Commit 7e85ee0c authored by Pekka Enberg's avatar Pekka Enberg
Browse files

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: default avatarPekka Enberg <penberg@cs.helsinki.fi>
parent eb91f1d0
......@@ -85,6 +85,9 @@ struct vm_area_struct;
__GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\
__GFP_NORETRY|__GFP_NOMEMALLOC)
/* Control slab gfp mask during early boot */
#define SLAB_GFP_BOOT_MASK __GFP_BITS_MASK & ~(__GFP_WAIT|__GFP_IO|__GFP_FS)
/* Control allocation constraints */
#define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
......
......@@ -319,4 +319,6 @@ static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
return kmalloc_node(size, flags | __GFP_ZERO, node);
}
void __init kmem_cache_init_late(void);
#endif /* _LINUX_SLAB_H */
......@@ -34,4 +34,9 @@ static __always_inline void *__kmalloc(size_t size, gfp_t flags)
return kmalloc(size, flags);
}
static inline void kmem_cache_init_late(void)
{
/* Nothing to do */
}
#endif /* __LINUX_SLOB_DEF_H */
......@@ -302,4 +302,6 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
}
#endif
void __init kmem_cache_init_late(void);
#endif /* _LINUX_SLUB_DEF_H */
......@@ -640,6 +640,7 @@ asmlinkage void __init start_kernel(void)
"enabled early\n");
early_boot_irqs_on();
local_irq_enable();
kmem_cache_init_late();
/*
* HACK ALERT! This is early. We're enabling the console before
......
......@@ -303,6 +303,12 @@ struct kmem_list3 {
int free_touched; /* updated without locking */
};
/*
* 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;
/*
* Need this for bootstrapping a per node allocator.
*/
......@@ -1654,6 +1660,14 @@ void __init kmem_cache_init(void)
*/
}
void __init kmem_cache_init_late(void)
{
/*
* Interrupts are enabled now so all GFP allocations are safe.
*/
slab_gfp_mask = __GFP_BITS_MASK;
}
static int __init cpucache_init(void)
{
int cpu;
......@@ -3354,6 +3368,8 @@ __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
unsigned long save_flags;
void *ptr;
flags &= slab_gfp_mask;
lockdep_trace_alloc(flags);
if (slab_should_failslab(cachep, flags))
......@@ -3434,6 +3450,8 @@ __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
unsigned long save_flags;
void *objp;
flags &= slab_gfp_mask;
lockdep_trace_alloc(flags);
if (slab_should_failslab(cachep, flags))
......
......@@ -178,6 +178,12 @@ static enum {
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 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
unsigned long flags;
unsigned int objsize;
gfpflags &= slab_gfp_mask;
lockdep_trace_alloc(gfpflags);
might_sleep_if(gfpflags & __GFP_WAIT);
......@@ -3104,6 +3112,14 @@ void __init kmem_cache_init(void)
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
*/
......
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