From: Johannes Berg Date: Fri, 4 Dec 2020 11:34:34 +0000 (+0100) Subject: um: time-travel: avoid multiple identical propagations X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=58b09f68697066dfde948153c82dd5d85e10f127;p=linux.git um: time-travel: avoid multiple identical propagations If there is some kind of interrupt negotation or such then it may happen that we send an update message multiple times, avoid that in the interest of efficiency by storing the last transmitted value and only sending a new update if it's not the same as the last update. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger --- diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c index 80d33735cfd27..204ddb141b010 100644 --- a/arch/um/kernel/time.c +++ b/arch/um/kernel/time.c @@ -190,7 +190,13 @@ static void time_travel_ext_update_request(unsigned long long time) void __time_travel_propagate_time(void) { + static unsigned long long last_propagated; + + if (last_propagated == time_travel_time) + return; + time_travel_ext_req(UM_TIMETRAVEL_UPDATE, time_travel_time); + last_propagated = time_travel_time; } EXPORT_SYMBOL_GPL(__time_travel_propagate_time);