Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 22 Mar 2018 19:06:06 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Baoquan He <bhe@redhat.com>
Cc:     linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
        takahiro.akashi@linaro.org, ebiederm@xmission.com,
        vgoyal@redhat.com, dyoung@redhat.com, prudo@linux.vnet.ibm.com
Subject: Re: [PATCH 1/2] resource: add walk_system_ram_res_rev()
Message-Id: <20180322190606.859a0f1c7e2d1b2958daeb9f@linux-foundation.org>
In-Reply-To: <20180323005845.GA25740@localhost.localdomain>
References: <20180322033722.9279-1-bhe@redhat.com>
        <20180322033722.9279-2-bhe@redhat.com>
        <20180322152929.9b421af2f66cc819ad691207@linux-foundation.org>
        <20180323005845.GA25740@localhost.localdomain>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, 23 Mar 2018 08:58:45 +0800 Baoquan He <bhe@redhat.com> wrote:

> > erk, this is pretty nasty.  Isn't there a better way :(
> 
> Yes, this is not efficient.
> 
> In struct resource{}, ->sibling list is a singly linked list. I ever
> thought about changing it to doubly linked list, yet not very sure if
> it will have effect since struct resource is a core data structure.

Switching to a list_head sounds OK.  The only issue really is memory
consumption and surely we don't have tens of thousands of struct
resources floating about(?).  Or if we do have a lot, the machine is
presumably huge (hope?).

> AKASHI's method is more acceptable, and currently only kexec has this
> requirement.

What method is that?