From: Qian Cai <cai@lca.pw>
To: Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/hotplug: fix an imbalance with DEBUG_PAGEALLOC
Date: Tue, 26 Feb 2019 15:10:39 -0500 [thread overview]
Message-ID: <1551211839.6911.54.camel@lca.pw> (raw)
In-Reply-To: <20190226194024.GI10588@dhcp22.suse.cz>
On Tue, 2019-02-26 at 20:40 +0100, Michal Hocko wrote:
> It seems you have missed the point of my question. It simply doesn't
> make much sense to have offline memory mapped. That memory is not
> accessible in general. So mapping it at the offline time is dubious at
> best.
Well, kernel_map_pages() is like other debug features which could look
"unusual".
> Also you do not get through the offlining phase on a newly
> hotplugged (and not yet onlined) memory. So the patch doesn't look
> correct to me and it all smells like the bug you are seeing is a wrong
> reporting.
>
That (physical memory hotadd) is a special case like during the boot. The patch
is strictly to deal with offline/online memory, i.e., logical/soft memory
hotplug.
next prev parent reply other threads:[~2019-02-26 20:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-25 19:17 [PATCH] mm/hotplug: fix an imbalance with DEBUG_PAGEALLOC Qian Cai
2019-02-26 12:13 ` Souptick Joarder
2019-02-26 14:07 ` Qian Cai
2019-02-26 12:35 ` Michal Hocko
2019-02-26 14:16 ` Qian Cai
2019-02-26 14:23 ` Michal Hocko
2019-02-26 17:53 ` Qian Cai
2019-02-26 18:16 ` Michal Hocko
2019-02-26 18:20 ` Michal Hocko
2019-02-26 19:19 ` Qian Cai
2019-02-26 19:40 ` Michal Hocko
2019-02-26 20:10 ` Qian Cai [this message]
2019-02-26 20:40 ` Michal Hocko
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