c8757c6d87
When echoing a mask to /proc/irq/N/smp_affinity make sure to activate only CPUs which are online. Activating a CPU which is not online results in a EOVERFLOW. Originally fixed in Debian by Helge Deller <deller@gmx.de>.
92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
/*
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* Copyright (C) 2006, Intel Corporation
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* Copyright (C) 2012, Neil Horman <nhorman@tuxdriver.com>
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*
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* This file is part of irqbalance
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*
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* This program file is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program in a file named COPYING; if not, write to the
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* Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA
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*/
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/*
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* This file contains the code to communicate a selected distribution / mapping
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* of interrupts to the kernel.
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*/
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#include "config.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdint.h>
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#include "irqbalance.h"
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static int check_affinity(struct irq_info *info, cpumask_t applied_mask)
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{
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cpumask_t current_mask;
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char buf[PATH_MAX];
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sprintf(buf, "/proc/irq/%i/smp_affinity", info->irq);
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if (process_one_line(buf, get_mask_from_bitmap, ¤t_mask) < 0)
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return 1;
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return cpus_equal(applied_mask, current_mask);
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}
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static void activate_mapping(struct irq_info *info, void *data __attribute__((unused)))
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{
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char buf[PATH_MAX];
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FILE *file;
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int ret = 0;
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cpumask_t applied_mask;
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/*
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* only activate mappings for irqs that have moved
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*/
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if (!info->moved)
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return;
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if (!info->assigned_obj)
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return;
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/* activate only online cpus, otherwise writing to procfs returns EOVERFLOW */
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cpus_and(applied_mask, cpu_online_map, info->assigned_obj->mask);
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/*
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* Don't activate anything for which we have an invalid mask
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*/
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if (check_affinity(info, applied_mask))
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return;
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sprintf(buf, "/proc/irq/%i/smp_affinity", info->irq);
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file = fopen(buf, "w");
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if (!file)
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return;
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cpumask_scnprintf(buf, PATH_MAX, applied_mask);
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ret = fprintf(file, "%s", buf);
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if (ret < 0) {
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log(TO_ALL, LOG_WARNING, "cannot change irq %i's affinity, add it to banned list", info->irq);
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add_banned_irq(info->irq);
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remove_one_irq_from_db(info->irq);
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}
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fclose(file);
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info->moved = 0; /*migration is done*/
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}
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void activate_mappings(void)
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{
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for_each_irq(NULL, activate_mapping, NULL);
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}
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