appldata_mem.c

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/*
 * Data gathering module for Linux-VM Monitor Stream, Stage 1.
 * Collects data related to memory management.
 *
 * Copyright IBM Corp. 2003, 2006
 *
 * Author: Gerald Schaefer <[email protected]>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <asm/io.h>

#include "appldata.h"


#define P2K(x) ((x) << (PAGE_SHIFT - 10))   /* Converts #Pages to KB */

/*
 * Memory data
 *
 * This is accessed as binary data by z/VM. If changes to it can't be avoided,
 * the structure version (product ID, see appldata_base.c) needs to be changed
 * as well and all documentation and z/VM applications using it must be
 * updated.
 *
 * The record layout is documented in the Linux for zSeries Device Drivers
 * book:
 * http://oss.software.ibm.com/developerworks/opensource/linux390/index.shtml
 */
static struct appldata_mem_data {
    u64 timestamp;
    u32 sync_count_1;       /* after VM collected the record data, */
    u32 sync_count_2;   /* sync_count_1 and sync_count_2 should be the
                   same. If not, the record has been updated on
                   the Linux side while VM was collecting the
                   (possibly corrupt) data */

    u64 pgpgin;     /* data read from disk  */
    u64 pgpgout;        /* data written to disk */
    u64 pswpin;     /* pages swapped in  */
    u64 pswpout;        /* pages swapped out */

    u64 sharedram;      /* sharedram is currently set to 0 */

    u64 totalram;       /* total main memory size */
    u64 freeram;        /* free main memory size  */
    u64 totalhigh;      /* total high memory size */
    u64 freehigh;       /* free high memory size  */

    u64 bufferram;      /* memory reserved for buffers, free cache */
    u64 cached;     /* size of (used) cache, w/o buffers */
    u64 totalswap;      /* total swap space size */
    u64 freeswap;       /* free swap space */

// New in 2.6 -->
    u64 pgalloc;        /* page allocations */
    u64 pgfault;        /* page faults (major+minor) */
    u64 pgmajfault;     /* page faults (major only) */
// <-- New in 2.6

} __attribute__((packed)) appldata_mem_data;


/*
 * appldata_get_mem_data()
 *
 * gather memory data
 */
static void appldata_get_mem_data(void *data)
{
    /*
     * don't put large structures on the stack, we are
     * serialized through the appldata_ops_mutex and can use static
     */
    static struct sysinfo val;
    unsigned long ev[NR_VM_EVENT_ITEMS];
    struct appldata_mem_data *mem_data;

    mem_data = data;
    mem_data->sync_count_1++;

    all_vm_events(ev);
    mem_data->pgpgin     = ev[PGPGIN] >> 1;
    mem_data->pgpgout    = ev[PGPGOUT] >> 1;
    mem_data->pswpin     = ev[PSWPIN];
    mem_data->pswpout    = ev[PSWPOUT];
    mem_data->pgalloc    = ev[PGALLOC_NORMAL];
    mem_data->pgalloc    += ev[PGALLOC_DMA];
    mem_data->pgfault    = ev[PGFAULT];
    mem_data->pgmajfault = ev[PGMAJFAULT];

    si_meminfo(&val);
    mem_data->sharedram = val.sharedram;
    mem_data->totalram  = P2K(val.totalram);
    mem_data->freeram   = P2K(val.freeram);
    mem_data->totalhigh = P2K(val.totalhigh);
    mem_data->freehigh  = P2K(val.freehigh);
    mem_data->bufferram = P2K(val.bufferram);
    mem_data->cached    = P2K(global_page_state(NR_FILE_PAGES)
                - val.bufferram);

    si_swapinfo(&val);
    mem_data->totalswap = P2K(val.totalswap);
    mem_data->freeswap  = P2K(val.freeswap);

    mem_data->timestamp = get_clock();
    mem_data->sync_count_2++;
}


static struct appldata_ops ops = {
    .name      = "mem",
    .record_nr = APPLDATA_RECORD_MEM_ID,
    .size      = sizeof(struct appldata_mem_data),
    .callback  = &appldata_get_mem_data,
    .data      = &appldata_mem_data,
    .owner     = THIS_MODULE,
    .mod_lvl   = {0xF0, 0xF0},      /* EBCDIC "00" */
};


/*
 * appldata_mem_init()
 *
 * init_data, register ops
 */
static int __init appldata_mem_init(void)
{
    return appldata_register_ops(&ops);
}

/*
 * appldata_mem_exit()
 *
 * unregister ops
 */
static void __exit appldata_mem_exit(void)
{
    appldata_unregister_ops(&ops);
}


module_init(appldata_mem_init);
module_exit(appldata_mem_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Gerald Schaefer");
MODULE_DESCRIPTION("Linux-VM Monitor Stream, MEMORY statistics");