Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Sun, 4 Sep 2022 22:15:18 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Cheng Li <lic121@chinatelecom.cn>
Cc:     mike.kravetz@oracle.com, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: use mem_map_offset instead of mem_map_next
Message-ID: <YxUVZpsmukNW5NyK@casper.infradead.org>
References: <1662300161-22049-1-git-send-email-lic121@chinatelecom.cn>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1662300161-22049-1-git-send-email-lic121@chinatelecom.cn>
Precedence: bulk

On Sun, Sep 04, 2022 at 02:02:41PM +0000, Cheng Li wrote:
> To handle discontiguity case, mem_map_next() has a parameter named
> `offset`. As a function caller, one would be confused why "get
> next entry" needs a parameter named "offset". The other drawback of
> mem_map_next() is that the callers must take care of the map between
> parameter "iter" and "offset", otherwise we may get an hole or
> duplication during iteration. So we use mem_map_offset instead of
> mem_map_next.

I think we should go further and get rid of mem_map_offset().
nth_page() is now more efficient than mem_map_offset().