[PATCH] NUMA slab locking fixes: irq disabling from cahep->spinlock to l3 lock
Earlier, we had to disable on chip interrupts while taking the
cachep->spinlock because, at cache_grow, on every addition of a slab to a slab
cache, we incremented colour_next which was protected by the cachep->spinlock,
and cache_grow could occur at interrupt context. Since, now we protect the
per-node colour_next with the node's list_lock, we do not need to disable on
chip interrupts while taking the per-cache spinlock, but we just need to
disable interrupts when taking the per-node kmem_list3 list_lock.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/slab.c b/mm/slab.c
index 2317096..d3f6854 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -987,7 +987,7 @@
cpumask_t mask;
mask = node_to_cpumask(node);
- spin_lock_irq(&cachep->spinlock);
+ spin_lock(&cachep->spinlock);
/* cpu is dead; no one can alloc from it. */
nc = cachep->array[cpu];
cachep->array[cpu] = NULL;
@@ -996,7 +996,7 @@
if (!l3)
goto unlock_cache;
- spin_lock(&l3->list_lock);
+ spin_lock_irq(&l3->list_lock);
/* Free limit for this kmem_list3 */
l3->free_limit -= cachep->batchcount;
@@ -1004,7 +1004,7 @@
free_block(cachep, nc->entry, nc->avail, node);
if (!cpus_empty(mask)) {
- spin_unlock(&l3->list_lock);
+ spin_unlock_irq(&l3->list_lock);
goto unlock_cache;
}
@@ -1023,13 +1023,13 @@
/* free slabs belonging to this node */
if (__node_shrink(cachep, node)) {
cachep->nodelists[node] = NULL;
- spin_unlock(&l3->list_lock);
+ spin_unlock_irq(&l3->list_lock);
kfree(l3);
} else {
- spin_unlock(&l3->list_lock);
+ spin_unlock_irq(&l3->list_lock);
}
unlock_cache:
- spin_unlock_irq(&cachep->spinlock);
+ spin_unlock(&cachep->spinlock);
kfree(nc);
}
mutex_unlock(&cache_chain_mutex);
@@ -2011,18 +2011,18 @@
smp_call_function_all_cpus(do_drain, cachep);
check_irq_on();
- spin_lock_irq(&cachep->spinlock);
+ spin_lock(&cachep->spinlock);
for_each_online_node(node) {
l3 = cachep->nodelists[node];
if (l3) {
- spin_lock(&l3->list_lock);
+ spin_lock_irq(&l3->list_lock);
drain_array_locked(cachep, l3->shared, 1, node);
- spin_unlock(&l3->list_lock);
+ spin_unlock_irq(&l3->list_lock);
if (l3->alien)
drain_alien_cache(cachep, l3);
}
}
- spin_unlock_irq(&cachep->spinlock);
+ spin_unlock(&cachep->spinlock);
}
static int __node_shrink(struct kmem_cache *cachep, int node)
@@ -2338,7 +2338,6 @@
offset *= cachep->colour_off;
- check_irq_off();
if (local_flags & __GFP_WAIT)
local_irq_enable();
@@ -2725,6 +2724,7 @@
BUG_ON(!l3);
retry:
+ check_irq_off();
spin_lock(&l3->list_lock);
entry = l3->slabs_partial.next;
if (entry == &l3->slabs_partial) {
@@ -3304,11 +3304,11 @@
smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
check_irq_on();
- spin_lock_irq(&cachep->spinlock);
+ spin_lock(&cachep->spinlock);
cachep->batchcount = batchcount;
cachep->limit = limit;
cachep->shared = shared;
- spin_unlock_irq(&cachep->spinlock);
+ spin_unlock(&cachep->spinlock);
for_each_online_cpu(i) {
struct array_cache *ccold = new.new[i];
@@ -3564,8 +3564,7 @@
int node;
struct kmem_list3 *l3;
- check_irq_on();
- spin_lock_irq(&cachep->spinlock);
+ spin_lock(&cachep->spinlock);
active_objs = 0;
num_slabs = 0;
for_each_online_node(node) {
@@ -3573,7 +3572,8 @@
if (!l3)
continue;
- spin_lock(&l3->list_lock);
+ check_irq_on();
+ spin_lock_irq(&l3->list_lock);
list_for_each(q, &l3->slabs_full) {
slabp = list_entry(q, struct slab, list);
@@ -3600,7 +3600,7 @@
free_objects += l3->free_objects;
shared_avail += l3->shared->avail;
- spin_unlock(&l3->list_lock);
+ spin_unlock_irq(&l3->list_lock);
}
num_slabs += active_slabs;
num_objs = num_slabs * cachep->num;
@@ -3644,7 +3644,7 @@
}
#endif
seq_putc(m, '\n');
- spin_unlock_irq(&cachep->spinlock);
+ spin_unlock(&cachep->spinlock);
return 0;
}