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/*
* Linux /proc/meminfo metrics cluster
*
* Copyright (c) 2013-2014 Red Hat.
* Copyright (c) 2002 Silicon Graphics, Inc. All Rights Reserved.
*
* This program 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; either version 2 of the License, or (at your
* option) any later version.
*
* 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.
*/
#include <ctype.h>
#include "pmapi.h"
#include "pmda.h"
#include "indom.h"
#include <sys/stat.h>
#include "proc_meminfo.h"
static proc_meminfo_t moff;
extern size_t _pm_system_pagesize;
static struct {
char *field;
int64_t *offset;
} meminfo_fields[] = {
{ "MemTotal", &moff.MemTotal },
{ "MemFree", &moff.MemFree },
{ "MemAvailable", &moff.MemAvailable },
{ "MemShared", &moff.MemShared },
{ "Buffers", &moff.Buffers },
{ "Cached", &moff.Cached },
{ "SwapCached", &moff.SwapCached },
{ "Active", &moff.Active },
{ "Inactive", &moff.Inactive },
{ "Active(anon)", &moff.Active_anon },
{ "Inactive(anon)", &moff.Inactive_anon },
{ "Active(file)", &moff.Active_file },
{ "Inactive(file)", &moff.Inactive_file },
{ "Unevictable", &moff.Unevictable },
{ "Mlocked", &moff.Mlocked },
{ "HighTotal", &moff.HighTotal },
{ "HighFree", &moff.HighFree },
{ "LowTotal", &moff.LowTotal },
{ "LowFree", &moff.LowFree },
{ "MmapCopy", &moff.MmapCopy },
{ "SwapTotal", &moff.SwapTotal },
{ "SwapFree", &moff.SwapFree },
{ "Dirty", &moff.Dirty },
{ "Writeback", &moff.Writeback },
{ "AnonPages", &moff.AnonPages },
{ "Mapped", &moff.Mapped },
{ "Shmem", &moff.Shmem },
{ "Slab", &moff.Slab },
{ "SReclaimable", &moff.SlabReclaimable },
{ "SUnreclaim", &moff.SlabUnreclaimable },
{ "KernelStack", &moff.KernelStack },
{ "PageTables", &moff.PageTables },
{ "Quicklists", &moff.Quicklists },
{ "NFS_Unstable", &moff.NFS_Unstable },
{ "Bounce", &moff.Bounce },
{ "WritebackTmp", &moff.WritebackTmp },
{ "CommitLimit", &moff.CommitLimit },
{ "Committed_AS", &moff.Committed_AS },
{ "VmallocTotal", &moff.VmallocTotal },
{ "VmallocUsed", &moff.VmallocUsed },
{ "VmallocChunk", &moff.VmallocChunk },
{ "HardwareCorrupted", &moff.HardwareCorrupted },
{ "AnonHugePages", &moff.AnonHugePages },
/* vendor kernel patches, some outdated now */
{ "MemShared", &moff.MemShared },
{ "ReverseMaps", &moff.ReverseMaps },
{ "HugePages_Total", &moff.HugepagesTotal },
{ "HugePages_Free", &moff.HugepagesFree },
{ "HugePages_Rsvd", &moff.HugepagesRsvd },
{ "HugePages_Surp", &moff.HugepagesSurp },
{ "DirectMap4k", &moff.directMap4k },
{ "DirectMap2M", &moff.directMap2M },
{ "DirectMap1G", &moff.directMap1G },
{ NULL, NULL }
};
#define MOFFSET(ii, pp) (int64_t *)((char *)pp + \
(__psint_t)meminfo_fields[ii].offset - (__psint_t)&moff)
int
refresh_proc_meminfo(proc_meminfo_t *proc_meminfo)
{
char buf[1024];
char *bufp;
int64_t *p;
int i;
FILE *fp;
for (i = 0; meminfo_fields[i].field != NULL; i++) {
p = MOFFSET(i, proc_meminfo);
*p = -1; /* marked as "no value available" */
}
if ((fp = linux_statsfile("/proc/meminfo", buf, sizeof(buf))) == NULL)
return -oserror();
while (fgets(buf, sizeof(buf), fp) != NULL) {
if ((bufp = strchr(buf, ':')) == NULL)
continue;
*bufp = '\0';
for (i=0; meminfo_fields[i].field != NULL; i++) {
if (strcmp(buf, meminfo_fields[i].field) != 0)
continue;
p = MOFFSET(i, proc_meminfo);
for (bufp++; *bufp; bufp++) {
if (isdigit((int)*bufp)) {
sscanf(bufp, "%llu", (unsigned long long *)p);
*p *= 1024; /* kbytes -> bytes */
break;
}
}
}
}
fclose(fp);
/*
* MemAvailable is only in 3.x or later kernels but we can calculate it
* using other values, similar to upstream kernel commit 34e431b0ae.
* The environment variable is for QA purposes.
*/
if (!MEMINFO_VALID_VALUE(proc_meminfo->MemAvailable) ||
getenv("PCP_QA_ESTIMATE_MEMAVAILABLE") != NULL) {
if (MEMINFO_VALID_VALUE(proc_meminfo->MemTotal) &&
MEMINFO_VALID_VALUE(proc_meminfo->MemFree) &&
MEMINFO_VALID_VALUE(proc_meminfo->Active_file) &&
MEMINFO_VALID_VALUE(proc_meminfo->Inactive_file) &&
MEMINFO_VALID_VALUE(proc_meminfo->SlabReclaimable)) {
int64_t pagecache;
int64_t wmark_low = 0;
/*
* sum for each zone->watermark[WMARK_LOW];
*/
if ((fp = fopen("/proc/zoneinfo", "r")) != NULL) {
while (fgets(buf, sizeof(buf), fp) != NULL) {
if ((bufp = strstr(buf, "low ")) != NULL) {
int64_t low;
if (sscanf(bufp+4, "%lld", (long long int *)&low) == 1)
wmark_low += low;
}
}
fclose(fp);
wmark_low *= _pm_system_pagesize;
}
/*
* Free memory cannot be taken below the low watermark, before the
* system starts swapping.
*/
proc_meminfo->MemAvailable = proc_meminfo->MemFree - wmark_low;
/*
* Not all the page cache can be freed, otherwise the system will
* start swapping. Assume at least half of the page cache, or the
* low watermark worth of cache, needs to stay.
*/
pagecache = proc_meminfo->Active_file + proc_meminfo->Inactive_file;
pagecache -= MIN(pagecache / 2, wmark_low);
proc_meminfo->MemAvailable += pagecache;
/*
* Part of the reclaimable slab consists of items that are in use,
* and cannot be freed. Cap this estimate at the low watermark.
*/
proc_meminfo->MemAvailable += proc_meminfo->SlabReclaimable;
proc_meminfo->MemAvailable -= MIN(proc_meminfo->SlabReclaimable / 2, wmark_low);
if (proc_meminfo->MemAvailable < 0)
proc_meminfo->MemAvailable = 0;
}
}
/* success */
return 0;
}
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