Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 4/4] nohz: Prevent tilegx network driver interrupts | Date | Wed, 15 Jul 2015 00:37:53 +0200 |
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From: Chris Metcalf <cmetcalf@ezchip.com>
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@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> --- 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 -- 2.1.4
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