linux-kernel - Re: slow boot with 7fef431be9c9 ("mm/page_alloc: place pages to tail in __free_pages

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Message-ID: <YEzCm/Uwvw7kKpd7@linux.ibm.com>
Date:   Sat, 13 Mar 2021 15:48:11 +0200
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     David Hildenbrand <david@...hat.com>
Cc:     "Liang, Liang (Leo)" <Liang.Liang@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        linux-kernel@...r.kernel.org,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Huang, Ray" <Ray.Huang@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        George Kennedy <george.kennedy@...cle.com>
Subject: Re: slow boot with 7fef431be9c9 ("mm/page_alloc: place pages to tail
 in __free_pages_core()")

Hi,

On Sat, Mar 13, 2021 at 10:05:23AM +0100, David Hildenbrand wrote:
> > Am 13.03.2021 um 05:04 schrieb Liang, Liang (Leo) <Liang.Liang@....com>:
> > 
> > Hi David,
> > 
> > Which benchmark tool you prefer? Memtest86+ or else?
> 
> Hi Leo,
> 
> I think you want something that runs under Linux natively.
> 
> I‘m planning on coding up a kernel module to walk all 4MB pages in the
> freelists and perform a stream benchmark individually. Then we might be
> able to identify the problematic range - if there is a problematic range :)

My wild guess would be that the pages that are now at the head of free
lists have wrong caching enabled. Might be worth checking in your test
module.

> Guess I‘ll have it running by Monday and let you know.
> 
> Cheers!

-- 
Sincerely yours,
Mike.