diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2011-07-28 08:43:51 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2015-02-13 22:21:00 (GMT) |
| commit | f6c076ea841913dcaf4664b65828c3caf21ba602 (patch) | |
| tree | a90a99de8ea18f1854cd03354050fc24300b5fa6 /include/linux | |
| parent | d1b60e49575ff571df99e87c04ea21c60cbc7c4a (diff) | |
| download | linux-fsl-qoriq-f6c076ea841913dcaf4664b65828c3caf21ba602.tar.xz | |
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 <a.p.zijlstra@chello.nl>
[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. ]
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/highmem.h | 27 | ||||
| -rw-r--r-- | include/linux/sched.h | 7 |
2 files changed, 30 insertions, 4 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 7fb31da..cee935c 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -85,32 +85,51 @@ static inline void __kunmap_atomic(void *addr) #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) +#ifndef CONFIG_PREEMPT_RT_FULL DECLARE_PER_CPU(int, __kmap_atomic_idx); +#endif static inline int kmap_atomic_idx_push(void) { +#ifndef CONFIG_PREEMPT_RT_FULL int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1; -#ifdef CONFIG_DEBUG_HIGHMEM +# ifdef CONFIG_DEBUG_HIGHMEM WARN_ON_ONCE(in_irq() && !irqs_disabled()); BUG_ON(idx > KM_TYPE_NR); -#endif +# endif return idx; +#else + current->kmap_idx++; + BUG_ON(current->kmap_idx > KM_TYPE_NR); + return current->kmap_idx - 1; +#endif } static inline int kmap_atomic_idx(void) { +#ifndef CONFIG_PREEMPT_RT_FULL return __this_cpu_read(__kmap_atomic_idx) - 1; +#else + return current->kmap_idx - 1; +#endif } static inline void kmap_atomic_idx_pop(void) { -#ifdef CONFIG_DEBUG_HIGHMEM +#ifndef CONFIG_PREEMPT_RT_FULL +# ifdef CONFIG_DEBUG_HIGHMEM int idx = __this_cpu_dec_return(__kmap_atomic_idx); BUG_ON(idx < 0); -#else +# else __this_cpu_dec(__kmap_atomic_idx); +# endif +#else + current->kmap_idx--; +# ifdef CONFIG_DEBUG_HIGHMEM + BUG_ON(current->kmap_idx < 0); +# endif #endif } diff --git a/include/linux/sched.h b/include/linux/sched.h index b3e2490..2b49cf8 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -23,6 +23,7 @@ struct sched_param { #include <linux/nodemask.h> #include <linux/mm_types.h> +#include <asm/kmap_types.h> #include <asm/page.h> #include <asm/ptrace.h> #include <asm/cputime.h> @@ -1450,6 +1451,12 @@ struct task_struct { struct rcu_head put_rcu; int softirq_nestcnt; #endif +#ifdef CONFIG_PREEMPT_RT_FULL +# if defined CONFIG_HIGHMEM || defined CONFIG_X86_32 + int kmap_idx; + pte_t kmap_pte[KM_TYPE_NR]; +# endif +#endif }; #ifdef CONFIG_NUMA_BALANCING |