slab,slub: don't enable interrupts during early boot
As explained by Benjamin Herrenschmidt:
Oh and btw, your patch alone doesn't fix powerpc, because it's missing
a whole bunch of GFP_KERNEL's in the arch code... You would have to
grep the entire kernel for things that check slab_is_available() and
even then you'll be missing some.
For example, slab_is_available() didn't always exist, and so in the
early days on powerpc, we used a mem_init_done global that is set form
mem_init() (not perfect but works in practice). And we still have code
using that to do the test.
Therefore, mask out __GFP_WAIT, __GFP_IO, and __GFP_FS in the slab allocators
in early boot code to avoid enabling interrupts.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
diff --git a/mm/slub.c b/mm/slub.c
index 3964d3c..30354bf 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -178,6 +178,12 @@
SYSFS /* Sysfs up */
} slab_state = DOWN;
+/*
+ * The slab allocator is initialized with interrupts disabled. Therefore, make
+ * sure early boot allocations don't accidentally enable interrupts.
+ */
+static gfp_t slab_gfp_mask __read_mostly = SLAB_GFP_BOOT_MASK;
+
/* A list of all slab caches on the system */
static DECLARE_RWSEM(slub_lock);
static LIST_HEAD(slab_caches);
@@ -1595,6 +1601,8 @@
unsigned long flags;
unsigned int objsize;
+ gfpflags &= slab_gfp_mask;
+
lockdep_trace_alloc(gfpflags);
might_sleep_if(gfpflags & __GFP_WAIT);
@@ -3104,6 +3112,14 @@
nr_cpu_ids, nr_node_ids);
}
+void __init kmem_cache_init_late(void)
+{
+ /*
+ * Interrupts are enabled now so all GFP allocations are safe.
+ */
+ slab_gfp_mask = __GFP_BITS_MASK;
+}
+
/*
* Find a mergeable slab cache
*/