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authorJohannes Berg <johannes.berg@intel.com>2020-12-02 22:58:04 +0300
committerRichard Weinberger <richard@nod.at>2020-12-14 00:22:37 +0300
commit49da38a3ef330b7a1643e12c51913d58158e5abe (patch)
tree80b644e00334100084a64bb455d03a68555b7c1c /arch/um/os-Linux
parent3032b94587c78c52173a9b8488d15528481ffcdb (diff)
downloadlinux-49da38a3ef330b7a1643e12c51913d58158e5abe.tar.xz
um: Simplify os_idle_sleep() and sleep longer
There really is no reason to pass the amount of time we should sleep, especially since it's just hard-coded to one second. Additionally, one second isn't really all that long, and as we are expecting to be woken up by a signal, we can sleep longer and avoid doing some work every second, so replace the current clock_nanosleep() with just an empty select() that can _only_ be woken up by a signal. We can also remove the deliver_alarm() since we don't need to do that when we got e.g. SIGIO that woke us up, and if we got SIGALRM the signal handler will actually (have) run, so it's just unnecessary extra work. Similarly, in time-travel mode, just program the wakeup event from idle to be S64_MAX, which is basically the most you could ever simulate to. Of course, you should already have an event in the list that's earlier and will cause a wakeup, normally that's the regular timer interrupt, though in suspend it may (later) also be an RTC event. Since actually getting to this point would be a bug and you can't ever get out again, panic() on it in the time control code. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/os-Linux')
-rw-r--r--arch/um/os-Linux/time.c17
1 files changed, 4 insertions, 13 deletions
diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index 90f6de224c70..a61cbf73a179 100644
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -7,6 +7,7 @@
*/
#include <stddef.h>
+#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <time.h>
@@ -99,19 +100,9 @@ long long os_nsecs(void)
}
/**
- * os_idle_sleep() - sleep for a given time of nsecs
- * @nsecs: nanoseconds to sleep
+ * os_idle_sleep() - sleep until interrupted
*/
-void os_idle_sleep(unsigned long long nsecs)
+void os_idle_sleep(void)
{
- struct timespec ts = {
- .tv_sec = nsecs / UM_NSEC_PER_SEC,
- .tv_nsec = nsecs % UM_NSEC_PER_SEC
- };
-
- /*
- * Relay the signal if clock_nanosleep is interrupted.
- */
- if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL))
- deliver_alarm();
+ pause();
}