This is a note to let you know that I've just added the patch titled xen/time: remove blocked time accounting from xen "clockchip"
to the 3.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xen-time-remove-blocked-time-accounting-from-xen-clockchip.patch and it can be found in the queue-3.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@vger.kernel.org> know about it. >From 0b0c002c340e78173789f8afaa508070d838cf3d Mon Sep 17 00:00:00 2001 From: Laszlo Ersek <ler...@redhat.com> Date: Tue, 18 Oct 2011 22:42:59 +0200 Subject: xen/time: remove blocked time accounting from xen "clockchip" From: Laszlo Ersek <ler...@redhat.com> commit 0b0c002c340e78173789f8afaa508070d838cf3d upstream. ... 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. Signed-off-by: Laszlo Ersek <ler...@redhat.com> Signed-off-by: John Haxby <john.ha...@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/x86/xen/time.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -36,9 +36,8 @@ static DEFINE_PER_CPU(struct vcpu_runsta /* 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) @@ -115,7 +114,7 @@ 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); @@ -125,7 +124,6 @@ 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]; @@ -141,17 +139,6 @@ 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 */ Patches currently in stable-queue which might be from ler...@redhat.com are queue-3.4/xen-time-remove-blocked-time-accounting-from-xen-clockchip.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html