From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc: Rob Herring <robh@kernel.org>, Kees Cook <keescook@chromium.org>,
Nicholas Piggin <npiggin@gmail.com>,
linux-kernel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
Juliet Kim <minkim@us.ibm.com>,
Oliver O'Halloran <oohall@gmail.com>,
Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
Nathan Lynch <nathanl@linux.vnet.ibm.com>,
Thomas Falcon <tlfalcon@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, Guenter Roeck <linux@roeck-us.net>,
Corentin Labbe <clabbe@baylibre.com>
Subject: Re: [PATCH v03] powerpc/numa: Perform full re-add of CPU for PRRN/VPHN topology update
Date: Fri, 8 Feb 2019 11:14:03 +0530 [thread overview]
Message-ID: <20190208054403.GA24971@linux.vnet.ibm.com> (raw)
In-Reply-To: <305ed693-ea85-8a70-1d3c-ae405aebc0ad@linux.vnet.ibm.com>
>
> int arch_update_cpu_topology(void)
> {
> - return numa_update_cpu_topology(true);
> + int changed = topology_changed;
> +
> + topology_changed = 0;
> + return changed;
> }
>
Do we need Powerpc override for arch_update_cpu_topology() now? That
topology_changed sometime back doesn't seem to have help. The scheduler
atleast now is neglecting whether the topology changed or not.
Also we can do away with the new topology_changed.
> static void topology_work_fn(struct work_struct *work)
> {
> - rebuild_sched_domains();
> + lock_device_hotplug();
> + if (numa_update_cpu_topology(true))
> + rebuild_sched_domains();
> + unlock_device_hotplug();
> }
Should this hunk be a separate patch by itself to say why
rebuild_sched_domains with a changelog that explains why it should be under
lock_device_hotplug? rebuild_sched_domains already takes cpuset_mutex.
So I am not sure if we need to take device_hotplug_lock.
> static DECLARE_WORK(topology_work, topology_work_fn);
>
> -static void topology_schedule_update(void)
> +void topology_schedule_update(void)
> {
> - schedule_work(&topology_work);
> + if (!topology_update_in_progress)
> + schedule_work(&topology_work);
> }
>
> static void topology_timer_fn(struct timer_list *unused)
> {
> + bool sdo = false;
Is sdo any abbrevation?
> +
> + if (topology_scans < 1)
> + bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask),
> + nr_cpumask_bits);
Why do we need topology_scan? Just to make sure
cpu_associativity_changes_mask is populated only once?
cant we use a static bool inside the function for the same?
> +
> if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
> - topology_schedule_update();
> - else if (vphn_enabled) {
> + sdo = true;
> + if (vphn_enabled) {
Any reason to remove the else above?
> if (update_cpu_associativity_changes_mask() > 0)
> - topology_schedule_update();
> + sdo = true;
> reset_topology_timer();
> }
> + if (sdo)
> + topology_schedule_update();
> + topology_scans++;
> }
Are the above two hunks necessary? Not getting how the current changes are
different from the previous.
--
Thanks and Regards
Srikar Dronamraju
next prev parent reply other threads:[~2019-02-08 5:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-06 15:56 [PATCH v03] powerpc/numa: Perform full re-add of CPU for PRRN/VPHN topology update Michael Bringmann
2019-02-07 4:48 ` kbuild test robot
2019-02-08 5:44 ` Srikar Dronamraju [this message]
2019-02-08 19:43 ` Michael Bringmann
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