linux-kernel - Re: [RFC 2/3] mm: Add a new page flag PageLayzyFree() for MADV

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200315081854.rcqlmfckeqrh7fbt@master>
Date:   Sun, 15 Mar 2020 08:18:54 +0000
From:   Wei Yang <richard.weiyang@...il.com>
To:     "Huang, Ying" <ying.huang@...el.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        David Hildenbrand <david@...hat.com>,
        Mel Gorman <mgorman@...e.de>, Vlastimil Babka <vbabka@...e.cz>,
        Zi Yan <ziy@...dia.com>, Michal Hocko <mhocko@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Minchan Kim <minchan@...nel.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Hugh Dickins <hughd@...gle.com>
Subject: Re: [RFC 2/3] mm: Add a new page flag PageLayzyFree() for MADV_FREE

On Fri, Feb 28, 2020 at 11:38:18AM +0800, Huang, Ying wrote:
>From: Huang Ying <ying.huang@...el.com>
>
>Now !PageSwapBacked() is used as the flag for the pages freed lazily
>via MADV_FREE.  This isn't obvious enough.  So Dave suggested to add a
>new page flag for that to improve the code readability.

I am confused with the usage of PageSwapBacked().

Previously I thought this flag means the page is swapin, set in
swapin_readahead(). While I found page_add_new_anon_rmap() would set it too.
This means every anon page would carry this flag. Then what is this flag
means?


-- 
Wei Yang
Help you, Help me