Re: [PATCH 4/7] slub: fix error path bug in kmem_cache_alloc_bulk
On Tue, 16 Jun 2015 14:51:09 -0700 Andrew Morton wrote: > On Mon, 15 Jun 2015 17:52:26 +0200 Jesper Dangaard Brouer > wrote: > > > The current kmem_cache/SLAB bulking API need to release all objects > > in case the layer cannot satisfy the full request. > > > > If __kmem_cache_alloc_bulk() fails, all allocated objects in array > > should be freed, but, __kmem_cache_alloc_bulk() can't know > > about objects allocated by this slub specific kmem_cache_alloc_bulk() > > function. > > Can we fold patches 2, 3 and 4 into a single patch? > > And maybe patch 5 as well. I don't think we need all these > development-time increments in the permanent record. I agree. I'll fold them when submitting V2 -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 4/7] slub: fix error path bug in kmem_cache_alloc_bulk
On Mon, 15 Jun 2015 17:52:26 +0200 Jesper Dangaard Brouer wrote: > The current kmem_cache/SLAB bulking API need to release all objects > in case the layer cannot satisfy the full request. > > If __kmem_cache_alloc_bulk() fails, all allocated objects in array > should be freed, but, __kmem_cache_alloc_bulk() can't know > about objects allocated by this slub specific kmem_cache_alloc_bulk() > function. Can we fold patches 2, 3 and 4 into a single patch? And maybe patch 5 as well. I don't think we need all these development-time increments in the permanent record. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 4/7] slub: fix error path bug in kmem_cache_alloc_bulk
The current kmem_cache/SLAB bulking API need to release all objects
in case the layer cannot satisfy the full request.
If __kmem_cache_alloc_bulk() fails, all allocated objects in array
should be freed, but, __kmem_cache_alloc_bulk() can't know
about objects allocated by this slub specific kmem_cache_alloc_bulk()
function.
Signed-off-by: Jesper Dangaard Brouer
---
mm/slub.c | 21 -
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 753f88bd8b40..d10de5a33c03 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2760,24 +2760,27 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t
flags, size_t size,
void **p)
{
struct kmem_cache_cpu *c;
+ int i;
/* Debugging fallback to generic bulk */
if (kmem_cache_debug(s))
return __kmem_cache_alloc_bulk(s, flags, size, p);
- /* Drain objects in the per cpu slab */
+ /* Drain objects in the per cpu slab, while disabling local
+* IRQs, which protects against PREEMPT and interrupts
+* handlers invoking normal fastpath.
+*/
local_irq_disable();
c = this_cpu_ptr(s->cpu_slab);
- while (size) {
+ for (i = 0; i < size; i++) {
void *object = c->freelist;
if (!object)
break;
c->freelist = get_freepointer(s, object);
- *p++ = object;
- size--;
+ p[i] = object;
if (unlikely(flags & __GFP_ZERO))
memset(object, 0, s->object_size);
@@ -2785,7 +2788,15 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t
flags, size_t size,
c->tid = next_tid(c->tid);
local_irq_enable();
- return __kmem_cache_alloc_bulk(s, flags, size, p);
+ /* Fallback to single elem alloc */
+ for (; i < size; i++) {
+ void *x = p[i] = kmem_cache_alloc(s, flags);
+ if (unlikely(!x)) {
+ __kmem_cache_free_bulk(s, i, p);
+ return false;
+ }
+ }
+ return true;
}
EXPORT_SYMBOL(kmem_cache_alloc_bulk);
--
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