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authorPeter Zijlstra <peterz@infradead.org>2020-05-26 18:11:01 +0200
committerIngo Molnar <mingo@kernel.org>2020-05-28 10:54:15 +0200
commitb2a02fc43a1f40ef4eb2fb2b06357382608d4d84 (patch)
treebeedd3ab17cd9da7d49948aff6e1d82fe535dc81 /kernel/smp.c
parentafaa653c564da38c0b34c4baba31e88c46a8764c (diff)
smp: Optimize send_call_function_single_ipi()
Just like the ttwu_queue_remote() IPI, make use of _TIF_POLLING_NRFLAG to avoid sending IPIs to idle CPUs. [ mingo: Fix UP build bug. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200526161907.953304789@infradead.org
Diffstat (limited to 'kernel/smp.c')
-rw-r--r--kernel/smp.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/kernel/smp.c b/kernel/smp.c
index f720e38e880d..9f1181375141 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -135,6 +135,8 @@ static __always_inline void csd_unlock(call_single_data_t *csd)
static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
+extern void send_call_function_single_ipi(int cpu);
+
/*
* Insert a previously allocated call_single_data_t element
* for execution on the given CPU. data must already have
@@ -178,7 +180,7 @@ static int generic_exec_single(int cpu, call_single_data_t *csd,
* equipped to do the right thing...
*/
if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
- arch_send_call_function_single_ipi(cpu);
+ send_call_function_single_ipi(cpu);
return 0;
}
@@ -278,6 +280,18 @@ static void flush_smp_call_function_queue(bool warn_cpu_offline)
}
}
+void flush_smp_call_function_from_idle(void)
+{
+ unsigned long flags;
+
+ if (llist_empty(this_cpu_ptr(&call_single_queue)))
+ return;
+
+ local_irq_save(flags);
+ flush_smp_call_function_queue(true);
+ local_irq_restore(flags);
+}
+
/*
* smp_call_function_single - Run a function on a specific CPU
* @func: The function to run. This must be fast and non-blocking.