The following commit has been merged into the core/rcu branch of tip:
Commit-ID: e48c15b796d412ede883bb2ef7779b2a142f7962
Gitweb: https://git.kernel.org/tip/e48c15b796d412ede883bb2ef7779b2a142f7962
Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate: Mon, 29 Jun 2020 17:21:32 -07:00
Committer: Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Fri, 04 Sep 2020 11:50:50 -07:00
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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
include/linux/smp.h | 3 +++
include/linux/smp_types.h | 3 +++
kernel/smp.c | 6 ++++++
3 files changed, 12 insertions(+)
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 80d557e..9f13966 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -26,6 +26,9 @@ struct __call_single_data {
struct {
struct llist_node llist;
unsigned int flags;
+#ifdef CONFIG_64BIT
+ u16 src, dst;
+#endif
};
};
smp_call_func_t func;
diff --git a/include/linux/smp_types.h b/include/linux/smp_types.h
index 364b3ae..2e8461a 100644
--- a/include/linux/smp_types.h
+++ b/include/linux/smp_types.h
@@ -61,6 +61,9 @@ struct __call_single_node {
unsigned int u_flags;
atomic_t a_flags;
};
+#ifdef CONFIG_64BIT
+ u16 src, dst;
+#endif
};
#endif /* __LINUX_SMP_TYPES_H */
diff --git a/kernel/smp.c b/kernel/smp.c
index d0ae8eb..865a876 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);
}
|