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References: <20230117204617.1553748-1-pasha.tatashin@soleen.com> <20230117171312.13bdb3b2673bdac3c93c2ab7@linux-foundation.org>
In-Reply-To: <20230117171312.13bdb3b2673bdac3c93c2ab7@linux-foundation.org>
From:   Pasha Tatashin <pasha.tatashin@soleen.com>
Date:   Wed, 18 Jan 2023 10:01:46 -0500
Message-ID: <CA+CK2bCsYp839RVFLYTjx-NSwUxMJ9xG9Z=DDy7hgGn72+aMdw@mail.gmail.com>
Subject: Re: [PATCH] mm/page_ext: init page_ext early if there are no deferred
 struct pages
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     rppt@kernel.org, mhocko@suse.com, vbabka@suse.cz, david@redhat.com,
        quic_charante@quicinc.com, lizhe.67@bytedance.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
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On Tue, Jan 17, 2023 at 8:13 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Tue, 17 Jan 2023 20:46:17 +0000 Pasha Tatashin <pasha.tatashin@soleen.com> wrote:
>
> > page_ext must be initialized after all struct pages are initialized.
> > Therefore, page_ext is initialized after page_alloc_init_late(), and
> > can optionally be initialized earlier via early_page_ext kernel
> > parameter which as a side effect also disables deferred struct pages.
> >
> > Allow to automatically init page_ext early when there are no deferred
> > struct pages in order to be able to use page_ext during kernel boot
> > and track for example page allocations early.
>
> Compilation blows up with CONFIG_PAGE_EXTENSION=n.  I did

Thanks, I will update the patch and send it soon.

Pasha