linux-kernel - [Question] Why PageReadahead is not migrated by migration code?

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-next>] [day] [month] [year] [list]

Message-ID: <7691ab12-2e84-2531-f27d-2fae9045576d@linux.alibaba.com>
Date:   Thu, 13 Feb 2020 09:06:58 -0800
From:   Yang Shi <yang.shi@...ux.alibaba.com>
To:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: [Question] Why PageReadahead is not migrated by migration code?

Hi folks,

Recently we saw some PageReadahead related bugs, so I did a quick check 
about the use of PageReadahead. I just found the state is *not* migrated 
by migrate_page_states().

Since migrate_page() won't migrate writeback page, so if PageReadahead 
is set it should just mean PG_readahead rather than PG_reclaim. So, I 
didn't think of why it is not migrated.

I dig into the history a little bit, but the change in migration code is 
too overwhelming. But, it looks PG_readahead was added after migration 
was introduced. Is it just a simple omission?

Thanks,

Yang