linux-kernel - Re: [PATCH] mm: swap: Use memset to fill the swap_map with SWAP_HAS

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Message-ID: <16636ab4ebb746b4ba0a14eec8225cbc@huawei.com>
Date:   Mon, 26 Oct 2020 03:03:10 +0000
From:   linmiaohe <linmiaohe@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
CC:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Hugh Dickins <hughd@...gle.com>
Subject: Re: [PATCH] mm: swap: Use memset to fill the swap_map with
 SWAP_HAS_CACHE

Andrew Morton <akpm@...ux-foundation.org> wrote:
> On Mon, 21 Sep 2020 08:22:24 -0400 Miaohe Lin <linmiaohe@...wei.com> wrote:
>
>> We could use helper memset to fill the swap_map with SWAP_HAS_CACHE 
>> instead of a direct loop here to simplify the code. Also we can remove 
>> the local variable i and map this way.
>>  	*slot = swp_entry(si->type, offset);
>
>I suppose so.  But it does assume that the ->swapmap array has the type char.  If we ever change that, breakage will ensue.
>

The origin code already assumes that the ->swap_map array has the type char. So, this change is ok. ;)

And if we change the type of ->swap_map, each place uses the swap_map should be fixed accordingly.;(

Many thanks.