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dcc411e Apr 26, 2016
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@bonzini @posophe
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/*
* Copyright (C) 2006, Intel Corporation
* Copyright (C) 2012, Neil Horman <nhorman@tuxdriver.com>
*
* This file is part of irqbalance
*
* This program file is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program in a file named COPYING; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
/*
* This file contains the code to communicate a selected distribution / mapping
* of interrupts to the kernel.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include "irqbalance.h"
static int check_affinity(struct irq_info *info, cpumask_t applied_mask)
{
cpumask_t current_mask;
char buf[PATH_MAX];
char *line = NULL;
size_t size = 0;
FILE *file;
sprintf(buf, "/proc/irq/%i/smp_affinity", info->irq);
file = fopen(buf, "r");
if (!file)
return 1;
if (getline(&line, &size, file)==0) {
free(line);
fclose(file);
return 1;
}
cpumask_parse_user(line, strlen(line), current_mask);
fclose(file);
free(line);
return cpus_equal(applied_mask, current_mask);
}
static void activate_mapping(struct irq_info *info, void *data __attribute__((unused)))
{
char buf[PATH_MAX];
FILE *file;
cpumask_t applied_mask;
int valid_mask = 0;
/*
* only activate mappings for irqs that have moved
*/
if (!info->moved)
return;
if (info->assigned_obj) {
applied_mask = info->assigned_obj->mask;
valid_mask = 1;
}
/*
* Don't activate anything for which we have an invalid mask
*/
if (!valid_mask || check_affinity(info, applied_mask))
return;
if (!info->assigned_obj)
return;
sprintf(buf, "/proc/irq/%i/smp_affinity", info->irq);
file = fopen(buf, "w");
if (!file)
return;
cpumask_scnprintf(buf, PATH_MAX, applied_mask);
fprintf(file, "%s", buf);
fclose(file);
info->moved = 0; /*migration is done*/
}
void activate_mappings(void)
{
for_each_irq(NULL, activate_mapping, NULL);
}