On Wed, 3 Jun 2015, Jeremiah Mahler wrote:
> After a fresh boot, the Chrome web browser behaves normally. Pages
> load quickly and scroll fast. Even image heavy sites such as
> images.google.com work fine. However, after a suspend and resume
> cycle, Chrome becomes very slow. Pages take ten seconds or more to
> load. The scroll bars and buttons are almost completely
> unresponsive. Interestingly, I can run Firefox on the same sites
> and it has no issue whatsoever.
Weird.
> I have bisected the kernel and found that the following commit
> introduced the bug. It is present in the latest linux-next (20150602).
>
> From 868a3e915f7f5eba8f8cb4f7da2276760807c51c Mon Sep 17 00:00:00 2001
> From: Thomas Gleixner <t...@linutronix.de>
> Date: Tue, 14 Apr 2015 21:08:37 +0000
> Subject: [PATCH] hrtimer: Make offset update smarter
>
> On every tick/hrtimer interrupt we update the offset variables of the
> clock bases. That's silly because these offsets change very seldom.
>
> Add a sequence counter to the time keeping code which keeps track of
> the offset updates (clock_was_set()). Have a sequence cache in the
> hrtimer cpu bases to evaluate whether the offsets must be updated or
> not. This allows us later to avoid pointless cacheline pollution.
I had to wrap my head around that for quite a while, but I think I
have decoded the issue. Can you please test the patch below whether it
solves your problem?
Thanks,
tglx
------------------------>
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 278d4b36fd94..e9dfcd0b8c41 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1492,6 +1492,12 @@ static void init_hrtimers_cpu(int cpu)
cpu_base->cpu = cpu;
hrtimer_init_hres(cpu_base);
+ /*
+ * Force an update by setting the clock was set sequence to an
+ * odd value.
+ */
+ cpu_base->clock_was_set_seq = 1;
+ hrtimer_update_base(cpu_base);
}
#ifdef CONFIG_HOTPLUG_CPU
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 90ed5db67c1d..c97710137a9e 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -593,7 +593,7 @@ static void timekeeping_update(struct timekeeper *tk,
unsigned int action)
update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
if (action & TK_CLOCK_WAS_SET)
- tk->clock_was_set_seq++;
+ tk->clock_was_set_seq += 2;
}
/**
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