// SPDX-License-Identifier: GPL-2.0
/*
 * Data gathering module for Linux-VM Monitor Stream, Stage 1.
 * Collects data related to memory management.
 *
 * Copyright IBM Corp. 2003, 2006
 *
 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
 */

#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 <linux/slab.h>
#include <linux/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.
 */
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

} __packed;


/*
 * 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_node_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_tod_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,
        .owner     = THIS_MODULE,
        .mod_lvl   = {0xF0, 0xF0},              /* EBCDIC "00" */
};


/*
 * appldata_mem_init()
 *
 * init_data, register ops
 */
static int __init appldata_mem_init(void)
{
        int ret;

        ops.data = kzalloc_obj(struct appldata_mem_data);
        if (!ops.data)
                return -ENOMEM;

        ret = appldata_register_ops(&ops);
        if (ret)
                kfree(ops.data);

        return ret;
}

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


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");