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Subject: mm/vmalloc: Another preempt disable region which sucks
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 12 Jul 2011 11:39:36 +0200
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9.20-rt16.tar.xz
Avoid the preempt disable version of get_cpu_var(). The inner-lock should
provide enough serialisation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
mm/vmalloc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -845,7 +845,7 @@ static void *new_vmap_block(unsigned int
struct vmap_block *vb;
struct vmap_area *va;
unsigned long vb_idx;
- int node, err;
+ int node, err, cpu;
void *vaddr;
node = numa_node_id();
@@ -888,11 +888,12 @@ static void *new_vmap_block(unsigned int
BUG_ON(err);
radix_tree_preload_end();
- vbq = &get_cpu_var(vmap_block_queue);
+ cpu = get_cpu_light();
+ vbq = this_cpu_ptr(&vmap_block_queue);
spin_lock(&vbq->lock);
list_add_tail_rcu(&vb->free_list, &vbq->free);
spin_unlock(&vbq->lock);
- put_cpu_var(vmap_block_queue);
+ put_cpu_light();
return vaddr;
}
@@ -961,6 +962,7 @@ static void *vb_alloc(unsigned long size
struct vmap_block *vb;
void *vaddr = NULL;
unsigned int order;
+ int cpu;
BUG_ON(offset_in_page(size));
BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
@@ -975,7 +977,8 @@ static void *vb_alloc(unsigned long size
order = get_order(size);
rcu_read_lock();
- vbq = &get_cpu_var(vmap_block_queue);
+ cpu = get_cpu_light();
+ vbq = this_cpu_ptr(&vmap_block_queue);
list_for_each_entry_rcu(vb, &vbq->free, free_list) {
unsigned long pages_off;
@@ -998,7 +1001,7 @@ static void *vb_alloc(unsigned long size
break;
}
- put_cpu_var(vmap_block_queue);
+ put_cpu_light();
rcu_read_unlock();
/* Allocate new block if nothing was found */
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