From: Laszlo Ersek Date: Tue, 18 Oct 2011 20:42:59 +0000 (+0200) Subject: xen/time: remove blocked time accounting from xen "clockchip" X-Git-Tag: upstream/snapshot3+hdmi~4526^2~11 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0b0c002c340e78173789f8afaa508070d838cf3d;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git xen/time: remove blocked time accounting from xen "clockchip" ... because the "clock_event_device framework" already accounts for idle time through the "event_handler" function pointer in xen_timer_interrupt(). The patch is intended as the completion of [1]. It should fix the double idle times seen in PV guests' /proc/stat [2]. It should be orthogonal to stolen time accounting (the removed code seems to be isolated). The approach may be completely misguided. [1] https://lkml.org/lkml/2011/10/6/10 [2] http://lists.xensource.com/archives/html/xen-devel/2010-08/msg01068.html John took the time to retest this patch on top of v3.10 and reported: "idle time is correctly incremented for pv and hvm for the normal case, nohz=off and nohz=idle." so lets put this patch in. CC: stable@vger.kernel.org Signed-off-by: Laszlo Ersek Signed-off-by: John Haxby Signed-off-by: Konrad Rzeszutek Wilk --- diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index aec0b14..a690868 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -37,9 +37,8 @@ static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate); /* snapshots of runstate info */ static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot); -/* unused ns of stolen and blocked time */ +/* unused ns of stolen time */ static DEFINE_PER_CPU(u64, xen_residual_stolen); -static DEFINE_PER_CPU(u64, xen_residual_blocked); /* return an consistent snapshot of 64-bit time/counter value */ static u64 get64(const u64 *p) @@ -116,7 +115,7 @@ static void do_stolen_accounting(void) { struct vcpu_runstate_info state; struct vcpu_runstate_info *snap; - s64 blocked, runnable, offline, stolen; + s64 runnable, offline, stolen; cputime_t ticks; get_runstate_snapshot(&state); @@ -126,7 +125,6 @@ static void do_stolen_accounting(void) snap = &__get_cpu_var(xen_runstate_snapshot); /* work out how much time the VCPU has not been runn*ing* */ - blocked = state.time[RUNSTATE_blocked] - snap->time[RUNSTATE_blocked]; runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable]; offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline]; @@ -142,17 +140,6 @@ static void do_stolen_accounting(void) ticks = iter_div_u64_rem(stolen, NS_PER_TICK, &stolen); __this_cpu_write(xen_residual_stolen, stolen); account_steal_ticks(ticks); - - /* Add the appropriate number of ticks of blocked time, - including any left-overs from last time. */ - blocked += __this_cpu_read(xen_residual_blocked); - - if (blocked < 0) - blocked = 0; - - ticks = iter_div_u64_rem(blocked, NS_PER_TICK, &blocked); - __this_cpu_write(xen_residual_blocked, blocked); - account_idle_ticks(ticks); } /* Get the TSC speed from Xen */