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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-10-26 14:21:51 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-26 16:52:08 -0700 |
commit | 3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73 (patch) | |
tree | 2ce507f7ec7275563653e52f18606aba4f99b7f1 /mm | |
parent | 61ecdb801ef2cd28e32442383106d7837d76deac (diff) | |
download | linux-stable-3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73.tar.gz linux-stable-3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73.tar.bz2 linux-stable-3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73.zip |
mm: stack based kmap_atomic()
Keep the current interface but ignore the KM_type and use a stack based
approach.
The advantage is that we get rid of crappy code like:
#define __KM_PTE \
(in_nmi() ? KM_NMI_PTE : \
in_irq() ? KM_IRQ_PTE : \
KM_PTE0)
and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.
The downside is that FRV kmap_atomic() gets more expensive.
For now we use a CPP trick suggested by Andrew:
#define kmap_atomic(page, args...) __kmap_atomic(page)
to avoid having to touch all kmap_atomic() users in a single patch.
[ not compiled on:
- mn10300: the arch doesn't actually build with highmem to begin with ]
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/highmem.c | 62 |
1 files changed, 4 insertions, 58 deletions
diff --git a/mm/highmem.c b/mm/highmem.c index 7a0aa1be4993..781e754a75ac 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -42,6 +42,10 @@ unsigned long totalhigh_pages __read_mostly; EXPORT_SYMBOL(totalhigh_pages); + +DEFINE_PER_CPU(int, __kmap_atomic_idx); +EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx); + unsigned int nr_free_highpages (void) { pg_data_t *pgdat; @@ -422,61 +426,3 @@ void __init page_address_init(void) } #endif /* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */ - -#ifdef CONFIG_DEBUG_HIGHMEM - -void debug_kmap_atomic(enum km_type type) -{ - static int warn_count = 10; - - if (unlikely(warn_count < 0)) - return; - - if (unlikely(in_interrupt())) { - if (in_nmi()) { - if (type != KM_NMI && type != KM_NMI_PTE) { - WARN_ON(1); - warn_count--; - } - } else if (in_irq()) { - if (type != KM_IRQ0 && type != KM_IRQ1 && - type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ && - type != KM_BOUNCE_READ && type != KM_IRQ_PTE) { - WARN_ON(1); - warn_count--; - } - } else if (!irqs_disabled()) { /* softirq */ - if (type != KM_IRQ0 && type != KM_IRQ1 && - type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 && - type != KM_SKB_SUNRPC_DATA && - type != KM_SKB_DATA_SOFTIRQ && - type != KM_BOUNCE_READ) { - WARN_ON(1); - warn_count--; - } - } - } - - if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ || - type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ || - type == KM_IRQ_PTE || type == KM_NMI || - type == KM_NMI_PTE ) { - if (!irqs_disabled()) { - WARN_ON(1); - warn_count--; - } - } else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) { - if (irq_count() == 0 && !irqs_disabled()) { - WARN_ON(1); - warn_count--; - } - } -#ifdef CONFIG_KGDB_KDB - if (unlikely(type == KM_KDB && atomic_read(&kgdb_active) == -1)) { - WARN_ON(1); - warn_count--; - } -#endif /* CONFIG_KGDB_KDB */ -} - -#endif |