Messages in this thread | | | Date | Thu, 6 Jul 2023 12:33:00 -0400 | From | Steven Rostedt <> | Subject | Re: High cpu usage caused by kernel process when upgraded to linux 5.19.17 or later |
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On Mon, 3 Jul 2023 18:23:25 +0530 Vivek Anand <vivekanand754@gmail.com> wrote:
> Hi Thomas, > > Further analyzing, I found that I did set > "CONFIG_NETFILTER_XT_MATCH_LIMIT=m" in my kernel config earlier which was > causing high CPU consumption. > Setting it to "CONFIG_NETFILTER_XT_MATCH_LIMIT=n" resolved the high CPU > issue. > > Is there any suggestion regarding the use of this config > "CONFIG_NETFILTER_XT_MATCH_LIMIT" as I'm getting high CPU by setting it to > "m" ?
That config enables the compiling of: net/netfilter/xt_limit.c
The htable_gc that you reported is defined in: net/netfilter/xt_hashlimit.c
It has:
static void htable_gc(struct work_struct *work) { struct xt_hashlimit_htable *ht;
ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
htable_selective_cleanup(ht, false);
queue_delayed_work(system_power_efficient_wq, &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval)); }
So it queues itself every ht->cfg.gc_interval msecs. That variable seems to come from some configuration of netfilter, and I think you can see these in:
find /proc/sys/net -name 'gc_interval'
Perhaps you have it set off to go too much?
-- Steve
> > Thanks, > Vivek > > On Thu, Jun 29, 2023 at 7:48 PM Thomas Gleixner <tglx@linutronix.de> wrote: > > > On Thu, Jun 29 2023 at 12:05, Vivek Anand wrote: > > > I've tried booting with "spectre_v2=retpoline retbleed=off". > > > This change didn't work. Still CPU is 100% > > > > This does not make sense. > > > > retbleed=off has the same effect as CONFIG_X86_IBRS_ENTRY=n. > > > > The only difference is that with CONFIG_X86_IBRS_ENTRY=y and > > retbleed=off there is one extra jump in the low level entry code > > (syscall, interrupts, exceptions) and one extra jump on the exit side. > > > > But those extra jumps are completely irrelevant for the kworker threads. > > > > Can you please provide dmesg and the content of the files in > > > > /sys/devices/system/cpu/vulnerabilities/ > > > > on a kernel booted with "spectre_v2=retpoline retbleed=off" ? > > > > Thanks, > > > > tglx > >
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