litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'include/asm-ppc/cacheflush.h')

0 files changed, 0 insertions, 0 deletions

#ifndef _LINUX_PERCPU_COUNTER_H #define _LINUX_PERCPU_COUNTER_H /* * A simple "approximate counter" for use in ext2 and ext3 superblocks. * * WARNING: these things are HUGE. 4 kbytes per counter on 32-way P4. */ #include <linux/spinlock.h> #include <linux/smp.h> #include <linux/threads.h> #include <linux/percpu.h> #include <linux/types.h> #ifdef CONFIG_SMP struct percpu_counter { spinlock_t lock; s64 count; s32 *counters; }; #if NR_CPUS >= 16 #define FBC_BATCH (NR_CPUS*2) #else #define FBC_BATCH (NR_CPUS*4) #endif static inline void percpu_counter_init(struct percpu_counter *fbc, s64 amount) { spin_lock_init(&fbc->lock); fbc->count = amount; fbc->counters = alloc_percpu(s32); } static inline void percpu_counter_destroy(struct percpu_counter *fbc) { free_percpu(fbc->counters); } void percpu_counter_mod(struct percpu_counter *fbc, s32 amount); s64 percpu_counter_sum(struct percpu_counter *fbc); static inline s64 percpu_counter_read(struct percpu_counter *fbc) { return fbc->count; } /* * It is possible for the percpu_counter_read() to return a small negative * number for some counter which should never be negative. * */ static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) { s64 ret = fbc->count; barrier(); /* Prevent reloads of fbc->count */ if (ret >= 0) return ret; return 1; } #else struct percpu_counter { s64 count; }; static inline void percpu_counter_init(struct percpu_counter *fbc, s64 amount) { fbc->count = amount; } static inline void percpu_counter_destroy(struct percpu_counter *fbc) { } static inline void percpu_counter_mod(struct percpu_counter *fbc, s32 amount) { preempt_disable(); fbc->count += amount; preempt_enable(); } static inline s64 percpu_counter_read(struct percpu_counter *fbc) { return fbc->count; } static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc) { return fbc->count; } static inline s64 percpu_counter_sum(struct percpu_counter *fbc) { return percpu_counter_read_positive(fbc); } #endif /* CONFIG_SMP */ static inline void percpu_counter_inc(struct percpu_counter *fbc) { percpu_counter_mod(fbc, 1); } static inline void percpu_counter_dec(struct percpu_counter *fbc) { percpu_counter_mod(fbc, -1); } #endif /* _LINUX_PERCPU_COUNTER_H */


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