2006-05-10 20:55:37

by Mike Kravetz

[permalink] [raw]
Subject: [PATCH] add slab_is_available() routine for boot code

slab_is_available() indicates slab based allocators are available
for use. SPARSEMEM code needs to know this as it can be called
at various times during the boot process.

Signed-off-by: Mike Kravetz <[email protected]>

diff -Naupr linux-2.6.17-rc3-mm1/include/linux/slab.h linux-2.6.17-rc3-mm1.work3/include/linux/slab.h
--- linux-2.6.17-rc3-mm1/include/linux/slab.h 2006-05-03 22:19:15.000000000 +0000
+++ linux-2.6.17-rc3-mm1.work3/include/linux/slab.h 2006-05-10 19:15:20.000000000 +0000
@@ -150,6 +150,7 @@ static inline void *kcalloc(size_t n, si

extern void kfree(const void *);
extern unsigned int ksize(const void *);
+extern int slab_is_available(void);

#ifdef CONFIG_NUMA
extern void *kmem_cache_alloc_node(kmem_cache_t *, gfp_t flags, int node);
diff -Naupr linux-2.6.17-rc3-mm1/mm/slab.c linux-2.6.17-rc3-mm1.work3/mm/slab.c
--- linux-2.6.17-rc3-mm1/mm/slab.c 2006-05-03 22:19:16.000000000 +0000
+++ linux-2.6.17-rc3-mm1.work3/mm/slab.c 2006-05-10 21:43:08.000000000 +0000
@@ -694,6 +694,14 @@ static enum {
FULL
} g_cpucache_up;

+/*
+ * used by boot code to determine if it can use slab based allocator
+ */
+int slab_is_available(void)
+{
+ return g_cpucache_up == FULL;
+}
+
static DEFINE_PER_CPU(struct work_struct, reap_work);

static void free_block(struct kmem_cache *cachep, void **objpp, int len,
diff -Naupr linux-2.6.17-rc3-mm1/mm/sparse.c linux-2.6.17-rc3-mm1.work3/mm/sparse.c
--- linux-2.6.17-rc3-mm1/mm/sparse.c 2006-05-03 22:19:16.000000000 +0000
+++ linux-2.6.17-rc3-mm1.work3/mm/sparse.c 2006-05-10 19:15:56.000000000 +0000
@@ -32,7 +32,7 @@ static struct mem_section *sparse_index_
unsigned long array_size = SECTIONS_PER_ROOT *
sizeof(struct mem_section);

- if (system_state == SYSTEM_RUNNING)
+ if (slab_is_available())
section = kmalloc_node(array_size, GFP_KERNEL, nid);
else
section = alloc_bootmem_node(NODE_DATA(nid), array_size);


2006-05-10 22:53:22

by Andrew Morton

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Subject: Re: [PATCH] add slab_is_available() routine for boot code

Mike Kravetz <[email protected]> wrote:
>
> slab_is_available() indicates slab based allocators are available
> for use. SPARSEMEM code needs to know this as it can be called
> at various times during the boot process.
>
> Signed-off-by: Mike Kravetz <[email protected]>
>
> diff -Naupr linux-2.6.17-rc3-mm1/include/linux/slab.h linux-2.6.17-rc3-mm1.work3/include/linux/slab.h
> --- linux-2.6.17-rc3-mm1/include/linux/slab.h 2006-05-03 22:19:15.000000000 +0000
> +++ linux-2.6.17-rc3-mm1.work3/include/linux/slab.h 2006-05-10 19:15:20.000000000 +0000
> @@ -150,6 +150,7 @@ static inline void *kcalloc(size_t n, si
>
> extern void kfree(const void *);
> extern unsigned int ksize(const void *);
> +extern int slab_is_available(void);
>
> #ifdef CONFIG_NUMA
> extern void *kmem_cache_alloc_node(kmem_cache_t *, gfp_t flags, int node);
> diff -Naupr linux-2.6.17-rc3-mm1/mm/slab.c linux-2.6.17-rc3-mm1.work3/mm/slab.c
> --- linux-2.6.17-rc3-mm1/mm/slab.c 2006-05-03 22:19:16.000000000 +0000
> +++ linux-2.6.17-rc3-mm1.work3/mm/slab.c 2006-05-10 21:43:08.000000000 +0000
> @@ -694,6 +694,14 @@ static enum {
> FULL
> } g_cpucache_up;
>
> +/*
> + * used by boot code to determine if it can use slab based allocator
> + */
> +int slab_is_available(void)
> +{
> + return g_cpucache_up == FULL;
> +}

Even I can understand this ;)

> static DEFINE_PER_CPU(struct work_struct, reap_work);
>
> static void free_block(struct kmem_cache *cachep, void **objpp, int len,
> diff -Naupr linux-2.6.17-rc3-mm1/mm/sparse.c linux-2.6.17-rc3-mm1.work3/mm/sparse.c
> --- linux-2.6.17-rc3-mm1/mm/sparse.c 2006-05-03 22:19:16.000000000 +0000
> +++ linux-2.6.17-rc3-mm1.work3/mm/sparse.c 2006-05-10 19:15:56.000000000 +0000
> @@ -32,7 +32,7 @@ static struct mem_section *sparse_index_
> unsigned long array_size = SECTIONS_PER_ROOT *
> sizeof(struct mem_section);
>
> - if (system_state == SYSTEM_RUNNING)
> + if (slab_is_available())
> section = kmalloc_node(array_size, GFP_KERNEL, nid);
> else
> section = alloc_bootmem_node(NODE_DATA(nid), array_size);

Is this a needed-for-2.6.17 fix?

2006-05-10 23:00:44

by Mike Kravetz

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Subject: Re: [PATCH] add slab_is_available() routine for boot code

On Wed, May 10, 2006 at 03:50:26PM -0700, Andrew Morton wrote:
> Mike Kravetz <[email protected]> wrote:
> > diff -Naupr linux-2.6.17-rc3-mm1/mm/sparse.c linux-2.6.17-rc3-mm1.work3/mm/sparse.c
> > --- linux-2.6.17-rc3-mm1/mm/sparse.c 2006-05-03 22:19:16.000000000 +0000
> > +++ linux-2.6.17-rc3-mm1.work3/mm/sparse.c 2006-05-10 19:15:56.000000000 +0000
> > @@ -32,7 +32,7 @@ static struct mem_section *sparse_index_
> > unsigned long array_size = SECTIONS_PER_ROOT *
> > sizeof(struct mem_section);
> >
> > - if (system_state == SYSTEM_RUNNING)
> > + if (slab_is_available())
> > section = kmalloc_node(array_size, GFP_KERNEL, nid);
> > else
> > section = alloc_bootmem_node(NODE_DATA(nid), array_size);
>
> Is this a needed-for-2.6.17 fix?

I'll let Arnd answer. He ran into this when doing some Cell work. Not
sure where in the development cycle the code is that exposes this bug.

--
Mike

2006-05-11 03:08:50

by Benjamin Herrenschmidt

[permalink] [raw]
Subject: Re: [PATCH] add slab_is_available() routine for boot code


> I'll let Arnd answer. He ran into this when doing some Cell work. Not
> sure where in the development cycle the code is that exposes this bug.

I want that too for some other unrelated patches :) I want request_irq()
to use alloc_bootmem when slab is not available so that some low level
arch irqs can be requested at init_IRQ() time.

(Typically IRQs for cascaded controllers). We currently define
statically irqaction structures for them and call setup_irq() on them,
this is gross :)

Cheers,
Ben.

2006-05-11 06:15:29

by Pekka Enberg

[permalink] [raw]
Subject: Re: [PATCH] add slab_is_available() routine for boot code

On Wed, 10 May 2006, Mike Kravetz wrote:
> +/*
> + * used by boot code to determine if it can use slab based allocator
> + */
> +int slab_is_available(void)
> +{
> + return g_cpucache_up == FULL;
> +}
> +

Please use proper kerneldoc format so you don't create extra work for
janitors.

Pekka

2006-05-11 12:40:23

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH] add slab_is_available() routine for boot code

On Thursday 11 May 2006 01:00, Mike Kravetz wrote:
> On Wed, May 10, 2006 at 03:50:26PM -0700, Andrew Morton wrote:
> >
> > Is this a needed-for-2.6.17 fix?
>
> I'll let Arnd answer. ?He ran into this when doing some Cell work. ?Not
> sure where in the development cycle the code is that exposes this bug.

The code in 2.6.17 breaks when spufs is non-modular. Currently, this is
a compile-time option so users can work around it by building spufs
as a loadable module.

For 2.6.18, we want to make the part of spufs that calls this
non-modular in order to avoid adding further EXPORT_SYMBOLs. I would
much prefer to have the fix in 2.6.17 already, but we could
alternatively force spufs to be a loadable module in 2.6.17 and
change it later.

Arnd <><