afb92adf4
Denys Vlasenko
2026-01-19
Subject
vmstat: smarter handling of header re-printing
Binary
No binary (build failed)
Architecture & Compiler Flags
gcc -Wp,-MD,applets/.usage.d -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -Iinclude -Iinclude -o applets/usage applets/usage.c
Build Log
(log yok)
Commit Diff GitHub →
procps/vmstat.c+30 -23
| @@ -7,7 +7,7 @@ | |
| * Licensed under GPLv2, see file LICENSE in this source tree. | |
| */ | |
| //config:config VMSTAT | |
| - | //config: bool "vmstat (3 kb)" |
| + | //config: bool "vmstat (2 kb)" |
| //config: default y | |
| //config: help | |
| //config: Report virtual memory statistics | |
| @@ -49,6 +49,8 @@ L("procs\0") "\2" L("r\0" )FROM_PROC_STAT M_DECREMENT "procs_running\ | |
| "\2" L("b\0" )FROM_PROC_STAT "procs_blocked\0" | |
| L("memory\0") "\6" L("swpd\0" )FROM_PROC_MEMINFO PSEUDO_SWPD "\0" | |
| "\6" L("free\0" )FROM_PROC_MEMINFO "MemFree\0" | |
| + | //TODO? "MemAvailable" in newer kernels may be a more useful indicator how much memory is "free" |
| + | //in the sense of being immediately availabe if allocation demand arises (e.g. by dropping cached filesystem data) |
| "\6" L("buff\0" )FROM_PROC_MEMINFO "Buffers\0" | |
| "\6" L("cache\0")FROM_PROC_MEMINFO PSEUDO_CACHE "\0" | |
| L("swap\0") "\4" L("si\0" )FROM_PROC_VMSTAT M_DELTA "pswpin\0" | |
| @@ -65,6 +67,8 @@ L("cpu\0") "\2" L("us\0" )FROM_PROC_STAT_CPU M_DPERCENT "\x0d" /* user | |
| // "gu"est columnt seems to be added in procps-ng 4.x.x (it makes the output not 80, but 83 chars): | |
| "\2" L("gu\0" )FROM_PROC_STAT_CPU M_DPERCENT "\x0c" /* guest */ | |
| ; | |
| + | /* Number of columns defined in coldescs[] */ |
| + | #define NCOLS (2+4+2+2+2+6) |
| /* Packed row data from coldescs[] is decoded into this structure */ | |
| struct col { | |
| L(const char *grplabel;) | |
| @@ -78,13 +82,9 @@ struct col { | |
| #define MOD_DECREMENT 0x04 | |
| }; | |
| - | /* Number of columns defined in coldescs[] */ |
| - | #define NCOLS (2+4+2+2+2+6) |
| - | |
| - | /* Globals. Sort by size and access frequency. */ |
| struct globals { | |
| - | unsigned data1[NCOLS]; |
| - | unsigned data2[NCOLS]; |
| + | unsigned data[NCOLS]; |
| + | unsigned prev[NCOLS]; |
| }; | |
| #define G (*(struct globals*)bb_common_bufsiz1) | |
| #define INIT_G() do { \ | |
| @@ -419,7 +419,6 @@ static void print_header(void) | |
| #if FIXED_HEADER | |
| /* The header is constant yet and can be hardcoded instead, | |
| * but adding options such as -wtd to match upstream will change that */ | |
| - | //TODO: remove grplabel/label from coldescs[], they are unused |
| puts( | |
| "procs -----------memory---------- ---swap-- -----io---- -system-- -------cpu-------""\n" | |
| " r b swpd free buff cache si so bi bo in cs us sy id wa st gu" | |
| @@ -480,16 +479,18 @@ int vmstat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; | |
| int vmstat_main(int argc UNUSED_PARAM, char **argv) | |
| { | |
| int opt; | |
| - | unsigned interval = 0; |
| - | int count = 1; |
| + | unsigned interval; |
| + | int count; |
| unsigned height; | |
| - | unsigned rows; |
| + | int row; |
| INIT_G(); | |
| /* Parse and process arguments */ | |
| opt = getopt32(argv, "n"); | |
| argv += optind; | |
| + | interval = 0; |
| + | count = 1; |
| if (*argv) { | |
| interval = xatoi_positive(*argv); | |
| count = (interval != 0 ? -1 : 1); | |
| @@ -500,23 +501,29 @@ int vmstat_main(int argc UNUSED_PARAM, char **argv) | |
| /* Prepare to re-print the header row after it scrolls off */ | |
| height = 0; | |
| - | if (!(opt & OPT_n)) |
| + | if (!(opt & OPT_n)) { |
| get_terminal_width_height(STDOUT_FILENO, NULL, &height); | |
| + | /* match 4.0.4 behavior: re-print header if terminal has 4 or more lines */ |
| + | height -= 3; /* can become zero or negative */ |
| + | } |
| + | load_row(G.prev); /* prevents incorrect deltas in 1st sample */ |
| + | row = 0; |
| /* Main loop */ | |
| - | load_row(G.data1); /* prevents incorrect deltas in 1st sample */ |
| - | for (rows = 0;; rows++) { |
| - | if (rows == 0 || (height > 5 && (rows % (height - 3)) == 0)) |
| + | for (;;) { |
| + | if (row == 0) { |
| print_header(); | |
| - | |
| - | /* Flip between using data1/2 and data2/1 for old/new */ |
| - | if (rows & 1) { |
| - | load_row(G.data1); |
| - | print_row(G.data1, G.data2); |
| - | } else { |
| - | load_row(G.data2); |
| - | print_row(G.data2, G.data1); |
| + | row = (int)height; |
| } | |
| + | row--; |
| + | //if (row < 0) /* height <= 0: -n, or 3 or fewer lines in terminal */ |
| + | // row = -1; /* do not count down, never become zero */ |
| + | /* equivalent to above: */ |
| + | row |= (row >> (sizeof(row)*8 - 1)); |
| + | |
| + | load_row(G.data); |
| + | print_row(G.data, G.prev); |
| + | memcpy(G.prev, G.data, sizeof(G.prev)); |
| if (count > 0 && --count == 0) | |
| break; | |