From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Toshi Kani <toshi.kani@hp.com>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
isimatu.yasuaki@jp.fujitsu.com,
vasilis.liaskovitis@profitbricks.com, Len Brown <lenb@kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/2 v2, RFC] Driver core: Introduce offline/online callbacks for memory blocks
Date: Wed, 22 May 2013 12:42:50 +0200 [thread overview]
Message-ID: <2525744.qpOuRMa9WS@vostro.rjw.lan> (raw)
In-Reply-To: <519C4D6E.6080902@cn.fujitsu.com>
On Wednesday, May 22, 2013 12:45:34 PM Tang Chen wrote:
> Hi Rafael,
>
> On 05/21/2013 07:15 PM, Rafael J. Wysocki wrote:
> ......
> >>> + mem->state = to_state;
> >>> + if (to_state == MEM_ONLINE)
> >>> + mem->last_online = online_type;
> >>
> >> Why do we need to remember last online type ?
> >>
> >> And as far as I know, we can obtain which zone a page was in last time it
> >> was onlined by check page->flags, just like online_pages() does. If we
> >> use online_kernel or online_movable, the zone boundary will be
> >> recalculated.
> >> So we don't need to remember the last online type.
> >>
> >> Seeing from your patch, I guess memory_subsys_online() can only handle
> >> online and offline. So mem->last_online is used to remember what user has
> >> done through the original way to trigger memory hot-remove, right ? And
> >> when
> >> user does it in this new way, it just does the same thing as user does last
> >> time.
> >>
> >> But I still think we don't need to remember it because if finally you call
> >> online_pages(), it just does the same thing as last time by default.
> >>
> >> online_pages()
> >> {
> >> ......
> >> if (online_type == ONLINE_KERNEL ......
> >>
> >> if (online_type == ONLINE_MOVABLE......
> >>
> >> zone = page_zone(pfn_to_page(pfn));
> >>
> >> /* Here, the page will be put into the zone which it belong to last
> >> time. */
> >
> > To be honest, it wasn't entirely clear to me that online_pages() would do the
> > same thing as last time by default. Suppose, for example, that the previous
> > online_type was ONLINE_MOVABLE. How online_pages() is supposed to know that
> > it should do the move_pfn_zone_right() if we don't tell it to do that? Or
> > is that unnecessary, because it's already been done previously?
>
> Yes, it is unnecessary. move_pfn_zone_right/left() will modify the zone
> related
> bits in page->flags. But when the page is offline, the zone related bits in
> page->flags will not change. So when it is online again, by dafault, it
> will
> be in the zone which it was in last time.
>
> ......
>
> >>
> >> I just thought of it. Maybe I missed something in your design. Please tell
> >> me if I'm wrong.
> >
> > Well, so what should be passed to __memory_block_change_state() in
> > memory_subsys_online()? -1?
>
> If you want to keep the last time status, you can pass ONLINE_KEEP.
> Or -1 is all right.
>
> Thanks. :)
OK, thanks for the info.
Since the $subject patch is on my acpi-hotplug branch which has gone public
already (and cannot be rebased), I'll prepare a patch with the change you're
recommending on top of it.
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
next prev parent reply other threads:[~2013-05-22 10:34 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-29 12:23 [PATCH 0/3 RFC] Driver core / ACPI: Add offline/online for graceful hot-removal of devices Rafael J. Wysocki
2013-04-29 12:26 ` [PATCH 1/3 RFC] Driver core: Add offline/online device operations Rafael J. Wysocki
2013-04-29 23:10 ` Greg Kroah-Hartman
2013-04-30 11:59 ` Rafael J. Wysocki
2013-04-30 15:32 ` Greg Kroah-Hartman
2013-04-30 20:05 ` Rafael J. Wysocki
2013-04-30 23:38 ` Toshi Kani
2013-05-02 0:58 ` Rafael J. Wysocki
2013-05-02 23:29 ` Toshi Kani
2013-05-03 11:48 ` Rafael J. Wysocki
2013-04-29 12:28 ` [PATCH 2/3 RFC] Driver core: Use generic offline/online for CPU offline/online Rafael J. Wysocki
2013-04-29 23:11 ` Greg Kroah-Hartman
2013-04-30 12:01 ` Rafael J. Wysocki
2013-04-30 15:27 ` Greg Kroah-Hartman
2013-04-30 20:06 ` Rafael J. Wysocki
2013-04-30 23:42 ` Toshi Kani
2013-05-01 14:49 ` Rafael J. Wysocki
2013-05-01 20:07 ` Toshi Kani
2013-05-02 0:26 ` Rafael J. Wysocki
2013-04-29 12:29 ` [PATCH 3/3 RFC] ACPI / hotplug: Use device offline/online for graceful hot-removal Rafael J. Wysocki
2013-04-30 23:49 ` Toshi Kani
2013-05-01 15:05 ` Rafael J. Wysocki
2013-05-01 20:20 ` Toshi Kani
2013-05-02 0:53 ` Rafael J. Wysocki
2013-05-02 12:26 ` [PATCH 0/4] Driver core / ACPI: Add offline/online for graceful hot-removal of devices Rafael J. Wysocki
2013-05-02 12:27 ` [PATCH 1/4] Driver core: Add offline/online device operations Rafael J. Wysocki
2013-05-02 13:57 ` Greg Kroah-Hartman
2013-05-02 23:11 ` Toshi Kani
2013-05-02 23:36 ` Rafael J. Wysocki
2013-05-02 23:23 ` Toshi Kani
2013-05-02 12:28 ` [PATCH 2/4] Driver core: Use generic offline/online for CPU offline/online Rafael J. Wysocki
2013-05-02 13:57 ` Greg Kroah-Hartman
2013-05-02 12:29 ` [PATCH 3/4] ACPI / hotplug: Use device offline/online for graceful hot-removal Rafael J. Wysocki
2013-05-02 12:31 ` [PATCH 4/4] ACPI / processor: Use common hotplug infrastructure Rafael J. Wysocki
2013-05-02 13:59 ` Greg Kroah-Hartman
2013-05-02 23:20 ` Toshi Kani
2013-05-03 12:05 ` Rafael J. Wysocki
2013-05-03 12:21 ` Rafael J. Wysocki
2013-05-03 18:27 ` Toshi Kani
2013-05-03 19:31 ` Rafael J. Wysocki
2013-05-03 19:34 ` Toshi Kani
2013-05-04 1:01 ` [PATCH 0/3 RFC] Driver core: Add offline/online callbacks for memory_subsys Rafael J. Wysocki
2013-05-04 1:03 ` [PATCH 1/3 RFC] ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes Rafael J. Wysocki
2013-05-04 1:04 ` [PATCH 2/3 RFC] Driver core: Introduce types of device "online" Rafael J. Wysocki
2013-05-04 1:06 ` [PATCH 3/3 RFC] Driver core: Introduce offline/online callbacks for memory blocks Rafael J. Wysocki
2013-05-04 11:11 ` [PATCH 0/2 v2, RFC] Driver core: Add offline/online callbacks for memory_subsys Rafael J. Wysocki
2013-05-04 11:12 ` [PATCH 1/2 v2, RFC] ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes Rafael J. Wysocki
2013-05-21 6:50 ` Tang Chen
2013-05-04 11:21 ` [PATCH 2/2 v2, RFC] Driver core: Introduce offline/online callbacks for memory blocks Rafael J. Wysocki
2013-05-06 16:28 ` Vasilis Liaskovitis
2013-05-07 0:59 ` Rafael J. Wysocki
2013-05-07 10:59 ` Vasilis Liaskovitis
2013-05-07 12:11 ` Rafael J. Wysocki
2013-05-07 21:03 ` Toshi Kani
2013-05-07 22:10 ` Rafael J. Wysocki
2013-05-07 22:45 ` Toshi Kani
2013-05-07 23:17 ` Rafael J. Wysocki
2013-05-07 23:59 ` Toshi Kani
2013-05-08 0:24 ` Rafael J. Wysocki
2013-05-08 0:37 ` Toshi Kani
2013-05-08 11:53 ` Rafael J. Wysocki
2013-05-08 14:38 ` Toshi Kani
2013-05-06 17:20 ` Greg Kroah-Hartman
2013-05-06 19:46 ` Rafael J. Wysocki
2013-05-21 6:37 ` Tang Chen
2013-05-21 11:15 ` Rafael J. Wysocki
2013-05-22 4:45 ` Tang Chen
2013-05-22 10:42 ` Rafael J. Wysocki [this message]
2013-05-22 22:06 ` [PATCH] Driver core / memory: Simplify __memory_block_change_state() Rafael J. Wysocki
2013-05-22 22:14 ` Greg Kroah-Hartman
2013-05-22 23:29 ` Rafael J. Wysocki
2013-05-23 4:37 ` Tang Chen
2013-05-06 10:48 ` [PATCH 0/2 v2, RFC] Driver core: Add offline/online callbacks for memory_subsys Rafael J. Wysocki
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