xref: /openbmc/qemu/migration/dirtyrate.h (revision 195801d7)
1 /*
2  *  Dirtyrate common functions
3  *
4  *  Copyright (c) 2020 HUAWEI TECHNOLOGIES CO., LTD.
5  *
6  *  Authors:
7  *  Chuan Zheng <zhengchuan@huawei.com>
8  *
9  *  This work is licensed under the terms of the GNU GPL, version 2 or later.
10  *  See the COPYING file in the top-level directory.
11  */
12 
13 #ifndef QEMU_MIGRATION_DIRTYRATE_H
14 #define QEMU_MIGRATION_DIRTYRATE_H
15 
16 #include "sysemu/dirtyrate.h"
17 
18 /*
19  * Sample 512 pages per GB as default.
20  */
21 #define DIRTYRATE_DEFAULT_SAMPLE_PAGES            512
22 
23 /*
24  * Record ramblock idstr
25  */
26 #define RAMBLOCK_INFO_MAX_LEN                     256
27 
28 /*
29  * Minimum RAMBlock size to sample, in megabytes.
30  */
31 #define MIN_RAMBLOCK_SIZE                         128
32 
33 /*
34  * Allowed range for dirty page rate calculation (in milliseconds).
35  * Lower limit relates to the smallest realistic downtime it
36  * makes sense to impose on migration.
37  */
38 #define MIN_CALC_TIME_MS                          50
39 #define MAX_CALC_TIME_MS                       60000
40 
41 /*
42  * Take 1/16 pages in 1G as the maxmum sample page count
43  */
44 #define MIN_SAMPLE_PAGE_COUNT                     128
45 #define MAX_SAMPLE_PAGE_COUNT                     16384
46 
47 struct DirtyRateConfig {
48     uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
49     int64_t calc_time_ms; /* desired calculation time (in milliseconds) */
50     DirtyRateMeasureMode mode; /* mode of dirtyrate measurement */
51 };
52 
53 /*
54  * Store dirtypage info for each ramblock.
55  */
56 struct RamblockDirtyInfo {
57     char idstr[RAMBLOCK_INFO_MAX_LEN]; /* idstr for each ramblock */
58     uint8_t *ramblock_addr; /* base address of ramblock we measure */
59     uint64_t ramblock_pages; /* ramblock size in TARGET_PAGE_SIZE */
60     uint64_t *sample_page_vfn; /* relative offset address for sampled page */
61     uint64_t sample_pages_count; /* count of sampled pages */
62     uint64_t sample_dirty_count; /* count of dirty pages we measure */
63     uint32_t *hash_result; /* array of hash result for sampled pages */
64 };
65 
66 typedef struct SampleVMStat {
67     uint64_t total_dirty_samples; /* total dirty sampled page */
68     uint64_t total_sample_count; /* total sampled pages */
69     uint64_t total_block_mem_MB; /* size of total sampled pages in MB */
70 } SampleVMStat;
71 
72 /*
73  * Store calculation statistics for each measure.
74  */
75 struct DirtyRateStat {
76     int64_t dirty_rate; /* dirty rate in MB/s */
77     int64_t start_time; /* calculation start time in units of second */
78     int64_t calc_time_ms; /* actual calculation time (in milliseconds) */
79     uint64_t sample_pages; /* sample pages per GB */
80     union {
81         SampleVMStat page_sampling;
82         VcpuStat dirty_ring;
83     };
84 };
85 
86 void *get_dirtyrate_thread(void *arg);
87 #endif
88