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- /* ionice.c - set or get process I/O scheduling class and priority
- *
- * Copyright 2015 Rob Landley <rob@landley.net>
- *
- * It would be really nice if there was a standard, but no. There is
- * Documentation/block/ioprio.txt in the linux source.
- USE_IONICE(NEWTOY(ionice, "^tc#<0>3=2n#<0>7=5p#", TOYFLAG_USR|TOYFLAG_BIN))
- USE_IORENICE(NEWTOY(iorenice, "<1>3", TOYFLAG_USR|TOYFLAG_BIN))
- config IONICE
- bool "ionice"
- default y
- help
- usage: ionice [-t] [-c CLASS] [-n LEVEL] [COMMAND...|-p PID]
- Change the I/O scheduling priority of a process. With no arguments
- (or just -p), display process' existing I/O class/priority.
- -c CLASS = 1-3: 1(realtime), 2(best-effort, default), 3(when-idle)
- -n LEVEL = 0-7: (0 is highest priority, default = 5)
- -p Affect existing PID instead of spawning new child
- -t Ignore failure to set I/O priority
- System default iopriority is generally -c 2 -n 4.
- config IORENICE
- bool "iorenice"
- default y
- help
- usage: iorenice PID [CLASS] [PRIORITY]
- Display or change I/O priority of existing process. CLASS can be
- "rt" for realtime, "be" for best effort, "idle" for only when idle, or
- "none" to leave it alone. PRIORITY can be 0-7 (0 is highest, default 4).
- */
- #define FOR_ionice
- #include "toys.h"
- GLOBALS(
- long p, n, c;
- )
- static int ioprio_get(void)
- {
- return syscall(__NR_ioprio_get, 1, (int)TT.p);
- }
- static int ioprio_set(void)
- {
- int prio = ((int)TT.c << 13) | (int)TT.n;
- return syscall(__NR_ioprio_set, 1, (int)TT.p, prio);
- }
- void ionice_main(void)
- {
- if (!TT.p && !toys.optc) error_exit("Need -p or COMMAND");
- if (toys.optflags == FLAG_p) {
- int p = ioprio_get();
- xprintf("%s: prio %d\n",
- (char *[]){"unknown", "Realtime", "Best-effort", "Idle"}[(p>>13)&3],
- p&7);
- } else {
- if (-1 == ioprio_set() && !FLAG(t)) perror_exit("set");
- if (!TT.p) xexec(toys.optargs);
- }
- }
- void iorenice_main(void)
- {
- char *classes[] = {"none", "rt", "be", "idle"};
- TT.p = atolx(*toys.optargs);
- if (toys.optc == 1) {
- int p = ioprio_get();
- if (p == -1) perror_exit("read priority");
- TT.c = (p>>13)&3;
- p &= 7;
- xprintf("Pid %ld, class %s (%ld), prio %d\n", TT.p, classes[TT.c], TT.c, p);
- return;
- }
- for (TT.c = 0; TT.c<4; TT.c++)
- if (!strcmp(toys.optargs[toys.optc-1], classes[TT.c])) break;
- if (toys.optc == 3 || TT.c == 4) TT.n = atolx(toys.optargs[1]);
- else TT.n = 4;
- TT.c &= 3;
- if (-1 == ioprio_set()) perror_exit("set");
- }
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