From: Michal Hocko <mhocko@kernel.org>
To: Zaslonko Mikhail <zaslonko@linux.ibm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>,
Mikhail Zaslonko <zaslonko@linux.ibm.com>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Pavel.Tatashin@microsoft.com,
schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
gerald.schaefer@de.ibm.com
Subject: Re: [PATCH v2 1/1] mm, memory_hotplug: Initialize struct pages for the full memory section
Date: Fri, 14 Dec 2018 11:19:59 +0100 [thread overview]
Message-ID: <20181214101651.GE5624@dhcp22.suse.cz> (raw)
In-Reply-To: <674c53e2-e4b3-f21f-4613-b149acef7e53@linux.bm.com>
[Your From address seems to have a typo (linux.bm.com) - fixed]
On Fri 14-12-18 10:33:55, Zaslonko Mikhail wrote:
[...]
> Yes, it might still trigger PF_POISONED_CHECK if the first page
> of the pageblock is left uninitialized (poisoned).
> But in order to cover these exceptional cases we would need to
> adjust memory_hotplug sysfs handler functions with similar
> checks (as in the for loop of memmap_init_zone()). And I guess
> that is what we were trying to avoid (adding special cases to
> memory_hotplug paths).
is_mem_section_removable should test pfn_valid_within at least.
But that would require some care because next_active_pageblock expects
aligned pages. Ble, this code is just horrible. I would just remove it
altogether. I strongly suspect that nobody is using it for anything
reasonable anyway. The only reliable way to check whether a block is
removable is to remove it. Everything else is just racy.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-12-14 10:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-12 17:27 [PATCH v2 0/1] Initialize struct pages for the full section Mikhail Zaslonko
2018-12-12 17:27 ` [PATCH v2 1/1] mm, memory_hotplug: Initialize struct pages for the full memory section Mikhail Zaslonko
2018-12-13 3:46 ` Wei Yang
[not found] ` <e4cebbae-3fcb-f03c-3d0e-a1a44ff0675a@linux.bm.com>
2018-12-13 15:12 ` Wei Yang
[not found] ` <674c53e2-e4b3-f21f-4613-b149acef7e53@linux.bm.com>
2018-12-14 10:19 ` Michal Hocko [this message]
2018-12-15 0:26 ` Wei Yang
2018-12-13 12:59 ` Michal Hocko
2018-12-14 15:22 ` David Hildenbrand
2018-12-14 15:49 ` David Hildenbrand
2018-12-14 19:23 ` Gerald Schaefer
2018-12-17 9:38 ` David Hildenbrand
2018-12-17 12:28 ` Michal Hocko
2018-12-17 13:29 ` David Hildenbrand
2018-12-17 13:35 ` Michal Hocko
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