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Date:   Tue, 9 Jun 2020 12:20:15 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Ritesh Harjani <ritesh.list@gmail.com>
Cc:     Marek Szyprowski <m.szyprowski@samsung.com>,
        Ritesh Harjani <riteshh@linux.ibm.com>,
        linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Jan Kara <jack@suse.com>, Theodore Ts'o <tytso@mit.edu>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCHv5 3/5] ext4: mballoc: Introduce pcpu seqcnt for freeing
 PA to improve ENOSPC handling
Message-ID: <20200609102015.GA7696@zn.tnic>
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On Wed, Jun 03, 2020 at 03:40:16PM +0530, Ritesh Harjani wrote:
> Yes, this is being discussed in the community.
> I have submitted a patch which should help fix this warning msg.
> Feel free to give this a try on your setup.
> 
> https://marc.info/?l=linux-ext4&m=159110574414645&w=2

I just triggered the same thing here too. Looking at your fix and not
even pretending to know what's going on with that percpu sequence
counting, I can't help but wonder why do you wanna do:

	seq = *raw_cpu_ptr(&discard_pa_seq);

instead of simply doing:

	seq = this_cpu_read(discard_pa_seq);

?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette