From 93234f6354d31d88d8987e374ca877979c7dbc15 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 28 Jul 2011 10:43:51 +0200 Subject: mm, rt: kmap_atomic scheduling In fact, with migrate_disable() existing one could play games with kmap_atomic. You could save/restore the kmap_atomic slots on context switch (if there are any in use of course), this should be esp easy now that we have a kmap_atomic stack. Something like the below.. it wants replacing all the preempt_disable() stuff with pagefault_disable() && migrate_disable() of course, but then you can flip kmaps around like below. Signed-off-by: Peter Zijlstra [dvhart@linux.intel.com: build fix] Link: http://lkml.kernel.org/r/1311842631.5890.208.camel@twins [tglx@linutronix.de: Get rid of the per cpu variable and store the idx and the pte content right away in the task struct. Shortens the context switch code. ] --- mm/highmem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/highmem.c') diff --git a/mm/highmem.c b/mm/highmem.c index 107b10f9878e..c7d81eaf48f7 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -30,9 +30,11 @@ #include #include - +#ifndef CONFIG_PREEMPT_RT #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) DEFINE_PER_CPU(int, __kmap_atomic_idx); +EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx); +#endif #endif /* @@ -108,8 +110,6 @@ static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color) atomic_long_t _totalhigh_pages __read_mostly; EXPORT_SYMBOL(_totalhigh_pages); -EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx); - unsigned int nr_free_highpages (void) { struct zone *zone; -- cgit v1.2.1