linux-kernel - Re: [RFC PATCH RESEND 00/28] per-VMA locks proposal

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] [day] [month] [year] [list]

Message-ID: <621612d7-c537-3971-9520-a3dec7b43cb4@suse.cz>
Date:   Thu, 29 Sep 2022 13:18:25 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Suren Baghdasaryan <surenb@...gle.com>
Cc:     Kent Overstreet <kent.overstreet@...ux.dev>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michel Lespinasse <michel@...pinasse.org>,
        Jerome Glisse <jglisse@...gle.com>,
        Michal Hocko <mhocko@...e.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Mel Gorman <mgorman@...e.de>,
        Davidlohr Bueso <dave@...olabs.net>,
        Matthew Wilcox <willy@...radead.org>,
        "Liam R. Howlett" <liam.howlett@...cle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Laurent Dufour <laurent.dufour@...ibm.com>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Song Liu <songliubraving@...com>, Peter Xu <peterx@...hat.com>,
        David Hildenbrand <david@...hat.com>, dhowells@...hat.com,
        Hugh Dickins <hughd@...gle.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        David Rientjes <rientjes@...gle.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Minchan Kim <minchan@...gle.com>,
        kernel-team <kernel-team@...roid.com>,
        linux-mm <linux-mm@...ck.org>,
        linux-arm-kernel@...ts.infradead.org,
        linuxppc-dev@...ts.ozlabs.org, x86@...nel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH RESEND 00/28] per-VMA locks proposal

On 9/28/22 04:28, Suren Baghdasaryan wrote:
> On Sun, Sep 11, 2022 at 2:35 AM Vlastimil Babka <vbabka@...e.cz> wrote:
>>
>> On 9/2/22 01:26, Suren Baghdasaryan wrote:
>> >
>> >>
>> >> Two complaints so far:
>> >>  - I don't like the vma_mark_locked() name. To me it says that the caller
>> >>    already took or is taking the lock and this function is just marking that
>> >>    we're holding the lock, but it's really taking a different type of lock. But
>> >>    this function can block, it really is taking a lock, so it should say that.
>> >>
>> >>    This is AFAIK a new concept, not sure I'm going to have anything good either,
>> >>    but perhaps vma_lock_multiple()?
>> >
>> > I'm open to name suggestions but vma_lock_multiple() is a bit
>> > confusing to me. Will wait for more suggestions.
>>
>> Well, it does act like a vma_write_lock(), no? So why not that name. The
>> checking function for it is even called vma_assert_write_locked().
>>
>> We just don't provide a single vma_write_unlock(), but a
>> vma_mark_unlocked_all(), that could be instead named e.g.
>> vma_write_unlock_all().
>> But it's called on a mm, so maybe e.g. mm_vma_write_unlock_all()?
> 
> Thank you for your suggestions, Vlastimil! vma_write_lock() sounds
> good to me. For vma_mark_unlocked_all() replacement, I would prefer
> vma_write_unlock_all() which keeps the vma_write_XXX naming pattern to

OK.

> indicate that these are operating on the same locks. If the fact that
> it accepts mm_struct as a parameter is an issue then maybe
> vma_write_unlock_mm() ?

Sounds good!

>>
>>