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Date:   Mon, 4 Jan 2021 15:23:57 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Hui Su <sh_def@163.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH] mm/page_alloc: remove the static for local variable
 node_order
Message-Id: <20210104152357.d56d10e0443bae984a174f18@linux-foundation.org>
In-Reply-To: <20201230124233.GE28221@casper.infradead.org>
References: <20201230114014.GA1934427@ubuntu-A520I-AC>
        <20201230124233.GE28221@casper.infradead.org>
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On Wed, 30 Dec 2020 12:42:33 +0000 Matthew Wilcox <willy@infradead.org> wrote:

> On Wed, Dec 30, 2020 at 07:40:14PM +0800, Hui Su wrote:
> > local variable node_order do not need the static here.
> 
> It bloody well does.  It can be up to 2^10 entries on x86 (and larger
> on others) That's 4kB which you've now moved onto the stack.

That being said, could we kmalloc the scratch area in
__build_all_zonelists()?  And maybe remove that static spinlock?

(what blocks node and cpu hotplug in there??)