mirror of
https://github.com/ibm-s390-linux/s390-tools.git
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b627b8d8e1
This commit is based on the s390-tools-1.39.0 version. Changes on top of s390-tools-1.39.0: - Add MIT license to all source files - Add LICENSE file - Transform REAMDE to README.md (markdown) - Add AUTHORS.md file - Add CONTRIBUTING.md file - Move changelog from README to CHANGELOG.md file Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
83 lines
1.7 KiB
C
83 lines
1.7 KiB
C
/*
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* cpuplugd - Linux for System z Hotplug Daemon
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*
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* cmm functions
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*
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* Copyright IBM Corp. 2007, 2017
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include "cpuplugd.h"
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/*
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* The cmm_pages value defines the size of the balloon of blocked memory.
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* Increasing the value is removing memory from Linux, which is an memunplug.
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* Decreasing the value is adding memory back to Linux, which is memplug.
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*/
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/*
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* Set the value of cmm_pages
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*/
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void set_cmm_pages(long pages)
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{
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FILE *filp;
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filp = fopen("/proc/sys/vm/cmm_pages", "w");
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if (!filp)
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cpuplugd_exit("Cannot open /proc/sys/vm/cmmpages: %s\n",
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strerror(errno));
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cpuplugd_debug("changing number of pages permanently reserved to %ld\n",
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pages);
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fprintf(filp, "%ld\n", pages);
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fclose(filp);
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return;
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}
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/*
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* Read number of pages permanently reserved
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*/
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long get_cmmpages_size()
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{
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FILE *filp;
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long size;
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int rc;
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filp = fopen("/proc/sys/vm/cmm_pages", "r");
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if (!filp)
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cpuplugd_exit("Cannot open /proc/sys/vm/cmm_pages: %s\n",
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strerror(errno));
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rc = fscanf(filp, "%ld", &size);
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if (rc == 0)
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cpuplugd_exit("Can not read /proc/sys/vm/cmm_pages: %s\n",
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strerror(errno));
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fclose(filp);
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return size;
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}
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/*
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* Reset cmm pagesize to value we found prior to daemon startup
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*/
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void cleanup_cmm()
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{
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set_cmm_pages(cmm_pagesize_start);
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return;
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}
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/*
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* Function to check if the cmm kernel module is loaded and the required
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* files below /proc exit
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*/
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int check_cmmfiles(void)
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{
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FILE *filp;
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filp = fopen("/proc/sys/vm/cmm_pages", "r");
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if (!filp)
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return -1;
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fclose(filp);
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return 0;
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}
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