Commit-ID: 03f6199a359e460714b6bd08c10b566760f150a6
Gitweb: http://git.kernel.org/tip/03f6199a359e460714b6bd08c10b566760f150a6
Author: Chris Metcalf <cmetcalf@xxxxxxxxxx>
AuthorDate: Fri, 10 Jul 2015 15:37:25 -0400
Committer: Frederic Weisbecker <fweisbec@xxxxxxxxx>
CommitDate: Wed, 29 Jul 2015 15:44:59 +0200
nohz: Prevent tilegx network driver interrupts
Normally the tilegx networking shim sends irqs to all the cores
to distribute the load of processing incoming-packet interrupts,
so that you can get to multiple Gb's of traffic inbound.
However, in nohz_full mode we don't want to interrupt the
nohz_full cores by default, so we limit the set of cores we use
to only the online housekeeping cores.
To make client code easier to read, we introduce a new nohz_full
accessor, housekeeping_cpumask(), which returns a pointer to the
housekeeping_mask if nohz_full is enabled, and otherwise returns
the cpu_possible_mask.
Signed-off-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
drivers/net/ethernet/tile/tilegx.c | 4 +++-
include/linux/tick.h | 9 +++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c
index a3f7610..0a15acc 100644
--- a/drivers/net/ethernet/tile/tilegx.c
+++ b/drivers/net/ethernet/tile/tilegx.c
@@ -40,6 +40,7 @@
#include <linux/tcp.h>
#include <linux/net_tstamp.h>
#include <linux/ptp_clock_kernel.h>
+#include <linux/tick.h>
#include <asm/checksum.h>
#include <asm/homecache.h>
@@ -2273,7 +2274,8 @@ static int __init tile_net_init_module(void)
tile_net_dev_init(name, mac);
if (!network_cpus_init())
- network_cpus_map = *cpu_online_mask;
+ cpumask_and(&network_cpus_map, housekeeping_cpumask(),
+ cpu_online_mask);
return 0;
}
diff --git a/include/linux/tick.h b/include/linux/tick.h
index edbfc9a..1ca93f2 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -163,6 +163,15 @@ static inline void tick_nohz_full_kick_all(void) { }
static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
#endif
+static inline const struct cpumask *housekeeping_cpumask(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_enabled())
+ return housekeeping_mask;
+#endif
+ return cpu_possible_mask;
+}
+
static inline bool is_housekeeping_cpu(int cpu)
{
#ifdef CONFIG_NO_HZ_FULL
--
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