085cce379a
If the system reaches a defined limit of processes in running state, udevd starts to count its own processes in running state from its session (all forked hotplug child processes, subprocesses and callouts) and throttles further process forking if the limit is reached. This should help setups with hundreds of events emitted hotplug events in parallel with hundreds of processes in "R" state. which makes the machine unresponsible. I placed a 100% cpu time consuming program in /etc/hotplug.d/ which runs for 5 seconds. With this patch I can load "scsi_debug add_host=100" without any major problem. Without the patch the box is completly unresponsible for many minutes.
66 lines
1.8 KiB
C
66 lines
1.8 KiB
C
/*
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* udevd.h
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*
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* Userspace devfs
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*
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* Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
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* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
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*
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*
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* This program 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
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include "list.h"
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#define UDEV_MAGIC "udevd_" UDEV_VERSION
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#define UDEVD_SOCK_PATH "udevd"
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#define SEND_WAIT_MAX_SECONDS 3
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#define SEND_WAIT_LOOP_PER_SECOND 10
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#define UDEVD_PRIORITY -4
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#define UDEV_PRIORITY -2
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/* duration of initialization phase with shorter timeout */
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#define INIT_TIME_SEC 5
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#define EVENT_INIT_TIMEOUT_SEC 2
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/* timeout to wait for missing events */
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#define EVENT_TIMEOUT_SEC 10
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/* start to throttle forking if maximum number of running childs in our session is reached */
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#define THROTTLE_MAX_RUNNING_CHILDS 10
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/* environment buffer, should match the kernel's size in lib/kobject_uevent.h */
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#define HOTPLUG_BUFFER_SIZE 1024
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#define HOTPLUG_NUM_ENVP 32
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struct udevsend_msg {
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char magic[20];
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char envbuf[HOTPLUG_BUFFER_SIZE+256];
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};
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struct hotplug_msg {
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struct list_head list;
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pid_t pid;
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long queue_time;
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char *action;
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char *devpath;
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char *subsystem;
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unsigned long long seqnum;
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char *physdevpath;
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char *envp[HOTPLUG_NUM_ENVP+1];
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char envbuf[];
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};
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