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Date: Fri, 5 Oct 2018 14:21:43 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch] mm, page_alloc: set num_movable in move_freepages()
Message-Id: <20181005142143.30032b7a4fb9dc2b587a8c21@linux-foundation.org>
In-Reply-To: <alpine.DEB.2.21.1810051355490.212229@chino.kir.corp.google.com>
References: <alpine.DEB.2.21.1810051355490.212229@chino.kir.corp.google.com>
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To: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>, Greg Thelen <gthelen@google.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On Fri, 5 Oct 2018 13:56:39 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:

> If move_freepages() returns 0 because zone_spans_pfn(), *num_movable can

     move_free_pages_block()?           !zone_spans_pfn()?

> hold the value from the stack because it does not get initialized in
> move_freepages().
> 
> Move the initialization to move_freepages_block() to guarantee the value
> actually makes sense.
> 
> This currently doesn't affect its only caller where num_movable != NULL,
> so no bug fix, but just more robust.
> 
> ...