Commit 84b12b75 authored by Rakib Mullick's avatar Rakib Mullick Committed by Paul E. McKenney
Browse files

rcu: Remove have_rcu_nocb_mask from tree_plugin.h 



Currently have_rcu_nocb_mask is used to avoid double allocation of
rcu_nocb_mask during boot up. Due to different representation of
cpumask_var_t on different kernel config CPUMASK=y(or n) it was okay.
But now we have a helper cpumask_available(), which can be utilized
to check whether rcu_nocb_mask has been allocated or not without using
a variable.

Removing the variable also reduces vmlinux size.

Unpatched version:
text	   data	    bss	    dec	    hex	filename
13050393	7852470	14543408	35446271	21cddff	vmlinux

Patched version:
 text	   data	    bss	    dec	    hex	filename
13050390	7852438	14543408	35446236	21cdddc	vmlinux

Signed-off-by: default avatarRakib Mullick <rakib.mullick@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent efd88b02

kernel/rcu/tree_plugin.h

+4 −7
Original line number Diff line number Diff line
@@ -61,7 +61,6 @@ DEFINE_PER_CPU(char, rcu_cpu_has_work); 


#ifdef CONFIG_RCU_NOCB_CPU

static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */

static bool have_rcu_nocb_mask;	    /* Was rcu_nocb_mask allocated? */

static bool __read_mostly rcu_nocb_poll;    /* Offload kthread are to poll. */

#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
@@ -1752,7 +1751,6 @@ static void increment_cpu_stall_ticks(void) 
static int __init rcu_nocb_setup(char *str)

{

	alloc_bootmem_cpumask_var(&rcu_nocb_mask);

	have_rcu_nocb_mask = true;

	cpulist_parse(str, rcu_nocb_mask);

	return 1;

}
@@ -1801,7 +1799,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp) 
/* Is the specified CPU a no-CBs CPU? */

bool rcu_is_nocb_cpu(int cpu)

{

	if (have_rcu_nocb_mask)

	if (cpumask_available(rcu_nocb_mask))

		return cpumask_test_cpu(cpu, rcu_nocb_mask);

	return false;

}
@@ -2295,14 +2293,13 @@ void __init rcu_init_nohz(void) 
		need_rcu_nocb_mask = true;

#endif /* #if defined(CONFIG_NO_HZ_FULL) */



	if (!have_rcu_nocb_mask && need_rcu_nocb_mask) {

	if (!cpumask_available(rcu_nocb_mask) && need_rcu_nocb_mask) {

		if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) {

			pr_info("rcu_nocb_mask allocation failed, callback offloading disabled.\n");

			return;

		}

		have_rcu_nocb_mask = true;

	}

	if (!have_rcu_nocb_mask)

	if (!cpumask_available(rcu_nocb_mask))

		return;



#if defined(CONFIG_NO_HZ_FULL)
@@ -2428,7 +2425,7 @@ static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp) 
	struct rcu_data *rdp_leader = NULL;  /* Suppress misguided gcc warn. */

	struct rcu_data *rdp_prev = NULL;



	if (!have_rcu_nocb_mask)

	if (!cpumask_available(rcu_nocb_mask))

		return;

	if (ls == -1) {

		ls = int_sqrt(nr_cpu_ids);

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