1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Data gathering module for Linux-VM Monitor Stream, Stage 1.
4  * Collects data related to memory management.
5  *
6  * Copyright IBM Corp. 2003, 2006
7  *
8  * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
9  */
10 
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/errno.h>
14 #include <linux/kernel_stat.h>
15 #include <linux/pagemap.h>
16 #include <linux/swap.h>
17 #include <linux/slab.h>
18 #include <linux/io.h>
19 
20 #include "appldata.h"
21 
22 
23 #define P2K(x) ((x) << (PAGE_SHIFT - 10))	/* Converts #Pages to KB */
24 
25 /*
26  * Memory data
27  *
28  * This is accessed as binary data by z/VM. If changes to it can't be avoided,
29  * the structure version (product ID, see appldata_base.c) needs to be changed
30  * as well and all documentation and z/VM applications using it must be
31  * updated.
32  */
33 struct appldata_mem_data {
34 	u64 timestamp;
35 	u32 sync_count_1;       /* after VM collected the record data, */
36 	u32 sync_count_2;	/* sync_count_1 and sync_count_2 should be the
37 				   same. If not, the record has been updated on
38 				   the Linux side while VM was collecting the
39 				   (possibly corrupt) data */
40 
41 	u64 pgpgin;		/* data read from disk  */
42 	u64 pgpgout;		/* data written to disk */
43 	u64 pswpin;		/* pages swapped in  */
44 	u64 pswpout;		/* pages swapped out */
45 
46 	u64 sharedram;		/* sharedram is currently set to 0 */
47 
48 	u64 totalram;		/* total main memory size */
49 	u64 freeram;		/* free main memory size  */
50 	u64 totalhigh;		/* total high memory size */
51 	u64 freehigh;		/* free high memory size  */
52 
53 	u64 bufferram;		/* memory reserved for buffers, free cache */
54 	u64 cached;		/* size of (used) cache, w/o buffers */
55 	u64 totalswap;		/* total swap space size */
56 	u64 freeswap;		/* free swap space */
57 
58 // New in 2.6 -->
59 	u64 pgalloc;		/* page allocations */
60 	u64 pgfault;		/* page faults (major+minor) */
61 	u64 pgmajfault;		/* page faults (major only) */
62 // <-- New in 2.6
63 
64 } __packed;
65 
66 
67 /*
68  * appldata_get_mem_data()
69  *
70  * gather memory data
71  */
72 static void appldata_get_mem_data(void *data)
73 {
74 	/*
75 	 * don't put large structures on the stack, we are
76 	 * serialized through the appldata_ops_mutex and can use static
77 	 */
78 	static struct sysinfo val;
79 	unsigned long ev[NR_VM_EVENT_ITEMS];
80 	struct appldata_mem_data *mem_data;
81 
82 	mem_data = data;
83 	mem_data->sync_count_1++;
84 
85 	all_vm_events(ev);
86 	mem_data->pgpgin     = ev[PGPGIN] >> 1;
87 	mem_data->pgpgout    = ev[PGPGOUT] >> 1;
88 	mem_data->pswpin     = ev[PSWPIN];
89 	mem_data->pswpout    = ev[PSWPOUT];
90 	mem_data->pgalloc    = ev[PGALLOC_NORMAL];
91 	mem_data->pgalloc    += ev[PGALLOC_DMA];
92 	mem_data->pgfault    = ev[PGFAULT];
93 	mem_data->pgmajfault = ev[PGMAJFAULT];
94 
95 	si_meminfo(&val);
96 	mem_data->sharedram = val.sharedram;
97 	mem_data->totalram  = P2K(val.totalram);
98 	mem_data->freeram   = P2K(val.freeram);
99 	mem_data->totalhigh = P2K(val.totalhigh);
100 	mem_data->freehigh  = P2K(val.freehigh);
101 	mem_data->bufferram = P2K(val.bufferram);
102 	mem_data->cached    = P2K(global_node_page_state(NR_FILE_PAGES)
103 				- val.bufferram);
104 
105 	si_swapinfo(&val);
106 	mem_data->totalswap = P2K(val.totalswap);
107 	mem_data->freeswap  = P2K(val.freeswap);
108 
109 	mem_data->timestamp = get_tod_clock();
110 	mem_data->sync_count_2++;
111 }
112 
113 
114 static struct appldata_ops ops = {
115 	.name      = "mem",
116 	.record_nr = APPLDATA_RECORD_MEM_ID,
117 	.size	   = sizeof(struct appldata_mem_data),
118 	.callback  = &appldata_get_mem_data,
119 	.owner     = THIS_MODULE,
120 	.mod_lvl   = {0xF0, 0xF0},		/* EBCDIC "00" */
121 };
122 
123 
124 /*
125  * appldata_mem_init()
126  *
127  * init_data, register ops
128  */
129 static int __init appldata_mem_init(void)
130 {
131 	int ret;
132 
133 	ops.data = kzalloc(sizeof(struct appldata_mem_data), GFP_KERNEL);
134 	if (!ops.data)
135 		return -ENOMEM;
136 
137 	ret = appldata_register_ops(&ops);
138 	if (ret)
139 		kfree(ops.data);
140 
141 	return ret;
142 }
143 
144 /*
145  * appldata_mem_exit()
146  *
147  * unregister ops
148  */
149 static void __exit appldata_mem_exit(void)
150 {
151 	appldata_unregister_ops(&ops);
152 	kfree(ops.data);
153 }
154 
155 
156 module_init(appldata_mem_init);
157 module_exit(appldata_mem_exit);
158 
159 MODULE_LICENSE("GPL");
160 MODULE_AUTHOR("Gerald Schaefer");
161 MODULE_DESCRIPTION("Linux-VM Monitor Stream, MEMORY statistics");
162