netdev - [PATCH 2/7] slub: Avoid irqoff/on in bulk allocation

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Date:	Mon, 28 Sep 2015 14:26:14 +0200
From:	Jesper Dangaard Brouer <brouer@...hat.com>
To:	linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>
Cc:	netdev@...r.kernel.org, Jesper Dangaard Brouer <brouer@...hat.com>,
	Alexander Duyck <alexander.duyck@...il.com>,
	Pekka Enberg <penberg@...nel.org>,
	David Rientjes <rientjes@...gle.com>,
	Christoph Lameter <cl@...ux.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH 2/7] slub: Avoid irqoff/on in bulk allocation

From: Christoph Lameter <cl@...ux.com>

NOTICE: Accepted by AKPM
 http://ozlabs.org/~akpm/mmots/broken-out/slub-avoid-irqoff-on-in-bulk-allocation.patch

Use the new function that can do allocation while
interrupts are disabled.  Avoids irq on/off sequences.

Signed-off-by: Christoph Lameter <cl@...ux.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>
---
 mm/slub.c |   24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 02cfb3a5983e..024eed32da2c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2821,30 +2821,23 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 		void *object = c->freelist;
 
 		if (unlikely(!object)) {
-			local_irq_enable();
 			/*
 			 * Invoking slow path likely have side-effect
 			 * of re-populating per CPU c->freelist
 			 */
-			p[i] = __slab_alloc(s, flags, NUMA_NO_NODE,
+			p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
 					    _RET_IP_, c);
-			if (unlikely(!p[i])) {
-				__kmem_cache_free_bulk(s, i, p);
-				return false;
-			}
-			local_irq_disable();
+			if (unlikely(!p[i]))
+				goto error;
+
 			c = this_cpu_ptr(s->cpu_slab);
 			continue; /* goto for-loop */
 		}
 
 		/* kmem_cache debug support */
 		s = slab_pre_alloc_hook(s, flags);
-		if (unlikely(!s)) {
-			__kmem_cache_free_bulk(s, i, p);
-			c->tid = next_tid(c->tid);
-			local_irq_enable();
-			return false;
-		}
+		if (unlikely(!s))
+			goto error;
 
 		c->freelist = get_freepointer(s, object);
 		p[i] = object;
@@ -2864,6 +2857,11 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 	}
 
 	return true;
+
+error:
+	__kmem_cache_free_bulk(s, i, p);
+	local_irq_enable();
+	return false;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
 

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