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Date: Wed, 04 Mar 2009 10:16:07 +0200
From: Pekka Enberg <penberg@...helsinki.fi>
To: Ingo Molnar <mingo@...e.hu>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
Mel Gorman <mel@....ul.ie>
Subject: Re: [PATCH] x86: set_highmem_pages_init() cleanup
On Tue, 2009-03-03 at 13:15 +0100, Ingo Molnar wrote:
> * Pekka Enberg <penberg@...helsinki.fi> wrote:
>
> > From: Pekka Enberg <penberg@...helsinki.fi>
> >
> > Impact: cleanup
> >
> > This patch moves set_highmem_pages_init() to arch/x86/mm/highmem_32.c. The
> > declaration of the function is kept in asm/numa_32.h because asm/highmem.h is
> > included only CONFIG_HIGHMEM is enabled so we can't put the empty static inline
> > function there.
> >
> > Signed-off-by: Pekka Enberg <penberg@...helsinki.fi>
> > ---
> > arch/x86/include/asm/numa_32.h | 6 +++++-
> > arch/x86/mm/highmem_32.c | 34 ++++++++++++++++++++++++++++++++++
> > arch/x86/mm/init_32.c | 12 ------------
> > arch/x86/mm/numa_32.c | 26 --------------------------
> > 4 files changed, 39 insertions(+), 39 deletions(-)
>
> Applied, thanks!
>
> One question:
>
> > diff --git a/arch/x86/include/asm/numa_32.h b/arch/x86/include/asm/numa_32.h
> > index e9f5db7..a372290 100644
> > --- a/arch/x86/include/asm/numa_32.h
> > +++ b/arch/x86/include/asm/numa_32.h
> > @@ -4,8 +4,12 @@
> > extern int pxm_to_nid(int pxm);
> > extern void numa_remove_cpu(int cpu);
> >
> > -#ifdef CONFIG_NUMA
> > +#ifdef CONFIG_HIGHMEM
> > extern void set_highmem_pages_init(void);
> > +#else
> > +static inline void set_highmem_pages_init(void)
> > +{
> > +}
> > #endif
> >
> > #endif /* _ASM_X86_NUMA_32_H */
> > diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
> > index bcc079c..13a823c 100644
> > --- a/arch/x86/mm/highmem_32.c
> > +++ b/arch/x86/mm/highmem_32.c
> > @@ -1,5 +1,6 @@
> > #include <linux/highmem.h>
> > #include <linux/module.h>
> > +#include <linux/swap.h> /* for totalram_pages */
> >
> > void *kmap(struct page *page)
> > {
> > @@ -156,3 +157,36 @@ EXPORT_SYMBOL(kmap);
> > EXPORT_SYMBOL(kunmap);
> > EXPORT_SYMBOL(kmap_atomic);
> > EXPORT_SYMBOL(kunmap_atomic);
> > +
> > +#ifdef CONFIG_NUMA
> > +void __init set_highmem_pages_init(void)
> > +{
> > + struct zone *zone;
> > + int nid;
> > +
> > + for_each_zone(zone) {
> > + unsigned long zone_start_pfn, zone_end_pfn;
> > +
> > + if (!is_highmem(zone))
> > + continue;
> > +
> > + zone_start_pfn = zone->zone_start_pfn;
> > + zone_end_pfn = zone_start_pfn + zone->spanned_pages;
> > +
> > + nid = zone_to_nid(zone);
> > + printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
> > + zone->name, nid, zone_start_pfn, zone_end_pfn);
> > +
> > + add_highpages_with_active_regions(nid, zone_start_pfn,
> > + zone_end_pfn);
> > + }
> > + totalram_pages += totalhigh_pages;
> > +}
> > +#else
> > +static void __init set_highmem_pages_init(void)
> > +{
> > + add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
> > +
> > + totalram_pages += totalhigh_pages;
> > +}
> > +#endif /* CONFIG_NUMA */
>
> Couldnt we just wrap the !NUMA case into the NUMA case and just
> have the NUMA function present, by making for_each_zone() a
> two-entries matter and making the second entry contain:
>
> zone->zone_start_pfn := highstart_pfn
> zone->spanned_pages := highend_pfn-highstart_pfn
OK, I don't quite understand your suggestion here. The zones are set up
completely at this stage so AFAICT, even for the UMA case, there should
be a highmem zone there. So unless I am missing something here, I think
we can get away with something as simple as the following.
I don't have any highmem machines to test this but some printk()'s seem
to confirm this (although for machines that don't have any highmem
available, ->zone_start_pfn is zero (whereas highstart_pfn is non-zero).
I think that's because of the !size test in free_area_init_core() but
AFAICT, it's fine as add_highpages_with_active_regions() takes care of
that nicely.
But I'll cc Mel just in case... :-)
Pekka
>>From 29c85778896d263ce5c59c496c13548488b7593c Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@...helsinki.fi>
Date: Wed, 4 Mar 2009 10:10:53 +0200
Subject: [PATCH] x86: unify uma and numa copies of set_highmem_pages_init()
Impact: cleanup
The zones are set up at this stage so there's a highmem zone available even for
the UMA case. The only difference there is that for machines that have
CONFIG_HIGHMEM enabled but don't have any highmem available, ->zone_start_pfn
is zero whereas highstart_pfn is non-zero). The field is left zeroed because of
the !size test in free_area_init_core() but shouldn't be a problem because
add_highpages_with_active_regions() handles empty ranges just fine.
Cc: Mel Gorman <mel@....ul.ie>
Signed-off-by: Pekka Enberg <penberg@...helsinki.fi>
---
arch/x86/mm/highmem_32.c | 9 ---------
1 files changed, 0 insertions(+), 9 deletions(-)
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index 00f127c..d117453 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -158,7 +158,6 @@ EXPORT_SYMBOL(kunmap);
EXPORT_SYMBOL(kmap_atomic);
EXPORT_SYMBOL(kunmap_atomic);
-#ifdef CONFIG_NUMA
void __init set_highmem_pages_init(void)
{
struct zone *zone;
@@ -182,11 +181,3 @@ void __init set_highmem_pages_init(void)
}
totalram_pages += totalhigh_pages;
}
-#else
-void __init set_highmem_pages_init(void)
-{
- add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
-
- totalram_pages += totalhigh_pages;
-}
-#endif /* CONFIG_NUMA */
--
1.5.4.3
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