linux-kernel - Re: [PATCH 3/3] mm: move mirrored memory specific code outside of memmap_init

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Message-ID: <20180725114847.GA16691@techadventures.net>
Date:   Wed, 25 Jul 2018 13:48:47 +0200
From:   Oscar Salvador <osalvador@...hadventures.net>
To:     Pavel Tatashin <pasha.tatashin@...cle.com>
Cc:     steven.sistare@...cle.com, daniel.m.jordan@...cle.com,
        linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
        kirill.shutemov@...ux.intel.com, mhocko@...e.com,
        linux-mm@...ck.org, dan.j.williams@...el.com, jack@...e.cz,
        jglisse@...hat.com, jrdr.linux@...il.com, bhe@...hat.com,
        gregkh@...uxfoundation.org, vbabka@...e.cz,
        richard.weiyang@...il.com, dave.hansen@...el.com,
        rientjes@...gle.com, mingo@...nel.org, abdhalee@...ux.vnet.ibm.com,
        mpe@...erman.id.au
Subject: Re: [PATCH 3/3] mm: move mirrored memory specific code outside of
 memmap_init_zone

On Tue, Jul 24, 2018 at 07:55:20PM -0400, Pavel Tatashin wrote:
> memmap_init_zone, is getting complex, because it is called from different
> contexts: hotplug, and during boot, and also because it must handle some
> architecture quirks. One of them is mirroed memory.
> 
> Move the code that decides whether to skip mirrored memory outside of
> memmap_init_zone, into a separate function.
> 
> Signed-off-by: Pavel Tatashin <pasha.tatashin@...cle.com>

Hi Pavel,

this looks good to me.
Over the past days I thought if it would make sense to have two
memmap_init_zone functions, one for hotplug and another one for early init,
so we could get rid of the altmap stuff in the early init, and also the 
MEMMAP_EARLY/HOTPLUG context thing could be gone.

But I think that they would just share too much of the code, so I do not think
it is worth.

I am working to do that for free_area_init_core, let us see what I come up with.

Anyway, this looks nicer, so thanks for that.
I also gave it a try, and early init and memhotplug code seems to work fine.

Reviewed-by: Oscar Salvador <osalvador@...e.de>

Thanks
-- 
Oscar Salvador
SUSE L3