19123a97b354 100644
+--- a/net/rds/ib_rdma.c
++++ b/net/rds/ib_rdma.c
+@@ -34,6 +34,7 @@
+ #include <linux/slab.h>
+ #include <linux/rculist.h>
+ #include <linux/llist.h>
++#include <linux/delay.h>
+
+ #include "rds.h"
+ #include "ib.h"
+@@ -313,7 +314,7 @@ static inline void wait_clean_list_grace(void)
+ for_each_online_cpu(cpu) {
+ flag = &per_cpu(clean_list_grace, cpu);
+ while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
+- cpu_relax();
++ cpu_chill();
+ }
+ }
+
+--
+2.9.3
+