From: Aaron Tomlin <atomlin@redhat.com>
To: Hillf Danton <hdanton@sina.com>
Cc: frederic@kernel.org, mtosatti@redhat.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
atomlin@atomlin.com
Subject: Re: [PATCH v8 5/5] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too
Date: Wed, 12 Oct 2022 13:41:01 +0100 [thread overview]
Message-ID: <20221012124101.zod6m2brlzpgx6nb@ava.usersys.com> (raw)
In-Reply-To: <20221003124435.1769-1-hdanton@sina.com>
> Given work canceled because per-CPU pages can be freed remotely from
> housekeeping CPUs (see patch 3/5), what is added here is not needed.
Hi Hillf,
Firstly, apologies for the delay!
The concern is to ensure CPU-specific vmstat counters are reset and folded
into NUMA node and zone specific and global counters too before entering
idle. It is necessary to invoke quiet_vmstat() on return to idle even if
the scheduling-clock tick has been previously stopped.
Please refer to the complete scenario I described again.
If I understand correctly, indeed the remote drain/or free of zone
CPU-specific pages can be initiated by a "housekeeping" CPU i.e.
refresh_cpu_vm_stats(true) via a worker thread/or kworker, yet the actual
free will only occur when the nohz_full CPU exits idle code and calls
schedule_idle().
Kind regards,
--
Aaron Tomlin
next prev parent reply other threads:[~2022-10-12 12:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-24 15:22 [PATCH v8 0/5] Ensure quiet_vmstat() is called when the idle tick was stopped too Aaron Tomlin
2022-09-24 15:22 ` [PATCH v8 1/5] mm/vmstat: Add CPU-specific variable to track a vmstat discrepancy Aaron Tomlin
2022-09-24 15:22 ` [PATCH v8 2/5] mm/vmstat: Use vmstat_dirty to track CPU-specific vmstat discrepancies Aaron Tomlin
2022-10-01 14:55 ` kernel test robot
2022-09-24 15:22 ` [PATCH v8 3/5] mm/vmstat: Do not queue vmstat_update if tick is stopped Aaron Tomlin
2022-10-24 11:03 ` Frederic Weisbecker
2022-11-09 19:40 ` Marcelo Tosatti
2022-11-10 19:15 ` Marcelo Tosatti
2022-11-14 12:12 ` Frederic Weisbecker
2022-10-24 11:54 ` Frederic Weisbecker
2022-09-24 15:22 ` [PATCH v8 4/5] tick/nohz_full: Ensure quiet_vmstat() is called on exit to user-mode when the idle " Aaron Tomlin
2022-09-27 16:17 ` Rafael Folco
2022-09-29 8:22 ` Aaron Tomlin
2022-09-29 12:49 ` Rafael Folco
2022-10-21 14:50 ` Frederic Weisbecker
2022-11-10 19:14 ` Marcelo Tosatti
2022-09-24 15:24 ` [PATCH v8 5/5] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too Aaron Tomlin
2022-09-25 1:05 ` Hillf Danton
2022-09-26 9:20 ` Aaron Tomlin
2022-10-03 12:44 ` Hillf Danton
2022-10-12 12:41 ` Aaron Tomlin [this message]
2022-10-17 16:04 ` Marcelo Tosatti
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