linux-kernel - Re: [PATCH v20 08/20] mm: page_idle_get_page() does not need lru

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: <a7ed8ebf-0d7b-2f01-eaad-14a07e660f68@linux.alibaba.com>
Date:   Fri, 6 Nov 2020 09:11:12 +0800
From:   Alex Shi <alex.shi@...ux.alibaba.com>
To:     Johannes Weiner <hannes@...xchg.org>
Cc:     Matthew Wilcox <willy@...radead.org>, akpm@...ux-foundation.org,
        mgorman@...hsingularity.net, tj@...nel.org, hughd@...gle.com,
        khlebnikov@...dex-team.ru, daniel.m.jordan@...cle.com,
        lkp@...el.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        cgroups@...r.kernel.org, shakeelb@...gle.com,
        iamjoonsoo.kim@....com, richard.weiyang@...il.com,
        kirill@...temov.name, alexander.duyck@...il.com,
        rong.a.chen@...el.com, mhocko@...e.com, vdavydov.dev@...il.com,
        shy828301@...il.com, Vlastimil Babka <vbabka@...e.cz>,
        Minchan Kim <minchan@...nel.org>
Subject: Re: [PATCH v20 08/20] mm: page_idle_get_page() does not need lru_lock



在 2020/11/5 下午11:36, Johannes Weiner 写道:
>>> 	 */
>>>
> Yeah, I don't think this scenario warrants the full race diagram in
> the code itself.
> 
> But the code is highly specific - synchronizing one struct page member
> for one particular use case. Let's keep at least a reference to what
> we are synchronizing against. There is a non-zero chance that if the
> comment goes out of date, so does the code. How about this?
> 
> 	/*
> 	 * page_idle does a lockless/optimistic rmap scan on page->mapping.
> 	 * Make sure the compiler doesn't split the stores of anon_vma and
> 	 * the PAGE_MAPPING_ANON type identifier, otherwise the rmap code
> 	 * could mistake the mapping for a struct address_space and crash.
> 	 */

Thanks a lot to you all. I will update to v21 patch

Alex