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Commit 52f2b34f authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'for-mingo' of... 

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

 into core/rcu

Pull RCU fix from Paul E. McKenney:

 "This additional v4.18 pull request contains a single commit that fell
  through the cracks:

      Provide early rcu_cpu_starting() callback for the benefit of the
      x86/mtrr code, which needs RCU to be available on incoming CPUs
      earlier than has been the case in the past."

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 13a55319 f64c6013

arch/x86/kernel/cpu/mtrr/main.c

+4 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
#include <linux/pci.h>

#include <linux/smp.h>

#include <linux/syscore_ops.h>

#include <linux/rcupdate.h>



#include <asm/cpufeature.h>

#include <asm/e820/api.h>
@@ -793,6 +794,9 @@ void mtrr_ap_init(void) 


	if (!use_intel() || mtrr_aps_delayed_init)

		return;



	rcu_cpu_starting(smp_processor_id());



	/*

	 * Ideally we should hold mtrr_mutex here to avoid mtrr entries

	 * changed, but this routine will be called in cpu boot time,

include/linux/rcupdate.h

+0 −1
Original line number Diff line number Diff line
@@ -108,7 +108,6 @@ void rcu_sched_qs(void); 
void rcu_bh_qs(void);

void rcu_check_callbacks(int user);

void rcu_report_dead(unsigned int cpu);

void rcu_cpu_starting(unsigned int cpu);

void rcutree_migrate_callbacks(int cpu);



#ifdef CONFIG_RCU_STALL_COMMON

include/linux/rcutiny.h

+1 −0
Original line number Diff line number Diff line
@@ -132,5 +132,6 @@ static inline void rcu_all_qs(void) { barrier(); } 
#define rcutree_offline_cpu      NULL

#define rcutree_dead_cpu         NULL

#define rcutree_dying_cpu        NULL

static inline void rcu_cpu_starting(unsigned int cpu) { }



#endif /* __LINUX_RCUTINY_H */

include/linux/rcutree.h

+1 −0
Original line number Diff line number Diff line
@@ -101,5 +101,6 @@ int rcutree_online_cpu(unsigned int cpu); 
int rcutree_offline_cpu(unsigned int cpu);

int rcutree_dead_cpu(unsigned int cpu);

int rcutree_dying_cpu(unsigned int cpu);

void rcu_cpu_starting(unsigned int cpu);



#endif /* __LINUX_RCUTREE_H */

kernel/rcu/tree.c

+9 −0
Original line number Diff line number Diff line
@@ -3665,6 +3665,8 @@ int rcutree_dead_cpu(unsigned int cpu) 
	return 0;

}



static DEFINE_PER_CPU(int, rcu_cpu_started);



/*

 * Mark the specified CPU as being online so that subsequent grace periods

 * (both expedited and normal) will wait on it.  Note that this means that
@@ -3686,6 +3688,11 @@ void rcu_cpu_starting(unsigned int cpu) 
	struct rcu_node *rnp;

	struct rcu_state *rsp;



	if (per_cpu(rcu_cpu_started, cpu))

		return;



	per_cpu(rcu_cpu_started, cpu) = 1;



	for_each_rcu_flavor(rsp) {

		rdp = per_cpu_ptr(rsp->rda, cpu);

		rnp = rdp->mynode;
@@ -3742,6 +3749,8 @@ void rcu_report_dead(unsigned int cpu) 
	preempt_enable();

	for_each_rcu_flavor(rsp)

		rcu_cleanup_dying_idle_cpu(cpu, rsp);



	per_cpu(rcu_cpu_started, cpu) = 0;

}



/* Migrate the dead CPU's callbacks to the current CPU. */