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Date:   Mon, 15 Jul 2019 09:58:14 -0700
From:   Yang Shi <>
To:     Qian Cai <>, Catalin Marinas <>,
        Michal Hocko <>
Cc:     "" <>,
        "" <>,
        "" <>,
        "" <>
Subject: Re: [PATCH] mm: page_alloc: document kmemleak's non-blockable
 __GFP_NOFAIL case

On 7/15/19 8:18 AM, Qian Cai wrote:
> On Mon, 2019-07-15 at 10:01 -0500, Catalin Marinas wrote:
>> On 15 Jul 2019, at 08:17, Michal Hocko <> wrote:
>>> On Sat 13-07-19 04:49:04, Yang Shi wrote:
>>>> When running ltp's oom test with kmemleak enabled, the below warning was
>>>> triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
>>>> passed in:
>>> kmemleak is broken and this is a long term issue. I thought that
>>> Catalin had something to address this.
>> What needs to be done in the short term is revert commit
>> d9570ee3bd1d4f20ce63485f5ef05663866fe6c0. Longer term the solution is to embed
>> kmemleak metadata into the slab so that we don’t have the situation where the
>> primary slab allocation success but the kmemleak metadata fails.
>> I’m on holiday for one more week with just a phone to reply from but feel free
>> to revert the above commit. I’ll follow up with a better solution.
> Well, the reverting will only make the situation worst for the kmemleak under
> memory pressure. In the meantime, if someone wants to push for the mempool

I think this is expected by reverting that commit since kmemleak 
metadata could fail. But, it could fail too even though that commit is 
not reverted if the context is non-blockable.

> solution with tunable pool sizes along with the reverting, that could be an
> improvement.

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