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Subject: net: Use cpu_chill() instead of cpu_relax()
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 07 Mar 2012 21:10:04 +0100
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.10-rt8.tar.xz
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>
---
net/packet/af_packet.c | 5 +++--
net/rds/ib_rdma.c | 3 ++-
2 files changed, 5 insertions(+), 3 deletions(-)
--- 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>
@@ -667,7 +668,7 @@ static void prb_retire_rx_blk_timer_expi
if (BLOCK_NUM_PKTS(pbd)) {
while (atomic_read(&pkc->blk_fill_in_prog)) {
/* Waiting for skb_copy_bits to finish... */
- cpu_relax();
+ cpu_chill();
}
}
@@ -929,7 +930,7 @@ static void prb_retire_current_block(str
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);
--- 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_single_path.h"
#include "ib_mr.h"
@@ -222,7 +223,7 @@ static inline void wait_clean_list_grace
for_each_online_cpu(cpu) {
flag = &per_cpu(clean_list_grace, cpu);
while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
- cpu_relax();
+ cpu_chill();
}
}
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