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Commit 3c446b3d authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: SIGIO support 



Provide support for fcntl() I/O availability signals.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094517.579788800@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9c03d88e

include/linux/perf_counter.h

+2 −0
Original line number Diff line number Diff line
@@ -238,6 +238,7 @@ enum perf_event_type { 
#include <linux/rcupdate.h>

#include <linux/spinlock.h>

#include <linux/hrtimer.h>

#include <linux/fs.h>

#include <asm/atomic.h>



struct task_struct;
@@ -398,6 +399,7 @@ struct perf_counter { 


	/* poll related */

	wait_queue_head_t		waitq;

	struct fasync_struct		*fasync;

	/* optional: for NMIs */

	struct perf_wakeup_entry	wakeup;

kernel/perf_counter.c

+19 −1
Original line number Diff line number Diff line
@@ -1526,6 +1526,22 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) 
	return ret;

}



static int perf_fasync(int fd, struct file *filp, int on)

{

	struct perf_counter *counter = filp->private_data;

	struct inode *inode = filp->f_path.dentry->d_inode;

	int retval;



	mutex_lock(&inode->i_mutex);

	retval = fasync_helper(fd, filp, on, &counter->fasync);

	mutex_unlock(&inode->i_mutex);



	if (retval < 0)

		return retval;



	return 0;

}



static const struct file_operations perf_fops = {

	.release		= perf_release,

	.read			= perf_read,
@@ -1533,6 +1549,7 @@ static const struct file_operations perf_fops = { 
	.unlocked_ioctl		= perf_ioctl,

	.compat_ioctl		= perf_ioctl,

	.mmap			= perf_mmap,

	.fasync			= perf_fasync,

};



/*
@@ -1549,7 +1566,7 @@ void perf_counter_wakeup(struct perf_counter *counter) 
	rcu_read_lock();

	data = rcu_dereference(counter->data);

	if (data) {

		(void)atomic_xchg(&data->wakeup, POLL_IN);

		atomic_set(&data->wakeup, POLL_IN);

		/*

		 * Ensure all data writes are issued before updating the

		 * user-space data head information. The matching rmb()
@@ -1561,6 +1578,7 @@ void perf_counter_wakeup(struct perf_counter *counter) 
	rcu_read_unlock();



	wake_up_all(&counter->waitq);

	kill_fasync(&counter->fasync, SIGIO, POLL_IN);

}



/*