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 <asm/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  * The record layout is documented in the Linux for zSeries Device Drivers
34  * book:
35  * http://oss.software.ibm.com/developerworks/opensource/linux390/index.shtml
36  */
37 struct appldata_mem_data {
38 	u64 timestamp;
39 	u32 sync_count_1;       /* after VM collected the record data, */
40 	u32 sync_count_2;	/* sync_count_1 and sync_count_2 should be the
41 				   same. If not, the record has been updated on
42 				   the Linux side while VM was collecting the
43 				   (possibly corrupt) data */
44 
45 	u64 pgpgin;		/* data read from disk  */
46 	u64 pgpgout;		/* data written to disk */
47 	u64 pswpin;		/* pages swapped in  */
48 	u64 pswpout;		/* pages swapped out */
49 
50 	u64 sharedram;		/* sharedram is currently set to 0 */
51 
52 	u64 totalram;		/* total main memory size */
53 	u64 freeram;		/* free main memory size  */
54 	u64 totalhigh;		/* total high memory size */
55 	u64 freehigh;		/* free high memory size  */
56 
57 	u64 bufferram;		/* memory reserved for buffers, free cache */
58 	u64 cached;		/* size of (used) cache, w/o buffers */
59 	u64 totalswap;		/* total swap space size */
60 	u64 freeswap;		/* free swap space */
61 
62 // New in 2.6 -->
63 	u64 pgalloc;		/* page allocations */
64 	u64 pgfault;		/* page faults (major+minor) */
65 	u64 pgmajfault;		/* page faults (major only) */
66 // <-- New in 2.6
67 
68 } __packed;
69 
70 
71 /*
72  * appldata_get_mem_data()
73  *
74  * gather memory data
75  */
76 static void appldata_get_mem_data(void *data)
77 {
78 	/*
79 	 * don't put large structures on the stack, we are
80 	 * serialized through the appldata_ops_mutex and can use static
81 	 */
82 	static struct sysinfo val;
83 	unsigned long ev[NR_VM_EVENT_ITEMS];
84 	struct appldata_mem_data *mem_data;
85 
86 	mem_data = data;
87 	mem_data->sync_count_1++;
88 
89 	all_vm_events(ev);
90 	mem_data->pgpgin     = ev[PGPGIN] >> 1;
91 	mem_data->pgpgout    = ev[PGPGOUT] >> 1;
92 	mem_data->pswpin     = ev[PSWPIN];
93 	mem_data->pswpout    = ev[PSWPOUT];
94 	mem_data->pgalloc    = ev[PGALLOC_NORMAL];
95 	mem_data->pgalloc    += ev[PGALLOC_DMA];
96 	mem_data->pgfault    = ev[PGFAULT];
97 	mem_data->pgmajfault = ev[PGMAJFAULT];
98 
99 	si_meminfo(&val);
100 	mem_data->sharedram = val.sharedram;
101 	mem_data->totalram  = P2K(val.totalram);
102 	mem_data->freeram   = P2K(val.freeram);
103 	mem_data->totalhigh = P2K(val.totalhigh);
104 	mem_data->freehigh  = P2K(val.freehigh);
105 	mem_data->bufferram = P2K(val.bufferram);
106 	mem_data->cached    = P2K(global_node_page_state(NR_FILE_PAGES)
107 				- val.bufferram);
108 
109 	si_swapinfo(&val);
110 	mem_data->totalswap = P2K(val.totalswap);
111 	mem_data->freeswap  = P2K(val.freeswap);
112 
113 	mem_data->timestamp = get_tod_clock();
114 	mem_data->sync_count_2++;
115 }
116 
117 
118 static struct appldata_ops ops = {
119 	.name      = "mem",
120 	.record_nr = APPLDATA_RECORD_MEM_ID,
121 	.size	   = sizeof(struct appldata_mem_data),
122 	.callback  = &appldata_get_mem_data,
123 	.owner     = THIS_MODULE,
124 	.mod_lvl   = {0xF0, 0xF0},		/* EBCDIC "00" */
125 };
126 
127 
128 /*
129  * appldata_mem_init()
130  *
131  * init_data, register ops
132  */
133 static int __init appldata_mem_init(void)
134 {
135 	int ret;
136 
137 	ops.data = kzalloc(sizeof(struct appldata_mem_data), GFP_KERNEL);
138 	if (!ops.data)
139 		return -ENOMEM;
140 
141 	ret = appldata_register_ops(&ops);
142 	if (ret)
143 		kfree(ops.data);
144 
145 	return ret;
146 }
147 
148 /*
149  * appldata_mem_exit()
150  *
151  * unregister ops
152  */
153 static void __exit appldata_mem_exit(void)
154 {
155 	appldata_unregister_ops(&ops);
156 	kfree(ops.data);
157 }
158 
159 
160 module_init(appldata_mem_init);
161 module_exit(appldata_mem_exit);
162 
163 MODULE_LICENSE("GPL");
164 MODULE_AUTHOR("Gerald Schaefer");
165 MODULE_DESCRIPTION("Linux-VM Monitor Stream, MEMORY statistics");
166