linux-kernel - Re: Solve section mismatch for free_area_init

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Date:	Tue, 19 Feb 2008 09:30:42 +0100 (CET)
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Sam Ravnborg <sam@...nborg.org>
cc:	Alexander van Heukelum <heukelum@...lshack.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Alexander van Heukelum <heukelum@...tmail.fm>
Subject: Re: Solve section mismatch for free_area_init_core.

On Mon, 18 Feb 2008, Sam Ravnborg wrote:
> I have (triggered by Geert) spend some time reviewing this patch
> and I see no better way to fix it.
> 
> So it gets my:
> 
> Reviewed-by: Sam Ravnborg <sam@...nborg.org>

Acked-by: Geert Uytterhoeven <geert@...ux-m68k.org>

> Original mail is here:
> http://lkml.org/lkml/2008/2/3/129
> 
> Can you take it in -mm so we get some testing coverage.
> 
> Thanks,
> 	Sam
> 
> On Sun, Feb 03, 2008 at 06:21:48PM +0100, Alexander van Heukelum wrote:
> > Solve section mismatch for free_area_init_core:
> > 
> > WARNING: vmlinux.o(.meminit.text+0x649): 
> > Section mismatch in reference from the 
> > function free_area_init_core() to the function .init.text:setup_usemap()
> > The function __meminit free_area_init_core() references
> > a function __init setup_usemap().
> > If free_area_init_core is only used by setup_usemap then
> > annotate free_area_init_core with a matching annotation.
> > 
> > The warning is covers this stack of functions in mm/page_alloc.c:
> > 
> > alloc_bootmem_node must be marked __init.
> > alloc_bootmem_node is used by setup_usemap, if !SPARSEMEM.
> > (usemap_size is only used by setup_usemap, if !SPARSEMEM.)
> > setup_usemap is only used by free_area_init_core.
> > free_area_init_core is only used by free_area_init_node.
> > 
> > free_area_init_node is used by:
> > arch/alpha/mm/numa.c: __init paging_init()
> > arch/arm/mm/init.c: __init bootmem_init_node()
> > arch/avr32/mm/init.c: __init paging_init()
> > arch/cris/arch-v10/mm/init.c: __init paging_init()
> > arch/cris/arch-v32/mm/init.c: __init paging_init()
> > arch/m32r/mm/discontig.c: __init zone_sizes_init()
> > arch/m32r/mm/init.c: __init zone_sizes_init()
> > arch/m68k/mm/motorola.c: __init paging_init()
> > arch/m68k/mm/sun3mmu.c: __init paging_init()
> > arch/mips/sgi-ip27/ip27-memory.c: __init paging_init()
> > arch/parisc/mm/init.c: __init paging_init()
> > arch/sparc/mm/srmmu.c: __init srmmu_paging_init()
> > arch/sparc/mm/sun4c.c: __init sun4c_paging_init()
> > arch/sparc64/mm/init.c: __init paging_init()
> > mm/page_alloc.c: __init free_area_init_nodes()
> > mm/page_alloc.c: __init free_area_init()
> > and
> > mm/memory_hotplug.c: hotadd_new_pgdat()
> > 
> > hotadd_new_pgdat can not be an __init function, but:
> > 
> > It is compiled for MEMORY_HOTPLUG configurations only
> > MEMORY_HOTPLUG depends on SPARSEMEM || X86_64_ACPI_NUMA
> > X86_64_ACPI_NUMA depends on X86_64
> > ARCH_FLATMEM_ENABLE depends on X86_32
> > ARCH_DISCONTIGMEM_ENABLE depends on X86_32
> > So X86_64_ACPI_NUMA implies SPARSEMEM, right?
> > 
> > So we can mark the stack of functions __init for !SPARSEMEM,
> > but we must mark them __meminit for SPARSEMEM configurations.
> > This is ok, because then the calls to alloc_bootmem_node are
> > also avoided.
> > 
> > Compile-tested on:
> > silly minimal config
> > defconfig x86_32
> > defconfig x86_64
> > defconfig x86_64 -HIBERNATION +MEMORY_HOTPLUG
> > 
> > Comments?
> > 
> > Signed-off-by: Alexander van Heukelum <heukelum@...tmail.fm>
> > 
> > 
> > diff --git a/mm/internal.h b/mm/internal.h
> > index 953f941..5b46b32 100644
> > --- a/mm/internal.h
> > +++ b/mm/internal.h
> > @@ -47,4 +47,17 @@ static inline unsigned long page_order(struct page *page)
> >  	VM_BUG_ON(!PageBuddy(page));
> >  	return page_private(page);
> >  }
> > +
> > +/*
> > + * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
> > + * so all functions starting at paging_init should be marked __init
> > + * in those cases. SPARSEMEM, however, allows for memory hotplug,
> > + * and alloc_bootmem_node is not used.
> > + */
> > +#ifdef CONFIG_SPARSEMEM
> > +#define __paginginit __meminit
> > +#else
> > +#define __paginginit __init
> > +#endif
> > +
> >  #endif
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index b2838c2..859be40 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -3321,7 +3321,7 @@ static inline int pageblock_default_order(unsigned int order)
> >   *   - mark all memory queues empty
> >   *   - clear the memory bitmaps
> >   */
> > -static void __meminit free_area_init_core(struct pglist_data *pgdat,
> > +static void __paginginit free_area_init_core(struct pglist_data *pgdat,
> >  		unsigned long *zones_size, unsigned long *zholes_size)
> >  {
> >  	enum zone_type j;
> > @@ -3445,7 +3445,7 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
> >  #endif /* CONFIG_FLAT_NODE_MEM_MAP */
> >  }
> >  
> > -void __meminit free_area_init_node(int nid, struct pglist_data *pgdat,
> > +void __paginginit free_area_init_node(int nid, struct pglist_data *pgdat,
> >  		unsigned long *zones_size, unsigned long node_start_pfn,
> >  		unsigned long *zholes_size)
> >  {
> > --
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Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
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