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authorPaul E. McKenney <paulmck@kernel.org>2020-06-29 17:21:32 -0700
committerPaul E. McKenney <paulmck@kernel.org>2020-09-04 11:50:50 -0700
commite48c15b796d412ede883bb2ef7779b2a142f7962 (patch)
treef59df2675d2b3326e583e8dfeb661394f0054702 /kernel/smp.c
parent160c7ba34605d9b59ee406a1b4a61b0f942b1ae9 (diff)
downloadlinux-e48c15b796d412ede883bb2ef7779b2a142f7962.tar.gz
smp: Add source and destination CPUs to __call_single_data
This commit adds a destination CPU to __call_single_data, and is inspired
by an earlier commit by Peter Zijlstra.  This version adds #ifdef to
permit use by 32-bit systems and supplying the destination CPU for all
smp_call_function*() requests, not just smp_call_function_single().

If need be, 32-bit systems could be accommodated by shrinking the flags
field to 16 bits (the atomic_t variant is currently unused) and by
providing only eight bits for CPU on such systems.

It is not clear that the addition of the fields to __call_single_node
are really needed.

[ paulmck: Apply Boqun Feng feedback on 32-bit builds. ]
Link: https://lore.kernel.org/lkml/20200615164048.GC2531@hirez.programming.kicks-ass.net/
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/smp.c')
-rw-r--r--kernel/smp.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/smp.c b/kernel/smp.c
index d0ae8eb6bf8b..865a876f83ce 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -375,6 +375,9 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
 
 	csd->func = func;
 	csd->info = info;
+#ifdef CONFIG_64BIT
+	csd->dst = cpu;
+#endif
 
 	err = generic_exec_single(cpu, csd);
 
@@ -540,6 +543,9 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 			csd->flags |= CSD_TYPE_SYNC;
 		csd->func = func;
 		csd->info = info;
+#ifdef CONFIG_64BIT
+		csd->dst = cpu;
+#endif
 		if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
 			__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
 	}