linux-kernel - Re: [RFC PATCH] mm: hugetlb: remove __GFP_THISNODE flag when dissolving the old hugetlb

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <67e0d81f-7125-455c-b02f-a9e675d55c6c@linux.alibaba.com>
Date: Tue, 6 Feb 2024 16:18:22 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: Michal Hocko <mhocko@...e.com>
Cc: akpm@...ux-foundation.org, muchun.song@...ux.dev, osalvador@...e.de,
 david@...hat.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] mm: hugetlb: remove __GFP_THISNODE flag when
 dissolving the old hugetlb



On 2024/2/5 22:23, Michal Hocko wrote:
> On Mon 05-02-24 21:06:17, Baolin Wang wrote:
> [...]
>>> It is quite possible that traditional users (like large DBs) do not use
>>> CMA heavily so such a problem was not observed so far. That doesn't mean
>>> those problems do not really matter.
>>
>> CMA is just one case, as I mentioned before, other situations can also break
>> the per-node hugetlb pool now.
> 
> Is there any other case than memory hotplug which is arguably different
> as it is a disruptive operation already.

Yes, like I said before the longterm pinning, memory failure and the 
users of alloc_contig_pages() may also break the per-node hugetlb pool.

>> Let's focus on the main point, why we should still keep inconsistency
>> behavior to handle free and in-use hugetlb for alloc_contig_range()? That's
>> really confused.
> 
> yes, this should behave consistently. And the least surprising way to
> handle that from the user configuration POV is to not move outside of
> the original NUMA node.

So you mean we should also add __GFP_THISNODE flag in 
alloc_migration_target() when allocating a new hugetlb as the target for 
migration, that can unify the behavior and avoid breaking the per-node pool?