linux-kernel - Re: [PATCH v4 01/14] mm/mm_init: rename init_reserved_page to init_deferred

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Message-ID: <Z7dCG3ihTnDuJ8_c@kernel.org>
Date: Thu, 20 Feb 2025 16:54:19 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Wei Yang <richard.weiyang@...il.com>
Cc: linux-kernel@...r.kernel.org, Alexander Graf <graf@...zon.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Lutomirski <luto@...nel.org>,
	Anthony Yznaga <anthony.yznaga@...cle.com>,
	Arnd Bergmann <arnd@...db.de>, Ashish Kalra <ashish.kalra@....com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Borislav Petkov <bp@...en8.de>,
	Catalin Marinas <catalin.marinas@....com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Eric Biederman <ebiederm@...ssion.com>,
	Ingo Molnar <mingo@...hat.com>, James Gowans <jgowans@...zon.com>,
	Jonathan Corbet <corbet@....net>,
	Krzysztof Kozlowski <krzk@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Pasha Tatashin <pasha.tatashin@...een.com>,
	"H. Peter Anvin" <hpa@...or.com>,
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	Stanislav Kinsburskii <skinsburskii@...ux.microsoft.com>,
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	Will Deacon <will@...nel.org>, devicetree@...r.kernel.org,
	kexec@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
	linux-doc@...r.kernel.org, linux-mm@...ck.org, x86@...nel.org
Subject: Re: [PATCH v4 01/14] mm/mm_init: rename init_reserved_page to
 init_deferred_page

On Thu, Feb 20, 2025 at 08:36:01AM +0000, Wei Yang wrote:
> On Wed, Feb 19, 2025 at 09:13:22AM +0200, Mike Rapoport wrote:
> >Hi,
> >
> >On Tue, Feb 18, 2025 at 02:59:04PM +0000, Wei Yang wrote:
> >> On Thu, Feb 06, 2025 at 03:27:41PM +0200, Mike Rapoport wrote:
> >> >From: "Mike Rapoport (Microsoft)" <rppt@...nel.org>
> >> >
> >> >When CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, init_reserved_page()
> >> >function performs initialization of a struct page that would have been
> >> >deferred normally.
> >> >
> >> >Rename it to init_deferred_page() to better reflect what the function does.
> >> 
> >> Would it be confused with deferred_init_pages()?
> >
> >Why? It initializes a single page, deferred_init_pages() initializes many.
> >
> 
> See below.
> 
> >> And it still calls __init_reserved_page_zone(), even we __SetPageReserved()
> >> after it. Current logic looks not clear.
> >
> >There's no __init_reserved_page_zone(). Currently init_reserved_page()
> >detects the zone of the page and calls __init_single_page(), so essentially
> >it initializes one struct page.
> >
> >And we __SetPageReserved() in reserve_bootmem_region() after call to
> >init_reseved_page() because pages there are indeed reserved.
> > 
> 
> Hmm... I am not sure we are looking at the same code. I take a look at current
> mm-unstable, this patch set is not included.

I was looking at Linus tree, it was not there yet :)

> So I am looking at previous version with this last commit:
> 
>   8bf30f9d23eb 2025-02-06 Documentation: KHO: add memblock bindings
> 
> Here is what I see for init_deferred_page()'s definition:
> 
> init_deferred_page()
>   __init_deferred_page()
>     __init_reserved_page_zone()   <--- I do see this function, it is removed?
>       __init_single_page()
> 
> What I want to say is __init_deferred_page() calls
> __init_reserved_page_zone(). This sounds imply a deferred page is always
> reserved page. But we know it is not.  deferred_init_pages() initialize the
> pages are not reserved one. Or we want to have this context in
> __init_deferred_page()?

If the commit that introduced __init_reserved_page_zone goes in before KHO,
I'll just rename both functions, there is nothing about reserved pages
there.
 
> >-- 
> >Sincerely yours,
> >Mike.
> 
> -- 
> Wei Yang
> Help you, Help me

-- 
Sincerely yours,
Mike.