[PATCH v2] nohz: prevent tilegx network driver interrupts
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STALE4112d
From: Chris Metcalf <hidden>
Date: 2015-07-10 19:39:35
Also in:
lkml
Subsystem:
networking drivers, nohz, dynticks support, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Anna-Maria Behnsen, Frederic Weisbecker, Ingo Molnar, Thomas Gleixner, Linus Torvalds
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 <redacted> --- 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 a3f7610002aa..0a15acc075b3 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 3741ba1a652c..d3b00f0b2221 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h@@ -160,6 +160,15 @@ 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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2.1.2