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0a418cd117
There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/**
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* @file cpu_buffer.h
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*
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* @remark Copyright 2002-2009 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon <levon@movementarian.org>
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* @author Robert Richter <robert.richter@amd.com>
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*/
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#ifndef OPROFILE_CPU_BUFFER_H
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#define OPROFILE_CPU_BUFFER_H
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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#include <linux/cache.h>
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#include <linux/sched.h>
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#include <linux/ring_buffer.h>
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struct task_struct;
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int alloc_cpu_buffers(void);
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void free_cpu_buffers(void);
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void start_cpu_work(void);
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void end_cpu_work(void);
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void flush_cpu_work(void);
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/* CPU buffer is composed of such entries (which are
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* also used for context switch notes)
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*/
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struct op_sample {
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unsigned long eip;
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unsigned long event;
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unsigned long data[];
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};
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struct op_entry;
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struct oprofile_cpu_buffer {
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unsigned long buffer_size;
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struct task_struct *last_task;
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int last_is_kernel;
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int tracing;
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unsigned long sample_received;
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unsigned long sample_lost_overflow;
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unsigned long backtrace_aborted;
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unsigned long sample_invalid_eip;
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int cpu;
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struct delayed_work work;
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};
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DECLARE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);
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/*
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* Resets the cpu buffer to a sane state.
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*
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* reset these to invalid values; the next sample collected will
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* populate the buffer with proper values to initialize the buffer
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*/
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static inline void op_cpu_buffer_reset(int cpu)
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{
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struct oprofile_cpu_buffer *cpu_buf = &per_cpu(op_cpu_buffer, cpu);
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cpu_buf->last_is_kernel = -1;
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cpu_buf->last_task = NULL;
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}
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/*
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* op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
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* called only if op_cpu_buffer_write_reserve() did not return NULL or
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* entry->event != NULL, otherwise entry->size or entry->event will be
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* used uninitialized.
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*/
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struct op_sample
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*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
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int op_cpu_buffer_write_commit(struct op_entry *entry);
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struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu);
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unsigned long op_cpu_buffer_entries(int cpu);
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/* returns the remaining free size of data in the entry */
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static inline
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int op_cpu_buffer_add_data(struct op_entry *entry, unsigned long val)
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{
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if (!entry->size)
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return 0;
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*entry->data = val;
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entry->size--;
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entry->data++;
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return entry->size;
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}
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/* returns the size of data in the entry */
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static inline
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int op_cpu_buffer_get_size(struct op_entry *entry)
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{
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return entry->size;
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}
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/* returns 0 if empty or the size of data including the current value */
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static inline
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int op_cpu_buffer_get_data(struct op_entry *entry, unsigned long *val)
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{
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int size = entry->size;
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if (!size)
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return 0;
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*val = *entry->data;
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entry->size--;
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entry->data++;
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return size;
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}
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/* extra data flags */
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#define KERNEL_CTX_SWITCH (1UL << 0)
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#define IS_KERNEL (1UL << 1)
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#define TRACE_BEGIN (1UL << 2)
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#define USER_CTX_SWITCH (1UL << 3)
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#endif /* OPROFILE_CPU_BUFFER_H */
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