From: Michal Hocko <mhocko@kernel.org>
To: Qian Cai <cai@lca.pw>
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 13:35:21 +0100 [thread overview]
Message-ID: <20190226123521.GZ10588@dhcp22.suse.cz> (raw)
In-Reply-To: <20190225191710.48131-1-cai@lca.pw>
On Mon 25-02-19 14:17:10, Qian Cai wrote:
> When onlining memory pages, it calls kernel_unmap_linear_page(),
> However, it does not call kernel_map_linear_page() while offlining
> memory pages. As the result, it triggers a panic below while onlining on
> ppc64le as it checks if the pages are mapped before unmapping,
> Therefore, let it call kernel_map_linear_page() when setting all pages
> as reserved.
This really begs for much more explanation. All the pages should be
unmapped as they get freed AFAIR. So why do we need a special handing
here when this path only offlines free pages?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-02-26 12:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-25 19:17 Qian Cai
2019-02-26 12:13 ` Souptick Joarder
2019-02-26 14:07 ` Qian Cai
2019-02-26 12:35 ` Michal Hocko [this message]
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
2019-02-26 20:40 ` Michal Hocko
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